Viral gene detection based on multifunctional microspheres and AgNPs coated substrate interface area SERS scheme

Surface-enhanced Raman spectroscopy (SERS) has emerged as an effective method for detecting viral genes in aqueous solutions. However, SERS has a low efficiency and poor reproducibility in multi-component aqueous solutions. Thus, developing a SERS scheme with stable hotspots generation, significant enhancement effects, and efficient viral gene enrichment remains a challenge. This study sought to proposes an enhanced hotspot generation scheme combining multifunctional microspheres and SERS substrates, which can achieve stable enhancement in the interface area. Multifunctional microspheres can be used to selectively enrich target biomolecules in aqueous solutions. Furthermore, simulation results show that these microspheres can synergistically form a stable enhancement area with SERS substrates. Finally, this scheme was used for immunocapture and Raman detection of hemagglutinin 7 (H7) and neuraminidase 9 (N9) specific gene in an aqueous solution containing multiple types of influenza viral genes. The relationship between the characteristic peaks and concentrations was analysed using two-dimensional correlation analysis. Spectral data analysis revealed an exceedingly high linear correlation between the selected characteristic peak intensity and concentrations. The calculation results show that the SERS enhancement factor of the proposed scheme for the H7 and N9 specific gene are 9.23×107 and 1.59×108, respectively. Notably, the detection limit of this scheme was 1 pM. Therefore, this scheme holds the promise to realize the detection of viral genes in heterogeneous, complex, and dynamic aqueous biological samples.