Nanoscale interactions of <i>Salmonella typhimurium</i> on ZnO nanowires biosensing interfaces

Abstract The rapid and efficient detection of pathogenic bacteria is crucial for ensuring food safety and minimizing public health risks. In this study, the optical detection of Salmonella typhimurium was achieved using ZnO nanoplatforms biofunctionalized with antibodies as a bioreceptor. The ZnO nanowires were grown using a vapor–liquid–solid metal-catalyzed method, with a preferential orientation along the (002) plane as determined by x-ray diffraction, yielding homogeneous structures with a high surface-to-volume ratio. The synthesized nanostructures exhibit a strong 529 nm peak, attributed to deep-level emission, as confirmed by photoluminescence measurements. The presence of defect-related sites contributing to biofunctionalization was confirmed by Fourier transform infrared (FTIR) spectroscopy, where we also monitored surface modification and antibody immobilization. Bacterial cells produced discernible optical responses in FTIR spectra over the concentration range of 1 × 10 1 –1 × 10⁸ CFU ml −1 after 60 min of interaction with the biosensing nanoplatforms. Our results, along with scanning electron microscopy observations, provide spectral and morphological evidence of antigen–antibody binding and membrane attachment, confirming effective detection across different bacterial concentrations. This work highlights the potential of ZnO nanowires as a platform for the further development of low-cost, rapid, and sensitive biosensors for S. typhimurium detection, providing a reference for the appropriate management of biofunctionalized nanoplatforms and their preservation under buffer conditions, with promising applications across different sectors.