Carbon Nanotube Electrode Coating

The carbon nanotube coating is mechanically stable, chemically inert, and completely biocompatible. The carbon nanotube coating significantly enhances the recording and stimulation capabilites of metal electrodes by decreasing electrode impedance and increasing charge transference, while leaving the cross-sectional area of the electrode surface unchaged. The carbon nanotube coating significantly decreases impedance while keeping the electrode tip size small, which enhances electrode selectivity and sensitivity.

Please contact Plexon at info@plexon.com if you interested in carbon nanotube electrode coating. 

Uncoated tungsten microelectrode	Carbon nanotube coated microelectrode	Magnified carbon nanotubes

Uncoated (Z=900 kOhm)

• Special patent-pending CNT coating process
• CNT coatings can be attached to most metal electrode surfaces (tungsten, platinum, iridium, etc
• Lowers impedance by factor of 25 while not changing the cross-sectional area of the electrode
• Dramatically improes signal-to-noise sensitivity in both the high-frequency spike band and the lower-frequency field potential band
• Adheres strongly to the metal substrate and is durable, CNT coating remains intact as electrode is pushed through monkey dura
• Increases charge transfer 45-fold for more efficient stimulation at lower voltages, resulting in less tissue and electrode damage from stimulation
• Lower RMS noise levels by 65% compared to gold-coated electrodes
• CNT coatings are chemically inert and biocompatible

23-fold reduction in impedance 45-fold increase in charge transfer

CNT coated electrodes record significantly more identifiable single units than uncoated tungsten (W) RMS noise of CNT coated electrodes is one third that of electrodes coated with gold

Recordings from identical tungsten stereotrodes, with and without CNT coating (125 um tip separation). Note the enhanced sensitivity of CNT-coated electrodes at both the high frequency spike frequency band and the lower frequency LFP band.

Histogram summarizing population action potential response to 400 sonseutive 750 mV electrical pulses given through gold-coated vs CNT- coated electrodes. The population spike response to CNT-mediated stimuli was 40 times larger than to gold-mediated simuli in this experiment.

Stimulus-response curve summarizing 7 separate experiments. CNT-coated electrodes lowered the threshold for eliciting at least one population response for each simulus by an average of 530 mV.

*Results from Keefer, E.W., Botterman, B.R., Romero, M.I., Rossi, A.F., and Gross,G.W. (2008) Carbon nanotube coating improves neuronal recordings. Nature Nanotechnology 3:434-439.