The use of a double-layer platinum black-conducting polymer coating for improvement of neural recording and mitigation of photoelectric artifact

The impedance of electrode and photostimulation artifacts (short-duration and high-amplitude spikes) are still hindering the employment of silicon-based neural probe in optogenetics. A fiber-based optrode modified with a double-layer platinum black-poly (3,4ethylenedioxythiophene) PEDOT/poly (4-styrenesulfonate) PSS (Pt-PP) coating has been developed for improvement of neural recording quality and mitigation of photoelectric artifact simultaneously. The Pt-PP coating was made by layer-by-layer electrochemical deposition followed by the ultrasonication and Cyclic Voltammetry (CV) scanning to verify its mechanical and electrochemical stability. Both in-vitro and in-vivo experiments demonstrated that Pt-PP coated optrode had outstanding recording performance (high signal-to-noise ratio about 9.64) and low photoelectric amplitude (850 μV). The artifact recovery time of Pt-PP coated optrode (0.3 ms) after photostimulation was significantly decreased when compared to platinum black (6 ms) or PEDOT/PSS (0.7 ms) coated one which has potential to retain high-quality neural signals in animal experiments. At last, the optogenetics experiments revealed the capability of Pt-PP coated optrode to record the change in neural spike rate with certain spatial resolution and shorter artifact recovery time. These results suggest that Pt-PP coating has great potential for neural electrodes in the application of neuroscience.