A Polynorbornene-Based Microelectrode Array for Neural Interfacing

This paper reports the development of a mechanically-flexible microfabricated flat interface nerve electrode using polynorbornene (PNB) as the structural material. The device consists of two electrode arrays each fabricated on a photolithographically-defined PNB base with thin film Pt electrodes and a photolithographically patterned PNB capping layer. The two arrays are inserted into a silicone housing designed to create a flat interface between the electrodes and the nerve bundle. Electrical tests showed that the resistance of the Pt electrode interconnect traces are unaffected by flexing around a 1.8 mm radius. Electrical testing in phosphate-buffered saline (PBS) shows that resistance of the traces is about 3 kOmega. A 10 day leakage current test in PBS did not produce a detectable change in leakage current. These and other tests indicate that a PNB multilayer system may be viable for microfabricated electrodes.