Surface-enhanced Raman spectroscopic single step detection of Vibrio parahaemolyticus using gold coated polydimethylsiloxane as the active substrate and aptamer modified gold nanoparticles

A method is described for single-step detection of V. parahaemolyticus in seafood via aptamer-based SERS. A gold-coated polydimethylsiloxane (PDMS) film was used for the enhancement of Raman scattering. The Raman reporter 4-mercaptobenzoic acid was linked to aptamer modified gold nanoparticles (AuNPs) served as a signalling probe. The negatively charged signalling probe was assembled onto the cysteamine-modified Au-PDMS film through electrostatic adsorption. On addition of V. parahaemolyticus, it will be bound by the aptamer as a biorecognition element, and this leads to the dissociation of the signalling probe from the Au-PDMS film. Hence, the Raman signal (at 1592 cm⁻¹) decreases. The assay has a wide linear response that covers the 1.2 × 10² to 1.2 × 10⁶ cfu·mL⁻¹ V. parahaemolyticus concentration range. The detection limit is 12 cfu·mL⁻¹. The method was successfully applied to the determination of V. parahaemolyticus in oyster and salmon samples.

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