In–situ self–reduction preparation of Ti3C2Tx/Ag on flexible PMMA chip for quantitative detection of SARS–CoV–2

Surface enhanced Raman scattering (SERS) has proven to be of great superiority in the assay and prevention of infectious disease attributed to its rapid and specific fingerprint recognition ability toward trace molecules. However, it is still crucial to develop portable and precise chip for the reliable realization of on–site and large–scale screening. Here, a robust in–situ reduction strategy was employed to prepare Ti₃C₂T_x@Ag nanocomposites, which was installed on a polymethyl methacrylate (PMMA) matrix to construct a novel flexible SERS chip with self–rectification capability. The resulting Ti₃C₂T_x@Ag nanocomposites exhibited both electromagnetic and chemical enhancement effects, enabling high SERS activity. In particular, the as–developed SERS chip demonstrated fascinating signal reproducibility and quantitative detection capability by conducting the intrinsic Raman signal of PMMA as an internal standard. Furthermore, the PMMA–Ti₃C₂T_x@Ag chip facilitated the visualization of severe acute respiratory syndrome coronavirus 2 (SARS–CoV–2) nucleocapsid (N) with ultra–low limit of detection, stressing the potential application of this smart self–rectification SERS chip with high activity in real time and rapid monitoring of sudden infectious diseases.