Conductive Hydrogels for Bioelectronic Interfaces

Abstract

Neural implants establish information exchange between electronics and tissues of the nervous system. Depending on the therapeutic context, they can be implanted in the brain, spinal cord, or peripheral nerves. Traditionally, implanted probes are made from stiff materials such as metals or silicon because of their favorable conductive and electrochemical properties. From a mechanical perspective, electrodes are very different from the soft and hydrated host tissues. This is implicated as a cause for suboptimal biointegration, especially when long-term implantation is required. Hydrogels have recently gained attention in bioelectronics, owing to their similarity with tissues in terms of mechanical properties, water content, and bioactivity. A number of approaches have been developed to improve their electrical properties and processability to make this class of material suitable for integration in electrode arrays. This chapter covers current development of conductive hydrogels for bioelectronic interfaces, including fabrication methods, common characterization techniques, strategy for patterning, and some examples of their applications.