A novel bioinspired SERS platform for ultrasensitive bacterial detection

Typhimurium ( S. Typhimurium) is one of the greatest global concerns, as it causes zoonotic diseases. Human disease caused by the consumption of raw meat contaminated with S. Typhimurium are a major problem. Surface-enhanced Raman spectroscopy (SERS) has gained much attention as an ultrasensitive detection technique for the early monitoring of bacterial contamination. In this study, we proposed a SERS sandwich sensing method for developing a sensitive SERS bacterial sensor by integrating a signal element of dendritic mesoporous silica nanocarriers (DMSNs) loaded with plasma nanoparticles and SERS tags and an enrichment element of covalent organic frameworks encapsulated with magnetic Fe 3 O 4 nanoparticles with a sensitive magnetic response, which can synergistically increase the quantity and intensity of hotspots. The proposed SERS sandwich sensor demonstrated ultrahigh detection sensitivity (6.5 CFU/mL) and selectivity for S. Typhimurium. The constructed sensor could rapidly and accurately detect the target bacteria in spiked chicken samples. Thus, it provided a new approach and direction for the early detection of bacterial contamination in fresh meat. • A SERS sandwich biosensor was fabricated‌ using DMSN-Au@Ag and MCOF@Au for ultrasensitive bacterial detection. • MCOF@Au@Apt exhibited excellent bacterial recognition and high enrichment efficiency functionality. • The sensor achieved a detection limit of 6.5 CFU/mL for S. typhimurium and exhibited promising application in real samples.