Nanowire Transistor-Based Ultrasensitive Virus Detection with Reversible Surface Functionalization

We have applied a reusable silicon nanowire field-effect transistor (SiNW-FET) as a biosensor to conduct
ultrasensitive detection of H5N2 avian influenza virus (AIV) in very dilute solution. The reversible surface functionalization of SiNW-FET was made possible using a disulfide linker. In the surface functionalization, 3-mercaptopropyltrimethoxysilane (MPTMS) was first modified on the SiNW-FET (referred to as MPTMS/SiNW-FET), with subsequent dithiothreitol washing to reduce any possible disulfide bonding between the thiol groups of MPTMS. Subsequently, receptor molecules could be
immobilized on the MPTMS/SiNWFET by the formation of a disulfide bond. The success of the reversible surface functionalization was verified with fluorescence examination and electrical measurements. A surface topograph of the SiNW-FET biosensor modified
with a monoclonal antibody against H5N2 virus (referred to as mAbH5/ SiNW-FET) after detecting approximately 1017m H5N2 AIVs was scanned by atomic force microscopy to demonstrate that the SiNW-FET is capable of detecting very few H5N2 AIV particles.