In Vitro Isothermal Nucleic Acid Amplification Assisted Surface-Enhanced Raman Spectroscopic for Ultrasensitive Detection of Vibrio parahaemolyticus.

Detection of pathogenic microorganisms is of great importance for public health and food safety. Traditional protocols can hardly meet the continuously increasing demand in sensitivity and specificity of pathogen detections. In this study, we adopted Vibrio parahaemolyticus (V. parahaemolyticus, Vp) as the model analyte, and developed an antibody-Vp-aptamer heterosandwich-based surface-enhanced Raman scattering (SERS) method in conjunction with in vitro isothermal amplification for sensitive detection of V. parahaemolyticus. The rolling circular amplification (RCA) products provided enormous sites for assembling the Au@Ag nanoparticles and forming excess "hot-spot" sites for Raman measurement. By using this enhanced Raman signal strategy in the detection, a limit of detection (LOD) as low as 1 cfu/mL was successfully achieved for ultrasensitive detection of V. parahaemolyticus. In addition, we have applied this method to artificially contaminated food samples. The detection data indicated that this method is able to determine the concentrations of V. parahaemolyticus in the spiked food samples with satisfactory sensitivity and specificity and, thus, this developed ultrasensitive SERS scheme is well suited for the urgent need in pathogen detection and demonstrated great potential in food safety, environment monitoring, and a clinical setting.