Novel sensing signal mode constructed by dual responsive silence layer combined with catalytic hydrogen evolution

Abstract

For electrochemical assays, to obtain sensing signals, the redox of the modified electrochemical signal substance to provide a detectable signal is commonly required. However, during the process of assembly and sensing, the loss of signal substance caused by multiple steps of modification, incubation, and washing would lead to non-negligible fluctuation of signal and lack of reproducibility. To overcome this issue, a novel sensing signal mode without electrochemical signal substance was developed. By introducing electrochemical catalytic hydrogen evolution into the sensing scheme, and taking the overpotential as the detectable signal, the sensing system was constructed in the absence of electrochemical signal substance. As a proof of concept, the sensor was used to quantify squamous cell carcinoma antigen, a model analyte, and exhibited an excellent analytical performance with a wide linear range from 0.100 ng mL−1 to 100 ng mL−1 and a low detection limit of 52.4 fg mL−1. As envisioned, the sensor exhibited excellent long-term stability and reproducibility due to the avoidance of signal substance. This method provided a new way for the design of electrochemical sensors.