Bimetallic AuAg-coated porous silicon nanowire platform for rapid SERS-based antibiotic susceptibility testing

Rapid antibiotic susceptibility testing (AST) is crucial for selecting appropriate antibiotic treatments and customizing empirical therapy to effectively manage serious bacterial infections. This study focuses on developing and characterizing surface-enhanced Raman scattering (SERS)-active nanostructured composite substrates designed for swift and highly sensitive bacterial detection, followed by accelerated AST. The substrates were fabricated by depositing noble metal nanoparticles (Au, Ag) onto porous silicon nanowires (pSiNWs) formed through metal-assisted chemical etching (MACE) of crystalline silicon. Scanning electron microscopy (SEM) images depict Listeria innocua bacteria localized in close proximity to AuAg nanoparticles atop pSiNWs. SERS spectra of L.innocua were acquired using a 633 nm laser beam, enabling rapid label-free bacterial detection. Comparisons with the traditional disk diffusion method show that the developed SERS approach allows for real-time monitoring of bacterial antibiotic susceptibility within 3 h, in contrast to the standard 24-h test duration. These findings underscore the potential of AuAg@pSiNWs substrates to expedite the AST process, offering a significant advantage in clinical diagnostics and antimicrobial resistance monitoring. • AuAg-coated porous silicon nanowires enable robust SERS-based bacterial detection • Label-free SERS spectra of L.innocua show reproducible species-specific fingerprints • AuAg@pSiNWs provide a sensitive SERS platform for label-free antibiotic susceptibility testing • SERS enables rapid AST in 3 h versus 24 h for standard assay