A visible and near-infrared light dual-responsive PEC immunosensor for archaeological silk microtrace detection based on in situ growth of Ag2S on ZnO-MXene nanocomposites

Developing an effective analytical method for microtrace detection of ancient silk is highly desirable and vitally crucial for exploring the origin and spread of silk. Herein, a taxonomically specific anti-fibroin monoclonal antibody was prepared and an elaborate visible/near-infrared (vis/NIR) photoelectrochemical (PEC) immunosensor was proposed. The sensor employed Ag2S nanoparticles (NPs) grown in situ on ZnO nanowire array-MXene nanocomposites (ZnO-MX) via a sonochemical method as a photosensitive material. The experimental results illustrated that the ZnO-MX/Ag2S-based sensor presented 6.8 times larger PEC responses than a ZnO-MX-based sensor under visible light illumination, and the PEC signal of the ZnO-MX/Ag2S nanocomposites was 30 times as high as that of ZnO-MX under 808 nm NIR light, indicating enhanced photoelectric activity and a matched energy band structure of ZnO with MXene and Ag2S. This PEC immunosensor exhibited excellent potential for the ultrasensitive detection of Bombyx mori silk traces due to its wide linear range of 0.005–50 ng mL−1 and low detection limit of 1.51 pg mL−1. Additionally, the immunosensor showed outstanding specificity, stability, and repeatability, particularly for the qualitative detection of archeological artifacts. Given its aforementioned benefits, ZnO-MX/Ag2S nanocomposites are potentially attractive photoactive materials for use in vis/NIR PEC immunosensors. Moreover, this demonstrated method offers a feasible method to investigate the history and distribution of ancient silk.