SnO2 nanowire bio-transistor for electrical DNA sensing

An innovative JFET bio-transistor, based on a metal oxide (MOX) nanowire bundle, was developed in order to electrically detect biological binding. The working principle of this device relies on modulation of a MOX space charge region (SCR), acting as the channel of a field effect transistor, instead of an enriched/depleted Si channel like in chem.-FETs. The feasibility was at first demonstrated by the development of a bio-sensor made of an SnO₂ thin film derivatized with oligodeoxyribonucleotide-probes. We implemented a protocol to immobilize single strands of nucleic acid over SnO₂ and developed a system for electrical sensing of hybridization in liquid solution. The same protocol was then applied on a SnO₂ nanowire bundle, synthesized by thermal evaporation of oxide powders under controlled conditions with the presence of Pt catalyst. The results obtained on a group of nanowires suggest the possibility -now under development -to produce nano-bio-transistors based on single nanowires of metal oxides.