Polydimethylsiloxane Gold Nanoparticle Composite Film as Structure for Aptamer-Based Detection of Vibrio parahaemolyticus by Surface-Enhanced Raman Spectroscopy

This paper investigated a new detection method for food pathogenic bacteria Vibrio parahaemolyticus based on surface-enhanced Raman scattering (SERS). Nanostructures consisting of Aptamer-Au nanoparticles-polydimethylsiloxane (Apt-Au-PDMS film) were firstly used as SERS substrate. Aptamers were immobilized on the functionalized PDMS film covered with Au nanoparticles (AuNPs) to act as a capture structure via the affinity binding of aptamer, and Vibrio parahaemolyticus. AuNPs were modified with the aptamer and Raman reporter molecule 4-mercaptobenzoic acid (4-MBA) to act as SERS-sensing probes that bind to the target in the same way as the Apt-Au-PDMS film. The solid sandwich structure was formed by capture structure-target-SERS-sensing probes. The concentration of Vibrio parahaemolyticus can be quantified by measurement of the SERS intensity of 4-MBA. Under optimal conditions, the signal of 4-MBA at 1590 cm−1 was linearly related to the Vibrio parahaemolyticus concentration in the range between 1.2 × 102 and 1.2 × 106 cfu·mL−1. Recoveries ranging from 97.7% to 105.3% were found when analyzing spiked prawn samples. This developed ultrasensitive aptamer-based SERS detection structure suggested that it would be a promising strategy for a variety of sensing applications.