Characterization of functional biointerface on silicon nanowire MOSFET

Biointerface between biological organisms and electronic devices has attracted a lot of attention since a biocompatible and functional interface can revolutionize medical applications of bioelectronics. Here, we used 3-aminopropyl trimethoxysilane (APTMS) self-assembled monolayer (SAM) to modify the surface of nanowire-based metal-oxide-semiconductor field-effect transistors (NW-MOSFETs) for pH sensing and later creation of biointerface. Electrical measurement was utilized to first verify the sensing response of unmodified NW-MOSFETs and then examine pH sensing on APTMS modified NW-MOSFETs. A biointerface was then created by immobilizing polylysine, either poly-D-lysine (PDL) or poly-L-lysine (PLL), on APTMS modified NW-MOSFETs. This biointerface was characterized by electron spectroscopy for chemical analysis (ESCA), cell biocompatibility, and fluorescent images. The results of ESCA verified the amide bonding (CONH) between polylysine and APTMS modified surface. After PC12 cultured on polylysine-APTMS modified area, highly selective areas for cell growth were observed by fluorescent microscope. Analysis and improvement of selectively cell-growth biointerface on the NW-MOSFETs gave us an insight into future development of neuronal biosensors.