Application of a Thin-Film Transistor Array for Cellular-Resolution Electrophysiology and Electrochemistry

The constant development and improvement of microelectromechanical systems (MEMS) have been given a great opportunity to develop new reliable microsystems devices for biomedical research. This article presents a locally addressable 2-D arrayed indium-tin oxide microelectrode platform with integrated thin-film transistors (TFTs) for biological and chemical sensing. Microelectrode arrays (MEAs) using TFT have the advantage of being transparent with a high density of microelectrodes on a large surface. In vitro 2-D electrical measurements on 28 parallel-connected lines selected from a 22 500 MEA were successfully performed with heart cells for the first time. Observation of cell contraction was performed simultaneously with an inverted microscope. Voltammetry and amperometry measurements were also demonstrated using the transparent microelectrodes as working electrodes and an integrated Ag/AgCl reference electrode. Due to its unique features, we believe that the TFT platform can provide more understanding of the key communication between heart cells, and large-scale cardiovascular and nervous systems. As a result, the platform offers unique access to versatile lab-on-a-chip devices that integrate many measurement techniques on one chip for the study of cell cultures, tissues, and organoids.