Highly sensitive and rapid biosensing on a three-dimensional polymer platform

Abstract

Increasing sensitivity and decreasing assay time are two of the most crucial goals in the development of biosensing devices, such as immunoassays, protein electrophoresis, and bioimaging nanoprobes. We have developed three-dimensional (3D) nano/microstructured platforms for biosensing devices aimed at highly sensitive and rapid immunoassays. One such platform is a nanosphere structure with poly[2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate-co-p-nitrophenyloxycarbonyl poly(ethylene glycol) methacrylate] (PMBN) prepared by the electrospray deposition (ESD) method. Compared with flat PMBN, the 3D nanosphere surface enables the immobilization of a large amount of antibody to enhance the specific signal of the immunoassay. Furthermore, PMBN is resistant to non-specific protein adsorption. Thus, this 3D nanosphere structure can be applied in microchip environments, leading to highly sensitive and rapid immunoassays. To obtain a more rapid assay that takes at most 5 min, we utilized another platform: a 3D polystyrene (PS) microfiber structure prepared by ESD paired with vacuum pump pressurization to induce bulk flow. This system takes advantage of the increased amount of antibody immobilized on the 3D microfiber and the accelerated propagation of antigens through the microfiber induced by the vacuum pump to enable an efficient and rapid immunoassay.