Design of TMV-based Au@Au-Ag nanostructures for enhanced in-solution biosensing of SERS reporters

Gold-silver alloy nanoparticles (Au-Ag NPs) exhibit unique plasmonic properties due to their tunable composition and size, making them promising candidates for biosensing applications. In this study, we report the functionalization of mutated Tobacco mosaic virus (TMV-C) with core shell Au@Au-Ag alloy nanoparticles with different ratios of Au:Ag for surface-enhanced Raman spectroscopy (SERS) biosensing. The alloy composition and size of the nanoparticles were precisely controlled via seeded growth method, ensuring uniformity and reproducible optical properties. Using rhodamine 6G (Rh6G) as SERS reporter, nanohybrids grafted with Au-Ag nanoparticles onto TMV-C were characterised to achieve enhanced SERS activity. Our results demonstrate the potential of TMV-functionalized alloy nanoparticles as more efficient SERS platforms for biosensing applications. Furthermore, the enhanced SERS activity of nanohybrids was used for the detection of 4-mercaptobenzoic acid (4-MBA), and holds promise for the detection of cancer-related DNA biomarkers.