Quantitative monitoring of SARS-CoV-2 mediated by the intrinsic Raman signal of silicon nanoparticles and SiC@RP composite semiconductor SERS substrate

Non-metallic surface-enhanced Raman scattering (SERS) demonstrates an attractive potential in clinical immunoassay thanks to the brilliant biocompatibility and chemical enhancement of semiconductor substrates. Herein, SERS-based quantitative assay of SARS-CoV-2 in saliva was carried out by constructing SiC@RP nanotowers (NTs) and Si nanoparticles. Ascribed to the efficient light absorption and molecular enrichment capacity of the hierarchical tower morphology as well as the synergistic chemical enhancement in the semiconductor heterojunction, the SiC@RP NTs achieved a minimum limit of detection as 7.6 × 10-11 g/mL for SARS-CoV-2. Concurrently, the correction of the detection signal by the intrinsic Raman signal of Si nanoparticles drastically improved the stability and reliability of the detection, facilitating a relative standard deviation (RSD) data within ± 9.53%. Ultimately, the real-time SERS monitoring of saliva samples displayed an ultra-high response rate of no less than 83.2%. Such a non-metallic SERS immunoassay with high sensitivity and attractive reliability is expected to play a key role in future clinical monitoring application.