4 min read
Updated September 24, 2025
A silicon probe fails for one of three reasons. Something dried on it, something touched the sites, or something pulled on the reference wire. All three are avoidable, and the window for the first one is minutes.
Research use only. NeuroNexus products and the procedures described here are for non-clinical research use, and must not be used in human or veterinary medical procedures.
Cleaning, in order#
The sequence matters more than any individual step. Alcohol before enzyme fixes protein onto the sites permanently.
1. Rinse, immediately#
Rinse in distilled water as soon as the probe is out of the tissue. Immerse and withdraw gently to dislodge loose material.
Do not let biological material dry on the probe. This is the single most consequential rule in the document. A probe rinsed within a minute usually recovers; one left until the end of the session often does not.
Use fresh distilled water each time.
2. Dissolve protein with an enzyme#
Tergazyme is the usual choice. A contact-lens cleaning solution or a diluted surgical-instrument detergent also works.
Immerse the shank only — keep the PCB dry. Soak at room temperature, up to four hours.
3. Rinse thoroughly#
Deionized water, with repeated immersion and withdrawal or gentle stirring, until no detergent remains. Inspect under magnification.
4. Then, and only then, alcohol#
70% isopropyl alcohol, brief contact.
Alcohol applied to a probe that still carries protein fixes that protein to the sites. The impedance change that follows is not reversible. Confirm step 2 has finished before this step begins.
Two things that destroy probes#
Never use an ultrasonic cleaner. Cavitation damages sites, substrate and bond wires. The damage is often invisible and shows up as an impedance change.
Never autoclave. Steam and pressure degrade polymer components and adhesives, and change electrical characteristics permanently. Use the alcohol step above for sterilization.
Ground and reference wires#
These wires are thin and flexible by design, so that they disturb as little tissue as possible. That same property makes them the most fragile part of the assembly.
A damaged ground or reference wire does not produce an obvious failure. It produces a noisy recording that looks like an environmental problem, and labs lose days to the wrong diagnosis.
Handling. Support the wire rather than the joint. No tension, no repeated bending, and as little manipulation as the procedure allows.
During experiments. Plan the routing before surgery. Use strain relief at every point where the wire crosses from one fixed thing to another.
During cleaning. Work on the shank. Do not manipulate the wire joints, and inspect them afterwards.
Storage#
Store in the original shipping box, in a clean, dry place at room temperature, away from temperature swings and humidity.
Keep connector covers on chronic packages — CM series, H series, and any long-term package. They prevent contamination and protect the connector mechanically.
Keep the probe's identification documents with the probe. The design name and channel map are what let you plan the next experiment; a probe with no paperwork is a probe you cannot cite.
Track condition over time#
Measure impedance before each use and compare to the value at first use. The trend is the signal — a steady rise means the site is degrading, a jump means something mechanical happened.
Inspect visually under magnification: shank straightness, site appearance, wire joints.
Log each cleaning cycle. Probes do not fail on a schedule. A probe with a long cleaning history and a rising impedance trend is one to retire before it costs an experiment.
When cleaning does not work#
Material remains after the enzyme step. Fresh solution, longer soak within the four-hour limit, then a soft brush used gently. If it persists, contact support rather than escalating the mechanical effort.
Impedance is higher after cleaning than before. Compare against the pre-cleaning values. A uniform rise across sites usually means residue; a rise on some sites usually means damage.
Support#
Technical questions: support@neuronexus.com · +1.734.913.8858