Black phosphorus-Au filter paper-based three-dimensional SERS substrate for rapid detection of foodborne bacteria

Rapid and accurate detection of foodborne bacteria is believed to be of vital importance in assuring food safety. In this work, we explored a novel label-free three-dimensional surface-enhanced Raman scattering (3D-SERS) substrate based on black phosphorus-Au (BP-Au) filter paper for the detection and discrimination of three common foodborne bacteria including Staphylococcus aureus, Listeria monocytogenes and Escherichia coli without complicated sample processing. It was found that the BP-Au filter paper-based 3D-SERS substrate could offer larger surface area as well as more “hotspots” than 2D-SERS substrate for sample detection. Moreover, our results showed that this 3D substrate could efficiently enhance Raman signals from model molecules and exhibit satisfactory SERS activity allowing for specific recognition and discrimination of three types of target bacteria at a concentration of 107 CFU/mL. Subsequently, SERS spectral data from three bacteria were successfully distinguished by principle component analysis (PCA) and linear discriminant analysis (LDA). These results demonstrated that the novel 3D SERS substrate with facile, low-cost, green fabrication process as well as high sensitivity could serve as an excellent alternative to conventional substrates for rapid label-free detection and identification of foodborne bacteria with the aid of statistical discriminant analysis PCA-LDA in food safety application.