Poly[2-(dimethylamino)ethyl methacrylate]/gold nanoparticle composite dual-stripe nanowire arrays as optical biosensors for label-free plague diagnosis

Abstract

BackgroundMost commercial kit provides a meager limit of detection of 104 CFU/mL. Antigen determination remains an urgent need for further development of rapid, sensitive, and reliable diagnostic methods for use at the point of need. MethodsAmide-terminated silane, a water immiscible compound before hydrolysis, was evaporated for deposition on the alternative wetting and dewetting regions. The silane compound was hydrolyzed along the interfaces of wetting and dewetting regions to form a dual-stripe of an initiator after halogenation. Poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) was grafted from the dual-stripe of the initiator to attract gold nanoparticles (AuNPs) as AuNP-PDMAEMA composite dual-stripe nanowire (APDW) arrays via alternate phase transition cycles. The APDW arrays were modified with a Yersinia pestis (abY) antibody to detect the antigen of Yersinia pestis (agY) for plague diagnosis. Significant findingsThe binding of the agY onto the abY-anchored APDW array resulted in a geometrical change from a dual-stripe to a two-humped structure. The reflectance spectra could be used to analyze the AuNP attachment and the agY binding onto the abY-anchored APDW array. The linear range between the wavelength shift and agY concentration from 20 to 440 pg mL−1 was established to obtain the detection limit of ∼14.2 pg mL−1.