Advanced nanoparticle-based aptasensor for Vibrio parahaemolyticus detection in fresh shrimp: GO as an internal standard in SERS sensor

In this work, an aptamer sensor (aptasensor) for SERS detection of Vibrio parahaemolyticus was prepared by utilizing flower-shaped silver nanoparticles coated with graphene oxide (Ag@GO) and core–shell Au@Ag nanoparticles embedded with the Raman reporter 4-mercaptobenzoic acid (4MBA). Graphene oxide (GO) was synthesized using an improved Hummers method and wrapped around thiol-functionalized Ag nanoflowers to form the Ag@GO composite. The SERS aptamer sensor with the strongest Raman signal of 4MBA was developed by combining Ag@GO with Au@4MBA@Ag NPs modified by aptamer through hydrogen bonding and π-π stacking interactions. The aptasensor exhibited good repeatability and stability, and demonstrated high specificity. And it showed a good linear relationship for Vibrio parahaemolyticus detection within the concentration range of 10 2  cfu/mL–10 7  cfu/mL. Introducing GO as an internal standard improved the linear regression coefficient (R 2 ) of detection from 0.9885 to 0.9956. Additionally, spiked real samples of fresh shrimp were tested, yielding recovery rates between 94.1 % and 104.7 %, which demonstrate the feasibility and practicality of this method.