Micromachining techniques for realization of three-dimensional microelectrode arrays

Abstract

Cellular function and response has been a significant subject of human fascination since time immemorial and a major field of study that has improved understanding of the mechanics of the human body. Specifically the functioning of electrogenic or electrically active cells is of particular interest as these cells control several important physiological functions such as visualization, locomotion, and activities of key organs such as the brain, heart, eyes, ears, and spinal cord. Advances in both engineering (including microelectronics, signal processing, microelectronic and biomedical packaging techniques, and micromachining technologies) and biology (including electrophysiology, neuroscience, cardiology, etc.) have contributed toward a better understanding of this field by introducing instrumentation capable of interfacing with cells and tissue. This chapter summarizes the technological achievements in the development of one such instrument which has been fundamental toward electrical interfacing with biological constructs-three-dimensional microelectrode arrays (3-D MEAs), also called 3-D multielectrode arrays or 3-D micromachined probes. These electrode arrays are utilized in stimulating and recording applications both in vitro (outside the body) and in vivo (within the body) from neural tissue, neural cultures, neuromuscular tissue, cardiac tissue, cardiac cultures, 3-D cocultures of electrically active cells, stem cell cultures, and cultured networks of various electrically active cells (e.g., retinal cells).