In-situ dynamic reaction of Ag NPs: Strategy for the construction of a sensitive electrochemical chiral sensor

Abstract

A novel concept for the development of chiral sensor is proposed based on electrochemical phase transformation of silver nanoparticles (Ag NPs), which is shown for in situ photoelectric cooperative analysis mode. To demonstrate this, self-assembled Ag NPs on gold microelectrode (Ag-Au ME) serve as the sensing platform for chiral cysteine (D/L-Cys) detection. Through differences in the specific binding force, the system was validated with efficient synergistic electrochemical redox reactions and complexation of D/L-Cys with silver ions, and a novel sensing mode was developed based on the shift of oxidation peak potential of silver ions. In the proposed assay procedure, the simple principle of electrochemical phase transformation of Ag NPs, which can be monitored by electrochemical-surface enhanced Raman scattering (EC-SERS), was used as an in situ, rapid, dynamic analysis strategy for improving the detection sensitivity. Moreover, the proposed assay strategy with satisfactory sensitivity up to 74.88 μA μM−1 cm−2 was achieved, the limit of detection (LOD) is reduced to nanomolar level (8.7 nM) for D-Cys. Going beyond the conventional chiral biosensing, more importantly, the elaborate dynamic coupling of multiple mechanisms in a micro/nanoscale interface may provide a new approach for future highly sensitive biosensing.