A microscale electrochemical DNA biosensor based on sandwich structure and enzyme-mediated electrocatalysis for sensitive determination of hand, foot and mouth disease-related gene

Abstract

Considering the spatially and temporally rapid spread of hand, foot and mouth disease (HFMD) incidence, point-of-care testing (POCT) is in great demand for HFMD early diagnosis to prevent outbreak. Herein, a miniaturized gold microelectrode (Au-Me), as a promising alternative to the traditional electrode due to its own essence of high mass transfer, high current density and rapid response, was developed to construct a sensitive, accurate and rapid biosensor suitable for POCT. Specifically, a sandwich-type electrochemical deoxyribonucleic acid (DNA) biosensor based on Au-Me was constructed to sensitively determine HFMD-related gene. The binding capabilities of probes towards the target sequences were investigated by native PAGE and isothermal titration calorimetry (ITC). The detection limit of the biosensor was as low as 35 fM (S/N = 3). Interaction binding between capture/signal probes and the target DNA had an association constant (Ka) of ca. 1.1 × 109 M−1via ITC. This biosensor exhibited excellent specificity and anti-interference performance toward target DNA in complex serum milieu, demonstrating the potential utility in clinical POCT applications for HFMD.