MACS Matchmaker
Maintenance
Regular maintenance of the MACS Matchmaker ensures optimal performance and longevity of the instrument. A cleaning of the MACS Matchmaker and MACS Sampler is recommended after working with complex media such as blood or cell lysate. Furthermore, we recommend to perform a cleaning of the fluidics system at least once a month. Cleaning solutions and maintenance cartridges can be ordered from the Lino Biotech webshop. The following maintenance procedures are recommended:
- Fluidic System Cleaning: Requires cleaning using MACS Matchmaker cleaning solutions (Clean 1 and Clean 2) and the maintenance cartridge. Follow the cleaning protocol in the MACS Matchmaker software in the Liquid Handler under "Clean Fluidic System". This should be performed after each run with complex samples and at least once a month. When the fluidic system has been in use for a week since its last cleaning, MACS Matchmaker reminds you to run Clean Fluidic System. The Liquid Handler page also shows when Clean Fluidic System last ran and how many times it ran in the last 3 months.
- Rinsing After Each Use: Flush the fluidics system with ultrapure water by running the rinsing protocol in the MACS Matchmaker software in the Liquid Handler under "Flush Fluidic System" to remove residuals from previous samples. When the fluidic lines have been idle for several hours after an experiment, MACS Matchmaker reminds you to run Flush Fluidics. The Liquid Handler page also shows when Flush Fluidics last ran and how many times it ran in the last 30 days. If a dedicated wash port is configured on the pump distribution valve (in the pump configuration), MACS Matchmaker instead flushes the fluidics automatically after every experiment that ran injections, drawing washing solution from the wash port; the manual reminder is not shown after such a wash. An experiment without injections leaves the fluidics clean, so it is not washed automatically and the manual reminder still applies.
- Short-term Storage (Up to 24 hours): Perform rinsing procedure using the maintenance cartridge and ultrapure water.
- Long-term Storage: Decontaminate the instrument, then run 20% ethanol through the system.
- Surface Cleaning: Outer surfaces can be disinfected using 70% isopropanol or 70% ethanol.
Most of what follows is fluidics, so it helps to have the path in mind — and in particular where one instrument's ends and the other's begins, since a symptom seen at the chip often has its cause upstream of the injection point.
Routine Operating Checklist
Beyond the scheduled cleaning above, a few checks before and after each experiment keep the fluidics reliable and protect the syringe and tubing between runs.
The flow rates, durations and intervals given here and in the schedule below are the recommended starting procedure for a MACS Matchmaker with a MACS Sampler, not a qualified SOP. Where your site operates under its own validated maintenance procedure, that one governs.
Before each experiment
- Confirm the MACS Sampler wash bottle is filled with ultrapure water. An empty bottle lets air into the syringe and buffer line, a common cause of no response during the association phase.
- Check that the MACS Sampler syringe is free of air bubbles before starting, to avoid injecting air during the assay.
- Verify the MACS Sampler waste tubing has no kinks and drains freely into the waste bottle, so condensate and wash media do not collect underneath the instrument.
- Confirm the running buffer is fresh and free of flakes or other visible contamination.
- Check that the running buffer and the sample are compatible. Incompatible combinations can precipitate or gel and clog the tubing — for example, a multivalent analyte cross-linking with its binding partner into large immune complexes, or divalent cations in the sample reacting with a phosphate-based buffer. Verify compatibility before running samples that may coagulate.
- With the fluidic head open, flush each channel you will use and confirm that buffer runs out. Blocked tubing causes overpressure and leakage onto the stage.
- For runs that continue overnight, add a holding phase at a low flow rate (6 µL/min) until the next morning to keep buffer moving and prevent salt crystallization in the tubing.
At the end of each experiment
- Return the running buffer to 4 °C and replace it with ultrapure water at the instrument. Buffer that has stood at room temperature goes back to the fridge or into the waste — never onto the instrument for the next run.
- Flush the MACS Sampler syringe three times with ultrapure water, then run buffer for 5 min at 1000 µL/min to clear salt from the syringe and tubing.
- Remove the chip, rinse it, dry it, and store it at 4 °C.
- Mount the maintenance chamber and push in the fluidic head. This protects the flow path and signals to other users that the instrument is free.
- After complex samples, run the full cleaning protocol (Clean 1 and Clean 2) with the maintenance chamber before the next experiment, as described in the schedule below.
Maintenance Schedule
| Frequency | Task | Details |
|---|---|---|
| After each use | Flush fluidics | Run the "Flush Fluidic System" protocol with ultrapure water to remove sample residuals. |
| After complex samples | Full cleaning | Run the cleaning protocol with Clean 1 and Clean 2 using the maintenance cartridge after blood, serum, plasma, or cell lysate. |
| Weekly | Inspect consumables | Check MilliQ wash bottle level, waste bottle fill level, and running buffer supply. Replace or refill as needed. |
| Weekly | Syringe pump cleaning | Clean the MACS Matchmaker syringe pump: insert the maintenance cartridge, then flush with ultrapure water (Reset + Fill syringe + Run flow rate at 1000 µL/min for 2 min). |
| Weekly | Wipe sampler surfaces | Wipe the MACS Sampler buffer syringe and the buffer platform with ultrapure water to prevent salt crystallization. |
| Monthly | Preventive fluidic cleaning | Perform full cleaning protocol (Clean 1 and Clean 2) even if only simple buffer samples were used, to prevent buildup. |
| Monthly | Inspect tubing and connections | Check for wear, discoloration, or loose fittings on all fluidic connections. Replace tubing if degradation is visible. |
| Monthly | Tighten fluidic fittings | Finger-tighten the MACS Sampler syringe fittings at all three connection points and the nut on the needle assembly, to prevent air bubbles during sample aspiration and injection. |
| Monthly | Tighten module syringes | Tighten the syringe in the liquid handler module (to the left of the MACS Matchmaker) and the syringe in the MACS Sampler (on its left), to prevent leaks and air ingress during operation. |
| Monthly | Wipe instrument surfaces | Wipe the MACS Matchmaker and MACS Sampler with a paper towel dampened with 70% isopropanol. |
Cleaning Verification
After running a cleaning protocol, verify that the system is clean before starting the next experiment:
- Baseline stability: Run buffer for 5 minutes and verify that the baseline signal is flat and stable (drift < 0.5 pg/mm² over 5 min). Excessive drift may indicate residual contamination.
- Blank injection: Perform a blank buffer injection and confirm that no signal response is observed. A response during a blank indicates incomplete removal of previous analyte.
- Visual check: Use the surface camera to inspect the chip area for visible residue, particles, or air bubbles trapped in the flow path.
- If verification fails: Repeat the cleaning protocol. If the issue persists after two cleaning cycles, run the full cleaning protocol (Clean 1 and Clean 2).
Chemical and Material Compatibility
Ensure that all chemicals and materials used with the MACS Matchmaker are compatible to avoid damage and ensure optimal performance. Verify compatibility of all cleaning and regeneration solutions with:
- Flow cell materials (PDMS, PEEK, glass).
- Tubing and seals (PTFE, FFKM, silicone).
- Sensor chips and mologram surfaces.
- External surfaces (especially under BSL-2 cleaning requirements)
Recommended cleaners: ethanol, mild surfactants, or specific biosafety-approved agents. Avoid strong oxidizers unless validated.
Troubleshooting
| Issue | Likely cause | Recommended action |
|---|---|---|
| No fluid flow | Pump not primed, air in line, or blocked tubing | Prime the pump, inspect tubing for kinks or blockages, run maintenance chamber with ultrapure water using the flush fluidics option in the liquid handler |
| Intermittent or unstable flow | Loose MACS sampler tubing or pump slip | Tighten tubing in the MACS sampler, verify pump mounting and tightness and flush pump syringe with ultrapure water. |
| Air bubbles in line | Incomplete priming or permeable/loose connections | Re-prime system with ultrapure water, check connectors |
| High backpressure or flow restriction | Clogged flow chamber or tubing or debris in lines | Stop run, flush with the MACS Matchmaker cleaning solutions (Clean 1 and Clean 2), inspect/replace flow chamber |
| Fluidics locked out after an overpressure | The pressure reached 10 bar, so the instrument stopped the pump and refused further fluid movement | Find and clear the restriction (flow chamber, tubing, MACS sampler), then press Reset Pressure Monitor under Pump on the Liquid Handler page. The lockout stays until you reset it, even once the pressure has fallen back |
| Measurement stopped with a pump message | The pump refused a movement, could not finish one, stopped answering, or lost the syringe home position | Follow the message, which names what to check for that failure. Where it asks for Init, press Init on the pump panel and check that the plunger moves freely. Start the measurement again, and contact lino Biotech Support if the same message returns |
| Contamination or carryover | Insufficient cleaning after complex samples | Run the full cleaning protocol (Clean 1 and Clean 2); for long-term storage run 20% ethanol |
| Poor assay performance / low yield | Incorrect buffers, pH drift or degraded reagents | Verify buffer composition and pH, replace expired reagents, rerun control sample |
| Signal Drift | Flow instability, contamination | Equalize flow rates, allow equilibration, clean the MACS sampler and MACS Matchmaker fluidics with cleaning solutions |
| Cannot couple | Coupling not found on Prepare Reader | Escalate through the coupling procedure: prime the chip, retry on Prepare Reader, then try the more detailed coupling on the Instrument Operation page, and finally couple manually via System Control. See Chip Coupling. |
| Weak Focus | Poor coupling or optical misalignment | Check focus alignment and adjust manually |
| High Noise | Poor coupling, poor or no backfilling | Improve coupling by repeating Prepare reader or manual adjustment, use backfilling |
| Unrecognized molograms | Software recognition issue | Verify pattern alignment and coupling, repeat Prepare reader |
| Air Bubbles on the Chip | Bubble present in the MACS sampler syringe or in the samples | Verify that MACS sampler buffer bottle has sufficient volume, prime system 5 times with MQ, if still present, prime system 3x with IPA and 5x with MQ |
| Sample not Injected | Bubble present in the MACS sampler syringe or MACS Sampler pump water empty | Verify that MACS sampler pump bottle has sufficient volume, prime system 5 times with MQ, if still present, prime system 3x with IPA and 5x with MQ |
| Fluid Leakage from the Fluidic Head | Damaged flow chamber, improperly mounted or clogged flow chamber | Remove and inspect the flow chamber for damage, replace if necessary, remount the flow chamber ensuring proper alignment. Clean the spilled area with ultrapure water. |
| Bubbles while sample injected | Not sufficient dead volume | Adjust dead volume in the vials/well plate |
| No response during association phase | Autosampler wash bottle empty or low on MilliQ — an air plug forms in the syringe and buffer tubing, preventing sample aspiration | Refill the wash bottle with fresh MilliQ. Purge the syringe and buffer tubing until all air is removed. Verify proper aspiration before resuming measurements. |
| No response during association phase | Injection valve blocked — wash bottle is filled but sample still cannot be aspirated, syringe plunger meets abnormal resistance | Do not attempt to clear the blockage yourself. Contact lino Biotech Support for assistance. |
Assay-Level Troubleshooting
The following issues are related to assay performance rather than instrument hardware:
| Issue | Possible cause | Recommended action |
|---|---|---|
| High baseline drift | Incomplete passivation or backfilling, temperature fluctuations, or buffer mismatch | Verify passivation or backfilling step was completed. Allow instrument to equilibrate for 15 min. Ensure running buffer and sample buffer are identical. |
| Non-specific binding (control molograms show signal) | Insufficient backfilling, analyte aggregation, or surface contamination | Increase backfilling level to match frontfilling. Centrifuge or filter the analyte. Check for affinity-matched backfilling. |
| Incomplete regeneration | Regeneration conditions too mild, very slow koff, or surface fouling | Try stronger regeneration (e.g., 3 M GuHCl + 125 mM NaOH). Extend regeneration time. If fouling persists, retire the assay surface; trypsin is only a terminal cleaning step because it also digests the immobilized proteins. Verify regeneration efficiency by checking baseline return (> 95% is good, < 80% is poor). |
| No binding response despite sample injection | Failed ligand immobilization, inactive analyte, wrong buffer conditions, or solubility issues | Verify immobilization by checking capture level. Test analyte activity with a known positive control. Check buffer pH and ionic strength. |
No Response During Association — Recommended Check Sequence
- Confirm the response is truly absent (not just low).
- Inspect the MilliQ wash bottle level. If low or empty, refill, purge air from the syringe and buffer tubing, and retry.
- If the bottle is sufficiently filled and the problem persists, suspect an injection valve blockage and contact lino Biotech Support.
Prevention: Check the MilliQ wash bottle level before each measurement session to prevent air ingress into the fluidic system.
Contact Support
If you are unable to resolve an issue using the steps above, contact lino Biotech Support at support@lino-biotech.com. What to Include lists the details that let support start on the problem.