Vancomycin functionalization of gold nanostars for sensitive detection of foodborne pathogens through surface‐enhanced Raman scattering
Sandhiya Dayalan, Gangaraju Gedda, Ruei–Nian Li, Muhammad Zulfajri, Genin Gary Huang
Abstract
Abstract In this paper, we report a sensitive surface‐enhanced Raman scattering (SERS) biosensor for the detection of food‐borne pathogens on the basis of recognition of bacterial cells through the specific targeting agent vancomycin. Vancomycin‐functionalized gold nanostars (GNSs–4–MBA–van) were synthesized as SERS tags for specific and sensitive quantification of food pathogens. The Raman reporter molecule 4–mercaptobenzoic acid (4–MBA) was also a linker molecule to attach vancomycin to gold nanostars. The proposed vancomycin‐based SERS technique achieved a detection limit of 5.7 and 8.2 CFU/ml for Staphylococcus aureus and Escherichia coli , respectively. The logarithm of the bacterial concentration ranged from 10 1 to 10 7 CFU/ml and demonstrated a linear relationship with the SERS intensity of the characteristic 4–MBA Raman peak at 1,081 cm −1 . Principle component analysis was used to discriminate the two pathogens simultaneously by using reproducible and specific intrinsic fingerprints and intracellular components obtained through SERS. Moreover, the spiking tests revealed that GNSs–4–MBA–van is effective as a potential biosensor for detecting pathogens in the fresh meat and food‐processing industries.