Nanowire integrated microelectrode arrays for lab-on-a-chip applications

Abstract

The monitoring of biological signals generated during nerve excitation and cell-to-cell communication are important for design and development of novel materials and methods for laboratory analysis. In-vitro biological applications such as drug screening and cell separation also require cell-based biosensors. The sensing technology is based on the optical or electrical read-out from the lab-on-a-chip. The electrophysiological activity of certain cells such as neurons and cardiac cells are monitored using planar microelectrode arrays integrated with microfluidic devices. One of the main issues of the current microelectrode array design is the difficulty in selective integration and the size dependency of its impedances along with a large amount of noise in the circuit due to this mismatch. It is quite evident that nanotechnology can solve these problems and an efficient electrical interconnection is possible using nanodevices. This paper presents the design and development of planar microelectrode arrays integrated with vertically aligned nanowires for lab-on-a-chip device applications. The higher surface area densities of such nanowire integrated microelectrode arrays show promising results in impedance control for the integration of lab-on-a-chip devices. We have fabricated microelectrode arrays on silicon and flexible polymer substrates and vertically aligned nanowires were fabricated onto it using template method. High degree of specific growth is obtained by controlling the nanowire growth parameters.