Thin Film Polycrystalline\nSilicon Nanowire Biosensors

Abstract

Polysilicon nanowire biosensors have been fabricated\nusing a top-down\nprocess and were used to determine the binding constant of two inflammatory\nbiomarkers. A very low cost nanofabrication process was developed,\nbased on simple and mature photolithography, thin film technology,\nand plasma etching, enabling an easy route to mass manufacture. Antibody-functionalized\nnanowire sensors were used to detect the proteins interleukin-8 (IL-8)\nand tumor necrosis factor-alpha (TNF-α) over a wide range of\nconcentrations, demonstrating excellent sensitivity and selectivity,\nexemplified by a detection sensitivity of 10 fM in the presence of\na 100 000-fold excess of a nontarget protein. Nanowire titration\ncurves gave antibody–antigen dissociation constants in good\nagreement with low-salt enzyme-linked immunosorbent assays (ELISAs).\nThis fabrication process produces high-quality nanowires that are\nsuitable for low-cost mass production, providing a realistic route\nto the realization of disposable nanoelectronic point-of-care (PoC)\ndevices.