Facilely prepared low-density DNA monolayer–based electrochemical biosensor with high detection performance in human serum

Abstract

Presently, most reported electrochemical biosensors, for highly sensitive and selective detection of nucleic acid, still require multiple, time-consuming assembly steps and high-consumption DNA probes as well as lack good performance in human serum, which greatly limit their applicability. Herein, an easy-to-fabricate electrochemical DNA biosensor constructed by assembly of bovine serum albumin (BSA) followed with direct incubation of amplified products has been proposed. This method combined terminal deoxynucleoside transferase (TdTase)–mediated isothermal amplification and polyHRP catalysis to achieve dual-signal enhancement, and was featured with low-density DNA monolayer for its employment of only 2 nM capture probes. Surprisingly, based on the low-density DNA monolayer, the steric hindrance effect of polyHRP could effectively restrain the background compared with HRP, which further pushes the signal-to-noise (S/N) ratio to 70 than that of most currently available methods. Additionally, this strategy also showed favorable specificity and powerful anti-interference in human serum, and thus potentially attractive for diagnosis of diseases. [Figure not available: see fulltext.].