Global Journal of Engineering, Design & Technology
Open Access

Microelectrode Arrays

Implantable microelectrode arrays (MEAs) offer the promise of restoring function to individuals with paralysis or amputation [1,2], of restoring vision to the blind [3,4], and of treating neurological diseases [5]. MEAs typically consist of microwire structures coated with polymeric encapsulation or silicon (Si) and thin-film polymer structures fabricated through methods common to the semiconductor device industry. While promising, neural signals recorded with these devices degrade over time and occasionally device failure is observed such that the reliability of this approach has been the subject of recent attention [6-8]. Most MEA devices are fabricated from some combination of noble metals/alloys, silicon, polymers (eg, parylene-C, silicones, polyimide), and conventional dielectric passivation (silicon oxide or silicon nitride). Silicon carbide (SiC) has emerged as a promising material for biomedical devices, which may convey advantages for MEAs. The purpose of this chapter is to discuss mechanisms involved in the degradation of MEA performance, the role of material choice in the tissue response, the biological response of neural tissue to amorphous silicon carbide (a-SiC) both in vitro and in vivo, and a-SiC as an encapsulant for MEA devices.