M13 phage-based nanoprobe for SERS detection and inactivation of Staphylococcus aureus.

Rapid and sensitive diagnosis of bacterial infections at early stage is of great significance for food safety monitoring as well as clinical treatment. Herein, we construct a surface-enhanced Raman scattering (SERS) nanoprobe based on M13 phages for the selective detection and inactivation of Staphylococcus aureus (S. aureus). M13 phage with specific S. aureus-binding heptapeptide displayed on the N-terminal of pIII protein is selected from phage display peptide library. The S. aureus-specific SERS probe is thus constructed by in situ growth of gold nanoparticles (AuNPs) on M13 phage surface, followed by modification with 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB) as SERS active molecule. Upon the addition of this SERS probe, M13 phage selectively binds with S. aureus to induce anchoring of AuNPs on S. aureus surface, and the SERS probe-labeled S. aureus cells are collected by centrifugation for SERS detection. For the quantification of S. aureus, a linear range of 10-10 cfu mL is achieved in aqueous medium. It is further demonstrated by spiking recovery in soft drinks. Furthermore, this SERS probe exhibits bactericidal capabilities towards S. aureus, which shows promising potential to serve as a multifunctional platform for simultaneous detection and inactivation of S. aureus.