Polycrystalline diamond-on-polymer microelectrode arrays for mechanically-flexible neural interfacing

Abstract

This paper reports the development of mechanically-flexible, polycrystalline diamond-on-polymer electrodes for use as neural interfaces. Boron-doped diamond has a number of properties that are attractive for use as electrodes in neural recording, stimulation, and electrochemical sensing. However, because the growth of polycrystalline diamond by chemical vapor deposition requires high temperatures (>800ºC), diamond thin films cannot be directly deposited on polymer substrates. To address this limitation, a transfer process was developed to incorporate diamond electrodes onto a polymer substrate. It was demonstrated that the diamond-on-polymer devices made using this transfer process retain the mechanical properties of the polymer. Electrical characterization showed that the diamond electrodes have an impedance of ~2-3 MΩ at 1 kHz. This and other tests indicate that the diamond-on-polymer electrodes have suitable characteristics for neural recording and stimulation.