Surface-enhanced Raman scattering biosensor-based sandwich-type for facile and sensitive detection of Staphylococcus aureus

Foodborne infections caused by Staphylococcus aureus (S. aureus) represent a serious health risk to the general public. In this study, we proposed a surface-enhanced Raman spectroscopy (SERS) biosensor based on a signal amplification sandwich-type system for detecting and quantifying S. aureus. Herein, the SERS response of SiO2- coated Au@Ag was studied using Raman signals from Au@Ag@SiO2 nanoparticles and van grafted PDMS for the target acquisition. It has been shown that SiO2 coated Au@Ag exhibited a robust and strong response to SERS. Therefore, the combination of vancomycin (Van) and polydimethylsiloxane (PDMS) allowed a more efficient capture of S. aureus, resulting in improved repeatability through simplified separation procedures. Consequently, as a result of the presence of S. aureus targets, sandwich-type conjugate structures between the capture and signal units, as well as synergistic Raman amplification, were observed. Based on optimized conditions, a good linear correlation (y = 1087.86x 540.75, R-2 = 0.9958) in a wide dynamic range of 38-3.8 x 107 cfu.mL(-1) was achieved with a limit of detection of 2 cfu.mL(-1). The accuracy of the sensors was evaluated using a standard addition technique, and the results were satisfactory. Finally, the overall biosensor demonstrated potential application for monitoring S. aureus with good recoveries.