Surface-imprinted SiO2@Ag nanoparticles for the selective detection of BPA using surface enhanced Raman scattering

To circumvent the limitations of natural antibodies, receptor, or enzyme, molecular imprinting technique has received intensive attention in analytical methods Herein, based on surface enhanced Raman scattering (SERS) molecularly imprinted polymer (SERS-MIP), a SERS-MIP sensor has been developed for the sensitive and selective detection of bisphenol A (BPA). To construct the BPA sensor, raspberry-type SiO2@Ag nanoparticles (SiO2@Ag NPs) were prepared to act as supporting substrate, and BPA was adopted as template molecule, tetraethyl orthosilicate (TEOS) as functional monomer and 3-aminopropyltriethoxysilane (APTES) as cross-linker. Due to the strong plasma resonance character of Ag NPs, the SERS-MIP sensor showed good sensitivity in the detection of BPA. The core-shell and satellite-like structure of the SiO2@Ag composites could provide a large surface area for BPA recognition by molecular binding domains. In addition, the sensor could prevent interferences such as 4,4′-(Hexafluoroisopropylidene) diphenol (BPAF) and 4,4′-Dihydroxybiphenyl (DOD). Moreover, the real water samples were tested to verify the reliability and feasibility of the method. Under the optimal conditions, the proposed method behaved good analytical performance to BPA with a wide linear range from 1.75 × 10−11 to 1.75 × 10−6 M and a detection limit of 1.46 × 10−11 M.