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Application Kit: EV Profiler 2

Component list
EV Profiler 2 Tetraspanin Profiling Component List
Component | Quantity | Volume | Hazard | Storage |
---|---|---|---|---|
Assay Chip | 3 | - | N/A | |
Surface Reagent | 3 | 55 µL | N/A | |
Wash Buffer | 1 | 12 mL | N/A | |
PS Capture | 1x | 55 µL | N/A | |
PS Capture Supplement | 1x | 16 mL | N/A | |
anti-CD81 Capture | 1x | 55 µL | N/A | |
anti-CD63 Capture | 1x | 55 µL | N/A | |
anti-CD9 Capture | 1x | 55 µL | N/A | |
Tetraspanin Trio Capture | 1x | 55 µL | N/A | |
HEK EV Standard Control | 1 | 15 µL | N/A | |
Fixative | 1 | 1.1 mL |
| |
Staining Buffer | 1 | 400 µL | N/A | |
anti-CD81 Capture (647) | 1 | 15 µL | N/A | |
anti-CD63 Capture (561) | 1 | 10 µL | N/A | |
anti-CD9 Capture (488) | 1 | 10 µL | N/A | |
dSTORM Imaging Buffer Part A | 3 | 400 µL |
| |
Part B Resuspension Buffer | 1 | 30 µL | N/A | |
dSTORM Imaging Buffer Part B | 1 | - | N/A |



Equipment needed
- Pipettes (p2.5, p20, and p200)
- Pipette Tips (10L, 20L, and 200 L)
- Microtubes (0.5 mL, 1 mL and 1.5 mL recommended)
- Timer(s)
- Humidity chamber e.g. Staintray™ 10 Slides Staining System (M918-1)
- Vortex mixer
- Personal protective equipment: gloves, goggles, biohazard bag
- MilliQ water
- Laboratory rocker or rotator
- Aspirator or vacuum pump (optional)
- Heat block at 37°C
- Bead slide
- Lens cleaning paper
- Objective oil
Components to be provided by the user
- Purified EV sample to be tested
- User-defined antibody against EV surface or luminal targets of interest conjugated to dSTORM-compatible fluorophores (Alexa Fluor 647® (AF647), or other far red dSTORM compatible fluorophore), in selected configurations.
- Isotype-control antibodies conjugated to the same fluorophores, in selected configurations.
Sample Prep Video Tutorial
Follow along with our ONI team to learn each step of the sample preparation process for the ONI EV Profiler 2 Application Kit.
Overview
The EV Profiler 2 kit provides a fast, user-friendly system for the characterization of EVs. EV Profiler 2 uses a combination of functionalized surface chemistry, biochemical capture and detection molecules, and is compatible with the ONI Nanoimager and ONI’s cloud-based analysis platform, Collaborative Discovery software (CODI), to streamline sample preparation, imaging, and analysis.
User-defined protein, Pan-EV, and Tetraspanin Trio Detection-EV Profiler 2 (900-00079)
The protocol for user-defined protein and Pan-EV Detection enables the identification of the EV population, characterization of EV size, combined CD81, CD63, and CD9 presence (1-color), and surface or luminal user-defined protein detection on human derived EVs. This protocol can also be used with either Tetraspanin Capture or phosphatidylserine (PS) Capture. The user shall provide the primary antibody for user-defined protein detection, and a matched isotype control, fluorescently labeled with dSTORM compatible fluorophore, such as AF647 or other far red dSTORM compatible fluorophore.
Tetraspanin detection-EV Profiler 2: Tetraspanin Profiling (900-00084)
The protocol for Tetraspanin Detection (3-color) is designed to characterize CD81, CD63, and CD9 expression on human-derived EVs. It can be used with either tetraspanin-specific EV capture (Tetraspanin Capture) or phosphatidylserine EV capture (PS Capture).
Quality control
Each lot of the EV Profiler 2 components is tested against predetermined specifications to ensure consistent product quality.
Intended use
EV Profiler 2 kits are intended for Research Use Only. The kits are intended for use by professional users with training in basic laboratory techniques. Care should be taken in the handling of products. We recommend that users adhere to the MISEV guidelines provided by the International Society of Extracellular Vesicles.
Experimental workflow overview
Advice before you start
EV Profiler 2 configurations:
Protocol | Capture options | Detection | Jump to |
---|---|---|---|
1 | anti-CD81 | Optional User-Defined (647) | pg. 8 |
2 | anti-CD81 | anti-CD81 (647) | pg. 10 |
Considerations for capture selection:
-
- Select anti-CD81, anti-CD63 or anti-CD9 Capture if you want to enrich in a specific tetraspanin. If the EV source is known to be enriched in an individual tetraspanin, isolating with that individual tetraspanin for capture can help isolate that EV sub-population. Otherwise, combined tetraspanin capture can be used to isolate a broad range of EVs.
- PS Capture may be used with EVs enriched in phosphatidylserine (e.g. cancer-derived EVs). PS Capture is useful when you do not want to enrich a protein biomarker.
- If phosphatidylserine (PS) content is unknown, we suggest comparing PS Capture to anti-CD81, anti-CD63, anti-CD9 (individual or combined) capture.
- To select a user-defined capture molecule, ensure that the target of interest is membrane-associated and accessible. To check for compatibility with EV Profiler 2, test a lane with the selected staining protocol but without EVs: analyze with the defined analysis parameters, and confirm fewer than 100 clusters per field of view in negative control lanes. For more detailed information regarding capture molecule selection, click here.
Considerations for detection selection:
-
- Detecting with the Pan-EV (488) and Tetraspanin Trio allows for the assessment of EV sizing and EV shape, as well as characterization of tetraspanin-negative EVs. Additionally, this configuration allows for detection of protein targets in the 647 channel. Follow the provided protocol to assess surface or luminal protein cargo associated with EVs. For more detailed information regarding capture molecule selection, click here.
- Detecting with anti-CD81 (647), anti-CD63 (561), and anti-CD9 (488) allows for the biotyping of EVs, and can aid in the understanding of EV populations. This can be useful in down-selecting EV capture and detection for future experiments, for characterizing new EV sources, or EV isolation methods.
- To maximize reproducibility and lane coverage, we recommend agitation on a laboratory rocker or oscillatory shaker. When rocking, Assay Chips lanes should be parallel to the direction of agitation.
- Prepared EV samples should be purified prior to deposition onto the Assay Chip. If assistance is needed regarding suggested EV purification for dSTORM imaging, please see EV Profiler 2 Protocol V4 – February 2025 oni.bio/contactour webinar on EV preparation. We suggest size exclusion chromatography purified EVs or differential centrifugation EVs.
- The HEK EV Standard Control (800-00166) may be used as a positive control because they are known to be enriched with PS and are captured efficiently with PS Capture.
- Dilute EVs to 108-1010 EVs / mL for deposition onto the Assay Chip.
- HEK EV Standard Control is a 10X solution. If using HEK EV Standard Control, dilute the reconstituted EVs in Wash Buffer (e.g., 1 μL HEK EV Standard Control in 9 μL Wash Buffer).
- PS Capture Supplement is needed:
- If using PS Capture and user-supplied EVs PS Capture Supplement is not needed:
- If using antibody based capture (including Tet. Trio Capture). If using PS Capture with HEK EV Standard Control reconstituted in Wash Buffer.
- PS Capture Supplement is a 10x concentrated solution. Dilute 1:10 in your EV sample (e.g. 2.5 uL of supplement per 25 uL EVs).
- If EVs are diluted at least 1:5 in Wash Buffer (i.g., 10uL of EVs into 40uL of Wash Buffer), there is no need to add additional capture supplement.
Guidance for using the Assay Chip
-
- Assay Chips should be brought to room temperature before opening and must be used upon opening.
- Do not store opened chips for later use.
- Once the Assay Chip is removed from the packaging, incubate it in a humidity chamber. This reduces the risk of evaporation and bubble introduction during the protocol.
- ONI recommends using a designated humidity chamber such as Simport Stain Tray M918-2™. This will provide three advantages: a humid environment to avoid evaporation from the lane inlet and outlet, protection of the sample from light, and avoiding chip movement during pipetting. Humidity chambers can be made with available lab equipment (such as slide storage boxes or dark-colored plastic freezer boxes) provided they meet the advantages listed above.
- Liquid should always be added to the inlet hole makered “IN”.
- To create a seal and ensure constant liquid delivery, insert the pipet tip at a 90° angle, hold the pipet vertically, and press down firmly before you begin dispensing liquid. If liquid spills out of the inlet, press the pipette tip down harder to ensure a full seal.
- Ensure that liquid is flowing into the chip lane by watching the meniscus during liquid deposition.
- It is important to minimize the introduction of bubbles when pipetting. To reduce bubbles, we suggest using p20 or p200 pipette tips, only pipetting to the first stop, and keeping consistent pressure until the pipette tip has been removed from the inlet (to reduce backflow).
- As you pipet liquid into the inlet hole, the liquid will flow through the lane and exit through the outlet marked “OUT”. We suggest removing excess liquid as it flows out of the outlet using a vacuum aspirator, by placing it gently next to the outlet hole. If you do not have access to an aspirator, use a laboratory dust-free wipe to remove excess liquid. Regardless of method, ensure there is minimal spillover from one lane outlet to another.
Note
Do not insert the aspirator directly into the outlet hole, this will result in liquid being completely removed from the lane.
-
- Lanes should contain liquid throughout the entire experiment. If there are bubbles within the lane, or liquid has been inadvertently removed, wash the lane with 100 µL of Wash Buffer to dislodge bubbles and reintroduce the intended liquid.
Important reagent handling considerations
-
- Do not vortex EVs.
- At the beginning of the assay, all assay components (except dSTORM Imaging Buffer) can be removed from the fridge and freezer.
- Prepare detection dilutions immediately prior to use.
Storage of Pan-EV Detection
-
- Once reconstituted Pan-EV Detection should be stored at–20ºC for a maximum of two months.
- We do not recommend long-term storage.
Guidance for using alternative capture molecule
The EV Profiler 2 Assay Chips can be used with any biotinylated capture molecule. An alternative biotinylated capture molecule can be selected to isolate EV subpopulations via a capture modality not provided in the kit.
Optimization of user-defined capture molecules should include the following steps:
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-
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- Assess capture molecule specificity: To determine specificity, stain tissue culture cells that express the target and a negative control (e.g., knockout or peptide blocking) with a fluorescent-labeled version of the capture molecule. Ideally, the negative controls should include less than 10% of the density of the positive control samples; however, this threshold should be predetermined by the user.
- Assess capture molecule compatibility with EV Profiler 2 assay: When using a new biotinylated capture molecule, ensure that at least one lane with the capture molecule does not contain EVs and that less than 100 clusters are detected in the EV negative lane when stained in the same manner as EVs.
- Optimize background: If negative control lanes with the new capture molecule result in high background, 0.5%-2.5% BSA can be included in the biotinylated capture molecule dilution.
- Optimize capture efficiency and reproducibility: For the most efficient capture, start with 70 nM of biotinylated capture molecule and test 20% higher and lower concentrations for ideal capture efficiency. A 75 min incubation time is recommended, but 20% shorter and longer incubation times can also be tested for ideal capture efficiency and reproducibility.
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-
Guidance for using alternative detection molecule
Surface or luminal user-defined molecules can be assessed in the 647 channel with the Pan-EV (488) and Tetraspanin Trio (561).
Optimization of user-defined detection molecules should include the following steps:
-
-
-
- Assess detection molecule specificity: To determine specificity, stain tissue culture cells that express the target and a negative control (e.g. knockout or peptide blocking) with a fluorescent-labeled version of the detection molecule. Ideally, the negative controls should include less than 10% of the density of the positive control samples, however, this threshold should be predetermined by the user.
- Optimize degree of labeling: Molecules (antibodies, proteins etc.) can be purchased fluorescently labeled or can easily be labeled by the user. Use a dSTORM compatible dye that fluoresces in the 647 channel (e.g, AF647). The number of fluorophores per protein can be modulated by increasing the molar ratio of dye to protein during the conjugation. ONI recommends starting with a degree of labeling of 2-6. Please reach out to ONI if support is needed for antibody labeling.
- Optimize concentration: For most efficient detection, start with 5 µg/mL of labeled antibody. The antibody or the detection molecule can be titrated around 1-10 µg/ mL. Use negative control lanes (no permeabilization for internal cargo, isotype controls for surface cargo) to guide detection molecule concentration.
- Optimize laser power: The laser power recommended in this protocol was optimized for AF647. If the user-def ined detection molecule is not AF647, titrate the 647 laser power to ensure fluorophore blinking throughout the acquisition. Optimal laser power and number of frames for the user-defined molecule can be determined using the CODI analysis software. The optimal laser power will minimize the localization precision (increased precision leading to a decreased numerical value) and maximize the photon count while still capturing several localizations per frame over the entirety of the imaging period. This can be determined by observing the number of localizations per frame, which should have a steep decline in the first frames leading to a blinking steady state for the remainder of the imaging time.
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Protocol: Pan-EV, Tetraspanin Trio, and user-defined protein detection
All steps are performed at room temperature. All volumes provided are per lane. Pan-EV detection can be used for size evaluation with or without permeabilization. All incubation steps should be performed in a humidity chamber. When applying reagents to the inlet use a vacuum aspirator to remove the flow through from the outlet.
Surface preparation - total time: 30 - 40 min
- Turn on and initiate microscope temperature control to allow the microscope temperature to equilibrate prior to imaging (see image acquisition protocol).
- Remove all kit components except for dSTORM Imaging Buffer from the fridge and freezer and place at room temperature. Place DMSO in 37ºC heat block for a minimum of 10 minutes.
- Allow unopened Assay Chip to reach room temperature. [10 min incubation]
- Open the chip pouch and place the Assay Chip in a humidity chamber. Set aside inlet/outlet sealing stickers until they are needed for imaging.
Note: it is essential that chips are placed in a humidity chamber during incubations to prevent evaporation. - Apply 10 µL of Surface Reagent.
[15 min incubation, rocking 30-45 RPM parallel to Assay Chip lanes]
- Wash with 100 µL Wash Buffer.
- Apply 10 µL Capture Reagent.
[15 min incubation, rocking 30-45 RPM parallel to Assay Chip lanes]
- Wash with 100 µL Wash Buffer.
Capture and fixation - total time: 85 min
-
Apply 10 µL EV solution (Click here for EV preparation)
[75 min incubation, rocking 30-45 RPM parallel to Assay Chip lanes]
Note: add PS Capture Supplement (1:10) to EVs if using PS Capture - Wash with 100 µL Wash Buffer.
-
Apply 20 µL Fixative.
[10 min incubation] - Wash with 100 µL Wash Buffer.
Staining - total time: 65 min
-
Apply 10 µL Staining Buffer
[10 min incubation] -
Prepare Detection Antibody dilution.
-
Reconstitute lyophilized Pan-EV Detection reagent
-
Centrifuge Pan-EV Detection
to ensure the reagent is at the bottom of the tube -
Add 48 µL DMSO
- Vortex for at least 20 seconds
- Centrifuge to bring the reconstituted reagent to the bottom of the tube
- Pipet and visually inspect to ensure even distribution and no visible flakes
-
Centrifuge Pan-EV Detection
-
Reconstitute lyophilized Pan-EV Detection reagent
Note
Reconstituted Pan-EV Detection can be stored at –20ºC for 2 months.
For the 4-lane chip prepare 50 µL (10 µL/lane + 25%).
Component | No target or target on surface | Luminal cargo target |
---|---|---|
Optional User-defined Detection Reagent 1-10ug/ml (647) | X µL | X µL |
Permeabilization Buffer | - | 30 µL |
Staining Buffer | 40.5- X µL | 10.5 - X µL |
Tetratspanin Trio Detection | 8 µL | 8 µL |
Pan-EV Stain** | 1.5 µL | 1.5 µL |
Final volume | 50 µL | 50 µL |
Note: The provided Tetraspanin Trio Detection (561) is only sufficient for 3 unique user-defined Detection Antibody Dilution Mixes (one per chip being processed). If using more than 3 unique Detection Antibody Dilution Mixes,e.g., 6 different User-Defined Proteins, additional Tetraspanin Trio Detection (561) should be purchased at the ONI online store or by a purchase order.
**Add Pan-EV detection last, and do not let it sit in aqueous media for >10 min
-
Apply 10 µL Detection Antibody dilution.
[50 min incubation, rocking 30 RPM parallel to Assay Chip lanes]
Note: Protect from light in an opaque or foil-covered humidity chamber. - Wash with 100 µL Wash Buffer.
- Apply 20 µL Fixative. [5 min incubation]
-
Wash with 100 µL Wash Buffer. Pause point: Chips can be stored in 4ºC for a maximum of 24 hours with lanes sealed with inlet/outlet sealing stickers in a humidity chamber. Data quality will be impacted if imaging is performed after 24 hours.
Note: If imaging more than one Assay Chip, only add dSTORM Imaging Buffer immediately prior to imaging. Preparing dSTORM Imaging Buffer – total time: 20 min -
Remove one vial of dSTORM Imaging Buffer Part A from –20ºC storage.
- Allow dSTORM Imaging Buffer Part A to reach room temperature. [10 min incubation]
- Centrifuge dSTORM Imaging Buffer Part A for 10 seconds.
- Add 99 µL of dSTORM Imaging Buffer Part A to a fresh microtube.
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Remove dSTORM Imaging Buffer Part B from –20ºC and immediately proceed to step 24, returning dSTORM Imaging Buffer Part B to –20ºC storage as quickly as possible.
- Add 25 µL of Part B Resuspension Buffer to the vial, then put it on ice for 5 minutes. Gently mix by pipetting up and down, avoiding bubbles or air. Do not shake or vortex the vial.
-
Add 1 µL of dSTORM Imaging Buffer Part B to the fresh tube of dSTORM Imaging Buffer Part A prepared in step 23. Carefully mix the solution by pipetting, making sure not to introduce bubbles.
Note: dSTORM Imaging Buffer Part B is viscous so pipette slowly and avoid introducing excess liquid from the outer walls of the pipet tip.
Note: Never flick, shake, invert, or vortex dSTORM Imaging Buffer. Introducing oxygen will affect its performance. -
Add 20 µL of prepared dSTORM Imaging Buffer to all Assay Chip lanes and seal lanes with inlet/outlet sealing stickers.
[10 min incubation]
Note
dSTORM Imaging Buffer requires an incubation to deplete the oxygen content. During this step, allow the oxygen content to be depleted. During this step prepare the microscope, including channel mapping and setting up imaging parameters. Note: After 90 min of imaging, the dSTORM imaging buffer should be replenished.
Note
If the chip will be re-imaged, dSTORM Imaging Buffer should be replaced with 100 µL of Wash Buffer and can be stored for a maximum of 24 hours at 4ºC when sealed with inlet/outlet sealing stickers inside a humidity chamber.
Protocol: Tetraspanin Detection
All steps are performed at room temperature. All volumes provided are per lane. Incubation steps should be performed in a humidity chamber. When applying reagents to the inlet use a vacuum aspirator to remove the flow through from the outlet (see detailed instructions here).
Surface preparation - total time: 30 - 40 min
- Turn on and initiate microscope temperature control to allow the microscope temperature to equilibrate prior to imaging (see image acquisition protocol).
- Remove all kit components except for dSTORM Imaging Buffer from the fridge and freezer and place at room temperature.
- Allow unopened Assay Chip to reach room temperature. [10 min incubation]
- Open the chip pouch and place the Assay Chip in a humidity chamber. Set aside inlet/outlet sealing stickers until they are needed for imaging (step 27).
Note: it is essential that chips are placed in a humidity chamber during incubations to prevent evaporation. - Apply 10 µL of Surface Reagent.
[15 min incubation, rocking 30-45 RPM parallel to Assay Chip lanes]
- Wash with 100 µL Wash Buffer.
- Apply 10 µL Capture Reagent.
[15 min incubation, rocking 30-45 RPM parallel to Assay Chip lanes]
- Wash with 100 µL Wash Buffer.
Capture and fixation – total time: 85 min - Apply 10 µL EV solution (Click here for EV preparation)
[75 min incubation, rocking 30-45 RPM parallel to Assay Chip lanes]
Note: add PS Capture Supplement (1:10) to EVs if using PS Capture (see page 7-8). - Wash with 100 µL Wash Buffer.
- Apply 20 µL Fixative.
[10 min incubation]
- Wash with 100 µL Wash Buffer.
- Apply 10 µL Staining Buffer. [10 min incubation]
- Prepare Detection Antibody dilution:
For the 4-lane chip prepare 50 µL (10 µL/lane + 25%)
Component | Volume |
---|---|
Staining Buffer | 42 µL |
anti-CD81 Detection (647) | 4 µL |
anti-CD63 Detection (561) | 2 µL |
anti-CD9 Detection (488) | 2 µL |
-
Apply 10 µL Detection Antibody dilution.
[50 min incubation, rocking 30 RPM parallel to Assay Chip lanes]
Note: Protect from light in an opaque or foil-covered humidity chamber. - Wash with 100 µL Wash Buffer.
- Apply 20 µL Fixative. [5 min incubation]
-
Wash with 100 µL Wash Buffer.
Pause point: Assay can be paused here. Chips can be stored in 4ºC for a maximum of 24 hours with lanes sealed with inlet/outlet sealing stickers in a humidity chamber. Data quality will be impacted if imaging is performed after 24 hours.
Note: If imaging more than one Assay Chip, only add dSTORM Imaging Buffer immediately prior to imaging. Preparing dSTORM Imaging Buffer – total time: 20 min - Remove one vial of dSTORM Imaging Buffer Part A from –20ºC storage.
- Allow dSTORM Imaging Buffer Part A to reach room temperature. [10 min incubation]
- Centrifuge dSTORM Imaging Buffer Part A for 10 seconds.
-
Carefully mix the solution by pipetting, making sure not to introduce bubbles.
Note: Never flick, shake, invert, or vortex dSTORM Imaging Buffer. Introducing oxygen will affect its performance. - Add 99 µL of dSTORM Imaging Buffer Part A to a fresh microtube.
- Remove dSTORM Imaging Buffer Part B from –20ºC and immediately proceed to step 25, returning dSTORM Imaging Buffer Part B to –20ºC storage as quickly as possible.
-
Add 25 µL of Part B Resuspension Buffer to the vial, then put it on ice for 5 minutes. Gently mix by pipetting up and down, avoiding bubbles or air. Do not shake or vortex the vial.
Note: dSTORM Imaging Buffer Part B is viscous so pipette slowly and avoid introducing excess liquid from the outer walls of pipet tip. - Add 1 µL of dSTORM Imaging Buffer Part B to the fresh tube of dSTORM Imaging Buffer Part A prepared in step 23. Carefully mix the solution by pipetting, making sure not to introduce bubbles.
-
Add 20 µL of prepared dSTORM Imaging Buffer to all Assay Chip lanes and seal lanes with inlet/outlet sealing stickers.
[10 min incubation]
Note
dSTORM Imaging Buffer requires an incubation to deplete the oxygen content. During this step, prepare the microscope, including channel mapping and setting up imaging parameters.
Note
After 90 min of imaging the dSTORM imaging buffer should be replenished.
Note
If the chip will be re-imaged, dSTORM Imaging Buffer should be replaced with 100 µL of Wash Buffer and can be stored for a maximum of 24 hours at 4ºC when sealed with inlet/outlet sealing stickers inside a humidity chamber.
AutoEV for Nanoimager
AutoEV is a CODI application that connects the ONI Nanoimager to CODI cloud-based analysis platform, enabling Extracellular Vesicle (EV) characterization using the ONI Application KitTM: EV Profiler 2. AutoEV consists of several advanced features that allow users to perform super-resolution imaging and analysis of an entire 4-lane EV Profiler 2 chip with reduced hands-on time and a robust pipeline.
Nanoimager requirements
- Requires active internet connection on the Nanoimager PC
- Requires a standard Nanoimager configuration:
- Lasers: 488, 561 and 640
- Nanoimager Mark III (contact ONI if unsure)
Prior to using AutoEV
Placing the chip holder on the Nanoimager
AutoEV comes with a chip holder that makes the Nanoimager feel like it was made for EV Profiler 2 chips. It also allows AutoEV to know where each lane is without any specific calibration.
Note
With the Nanoimager still switched off, place the chip holder on the Nanoimager before opening the CODI System App (CSA).
- Place the chip holder on the Nanoimager stage as shown in the illustration below.
- Place the EV Profiler 2 chip or bead slide (with magnets) inside the chip holder.
Installation
To run the EV Profiler 2 kit, you will need to register to ONI’s CODI software platform, download the CODI System App and use AutoEV app.
Navigate to https://alto.codi.bio to access the CODI platform. It is important to sign in and log in (see [1] on the image below) to CODI prior to starting AutoEV installation. If this is the first time creating an account in CODI, contact ONI to get the AutoEV app activated. Once logged in, go to Application apps [3], and select the AutoEV app.
To be able to run the EV Profiler 2 kit, the CODI System App (CSA) needs to be downloaded. The CSA operates in the background to connect the Nanoimager and light engine to CODI, this connection is crucial to operate AutoEV.
If this is the first time downloading the CODI System App, click “download” as shown in the popup message. Follow the instructions to install the CODI System App.
Note
If a “Windows Security Alert” appears, “allow access” to ensure that AutoEV functions correctly.
Once installed, open CODI system App and wait for the status indicator to change from “Initializing” to “Running”. CODI System App starts heating the Nanoimager as soon as the application is opened. Click the “Refresh Page” button to close the popup widget.
Key Tip
Ensure that the CODI System App is displaying “Running” prior to running AutoEV, to ensure that the Nanoimager communicates properly with CODI.
Setting a default Nanoimager temperature
Ithe top right corner of the CODI page [2], click on the temperature icon with a blue background, which will bring the System Status App, where users can set the desired temperature. This will be saved as the default temperature for the next time the CODI System App is launched. For EV Profiler 2 kit, the default recommended is 32°C. Whenever the CODI System App is launched, the Nanoimager will automatically start heating to 32°C and it takes 60 minutes to stabilize and be ready for imaging.
Do not start imaging before the temperature is stable. Any acquisition done during the heating process, will result in a lot of drift. See channel mapping section for more details.
To ensure these algorithms work well, there are a few initial values that may need to be adjusted:
- Starting z-position focus for channel mapping (ONI Bead Slide): the Nanoimager is aligned such that
the ONI bead slide’s focal position is near 0 µm. A starting focus of 0 µm ensures AutoEV’s
1-click channel mapping finds the right surface of the ONI bead slide.
- Starting focus z-position for system calibration (ONI 4-Lane Assay Chip):
a typical 4-lane Assay Chip will have a focus near -250 µm.
A starting focus of -250 µm ensures AutoEV’s system calibration, sample check,
and automated acquisition find the right surface of the ONI bead slide. - TIRF angle: choose between “auto” and “manual” illumination:
- In Auto mode, an illumination optimization process will run at the end
of the system calibration step, ensuring that the illumination angle is optimal
for the specific 4-lane Assay Chip being used. - In Manual mode, a specific TIRF angle can be specified and used for all data acquisition.
- In Auto mode, an illumination optimization process will run at the end
- Laser powers used during the system calibration step can be modified on a per-laser basis.
The default values of 25% should be lowered to 15% or lower in situations where the sample’s
signal is bleaching during the automated system calibration.
AutoEV
AutoEV is a linear workflow that helps guide users through the acquisition of the EV Profiler 2 kit, from experimental setup to acquisition summary. Each step of the workflow has a dedicated page, which can be accessed from the toolbar on the left hand side of CODI.
Move between the pages either by clicking on the individual tabs, or by using the action button on each page to proceed to the next step, e.g., Next, Run, Start acquisition etc.
Experimental setup
The first step of AutoEV is to input the experiment settings:
- AutoEV experiment title (chip/sample name) [1]:
Give the experiment a name. The datasets will be both saved locally (C:/data/CODI) and on CODI using the experiment name — pick a good one! - Dataset tags: Tags and Key/Value Tags (optional) [2]:
Add tags to the dataset to help distinguish them on CODI. Make sure to click the 💾 save button to save any changes. - Collaboration in CODI [3]:
Select a collaboration in CODI where to save the data, or use the 💼+ button to create a new collaboration.
Note: It is required to save the data to a Collaboration from AutoEV. - Analysis settings [4]:
The default settings for the analysis workflow are optimized for all the different kit combinations. This is called “EV Profiling” and can be changed if desired to suit different analysis needs.
- Experiment Settings [5]:
Optimal experiment settings to run the kit such as channel names, laser powers, number of frames and exposure time are selected as default.
Note: It’s important to ensure that settings are properly calibrated for each instrument by measuring the power in mW and adjusting accordingly. Details on how to adjust the laser power are in Appendix I of this guide.
Data and analysis settings
AutoEV automatically uploads the data to the selected CODI account and saves it locally in the C:/Data/CODI/ folder. AutoEV saves the acquisition data in subfolders with names corresponding to the Experiment and Lane titles inputted on this screen.
Applying modified settings across all lanes
AutoEV has a couple of options to simplify the process of applying settings to all lanes.
Start by inputting settings in lane 1, then use the buttons at the bottom of that lane to:
Start by inputting settings in lane 1, then use the buttons at the bottom of that lane to:
- Apply all settings: synchronize all sample and acquisition settings to all lanes
- Apply imaging settings: synchronize only the acquisition settings (channel and lane names will not be synchronized)
- Reset settings to default: reset all lanes to the default EV Profiler 2 Kit protocol settings
Setting up the acquisition should mimic the EV Profiler Assay Chip with a 4-lane design
- Enter a Lane Title that represents the EV sample in that lane.For example, use HEK EV standard control, negative control, or the name of the sample.
- Enter the labeling information for the 488 (cyan), 561 (yellow), and 640 (magenta) channels.
- If there is no dye in one of those channels, switch off that channel by using the vertical toggle on the left-hand side.
- The images will always be acquired from the longest to the shortest wavelength: 640, then 561, and finally 488.
- AutoEV app provides default settings recommended for running the EV Profiler 2 Kit protocol. Adjust the acquisition settings by clicking on the small text below and input:
- Laser powers need to be adjusted for each user prior to starting an experiment.
This may vary depending on the system. Contact ONI if additional information is needed after installation.
Laser power values can be updated in the AutoEV experiment settings page and saved using the Save Current Settings button.
See Appendix I for a guide on how to adjust the laser power with respect to the specific kit. - Auto TIRF automatically finds the optimal illumination angle for EV imaging by maximizing the signal-to-noise ratio of the spots with respect to the background.
The TIRF angle can be manually input in the System Info app.
See the “Check TIRF angle” sub-section under the “Calibration & Sample Check” section to select the optimal TIRF angle. - Using the default settings for the number of imaging frames and exposure duration is recommended, as they were optimized for this kit.
However, these can be adjusted on a per-channel and per-lane basis if needed.
- Laser powers need to be adjusted for each user prior to starting an experiment.
Save the experiment settings
If the imaging settings are updated, such as number of frames or laser power, these can be saved by clicking Save Current Settings. These can be loaded again using Load Settings.
Note: Settings are saved locally on the Nanoimager laptop only and NOT saved on CODI. If web browsers or users are changed, settings will need to be reentered and re-saved.
Channel mapping
Channel mapping is an essential step towards generating accurate multicolor super-resolution data, and AutoEV makes channel mapping even easier with a one click channel mapping of both regions of the camera (left and right) that ensures all the biomarker channels are mapped together.
AutoEV simplifies your work by informing when it is time to run a new channel mapping or if channel mapping might need to be re-run prior to acquiring images from the EV Profiler 2 chip.
Important
It is imperative to re-run channel mapping if:
- Channel mapping has not been done in the last 24 hours
- Nanoimager temperature has changed by >1°C since last channel mapping
- It is the first time running AutoEV
To run channel mapping, ensure the bead slide is in the chip holder on the Nanoimager stage and click the Run button at the top to automatically run channel mapping. Follow the progress of channel mapping thanks to a progress bar and see each step that has been run.
Stop channel mapping at any time by pressing the ◽️ button.
AutoEV will report back the accuracy and field of view coverage of the channel mapping. An accuracy of less than 15 nm and a field coverage of 100% are recommended. Details on how channel mapping works are in Appendix 2 of this guide.
Key Tip
Channel mapping usually takes ≈2 minutes. If channel mapping takes longer, it may mean that the bead slide might have a sparse bead density, requiring more fields of view. If channel mapping is not complete after several minutes, stop it and replace the bead slide.
If the accuracy is less than 15 nm and/or the coverage less than 100%:
- Clean the bead slide
- Replace the oil on the objective
- Click the Re-run button to re-run channel mapping until satisfactory
- Click the Microscope controls button to manually diagnose sample-related issues
when the bead slide is not optimal or autofocus isn’t working properly.
This will also display advanced microscope controls on the channel mapping page.
Channel mapping not required
While running channel mapping before the experiment is recommended, if it has been performed recently and that the Nanoimager temperature is stable, AutoEV will allow imaging without performing channel mapping, for instance, when imaging more than one chip at once.
Channel Mapping Procedure
The camera of the Nanoimager is split in two regions (left and right). Depending on the configuration of the Nanoimager being used, channel signal will be sent to the left camera region (like the 488 or 561 channel), or the right region (like for the 640 channel). Data acquired with CODI System App aligns channels from the 2 different camera regions before being uploaded to CODI. Channel mapping is used to allow the correction of chromatic aberration that results in image distortion. Specifically, the localizations in the 488 and 561 channels are mapped up to the right camera region where the 640 channel is acquired such that they overlap. The mapping correction file comes from the channel mapping calibration done with beads prior to the experiment, which is why this step is such a crucial step.
Calibration & Sample Check
For AutoEV to be successful at imaging of EV Profiler 2 Assay Chip, it is essential to ensure that the chip is ready to image prior to starting the super-resolution acquisition.
Key Tip
Anytime the EV Profiler 2 Assay Chip is placed on the Nanoimager, the system calibration step should be performed to ensure optimal autofocus and AutoTIRF.
System calibration
System calibration is a critical step that automatically finds the imaging surface of the EV Profiler 2 chip, locks the focus, and determines the optimal illumination angle with AutoTIRF.
Start calibration by selecting a lane [1] and channel [2] where a good density of EVs and a strong fluorescent signal are expected. For example, if using the HEK EV Standard Control provided with the EV Profiler Kit, select the lane that contains the HEK EV Standard Control, and any of the fluorescent channels. When ready, click the Calibrate focus & illumination [3] button to start the calibration.
When ready, click the Calibrate focus & illumination button [3] to start the calibration. Do not run the calibration in a negative control lane.
Calibration can take around 2 minutes to complete. If the wrong lane or channel is selected for calibration, this can be stopped using the ◽️ button at any time.
Once sample calibration has been successfully completed, the widget will update to display the calibrated focal plane and TIRF angle (bottom right). Use sample pre-check to assess the TIRF angle and modify it if needed (see details below).
Calibration or Refine Focus Failing
Note: Calibration may fail for several reasons. Errors will appear in the top right corner indicating the reason for failure. Common sources of failure are inability to find the lane surface or find the optimal focus based on the fluorescence signal due to too few points being detected. If the system calibration fails consistently or autoTIRF looks poor, follow these instructions:
- First, ensure the Assay Chip is properly positioned on the Nanoimager stage, and that the lanes are bubble free.
Note: If the failure appears to be focus related, select the Refresh z-lock calibration option. - Next, try a different channel or lane where a strong signal is expected and then re-run the calibration by clicking Calibration failed. Re-calibrate focus & illumination.
AutoEV will move to the next FOV and try again. This means if the area was bleached, or bad, or if oil was not well distributed, there is a chance to succeed by moving to a different area. - Verify that the system is not attempting to calibrate in a zone where there is a bubble in the chip.
This can be visually inspected by opening the Nanoimager lid after a failed calibration and observing the sample from directly above the objective.
If there is a bubble, try calibrating in another lane. - If the system fails to focus, it could be attempting to focus on the wrong surface of the chip.
See Setting global Acquisition Settings for more information on how to set the global settings to ensure best focus. - If the system focuses but fails to optimize the illumination angle, the sample could be bleaching before the optimization completes.
See Setting global Acquisition Settings for more information on how to lower the laser power for the system calibration to prevent bleaching.
If adjusting global acquisition settings does not resolve issues with the automated system calibration,
create a manual calibration using Manual System Calibration.
Key Tip
The TIRF angle is typically between 52° and 54° on the Nanoimager and should not deviate by more than 0.5° between acquisitions.
Autofocus and AutoTIRF commands might not provide the optimal value or fail due to the low signal in the sample. Thus, it is important to run the Sample pre-check.
Sample pre-check
Sample pre-check is a great tool that quickly scans each lane of the EV Profiler Assay Chip and provides a representative image of the sample in each lane. We recommend using it for each EV Profiler Assay Chip to get an overview of the sample prior to imaging. This will help check if the sample calibration is good and the sample in each lane is nicely focused and well illuminated, the EVs density per lane is the one expected and the EVs were correctly stained, and if sample was correctly washed with buffer added.
Click Start sample pre-check to begin the sample check, and AutoEV will start scanning each lane. It can then be stopped this by using the ◽️ button.
Key Tip
The sample pre-check is intended to give a representative image of the automated acquisition, and thus uses the imaging settings (laser power and TIRF angle) from the experiment settings page.
Focus check
The autofocus tool is an automatic function to find optimal sample focus in cases where the FOV has good a Signal to Noise ratio (SNR) and there are at least 3 objects (such as EVs or beads) when calibration is performed. Autofocus may fail or look poor if there are bubbles, low/no signal, etc.
TIRF angle check
AutoTIRF is an automatic function that finds the optimal angle for which the SNR is reduced. If the signal and the surrounding background change from sample to sample or lane to lane the AutoTIRF might provide different values every time it is run. This is because it is calculated based on the SNR of the FOV selected during the system calibration step.
An optimal TIRF angle is required to achieve accurate quantitation. Manually inspect each lane for poor TIRF alignment. This will be visible in all lanes. A good TIRF angle will result in an even FOV illumination, low background noise, and high signal from the particles. A poor TIRF angle will result in a lack of signal in the bottom or top of the field of view. If the TIRF angle in the sample check is poor, proceed to the optimizing and setting the TIRF manually.
Refine focus in the Sample pre-check
Sometimes focus found during System calibration might not be optimal, and refining focus might be needed.
In the sample pre-check step, select Check Focus in the lane title if AutoEV thinks manual refinement is needed, or Completed if the focus is good. If Check Focus is displayed, select the Refine Focus button.
Once Refine Focus is pressed, the Nanoimager will move to that lane, turn on the lasers, and allow the user to manually refine the focus. This is great for optimizing the focus in the rare case the sample is slightly out of focus.
Use the “up” and “down” arrows to move the Z-offset and find the optimal focus. Click the “Next FOV” button to move to the next FOV in that lane and get a view of the focus without bleaching the sample.
When ready, click the Save & Re-run button to save the optimal focus and acquire a new sample check image.
Key Tip
Any offset applied is lane-specific and used during image acquisition of that lane to ensure the best focal plane is imaged. These settings are stored in the local web browser storage and will reset to defaults if a different browser is used or browser caches are deleted. Double check these values prior to running any experiment.
Field of View (FOV) selection
In this section FOVs will be selected for image acquisition in each lane of the chip. Click the Select 6 default FOVs per lane button (top left) once to automatically select 6 default FOVs in all lanes. These are chosen to provide a good statistical distribution of EVs. The image above shows the default 6 FOVs, optimal for most experiments as they are centered in the sample lanes and are evenly distributed.
To select different FOVs, or if the lane has a specific fault in these areas (bubbles, drying out, etc), FOVs can be manually selected. Go to the “Choose FOVs” page for that.
- White vertical and horizontal lines indicate the middle and center of each lane.
- Multiple FOVs can be selected per lane, 6 is the recommended number.
- The selected FOVs will appear in purple.
Selecting FOVs
FOVs can be selected either by choosing a number of FOVs to be imaged at the top of each lane,
or by manual FOV selection.
- Number of FOVs to be imaged: Changing this option will automatically select consecutive FOVs
in the middle of each lane. All FOVs in a lane can be removed by typing “0” FOVs at the top of each lane. - Manual FOV Selection: FOVs to be imaged can be selected by clicking the squares in each lane,
and removed by hovering over the FOV and clicking the x.
Each time a new FOV is added, the ETA (estimated time) at the bottom left of the page is updated
with the new estimated experiment duration time.
The legend shows different possible FOV status:
- A FOV previously imaged in system calibration or sample check appears in gray.
- A FOV failed to be imaged because of focus appears in red.
- The current stage position appears in blue.
- A FOV imaged during the current experiment appears in green.
Note
The FOV in AutoEV covers an area of 50 µm (width) by 80 µm (length). Each FOV’s imaging area is surrounded by a bleaching safe zone, so that any acquisitions in the neighboring FOV will not be affected by stray laser light. The result is that each FOV rectangle in the FOV selector represents this bleaching safe area of 90 µm x 110 µm.
Save TIFF images to disk
Unchecking this box will only save the localization data to disk, saving precious disk space for long EV acquisitions.
Each FOV corresponds to a single dataset. Multiple datasets within the same lane can be generated by acquiring multiple FOVs. Six FOVs per lane should provide a good statistical power.
Acquisition
Before starting an acquisition
While many of the AutoEV steps workflow are optional (like Channel Mapping and Sample Check), there are 2 critical steps that must be completed prior to starting the super-resolution imaging:
- Selecting a Collaboration on CODI in which to store the data and analyses.
- Running a system calibration to ensure correct focus and illumination during the acquisition.
AutoEV will show a warning if either of these conditions are not met. The yellow warning on the banner can be clicked to explore the step to be fixed.
Starting an AutoEV acquisition
Now that the AutoEV acquisition is set up, click the Start Auto-EV Acquisition button ([1] in the image below). The EV Profiler 2 Kit chip will be scanned from Lane 1 to Lane 4, and the acquisition in each lane will follow the settings input in the Experiment Setup page.
During the acquisition, real-time information shows:
- Which lane [2] and FOV [3] are currently being imaged, allocated, or failed
- A live camera view [4] to see the blinking fluorophores
- A live progress bar [5] reporting frame count and estimated time of completion
- Live localizations [6] displayed from the blinking fluorophores
- A list of acquired FOVs and their status [7]:
- Acquiring: The FOV is currently being imaged
- Uploading: The FOV has completed imaging and is being uploaded to CODI
- Analyzing: The FOV is being analyzed on CODI
- # Clusters: The FOV is done being analyzed and is displaying the number of clusters found in the FOV
At any point during the acquisition, press the ◽️ button to stop the acquisition, or press the Skip FOV button can skip the acquisition of the current FOV being imaged. If a FOV is skipped, it will not be saved nor analysed, and the automated acquisition will proceed to the next FOV.
Each dataset will be automatically uploaded to CODI once acquired, and analyzed using the selected analysis app and settings from the Experiment Settings page. Click any dataset from the acquisition list [7] in the acquisition page to visually inspect the sample.
See Appendix IV for more information about how to view the dataset in CODI.
Summary & Report
- Imaging Setup [1]: gives an overview of the sample and imaging settings
- Analysis [2]: displays the analysis settings that were used and a link to view the data on CODI
- Acquisition List [3]: shows a list of all the imaged FOVs, with a link to the dataset and analysis on CODI.
- When the analysis completes, the number of clusters will also be displayed here, making it easy to see if the data had a consistent EV density or if some FOVs or lanes did not have a good capture.
- If an FOV failed to image (likely due to inability to properly find focus), it will not display in this list.
- Visual Experiment Overview [4]: displays each FOV that was imaged for calibration, sample check, or during the super-resolution acquisition.
- Mosaic View [5]: shows a representative image of each positivity class, providing a quick glance at the EV sample. Hovering over each image allows users to cycle through more EVs of each type and copy the image for quick sharing in a presentation.
Exporting acquisition data
When the data is done acquiring, uploading, and analyzing, it can be exported by:
- Generating a Montage [1]: of EV clusters per chip-lane. The montage contains a visual overview of the EV sample.
- Generating a Report [2]: that contains an overview of the chip’s EV count and positivity, by lane.
- Downloading CSV Data [3]: that contains all the clustering and positivity data.
A montage, report and CSV data can be generated even if a subset of datasets is acquired, or if the analysis of some of the datasets is not yet completed or failed by clicking Select datasets [4]. Select only the datasets for which the analysis is completed [5], and use the Data export widget [6] to generate the files.
Generating a montage
Generate a montage to visually inspect the size and morphology of the EV sample and the analysis outcome.
This feature allows the creation and saving of a montage of random EVs selected and ordered based on positivity and size (see image below). This feature is particularly useful not only to visualize the positivity results but also to assess assay quality.
At the end of an acquisition, a montage from the 4-lanes chip or a montage from individual FOVs can be generated.
Key Tip
Once new data is acquired it will not be possible to generate a montage image for the entire chip. Ensure a montage is generated at the end of the acquisition, before moving on to the next chip. It is always possible, on the other hand, to generate a FOV montage.
Generate a montage from the 4-lane chip
- In the summary page of the AutoEV app, go to the “Data Export” widget and select the channels to visualize in the montage.
- Select the number of clusters per positivity group (e.g. a montage generated with 10 clusters means 10 clusters per each positivity group present).
- Select the output file format.
- Click “Generate montage”.
Note: For 4-lane montages with 50 clusters each, generating a montage requires around 15 minutes.
- A montage for each lane will be saved locally in the experiment folder under the C:/Data/CODI path.
- Each lane montage will contain clusters coming from the FOVs acquired in that lane.
- Error messages may appear if there are no clusters (analysis failed or still ongoing), or if some lanes are missing clusters.
- To generate a montage with different clusters, click “Generate montage” again. Random clusters will be selected every time.
Generating a report
Click the Generate Report button to create a report that provides a good overview of the sample.
The report will give an overview of the experiment performed and sample outcome. In the report, experiment title, analysis performed, date and user name will be displayed. The report will show an overview of the sample within each lane, given the imaging settings used.
The data in the report is presented as one column for each lane, and 3 data rows to better understand the EV sample:
- EV count per FOV: Quickly comparing particle counts across lanes to compare EV numbers in different samples,
and for different FOVs in a single lane, it can help assess sample homogeneity. - Biomarkers positivity aggregated across the FOVs in each lane: Represented as a stacked bar chart to easily compare across lanes.
Positivity is displayed as a percent and as an absolute EV number. - EV size for each positivity class: Displayed as a box plot, allowing for easy comparison across positivity classes and across lanes. The overall EV size (gray distribution) is displayed as an aggregate of all positivity classes. The EV size is calculated as shown below, by using the convex hull area of the cluster (“Area (nm²)” in the -results CSV) and calculating the diameter of a circle with the same area.
To print or save the report after generating it, use the 🖨️ button. The link to the report can be saved on CODI by copying or favoriting the URL directly.
Download CSV readout
At the end of an analysis, download the CSV data with all EV outputs from the analysis.
These files can be used for additional analysis and plots outside CODI.
This can be done in the AutoEV app, under the Summary Page by clicking the
Download CSV Data button, or in the CODI analysis space within a single dataset in batch analysis.
When downloading the report from the Summary Page in the AutoEV app, two zip files will be saved in the local computer’s download folder:
- “Experiment data”: includes all the raw positivity results and clustering results in CSV format.
- “Experiment points data”: contains a list of all raw localizations before analysis tools are applied.
The most important CSV file is results.csv in the Experiment data folder.
This file contains a list of EVs clustered with their given ID, centroids, area, diameter, positivity values, and more.
Re-running the Chip
Once the summary of the acquisition is viewed and the report generated, more data from the same chip may be acquired. AutoEV makes this really easy with the Re-Run button, which shows the experiment info page, where the number of FOVs per lane can be increased/decreased, or acquisition settings changed.
Note: if re-running a chip with more FOVs, the FOV annotation will start again from 1. Changing the experiment title is recommended, for example, adding “run 2”, so that FOVs acquired in each run can be distinguished, e.g., FOV 1 acquired during the first run and FOV 1 acquired in the second run.
Run Next Chip
Remove the chip carefully and place the next one. Close the EV experiment tab and open a new one from the Acquisition apps. Load the saved experiment setting with the correct laser power that was optimized for the Nanoimager. All the next steps will be identical to the above. Only run channel mapping again if prompted by the system.
Help and Support
If at any time you experience a software issue, contact ONI through the Help Center (oni.bio/contact). Click on the question mark displayed in AutoEV and CODI and go to “report an issue”.
Visit the ONI Service desk to learn about common AutoEV troubleshooting.
Appendix I: Laser Power Percent to mW Conversion
Each EV Profiler 2 kit needs to be acquired with a specific optimised power to ensure proper blinking of the fluorophores. Follow these instructions to find the recommended power in the table below.
Experiment setting | Laser line (nm) | Power (mW) |
---|---|---|
EV Profiler 2 Tetraspanin | 638 nm | 170 mW |
EV Profiler 2 Tetraspanin | 561 nm | 44 mW |
EV Profiler 2 Tetraspanin | 488 nm | 180 mW |
EV Profiler 2 PanEV + Protein | 638 nm | 170 mW |
EV Profiler 2 PanEV + Protein | 561 nm | 44 mW |
EV Profiler 2 PanEV + Protein | 488 nm | 180 mW |
Laser power percent to mW conversion using the microscope control
On Nanoimagers manufactured after January 2021, the conversion of Laser power percent to mW is accurate as long as up-to-date maintenance is performed by an ONI technician. If needed, contact ONI support for further questions.
- Place an ONI Bead slide or ONI 4-lane Assay Chip on the Nanoimager
- Go to channel mapping page
- Click “Microscope controls”
- Turn on one laser at the time [1]:
- Using the slider [2], change the power percentage value until it reaches the desired mW power [3]. Specific percentage values can also be typed in the box.
- Change the power in percentage in the experiment settings page.
- Repeat with all channels and powers indicated in the table below. Use the table to record the values for the Nanoimager system in use.
- Once completed, save the current settings.
The next time the AutoEV is run, go to “Load Settings” in the Experiment settings page and select the settings saved. This operation needs to be done for every user account that will use the AutoEV, and repeated once a month to ensure that mW power and % values are always calibrated in the case the laser specs drop.
Light Program Acquisition
AutoEV uses the “Light Program” feature from NimOS to acquire data, which means that all of the lasers will be in “standby” mode. This ensures the lasers can be turned on/off very quickly and accurately, but may result in a small dose of laser excitation even when the laser is off or at 0%.
Appendix II: Manual System Calibration
Manual System Calibration allows the user to manually inspect the sample and create the illumination and per-lane focus calibration that is required to automatically and accurately acquire FOVs across all lanes.
The Manual System Calibration page can be accessed any time during an automated imaging workflow, and is conveniently located before the required steps of the workflow.
When to use Manual System Calibration
Manual calibration can be used at any point prior to starting an automated acquisition:
- The user can opt to manually create the focus and illumination calibration instead of using the automated system calibration for a variety of reasons:
- Speed: once familiar with the process of creating a manual calibration, this might be quicker than running the automated calibration and sample pre-check.
- Sparse samples: for very sparse samples with <100 particles per FOV, the automated algorithms may struggle and the user can opt to manually calibrate.
- Focus control: manual calibration allows the user to set and confirm the optimal focus per lane, ensuring data is acquired with optimal focus for all lanes.
- If an automated system calibration fails for any reason (including not enough signal detected at the autofocus position, or failure to optimize the illumination angle), the user will be prompted to create a manual calibration. In this case, the Manual System Calibration icon will be highlighted in yellow, indicating that the system is recommending the user to inspect their sample and manually calibrate.
When creating a manual calibration, the user can easily follow which step of the workflow they were on by looking for the icon with an upper outline in yellow.
Once the manual calibration is saved and being used for the experiment, the manual calibration page will appear with a green underline, reminding the user that they are using a manual calibration.
While the Manual System Calibration allows the user to manually find and optimize these values and save them for use during automated acquisition, the automated System Calibration step performs several automated routines to find the optimal focus and illumination angle. Read the “Creating an experiment calibration” section below for more details.
What is an Experiment Calibration
The Experiment Calibration contains information about the specific system and ONI Assay Chip
to ensure focus and illumination are optimized for automated imaging:
-
The stage z position where ONI 4-Lane Assay Chip is in focus and the z-lock is set.
Since the stage and the objective are not perfectly perpendicular, it is common to have
a small shift in this position across lanes. -
The z-lock offset for each lane. While most chips will have the same z-offset for each lane,
it is possible that certain systems or chips require a per-lane offset from the focus reference.
This is the same as the z-offset set for a lane during the “refine focus” step of sample pre-check. - The illumination angle (also called the TIRF angle) that will be used for the acquisition.
Note: The experiment calibration that is created is local to the current workflow
and is not shared across different experiments. A calibration must be created for each
instance of AutoEV independently to ensure accurate automated acquisition.
Creating an Experiment Calibration
To create an experiment calibration:
- Position the stage such that a lane is over the objective
- If starting a manual calibration from scratch, note that the sample stage will be at (0,0,0),
in between lanes 2 and 3. To properly focus, move to a lane where particles and a strong fluorescence
signal are expected (such as a positive control lane). Choose a lane from the Experiment Calibration [1]
and click the target icon [2] to move that lane. - If starting after an incomplete automated system calibration, the sample will be positioned in the lane chosen for calibration.
- If starting a manual calibration from scratch, note that the sample stage will be at (0,0,0),
- Find the focus of the particle surface
- Use “Scan for Surfaces” [3] to detect all the potential surfaces at the current (x,y) stage position.
This scans the stage in the Z direction and uses an internal focus camera to detect surfaces where there
is a strong refractive index difference. Optionally, turn on an imaging laser [4] to observe the focus
sweep on the live camera view to help see the best focus position during the scan. - Detected surfaces appear as purple dots along the focus indicator graph.
- Click on any of the detected surfaces (purple dots) to move the stage to that position
- It is common to have multiple (at least 2) surfaces from an ONI 4-Lane Assay Chip.
- Generally, the particle surface is the top-most surface.
- Turn on an imaging laser [4] to observe the fluorescence from the particles on the surface.
- Refine the focus [5] until the sample is in focus. Use the Up/Down arrows in the Stage Control widget. Use the W/S keys on the keyboard.
- If necessary, move to a new FOV using the up/down/left/right FOV buttons [6].
- Use “Scan for Surfaces” [3] to detect all the potential surfaces at the current (x,y) stage position.
- Calibrate the Z-lock [7]
- When the sample is in focus, click the “Calibrate” button to calibrate the z-lock.
This sweeps the stage in the z-direction and creates a calibration of the focus camera signal,
which is used to maintain the z-position over time. - If the calibration is successful, the z-lock will automatically engage (the lock icon will turn blue).
- When the sample is in focus, click the “Calibrate” button to calibrate the z-lock.
- Create the Experiment Calibration [8]
- Select the slide type being used for calibration. In general this will be the EV 4-lane Assay Chip.
- Set the illumination angle for the experiment
- With an imaging laser on, use the illumination angle slider to find the optimal angle for particle imaging.
This is generally near the TIRF zone, in the 45–55° range for a Nanoimager. - Once the optimal angle has been determined, click the “Set TIRF angle” button to save it to the calibration.
- With an imaging laser on, use the illumination angle slider to find the optimal angle for particle imaging.
- Set the focus reference and offset for each lane
- Click on Lane 1.
- Click on the target icon to move to Lane 1. While the stage is moving, the laser and z-lock are both off.
- Wait until the stage has reached Lane 1. Once the stage has arrived at its position, the laser will
turn on and the z-lock will engage. This can take several seconds. Wait for the system to complete these tasks.- If the z-lock cannot be re-engaged after moving to the designated lane, an error message will appear.
- This is likely due to a bubble being present in the lane.
- If this occurs, use the Up/Down/Left/Right FOV buttons to scan the stage until the imaging area is outside of the bubble.
- The best practice is to turn off the laser during this process.
- Once in a good FOV, click the lock button to re-engage the z-lock. It is OK if it is slightly out of focus.
- Use the up/down arrows in the experiment calibration widget to refine the focus until it is optimal for the designated lane.
- Click “Set Lane Z-Offset” to set the z-offset for this lane to the experiment calibration.
- Repeat this process for all lanes. Note that a z-offset must be set for each lane.
- Save the experiment calibration
- Once the TIRF angle and z-offsets for each lane have been set, the “Save & Return to Experiment” button will turn blue.
- Click this button to save the calibration and use it for the active experiment.
Important
The “Save & Return to Experiment” button will be enabled once the TIRF angle and the z-offset for all 4 lanes have been set. This button must be clicked in order for the AutoEV experiment to use manual calibration.
-
Continue to sample check, select FOVs, and imaging
- The AutoEV experiment will now use the values manually set during Manual System Calibration.
- The automated acquisition will now use the manually defined TIRF angle and apply the z-offset specified for each lane while imaging FOVs in the corresponding lane.
Optionally Setting the laser powers for optimal blinking
In some cases, it might be necessary to manually adjust the laser powers to ensure the sample is blinking correctly.
Manual System Calibration makes this process very simple:
-
Once focus and TIRF angle have been optimized, turn on one of the lasers that will be used for imaging and adjust
the power until optimal blinking is achieved for that fluorophore. This will depend on the fluorophore, sample type,
and labeling density. Contact ONI support for more information on how to determine the optimal power. -
Click the “Set laser powers” button, which will now indicate the active laser wavelength and power.
This will save the currently active laser power to be used for all lanes of the current experiment. - Repeat this for each laser that will be used for the experiment.
- When returning to the Experiment Setup page, note that the laser power for all lanes has been updated.
Optionally Setting Global System Settings [9]
Manual System Calibration can be used to set the “Acquisition Settings” from the System Info page with the correct values based on the current sample on the microscope.
- Starting focus position for autofocus used in channel mapping, automated system calibration, and automated acquisition
- Laser powers used during the automated system calibration step
- Manual TIRF angle
Best practice for using these quick actions is (with a 4-lane Assay Chip on Nanoimager):
-
Find the focus of the selected slide type using the focus controls, and calibrating and engaging the z-lock [1].
Click “Set as initial focus for ONI 4-lane Assay Chip” to save the current stage z-position as the global default
initial position when using autofocus in the system calibration, sample check, and automated FOV acquisition. -
Find the lowest laser power where fluorescence with a good signal-to-noise can still easily be detected, and where
the sample is not blinking. This may be anywhere from 3% to 25%, depending on the laser and the system.
Click “Set as laser power for calibration” to save this power as the power used for the autofocus and autoTIRF
during automated system calibration. -
With the laser set to a typical power used for data acquisition (generally around 50%), use the illumination angle
slider to find an angle where the sample has the highest signal-to-noise ratio.- Click “Set as manual TIRF angle” to save this as the default manual TIRF angle.
-
Note this does not set the system to manual TIRF mode. To do so, navigate to the system info page
and swap from “auto” TIRF mode to manual.
Appendix III: Viewing AutoEV Datasets in CODI
Once the acquisition of an FOV is completed, the dataset will be uploaded to CODI and the selected analysis will begin. Once the upload is complete, clicking on “View Dataset” will open the dataset with CODI’s visualization and analysis interface. The dataset info page contains all the information about the dataset, including:
[1] Export raw localizations as a CSV
[2] Channels acquired: Name, Type (SMLM) and number of localizations displayed
[3] Stage Z position at focus
[4] Z-offset
[5] TIRF angle
[6] Camera Pixel size
[7] Stop analysis button
It can be helpful to quickly inspect these values to ensure they’re coherent and consistent across acquisitions. For example, while the number of localizations per channel will vary based on EV concentration and staining, it should generally be similar for the FOVs in the same lane.
Notably, if the number of localizations is very low for a channel where there is expected to be a strong signal, that might be indicative of an issue during the data acquisition.
Appendix IV: Guide to the EV Profiling Analysis App
EV Profiling analysis
The datasets acquired with the AutoEV app can be analyzed using the EV Profiling analysis app, an automated, step-by-step, analysis workflow for EV characterization, consisting of EV counts, size and positivity. For each single EV the information on size and biomarker positivity can be obtained.
The workflow consists of several steps: [1] Drift correction, [2] Filtering, [3] Clustering and Cluster Filtering tool and [4] Counting tool, which are applied sequentially to the datasets. Each tool can be run individually by pressing the play button on the widget, or the entire workflow can be run in a single click by clicking the play button at the bottom of the workflow steps.
The entire analysis varies based on the number of localizations in the dataset, but generally takes around 5 minutes for typical acquisitions.
Drift correction
AutoEV app allows users to sequentially image 647, 561 and 488 channels, for a total of around 2 minutes per single field of view. During this time, the sample can drift in the order of a few tens of nanometers due to temperature change or physical sample movement. ONI’s drift correction algorithm allows correction for this.
Drift Correction Procedure
A standard Drift Correction at Minimum Entropy (DME) algorithm is applied to all the SMLM channels, with the last frame used as reference (see CODI user guide for more information).
Filtering
Each SMLM localization is characterized by sigma, precision and p-value. Minimum and maximum thresholds for these characteristics were optimized based on positive controls and negative controls. The analysis apps automatically filter out localizations that don’t meet these optimized thresholds as they are identified as noise.
These filters were very carefully defined for each of the EV Profiler 2 kit variants and acquisition on the Nanoimager to ensure the best quality results of the entire EV Profiling analysis tool. Notably, strict filters are applied to the frame range (where the first 50 frames of each channel are removed while the sample begins to blink) and the localization precision to ensure noisy localizations are removed from the analysis.
DBSCAN based clustering tool
An essential part of SMLM analysis of EVs is grouping adjacent localizations together so that they can be identified as single EVs through a process called clustering.
DBSCAN is a clustering algorithm which groups localizations into clusters by linking points that are densely packed within a distance threshold, while filtering out noise. This makes it well-suited for EV analysis, where it reveals nanoscale molecular assemblies of arbitrary shape with the need for only a single parameter, epsilon (ε), which defines the maximum distance between two points for them to be considered neighbors.
Choosing ε carefully is critical, as it determines how tightly localizations must pack together to form a biologically meaningful EV-associated cluster. CODI’s EV Profiling analysis app uses 85nm as a default value, which is generally a good starting point for most typically labeled EV samples. For very sparsely labeled EVs, or for very densely captured samples, it is recommended to adjust the epsilon distance to optimize clustering.
Furthermore, it is possible to select which channels are used for the clustering process, by clicking the “…” menu and selecting or de-selecting any of the channels in the dataset. Use the “merge selected channels” option to aggregate all localizations from the selected channels while clustering.
Additional parameters can be adjusted in the “…” menu of the clustering tool, including:
- “min samples”, which relates to the minimum density of the cluster
- “min size”, which refers to the minimum number of localizations required for a cluster
More information can be found on the ONI Service desk
Cluster filtering
Once the clustering of the localizations of an EV is completed, it is possible to refine the selection of the clusters to filter down to only those which meet the criteria of what an EV is expected to be.
The filtering parameters are based on the spatial characteristics of the clusters:
- Area (nm2): the area of the cluster. This can be used to remove clusters which are too small, and may represent unspecific binding of fluorophores to the surface, or clusters which are too large and might represent aggregates of EVs, which would ideally be excluded from single EV analysis.
- Circularity: a measure of the roundness of the clusters. In general, the expectation is that clusters which are truly EVs are likely round
- Radius of Gyration (nm): a measure of the size of the cluster. While this is not exactly the radius of the cluster, it is an indication of the size of the cluster.
- Density (per nm^2): the localization density within the cluster. Clusters with lower density have fewer localizations per unit area than those with higher density.
Counting tool
The counting tool is the last step of the EV Profiler analysis app, and is used to count the number of localizations across all channels for each cluster so that each individual EV can be assigned a biomarker positivity (single, double, or triple positive).
The counting tool works by counting the number of localizations in each channel in a specified radius around the center of the cluster. The user must define the size of this counting radius, which should generally be set to based on the largest expected EV size in the sample. For highly dense samples, it may be necessary to reduce the counting radius to ensure that the counted localizations pertain to each individual cluster (and not count localizations from adjacent clusters).
Biomarker positivity thresholds can be defined in the counting tool directly in the interface, by specifying a minimum and maximum number of localizations required for a cluster to be considered positive for the biomarker in that channel.
Generating EV montage from single dataset
A montage of representative images of the EVs in the dataset can be generated directly from the Counting tool page.
- Select Generate montage [1].
- Select the number of clusters per positivity group [2]. For a single dataset and 50 clusters per positivity group, this should take about 2 minutes.
- Select the output file format [2].
- Click Generate montage.
- A montage preview will appear. To generate a montage with new random clusters, click Generate montage again.
- Downloading the montage [3] will automatically save it in the computer’s Downloads folder.
Generating a summary report and saving data
Once the settings of the counting tool have been finalized, such as the counting radius and positivity thresholds for each channel, pressing the “Play” button in the summary report widget generates several CSV files containing the results of the EV Profiling analysis:
- A positivity report contains an overview of the biomarker positivity information of the datasets
- A results file contains information about each individual cluster and its biomarker positivity, and is the most useful for statistical analysis
- A parameters file contains information about the biomarker counting thresholds used in the analysis.
Batch analysis and aggregating analysis from multiple datasets
Once the parameters for a particular dataset have been finalized, clicking the “>>” button allows the user to save these settings for later analysis.
CODI makes it easy to apply these same settings to other datasets that have already been acquired via batch analysis, or datasets that will be acquired in the future with AutoEV by using those analysis settings directly in AutoEV.
For more information about how to run batch analysis, visit the ONI Service desk
Batch Report and generating a report from CODI analysis
If the EV report was not generated at the end of an acquisition in the AutoEV app (summary page),
it can be done at any time in CODI using the “batch report” feature, which provides a report
for a single chip with up to 4 lanes. To do that, navigate to the CODI collaboration
in which the data is saved and perform the following:
- Click the Analysis Results button to view all the analysis results in this collaboration.
- Click the Cross Dataset Report button.
-
Select the EV Profiling analysis App, and the settings used during the acquisition.
Note: If the user chooses to re-analyze the data acquired from AutoEV with different analysis settings,
all of the datasets must be batch analyzed with the same analysis settings to be included in the report. -
Select the datasets from one chip (one dataset corresponds to one FOV) to be featured in the report
and click Generate Report.
Note: The EV batch report is for a single chip and up to 4 lanes, i.e., it is not possible to generate a single analysis report for datasets acquired from different chips. Additionally, CODI does not support analyses and reports across different chips. To generate cross-chips reports, ONI provides EVP2 Axis, an offline python-based code tool. For more information on the EVP2 Axis, visit the ONI EVP2 Axis webpage.
Key Tip
Report generation only works for data generated from AutoEV, which contains the proper key/value tags to ensure that the report is calculated and displayed correctly. If an error message appears during the report generation process, it is likely because the datasets do not contain the proper tags, such as the “Lane” and “FOV” Key/Value tags.
Appendix V: System Info App
System Info is an app that provides the status of the microscope in real time and where users can control settings for calibration. It is accessed by clicking on the temperature icon in the top right corner of CODI, or by going to “Acquisition apps”.
Temperature widget
The temperature widget allows setting the Nanoimager temperature and starting or stopping heating, as explained in the “Setting a default Nanoimager temperature”.
Acquisition settings widget
The acquisition settings widget allows adjusting of some settings for the automated algorithms.
- Set the starting point for finding focus when doing channel mapping (beads slide) or during sample pre-check calibration (4-lane Assay Chip). It is recommended to set these values based on the ONI bead slide (“beads”) and a 4-lane EV Profiler Assay Chip (“EVs”).
- Set a fixed TIRF angle by clicking the Auto button to switch to a manual TIRF angle. Proceed to type the optimal value and click Save Settings.
- Adjust the default laser power values for system calibration. System calibration may fail if the sample is bleached during autofocus or autoTIRF. Reduce the default values to 10-15% to prevent the sample from bleaching during these automated calibration steps.
Remember to click Save Settings once modified. Settings can always be reset to default.
Note: These settings are stored in the local storage of the web browser, and will reset to defaults when using a different browser profile or delete browser caches. Double check these values prior to running any experiment.
Dataset upload status
To obtain insights into the EV sample, data acquired on AutoEV has to be analyzed on ONI’s cloud-based software, CODI. The raw imaging data is first saved locally on the C drive on the Nanoimager laptop and is then uploaded to CODI. Upload is automatic, but it requires a stable internet connection and for CSA to be open.
Since AutoEV is a CSA app, uploading to CODI will commence immediately after data acquisition, as long as the laptop is connected to the internet. If upload is not completed, it will begin automatically next time the AutoEV is opened on CSA as long as an internet connection is available. In the Nanoimager App, the dataset upload status widget displays information about the upload progress. This widget will show how many datasets are in the upload queue, as well as important information if that queue is stalled, for example, if the internet connection is unreliable or unavailable.
Key Tip
The CODI System App must be open for uploads to succeed. If stalled, and the internet connection is stable, closing and re-opening the CODI System App to re-initiate the upload queue is recommended.
Reporting bugs or requesting new features
Please refer to the AutoEV and AutoLNP Troubleshooting page on the ONI Service Desk for common issues and workarounds.
Use the ONI Service desk to submit bug reports or any feature requests, using the AutoEV category. To ensure that the ONI team can properly address any bugs reported, we kindly ask that the latest “experiment_server*.log” and “hal*.log” logs are provided. These are located in the following directory: C:\Users\ONI\AppData\Local\ONI\OHM
AutoEV for Aplo Scope
AutoEV is an application in CODI, ONI’s cloud-based analysis platform, that enables Extracellular Vesicle (EV) characterization through an end-to-end workflow using the ONI Application KitTM: EV Profiler 2, Aplo Scope and CODI. AutoEV consists of several advanced features that allow users to perform super-resolution image acquisition, analysis, and reporting of an entire 4-lane EV Profiler 2 Assay Chip with reduced hands-on time and a robust pipeline.
Aplo Scope requirements
AutoEV requires active internet connection on Aplo Scope PC.
Prior to using AutoEV
Placing the chip holder on the Aplo Scope
AutoEV comes with a chip holder that makes the Aplo Scope feel like it was made for EV Profiler 2 Assay Chips. It also allows AutoEV to know where each lane is without any specific calibration.
Note
With the Aplo Scope still switched off, place the chip holder on the Aplo Scope before opening the CODI System App (CSA).
- Place the chip holder on the Aplo Scope stage as shown in the illustration below.
- Place the EV Profiler 2 Assay Chip or bead slide (with magnets) inside the chip holder.
Installation
To run the EV Profiler 2 kit, first register to ONI’s CODI software platform, download the CODI System App and use AutoEV app.
Navigate to https://alto.codi.bio to access the CODI platform. It is important to sign in and log in (see [1] on the image below) to CODI prior to starting AutoEV installation. If this is the first time creating an account in CODI, contact ONI to get the AutoEV app activated. Once logged in, go to Application apps [3], and select the AutoEV app.
To be able to run the EV Profiler 2 kit, the CODI System App (CSA) needs to be downloaded. The CSA operates in the background to connect the Aplo Scope and light engine to CODI, this connection is crucial to operate AutoEV. If this is the first time downloading the CODI System App, click “download” as shown in the popup message. Follow the instructions to install the CODI System App.
Note
If a “Windows Security Alert” appears, “allow access” to ensure that AutoEV functions correctly.
Once installed, open CODI system App and wait for the status indicator to change from “Initializing” to “Running”. CODI System App starts heating the Aplo Scope as soon as the application is opened. Click the “Refresh Page” button to close the popup widget.
Key Tip
Ensure that the CODI System App is displaying “Running” prior to running AutoEV, to ensure that the Aplo Scope communicates properly with CODI.
Setting a default Aplo Scope temperature
In the top right corner of the CODI page [2], click on the temperature icon with a blue background, which will bring the System Status App, where users can set the desired temperature. This will be saved as the default temperature for the next time the CODI System App is launched. For EV Profiler 2 kit, the default recommended is 32°C. Whenever the CODI System App is launched, the Aplo Scope will automatically start heating to 32°C. This typically takes 2 hours to stabilize and be ready for imaging.
Do not start imaging before the temperature is stable. Any acquisition done during the heating process, will result in a lot of drift. See channel mapping section for more details.
To ensure these algorithms work well, there are a few initial values that may need to be adjusted:
- Starting z-position focus for channel mapping (ONI Bead Slide): the Aplo Scope is aligned such that
the ONI bead slide focal position is near 0 µm. A starting focus of 0 µm ensures AutoEV’s
1-click channel mapping finds the right surface of the ONI bead slide.
- Starting focus z-position for system calibration (ONI 4-Lane Assay Chip):
a typical 4-lane Assay Chip will have a focus near -250 µm.
A starting focus of -250 µm ensures AutoEV’s system calibration, sample check,
and automated acquisition find the right surface of the ONI bead slide. - TIRF angle: choose between “auto” and “manual” illumination:
- In Auto mode, an illumination optimization process will run at the end
of the system calibration step, ensuring the illumination angle is optimal for
the specific 4-lane Assay Chip being used. - In Manual mode, a specific TIRF angle can be specified and used
for all data acquisition.
- In Auto mode, an illumination optimization process will run at the end
- Laser powers used during the system calibration step can be modified on a per-laser basis.
The default values of 5% should be lowered in situations where the sample signal
is bleaching during automated system calibration.
AutoEV
AutoEV is a linear workflow that helps guide users through the acquisition of the EV Profiler 2 kit, from experimental setup to acquisition summary. Each step of the workflow has a dedicated page, which can be accessed from the toolbar on the left hand side of CODI.
Move between the pages either by clicking on the individual tabs, or by using the action button on each page to proceed to the next step, e.g., Next, Run, Start acquisition etc.
Experimental setup
The first step of AutoEV is to input the experiment settings:
- AutoEV experiment title (chip/sample name) [1]:
Give the experiment a name. The datasets will be both saved locally
(C:/data/CODI
) and on CODI using the experiment name — pick a good one! - Dataset tags: Tags and Key/Value Tags (optional) [2]:
Add tags to the dataset to help distinguish them on CODI.
Make sure to click the 💾 save button to save any changes. - Collaboration in CODI [3]:
Select a collaboration in CODI where to save the data, or use the 💼+ button
to create a new collaboration.
Note: It is required to save the data to a Collaboration from AutoEV.
- Analysis settings:
AutoEV on Aplo Scope automatically analyzes acquired datasets. By default, the AI EV Profiling analysis app is used, which is designed to deliver optimal analysis results with minimal need for parameter adjustments. The default settings for the analysis workflow are optimized for each kit configuration. Any CODI analysis app and analysis settings can be selected to be run automatically on acquired datasets. - Experiment settings:
Experiment settings allow the user to quickly save and load all the settings pertaining to an AutoEV experiment, including experiment metadata (lane names and channel names), illumination settings (per-lane laser powers, number of frames and exposure time), and analysis settings (analysis app and analysis settings). Optimal experiment settings for each kit variant are provided when clicking on the “load settings”.Note: It’s important to ensure that settings are properly calibrated for each instrument by measuring the power in mW and adjusting accordingly. Details on how to adjust the laser power are in Appendix I of this guide.
Data and analysis settings
AutoEV automatically uploads the data to the selected CODI account and saves it locally in the C:/Data/CODI/ folder. AutoEV saves the acquisition data in subfolders with names corresponding to the Experiment and Lane titles inputted on this screen.
Sample and acquisition settings
Setting up the acquisition should mimic the EV Profiler Assay Chip with a 4-lane design.
- Enter a Lane Title that represents the EV sample in that lane. For example, use HEK EV sandard control, negative control, or the name of the sample
- Enter the labeling information for the 488 (cyan), 561 (yellow), and 640 (magenta) channels.
- If there is no dye in one of those channels, switch off that channel by using the vertical toggle on the left hand side
- The images will always be acquired from the longest to the shortest wavelength: 640nm laser with 673/35 nm filter, then 561nm laser with 615/40 nm filter, and finally 488nm laser with 527/49 nm filter.
- AutoEV app provides default settings recommended for running the EV Profiler 2 Kit protocol. Adjust the acquisition settings by clicking on the small text below and input:
-
- Laser powers need to be adjusted for each user prior to starting an experiment. This may vary depending on the system. Contact ONI if additional information is needed after installation. Laser power values can be updated in the AutoEV experiment settings page and saved using the Save Current Settings button. See Appendix I for a guide on how to adjust the laser power with respect to the specific kit.
- Auto TIRF automatically finds the optimal illumination angle for EV imaging by maximizing the signal to noise ratio of the spots with respect to the background. The TIRF angle can be manually input in the System Info app. See the “Check TIRF angle” sub-section under the “Calibration & Sample Check” section to select the optimal TIRF angle.
Using the default settings for the number of imaging frames and exposure duration is recommended, as they were optimized for this kit. However, these can be adjusted on a per-channel and per-lane basis if needed.
Applying modified settings across all lanes
AutoEV has a couple of options to simplify the process of applying settings to all lanes.
Start by inputting settings in lane 1, then use the buttons at the bottom of that lane to:
- Apply all settings: synchronize all sample and acquisition settings to all lanes
- Apply imaging settings: synchronize only the acquisition settings (channel and lane names will not be synchronized)
- Reset settings to default: reset all lanes to the default EV Profiler 2 Kit protocol settings
Save the experiment settings
If the imaging settings are updated, such as number of frames or laser power, these can be saved by clicking Save Current Settings. These can be loaded again using Load Settings.
Note: Settings are saved locally on the Aplo Scope laptop only and NOT saved on CODI. If web browsers or users are changed, settings will need to be reentered and re-saved.
Laser power optimization
Each EV Profiler 2 kit needs to be acquired with a specific optimized power to ensure proper blinking of the fluorophores. Find the recommended laser power using the table below:
Experiment setting | Laser line (nm) | Power (mW) |
---|---|---|
EV Profiler 2 Tetraspanin | 638 nm | 250 mW |
EV Profiler 2 Tetraspanin | 561 nm | 92 mW |
EV Profiler 2 Tetraspanin | 488 nm | 240 mW |
EV Profiler 2 PanEV + Protein | 638 nm | 250 mW |
EV Profiler 2 PanEV + Protein | 561 nm | 92 mW |
EV Profiler 2 PanEV + Protein | 488 nm | 240 mW |
The Aplo Scope contains an internal laser power sensor, which is calibrated out of the factory to estimate the laser power at the sample. AutoEV leverages this internal sensor to find the optimal power for the EV Profiler 2 Kit.
In the channel mapping page, click Microscope controls and then Optimize powers [1]. Select the experiment for which the laser powers need to be optimized from the drop down menu. Once selected, an automated laser power optimization routine will run using the internal laser power sensor to automatically find the right output for each laser. This is required to achieve the adequate laser power at the sample, which may vary over time with laser output variation. This step takes less than one minute. Once completed, the laser power percentage in the experiment settings will be automatically updated for those specific experiment settings and a “Laser powers calibrated & applied to the experiment” message will appear. Values can be saved using the Save Current Settings button, and reloaded in a future experiment. The settings are saved for each CODI user.
If a particular power cannot be reached with a 10% tolerance range, AutoEV will display an error message. Should this occur, please contact the ONI Service Desk for assistance.
Key Tip
It is recommended to run the laser power optimization once a week.
Channel mapping
Channel mapping is an essential step towards generating accurate multicolor super-resolution data, and AutoEV makes channel mapping even easier with a one click channel mapping of both regions of the camera (left and right) that ensures all the biomarker channels are mapped together.
AutoEV simplifies your work by informing when it is time to run a new channel mapping or if channel mapping might need to be re-run prior to acquiring images from the EV Profiler 2 Assay Chip.
Important
It is imperative to re-run channel mapping if:
- Channel mapping has not been done in the last 24 hours
- Aplo Scope temperature has changed by >1°C since last channel mapping
- It is the first time running AutoEV
To run channel mapping, ensure the bead slide is in the chip holder on the Aplo Scope stage and click the Run button at the top to automatically run channel mapping. Follow the progress of channel mapping thanks to a progress bar and see each step that has been run.
Stop channel mapping at any time by pressing the ◽️ button.
AutoEV will report back the accuracy and field of view coverage of the channel mapping. An accuracy of less than 15 nm and a field coverage of 100% are recommended. Details on how channel mapping works are in Appendix 2 of this guide.
Key Tip
Channel mapping usually takes ≈2 minutes. If channel mapping takes longer, it may mean that the bead slide might have a sparse bead density, requiring more fields of view. If channel mapping is not complete after several minutes, stop it and replace the bead slide.
If the accuracy is less than 15 nm and/or the coverage less than 100%:
- Clean the bead slide
- Replace the oil on the objective
- Click the Re-run button to re-run channel mapping until satisfactory
- Click the Microscope controls button to manually diagnose sample-related issues
when the bead slide is not optimal or autofocus isn’t working properly.
This will also display advanced microscope controls on the channel mapping page.
Channel mapping not required
While running channel mapping before the experiment is recommended, if it has been performed recently and that the Aplo Scope temperature is stable, AutoEV will allow imaging without performing channel mapping, for instance, when imaging more than one chip at once.
Calibration & Sample Check
For AutoEV to be successful at imaging the EV Profiler 2 Assay Chip, it is essential to ensure that the chip is ready to image prior to starting the super-resolution acquisition.
Key Tip
Anytime the EV Profiler 2 Assay Chip is placed on the Aplo Scope, the system calibration step should be performed to ensure optimal focus and illumination.
System calibration
System calibration is a critical step that automatically finds the imaging surface of the EV Profiler 2 Assay Chip, locks the focus, and determines the optimal illumination angle with AutoTIRF.
Start calibration by selecting a lane [1] and channel [2] where a good density of EVs and a strong fluorescent signal are expected. A minimum of two FOVs will be used for calibrating the system, one for optimizing focus and another one for finding the optimal TIRF angle. The AutoTIRF algorithm will run up to a total of four times (using new FOVs) if an attempt fails to find an angle within a range of 53-65 degrees due to lack of signal. Each AutoTIRF attempt usually takes around 20 seconds to complete.
When ready, click the Calibrate focus & illumination button [3] to start the calibration. Do not run the calibration in a negative control lane. Calibration can take from 2 to 3 minutes to complete. The process can be stopped at any time using the ◽️ button.
Once sample calibration has been successfully completed, the widget will update to display the calibrated focal plane and TIRF angle (bottom right). Use sample pre-check to assess the TIRF angle and modify it if needed (see details below).
Calibration or Refine Focus Failing
Calibration may fail for several reasons. Errors will appear in the top right corner indicating the reason for failure. Common sources of failure are the inability to find the lane surface, inability to optimize the focus based on the fluorescence signal due to too few points being detected, or suboptimal TIRF value (60-65 degrees). AutoEV will inform the user of focus or TIRF failure. If the system calibration fails consistently or autoTIRF looks poor, follow these instructions:
- First, ensure the Assay Chip is properly positioned on the Aplo Scope stage, and that the lanes are bubble free.
Note: If the failure appears to be focus related, select the Refresh z-lock calibration option. - Next, try a different channel or lane where a strong signal is expected and then re-run the calibration by clicking Calibration failed. Re-calibrate focus & illumination.
AutoEV will move to the next FOV and try again. This means if the area was bleached, or bad, or if oil was not well distributed, there is a chance to succeed by moving to a different area. - Verify that the system is not attempting to calibrate in a zone where there is a bubble in the chip.
This can be visually inspected by opening the Aplo Scope lid after a failed calibration and observing the sample from directly above the objective.
If there is a bubble, try calibrating in another lane. - If the system fails to focus, it could be attempting to focus on the wrong surface of the chip.
See Setting global Acquisition Settings for more information on how to set the global settings to ensure best focus. - If the system focuses but fails to optimize the illumination angle, the sample could be bleaching before the optimization completes.
See Setting global Acquisition Settings for more information on how to lower the laser power for the system calibration to prevent bleaching.
If adjusting global acquisition settings does not resolve issues with the automated system calibration,
create a manual calibration using Manual System Calibration.
Key Tip
The TIRF angle is typically between 60 and 65° on the Aplo Scope and should not deviate by more than 2° between acquisitions.
To validate that Autofocus and AutoTIRF have provided optimal values, it is important to run the Sample pre-check.
Sample pre-check
Sample pre-check is a tool that quickly scans each lane of the EV Profiler Assay Chip and provides a representative image of the sample in each lane. We recommend using it for each EV Profiler Assay Chip to get an overview of the sample prior to imaging. This will help check if the sample calibration is good and the sample in each lane is nicely focused and well illuminated, the EVs density per lane is the one expected and the EVs were correctly stained, and if sample was correctly washed with buffer added.
Click Start sample pre-check to begin the sample check, and AutoEV will start scanning each lane. It can then be stopped this by using the ◽️ button.
Key Tip
The sample pre-check is intended to give a representative image of the automated acquisition, and thus uses the imaging settings (laser power and TIRF angle) from the experiment settings page.
Focus check
The autofocus tool is an automatic function to find optimal sample focus in cases where the FOV has good a Signal to Noise ratio (SNR) and there are at least 3 objects (such as EVs or beads) when calibration is performed. Autofocus may fail or look poor if there are bubbles, low/no signal, etc.
TIRF angle check
AutoTIRF is an automatic function that finds the optimal angle for which the SNR is reduced. If the signal and the surrounding background change from sample to sample or lane to lane the AutoTIRF might provide different values every time it is run. This is because it is calculated based on the SNR of the FOV selected during the system calibration step.
An optimal TIRF angle is required to achieve accurate quantitation. Manually inspect each lane for poor TIRF alignment. This will be visible in all lanes. A good TIRF angle will result in an even FOV illumination, low background noise, and high signal from the particles. A poor TIRF angle will result in a lack of signal in the bottom or top of the field of view. If the TIRF angle in the sample check is poor, proceed to the optimizing and setting the TIRF manually.
Refine focus in the Sample pre-check
Sometimes focus found during System calibration might not be optimal, and refining focus might be needed.
In the sample pre-check step, select Check Focus in the lane title if AutoEV thinks manual refinement is needed, or Completed if the focus is good. If Check Focus is displayed, select the Refine Focus button.
Once Refine Focus is pressed, the Aplo Scope will move to that lane, turn on the lasers, and allow the user to manually refine the focus. This is great for optimizing the focus in the rare case the sample is slightly out of focus.
Use the “up” and “down” arrows to move the Z-offset and find the optimal focus. Click the “Next FOV” button to move to the next FOV in that lane and get a view of the focus without bleaching the sample.
When ready, click the Save & Re-run button to save the optimal focus and acquire a new sample check image.
Key Tip
Any offset applied is lane-specific and used during image acquisition to ensure the best focal plane is imaged within that lane. These settings are stored in the local web browser and will reset to defaults if a different browser is used or browser caches are deleted. Double check these values prior to running any experiment.
Field of View (FOV) selection
In this section FOVs will be selected for image acquisition in each lane of the chip. Click the Select 6 default FOVs per lane button (top left) once to automatically select 6 default FOVs in all lanes. These are chosen to provide a good statistical distribution of EVs. The image above shows the default 6 FOVs, optimal for most experiments as they are centered in the sample lanes and are evenly distributed.
To select different FOVs, or if the lane has a specific fault in these areas (bubbles, drying out, etc), FOVs can be manually selected. Go to the “Choose FOVs” page for that.
- White vertical and horizontal lines indicate the middle and center of each lane.
- Multiple FOVs can be selected per lane, 6 is the recommended number.
- The selected FOVs will appear in purple.
Selecting FOVs
FOVs can be selected either by choosing a number of FOVs to be imaged at the top of each lane,
or by manual FOV selection.
- Number of FOVs to be imaged: Changing this option will automatically select consecutive FOVs
in the middle of each lane. All FOVs in a lane can be removed by typing “0” FOVs at the top of each lane. - Manual FOV Selection: FOVs to be imaged can be selected by clicking the squares in each lane,
and removed by hovering over the FOV and clicking the x.
Each time a new FOV is added, the ETA (estimated time) at the bottom left of the page is updated
with the new estimated experiment duration time.
The legend shows different possible FOV status:
- A FOV previously imaged in system calibration or sample check appears in gray.
- A FOV failed to be imaged because of focus appears in red.
- The current stage position appears in blue.
- A FOV imaged during the current experiment appears in green.
Note
The FOV in AutoEV covers an area of 110 µm (width) by 110 µm (length). Each FOV’s imaging area is surrounded by a bleaching safe zone, so that any acquisitions in the neighboring FOV will not be affected by stray laser light. The result is that each FOV rectangle in the FOV selector represents this bleaching safe area of 113µm x 113 µm.
Save TIFF images to disk
Unchecking this box will only save the localization data to disk, saving precious disk space for long EV acquisitions.
Each FOV corresponds to a single dataset. Multiple datasets within the same lane can be generated by acquiring multiple FOVs. Six FOVs per lane should provide a good statistical power.
Acquisition
Before starting an acquisition
While many of the AutoEV steps workflow are optional (like Channel Mapping and Sample Check), there are 2 critical steps that must be completed prior to starting the super-resolution imaging:
- Selecting a Collaboration on CODI in which to store the data and analyses.
- Running a system calibration to ensure correct focus and illumination during the acquisition.
AutoEV will show a warning if either of these conditions are not met. The yellow warning on the banner can be clicked to explore the step to be fixed.
Starting an AutoEV acquisition
Now that the AutoEV acquisition is set up, click the Start Auto-EV Acquisition button ([1] in the image below). The EV Profiler 2 Kit chip will be scanned from Lane 1 to Lane 4, and the acquisition in each lane will follow the settings input in the Experiment Setup page.
During the acquisition, real-time information shows:
- Which lane [2] and FOV [3] are currently being imaged, allocated, or failed
- A live camera view [4] to see the blinking fluorophores
- A live progress bar [5] reporting frame count and estimated time of completion
- Live localizations [6] displayed from the blinking fluorophores
- A list of acquired FOVs and their status [7]:
- Acquiring: The FOV is currently being imaged
- Uploading: The FOV has completed imaging and is being uploaded to CODI
- Analyzing: The FOV is being analyzed on CODI
- # Clusters: The FOV is done being analyzed and is displaying the number of clusters found in the FOV
At any point during the acquisition, press the ◽️ button to stop the acquisition, or press the Skip FOV button can skip the acquisition of the current FOV being imaged. If a FOV is skipped, it will not be saved nor analysed, and the automated acquisition will proceed to the next FOV.
Each dataset will be automatically uploaded to CODI once acquired, and analyzed using the selected analysis app and settings from the Experiment Settings page. Click any dataset from the acquisition list [7] in the acquisition page to visually inspect the sample.
See Appendix IV for more information about how to view the dataset in CODI.
Summary & Report
- Imaging Setup [1]: gives an overview of the sample and imaging settings
- Analysis [2]: displays the analysis settings that were used and a link to view the data on CODI
- Acquisition List [3]: shows a list of all the imaged FOVs, with a link to the dataset and analysis on CODI.
- When the analysis completes, the number of clusters will also be displayed here, making it easy to see if the data had a consistent EV density or if some FOVs or lanes did not have a good capture.
- If an FOV failed to image (likely due to inability to properly find focus), it will not display in this list.
- Visual Experiment Overview [4]: displays each FOV that was imaged for calibration, sample check, or during the super-resolution acquisition.
- Mosaic View [5]: shows a representative image of each positivity class, providing a quick glance at the EV sample. Hovering over each image allows users to cycle through more EVs of each type and copy the image for quick sharing in a presentation.
Exporting acquisition data
When the data is done acquiring, uploading, and analyzing, it can be exported by:
- Generating a Montage [1]: of EV clusters per chip-lane. The montage contains a visual overview of the EV sample.
- Generating a Report [2]: that contains an overview of the chip’s EV count and positivity, by lane.
- Downloading CSV Data [3]: that contains all the clustering and positivity data.
A montage, report and CSV data can be generated even if a subset of datasets is acquired, or if the analysis of some of the datasets is not yet completed or failed by clicking Select datasets [4]. Select only the datasets for which the analysis is completed [5], and use the Data export widget [6] to generate the files.
Generating a montage
Generate a montage to visually inspect the size and morphology of the EV sample and the analysis outcome.
This feature allows the creation and saving of a montage of random EVs selected and ordered based on positivity and size (see image below). This feature is particularly useful not only to visualize the positivity results but also to assess assay quality.
At the end of an acquisition, a montage from the 4-lane Assay Chip or a montage from individual FOVs can be generated.
Key Tip
Once new data is acquired it will not be possible to generate a montage image for the entire chip. Ensure a montage is generated at the end of the acquisition, before moving on to the next chip. It is always possible, on the other hand, to generate a FOV montage.
Generate a montage from the 4-lane chip
- In the summary page of the AutoEV app, go to the “Data Export” widget and select the channels to visualize in the montage.
- Select the number of clusters per positivity group (e.g. a montage generated with 10 clusters means 10 clusters per each positivity group present).
- Select the output file format.
- Click “Generate montage”.
Note: For 4-lane montages with 50 clusters each, generating a montage requires around 15 minutes.
- A montage for each lane will be saved locally in the experiment folder under the C:/Data/CODI path.
- Each lane montage will contain clusters coming from the FOVs acquired in that lane.
- Error messages may appear if there are no clusters (analysis failed or still ongoing), or if some lanes are missing clusters.
- To generate a montage with different clusters, click “Generate montage” again. Random clusters will be selected every time.
Generating a report
Click the Generate Report button to create a report that provides a good overview of the sample.
The report will give an overview of the experiment performed and sample outcome. In the report, experiment title, analysis performed, date and user name will be displayed. The report will show an overview of the sample within each lane, given the imaging settings used.
The data in the report is presented as one column for each lane, and 3 data rows to better understand the EV sample:
- EV count per FOV: Quickly comparing particle counts across lanes to compare EV numbers in different samples,
and for different FOVs in a single lane, it can help assess sample homogeneity. - Biomarkers positivity aggregated across the FOVs in each lane: Represented as a stacked bar chart to easily compare across lanes.
Positivity is displayed as a percent and as an absolute EV number. - EV size for each positivity class: Displayed as a box plot, allowing for easy comparison across positivity classes and across lanes.
The overall EV size (gray distribution) is displayed as an aggregate of all positivity classes. The EV size is calculated as shown below, by using the convex hull area of the cluster (“Area (nm²)” in the -results CSV) and calculating the diameter of a circle with the same area.
To print or save the report after generating it, use the 🖨️ button. The link to the report can be saved on CODI by copying or favoriting the URL directly.
Download CSV readout
At the end of an analysis, download the CSV data with all EV outputs from the analysis.
These files can be used for additional analysis and plots outside CODI.
This can be done in the AutoEV app, under the Summary Page by clicking the
Download CSV Data button, or in the CODI analysis space within a single dataset in batch analysis.
When downloading the report from the Summary Page in the AutoEV app, two zip files will be saved in the local computer’s download folder:
- “Experiment data”: includes all the raw positivity results and clustering results in CSV format.
- “Experiment points data”: contains a list of all raw localizations before analysis tools are applied.
The most important CSV file is results.csv in the Experiment data folder.
This file contains a list of EVs clustered with their given ID, centroids, area, diameter, positivity values, and more.
Re-running the Chip
Once the summary of the acquisition is viewed and the report generated, more data from the same chip may be acquired. AutoEV makes this really easy with the Re-Run button, which shows the experiment info page, where the number of FOVs per lane can be increased/decreased, or acquisition settings changed.
Note: if re-running a chip with more FOVs, the FOV annotation will start again from 1. Changing the experiment title is recommended, for example, adding “run 2”, so that FOVs acquired in each run can be distinguished, e.g., FOV 1 acquired during the first run and FOV 1 acquired in the second run.
Run Next Chip
Remove the chip carefully and place the next one. Close the EV experiment tab and open a new one from the Acquisition apps. Load the saved experiment setting with the correct laser power that was optimized for the Aplo Scope. All the next steps will be identical to the above. Only run channel mapping again if prompted by the system.
Help and Support
If at any time you experience a software issue, contact ONI through the Help Center (oni.bio/contact). Click on the question mark displayed in AutoEV and CODI and go to “report an issue”.
Visit the ONI Service desk to learn about common AutoEV troubleshooting.
Appendix I: Manual System Calibration
Manual System Calibration allows the user to manually inspect the sample and create the illumination and per-lane focus calibration that is required to automatically and accurately acquire FOVs across all lanes.
The Manual System Calibration page can be accessed any time during an automated imaging workflow, and is conveniently located before the required steps of the workflow.
When to use Manual System Calibration
Manual calibration can be used at any point prior to starting an automated acquisition:
- The user can opt to manually create the focus and illumination calibration instead of using the automated system calibration for a variety of reasons:
- Speed: once familiar with the process of creating a manual calibration, this might be quicker than running the automated calibration and sample pre-check.
- Sparse samples: for very sparse samples with <100 particles per FOV, the automated algorithms may struggle and the user can opt to manually calibrate.
- Focus control: manual calibration allows the user to set and confirm the optimal focus per lane, ensuring data is acquired with optimal focus for all lanes.
- If an automated system calibration fails for any reason (including not enough signal detected at the autofocus position, or failure to optimize the illumination angle), the user will be prompted to create a manual calibration. In this case, the Manual System Calibration icon will be highlighted in yellow, indicating that the system is recommending the user to inspect their sample and manually calibrate.
When creating a manual calibration, the user can easily follow which step of the workflow they were on by looking for the icon with an upper outline in yellow.
Once the manual calibration is saved and being used for the experiment, the manual calibration page will appear with a green underline, reminding the user that they are using a manual calibration.
While the Manual System Calibration allows the user to manually find and optimize these values and save them for use during automated acquisition, the automated System Calibration step performs several automated routines to find the optimal focus and illumination angle. Read the “Creating an experiment calibration” section below for more details.
What is an Experiment Calibration
The Experiment Calibration contains information about the specific system and ONI Assay Chip
to ensure focus and illumination are optimized for automated imaging:
-
The stage z position where ONI 4-Lane Assay Chip is in focus and the z-lock is set.
Since the stage and the objective are not perfectly perpendicular, it is common to have
a small shift in this position across lanes. -
The z-lock offset for each lane. While most chips will have the same z-offset for each lane,
it is possible that certain systems or chips require a per-lane offset from the focus reference.
This is the same as the z-offset set for a lane during the “refine focus” step of sample pre-check. - The illumination angle (also called the TIRF angle) that will be used for the acquisition.
Note
The experiment calibration that is created is local to the current workflow and is not shared across different experiments. A calibration must be created for each instance of AutoEV independently to ensure accurate automated acquisition.
Creating an Experiment Calibration
To create an experiment calibration:
- Position the stage such that a lane is over the objective
- If starting a manual calibration from scratch, note that the sample stage will be at (0,0,0), in between lanes 2 and 3. To properly focus, move to a lane where particles and a strong fluorescence signal are expected (such as a positive control lane). Choose a lane from the Experiment Calibration [1] and click the target icon [2] to move that lane.
- If starting after an incomplete automated system calibration, the sample will be positioned in the lane chosen for calibration.
- Find the focus of the particle surface
- Use “Scan for Surfaces” [3] to detect all the potential surfaces at the current (x,y) stage position. This scans the stage in the Z direction and uses an internal focus camera to detect surfaces where there is a strong refractive index difference. Optionally, turn on an imaging laser [4] to observe the focus sweep on the live camera view to help see the best focus position during the scan.
- Detected surfaces appear as purple dots along the focus indicator graph.
- Click on any of the detected surfaces (purple dots) to move the stage to that position
- It is common to have multiple (at least 2) surfaces from an ONI 4-Lane Assay Chip.
- Generally, the particle surface is the top-most surface.
- Turn on an imaging laser [4] to observe the fluorescence from the particles on the surface.
- Refine the focus [5] until the sample is in focus. Use the Up/Down arrows in the Stage Control widget. Use the W/S keys on the keyboard.
- If necessary, move to a new FOV using the up/down/left/right FOV buttons [6].
- Calibrate the Z-lock [7]
- When the sample is in focus, click the “Calibrate” button to calibrate the z-lock. This sweeps the stage in the z-direction and creates a calibration of the focus camera signal, which is used to maintain the z-position over time.
- If the calibration is successful, the z-lock will automatically engage (the lock icon will turn blue).
- Create the Experiment Calibration [8]
- Select the slide type being used for calibration. In general this will be the EV 4-lane Assay Chip.
- Set the illumination angle for the experiment
- With an imaging laser on, use the illumination angle slider to find the optimal angle for particle imaging. This is generally near the TIRF zone, in the 45–55° range for an Aplo Scope.
- Once the optimal angle has been determined, click the “Set TIRF angle” button to save it to the calibration.
- Set the focus reference and offset for each lane
- Click on Lane 1.
- Click on the target icon to move to Lane 1. While the stage is moving, the laser and z-lock are both off.
- Wait until the stage has reached Lane 1. Once the stage has arrived at its position, the laser will turn on and the z-lock will engage. This can take several seconds. Wait for the system to complete these tasks.
- If the z-lock cannot be re-engaged after moving to the designated lane, an error message will appear.
- This is likely due to a bubble being present in the lane
- If this occurs, use the Up/Down/Left/Right FOV buttons to scan the stage until the imaging area is outside of the bubble.
- The best practice is to turn off the laser during this process
- Once in a good FOV, click the lock button to re-engage the z-lock. It is OK if it is slightly out of focus.
- Use the up/down arrows in the experiment calibration widget to refine the focus until it is optimal for the designated lane.
- Click “Set Lane Z-Offset” to set the z-offset for this lane to the experiment calibration
- Repeat this process for all lanes. Note that a z-offset must be set for each lane
- Save the experiment calibration.
- Once the TIRF angle and z-offsets for each lane have been set, the “Save & Return to Experiment” button will turn blue.
- Click this button to save the calibration and use it for the active experiment.
Important
The “Save & Return to Experiment” button will be enabled once the TIRF angle and the z-offset for all 4 lanes have been set. This button must be clicked in order for the AutoEV experiment to use manual calibration.
- Continue to sample check, select FOVs, and imaging
- The AutoEV experiment will now use the values manually set during Manual System Calibration.
- The automated acquisition will now use the manually defined TIRF angle and apply the z-offset specified for each lane while imaging FOVs in the corresponding lane.
Optionally Setting the laser powers for optimal blinking
In some cases, it might be necessary to manually adjust the laser powers to ensure the sample is blinking correctly.
Manual System Calibration makes this process very simple:
- Once focus and TIRF angle have been optimized, turn on one of the lasers that will be used for imaging and adjust the power until optimal blinking is achieved for that fluorophore. This will depend on the fluorophore, sample type and labeling density. Contact ONI support for more information on how to determine the optimal power.
- Click the “Set laser powers” button, which will now indicate the active laser wavelength and power. This will save the currently active laser power to be used for all lanes of the current experiment.
- Repeat this for each laser that will be used for the experiment.
- When returning to the Experiment Setup page, note that the laser power for all lanes has been updated.
Optionally Setting Global System Settings [9]
Manual System Calibration can be used to set the “Acquisition Settings” from the System Info page with the correct values based on the current sample on the microscope.
- Starting focus position for autofocus used in channel mapping, automated system calibration, and automated acquisition
- Laser powers used during the automated system calibration step
- Manual TIRF angle
Best practice for using these quick actions is (with a 4-lane Assay Chip on Aplo Scope):
- Find the focus of the selected slide type using the focus controls, and calibrating and engaging the z-lock [1]. Click “Set as initial focus for ONI 4-lane Assay Chip” to save the current stage z-position as the global default initial position when using autofocus in the system calibration, sample check and automated FOV acquisition.
- Find the lowest laser power where fluorescence with a good signal to noise can still easily be detected, and where the sample is not blinking. This may be anywhere from 3% to 25%, depending on the laser and the system. Click the “Set as laser power for calibration” to save this power as the power used for the autofocus and autoTIRF during automated system calibration.
- With the laser set to a typical power used for data acquisition (generally around 50%), use the illumination angle slider to find an angle where the sample has the highest signal to noise ratio.
- Click the “Set as manual TIRF angle” to save this as the default manual TIRF angle. Note this does not set the system to manual TIRF mode. To do so, navigate to the system info page and swap from “auto” TIRF mode to manual.
Appendix II: Viewing AutoEV Datasets in CODI
Once the acquisition of an FOV is completed, the dataset will be uploaded to CODI and the selected analysis will begin. Once the upload is complete, clicking on “View Dataset” will open the dataset with CODI visualization and analysis interface. The dataset info page contains all the information about the dataset, including:
[1] Export raw localizations as a CSV
[2] Channels acquired: Name, Type (SMLM) and number of localizations displayed
[3] Stage Z position at focus
[4] Z-offset
[5] TIRF angle
[6] Camera Pixel size
[7] Stop analysis button
It can be helpful to quickly inspect these values to ensure they’re coherent and consistent across acquisitions. For example, while the number of localizations per channel will vary based on EV concentration and staining, it should generally be similar for the FOVs in the same lane.
Notably, if the number of localizations is very low for a channel where there is expected to be a strong signal, that might be indicative of an issue during the data acquisition.
Appendix III: Guide to Channel Mapping
AutoEV makes channel mapping simple to run by automating the entire process. First, it finds the best focus of the bead slide using the 638 laser with 673/35 filter. Next, it optimizes the laser powers for each of the channels to be mapped. This process slowly increases the laser power from 0% until the beads have a sufficient signal to noise ratio. On Aplo Scope, thanks to dedicated emission filters for each channel, laser powers are slightly increased over the minimum required power to achieve a better signal to noise ratio and higher quality mapping.
Once laser powers are optimized, the bead slide will be scanned in (X,Y) to ensure appropriate sampling of the entire field of view to create an accurate mapping between channels. During channel mapping, 10 imaging frames are acquired with 100 ms exposure time for each of the 3 illumination channels. Localizations from each channel are used to create a channel pairing matrix between all illumination channels (638-561 channels; 638-488 channels; 488-561 channels). For each pair of channels, only points that are stable across 10 frames and consistently match the respective point in the other channel are kept. The stage moves to a new FOV and continues to acquire images until at least 1000 localization pairs are found for each channel pair. These pairs of points are used to create a mapping transform which is used to ensure that all data across all channels is aligned with nanometer precision.
Key Tip
If channel mapping is proceeding very slowly (only a few localization pairs are found per FOV), it is recommended to make a new bead calibration slide. The 488 nm fluorophores may lose fluorescence intensity more quickly than the fluorophores in the other channels.
Appendix IV: Guide to the EV Profiling Analysis App
EV Profiling analysis
The datasets acquired with the AutoEV app can be analyzed using the EV Profiling analysis app, an automated, step-by-step, analysis workflow for EV characterization, consisting of EV counts, size and positivity. For each single EV the information on size and biomarker positivity can be obtained.
The workflow consists of several steps: [1] Drift correction, [2] Filtering, [3] machine learning (ML)-based clustering tool and [4] Counting tool, which are applied sequentially to the datasets.
Each tool can be run individually by pressing the play button on the widget, or the entire workflow can be run in a single click by clicking the play button at the bottom of the workflow steps.
The entire analysis varies based on the number of localizations in the dataset, but generally takes around 5 minutes for typical acquisitions.
Drift correction
AutoEV app allows users to sequentially image 647, 561 and 488 channels, for a total of around 2 minutes per single field of view. During this time, the sample can drift in the order of a few tens of nanometers due to temperature change or physical sample movement. ONI’s drift correction algorithm allows correction for this.
Drift Correction Procedure
A standard Drift Correction at Minimum Entropy (DME) algorithm is applied to all the SMLM channels, with the last frame used as reference (see CODI user guide for more information).
Filtering
Each SMLM localization is characterized by sigma, precision and p-value. Minimum and maximum thresholds for these characteristics were optimized based on positive controls and negative controls. The analysis apps automatically filter out localizations that don’t meet these optimized thresholds as they are identified as noise.
These filters were very carefully defined for each of the EV Profiler 2 kit variants and acquisition on the Aplo Scope to ensure the best quality results of the entire EV Profiling analysis tool. Notably, strict filters are applied to the frame range (where the first 50 frames of each channel are removed while the sample begins to blink) and the localization precision to ensure noisy localizations are removed from the analysis.
Machine Learning (ML)-based clustering tool
Clustering is applied to identify small and large EVs, as well as single EVs and aggregates. The clustering is performed on all channels acquired.
EVs are detected and segmented using an AI-based model, specifically a neural network vision model. Unlike algorithms like DBSCAN, which requires users to input multiple parameters, this is a one-click model with no parameters to fine-tune. Additional advantages of this model include:
- Flexibility: in accommodating different EVs types, size and morphology
- Speed: fast time from acquisition to answer
Once clusters are detected, any object that has less than 3 locs per EV localizations and a diameter that is less than 35 nm will be discarded as considered background noise. These filters can be changed by going to the back of the clustering widget (three dots, top right).
The ML model was trained using a combination of simulated data and real acquired EVs data with a variety of background noise levels. The model was validated over multiple independent EV datasets and it detects more than 95% of clusters. The clustering tool has a run time of approximately 2 minutes for a 110 µm x 110 µm FOV.
Model output
The clustering tool segments localizations into clusters [1] and noise [2]. The segmentation is displayed to the user via colour coded points in CODI. The properties of the identified clusters including size, number of localizations, and geometry are recorded, displayed in the single cluster widget [4] and as a population level summary in the AI EV Profiling workflow widget [3].
Note: the diameter [4] is based on the calculation of a circle with the convex hull area extracted from a single EV.
Counting tool
The counting tool is the last step of the EV Profiling analysis app, and is used to count the number of localizations across all channels for each cluster so that each individual EV can be assigned a biomarker positivity (single, double, or triple positive).
The counting tool works by counting the number of localizations in each channel in a specified radius around the center of the cluster. The user must define the size of this counting radius, which should generally be set to based on the largest expected EV size in the sample. For highly dense samples, it may be necessary to reduce the counting radius to ensure that the counted localizations pertain to each individual cluster (and not count localizations from adjacent clusters).
Biomarker positivity thresholds can be defined in the counting tool directly in the interface, by specifying a minimum and maximum number of localizations required for a cluster to be considered positive for the biomarker in that channel.
Generating EV montage from single dataset
A montage of representative images of the EVs in the dataset can be generated directly
from the Counting tool page.
- Select Generate montage [1].
-
Select the number of clusters per positivity group [2]. For a single dataset and 50 clusters
per positivity group, this should take about 2 minutes. - Select the output file format [2].
- Click Generate montage.
-
A montage preview will appear. To generate a montage with new random clusters,
click Generate montage again. - Downloading the montage [3] will automatically save it in the computer’s Downloads folder.
Batch Report and generating a report from CODI analysis
If the EV report was not generated at the end of an acquisition in the AutoEV app (summary page),
it can be done at any time in CODI using the “batch report” feature, which provides a report for a single chip with up to 4 lanes.
To do that, navigate to the CODI collaboration in which the data is saved and perform the following:
- Click the Analysis Results button to view all the analysis result in this collaboration
- Click on the “Cross Dataset Report” button
- Select the EV Profiling analysis App, and the settings used during the acquisition.
Note: If the user chooses to re-analyze the data acquired from AutoEV with different analysis settings,
all of the datasets must be batch analyzed with the same analysis settings to be included in the report. - Select the datasets from one chip (one dataset corresponds to one FOV) to be featured in the report and click “Generate Report”.
Note: The EV batch report is for a single chip and up to 4 lanes, i.e., it is not possible to generate a single analysis report for datasets acquired from different chips. Additionally, CODI does not support analyses and reports across different chips. To generate cross-chips reports, ONI provides EVP2 Axis, an offline python-based code tool. For more information on the EVP2 Axis, visit the ONI EVP2 Axis webpage.
Key Tip
Report generation only works for data generated from AutoEV, which contains the proper key/value tags to ensure that the report is calculated and displayed correctly. If an error message appears during the report generation process, it is likely because the datasets do not contain the proper tags, such as the “Lane” and “FOV” Key/Value tags.
Appendix V: System Info App
System Info is an app that provides the status of the microscope in real time and where users can control settings for calibration. It is accessed by clicking on the temperature icon in the top right corner of CODI, or by going to “Acquisition apps”.
Temperature widget
The temperature widget allows setting the Aplo Scope temperature and starting or stopping heating, as explained in the “setting a default Aplo Scope temperature”.
Acquisition settings widget
The acquisition settings widget allows adjusting of some settings for the automated algorithms.
- Set the starting point for finding focus when doing channel mapping (beads slide) or during sample pre-check calibration (4-lane Assay Chip). It is recommended to set these values based on the ONI bead slide (“beads”) and a 4-lane EV Profiler Assay Chip (“EVs”).
- Set a fixed TIRF angle by clicking the Auto button to switch to a manual TIRF angle. Proceed to type the optimal value and click Save Settings.
- Adjust the default laser power values for system calibration. System calibration may fail if the sample is bleached during autofocus or autoTIRF. Reduce the default values to 5-15% to prevent the sample from bleaching during these automated calibration steps.
Remember to click Save Settings once modified. Settings can always be reset to default.
Note: These settings are stored in the local storage of the web browser, and will reset to defaults when using a different browser profile or delete browser caches. Double check these values prior to running any experiment.
Dataset upload status
To obtain insights into the EV sample, data acquired on AutoEV has to be analyzed on ONI’s cloud-based software, CODI. The raw imaging data is first saved locally on the C drive on the Aplo Scope laptop and is then uploaded to CODI. Upload is automatic, but it requires a stable internet connection and for CSA to be open.
Since AutoEV is a CSA app, uploading to CODI will commence immediately after data acquisition, as long as the laptop is connected to the internet. If upload is not completed, it will begin automatically next time the AutoEV is opened on CSA as long as an internet connection is available. In the Aplo Scope App, the dataset upload status widget displays information about the upload progress. This widget will show how many datasets are in the upload queue, as well as important information if that queue is stalled, for example, if the internet connection is unreliable or unavailable.
Key Tip
The CODI System App must be open for uploads to succeed. If stalled, and the internet connection is stable, closing and re-opening the CODI System App to re-initiate the upload queue is recommended.
Reporting bugs or requesting new features
Please refer to the AutoEV and AutoLNP Troubleshooting page on the ONI Service Desk for common issues and workarounds.
Use the ONI Service desk to submit bug reports or any feature requests, using the AutoEV category. To ensure that the ONI team can properly address any bugs reported, we kindly ask that the latest “experiment_server*.log” and “hal*.log” logs are provided. These are located in the following directory: C:\Users\ONI\AppData\Local\ONI\OHM
Video Tutorials
Sample Preparation
Follow along with our ONI team to learn each step of the sample preparation process for the ONI EV Profiler 2 Application Kit.
AutoEV in CODI
Follow along with our ONI team to learn tips and tricks for AutoEV in CODI.