The implanted electrode is one of the key elements in implantable neural stimulators.One challenge is to reduce the electrode impedance and minimize tissue inflammatory response.Based on the requirements of interface characteristics

the study investigated a layer-by-layer modification approach.The electrodes（d=75 μm） made from Platinum-Iridium（Pt-Ir） alloy wire were electrochemically modified with iridium oxides

and then a thin coating of poly（vinyl alcohol）/poly（acrylic acid）（PVA/PAA） was grafted onto the silicone rubber serving as the insulating and supportive material for the electrodes.These electrodes were implanted into the motor area of a rat’s cortex for a month.The electrode impedance was measured on the 21st day after implantation.The results show that the electrode impedance is reduced by 53% compared with the impedance of non-modified electrodes.The chronic experiment in vivo does not cause adverse effects

as suggested by behavioral assessment experiments.