A Flexible a-SiC-Based Neural Interface Utilizing Pyrolyzed-Photoresist Film (C) Active Sites

Carbon containing materials, such as graphene, carbon-nanotubes (CNT), and graphene oxide, have gained prominence as possible electrodes in implantable neural interfaces due to their excellent conductive properties. While carbon is a promising electrochemical interface, many fabrication processes are difficult to perform, leading to issues with large scale device production and overall repeatability. Here we demonstrate that carbon electrodes and traces constructed from pyrolyzed-photoresist-film (PPF) when combined with amorphous silicon carbide (a-SiC) insulation could be fabricated with repeatable processes which use tools easily available in most semiconductor facilities. Directly forming PPF on a-SiC simplified the fabrication process which eliminates noble metal evaporation/sputtering and lift-off processes on small features. PPF electrodes in oxygenated phosphate buffered solution at pH 7.4 demonstrated excellent electrochemical charge storage capacity (CSC) of 14.16 C/cm2, an impedance of 24.8 ± 0.4 kΩ, and phase angle of −35.9 ± 0.6° at 1 kHz with a 1.9 kµm2 recording site area.

Realization and Characterization of Carbonic Layers on 4H-SiC for Electrochemical Detections

Carbon materials are considered building blocks for most of electrochemical sensors. Their biocompatibility allows their use as transducers for biosensors. Furthermore, they can be patterned, giving interest in all-inclusive bioelectrochemical detection devices. In particular, graphene, boron doped diamond, and pyrolyzed photoresist films are suitable for this kind of application, which would give the ability to use these working electrodes within a fully designed apparatus completed by counter and reference electrode. In this paper, a pioneer work is exposed on the synthesis of these materials for use as electrochemical sensors and as transducers for biodetection of acetylcholine by adsorption of acetylthiocholinesterase. The lowest limit of detection reaches 6.98 μM, sensitivity 5.91 μA/mM, and a linear range from 6.98 μM to 0.55 mM.