Fast and Single-step Fluorescence-based Competitive Bioassay Microdevice Combined PDMS Microchannel Arrays Separately Immobilizing Graphene Oxide–Analyte Conjugates and Fluorescently-labelled Receptor Proteins

Abstract

In this study, a fast and easy-to-use capillary-type microdevice for competitive bioassay is proposed. The device is composed of polydimethylsiloxane (PDMS) microchannel arrays that separately immobilize polyethylene glycol (PEG) coating, which contained graphene oxide (GO)–analyte conjugates and fluorescently-labelled receptor proteins. The working principle of the device involved the spontaneous dissolution of the PEG coating, subsequent mixing and reaction with analyte to give fluorescence response, triggered by the capillary action-mediated introduction of a sample solution. For principle verification, a competitive biotin assay was successfully demonstrated within 20 s in a single-step operation by detecting the change in fluorescence via microscopy.