Surface molecular imprinting onto silver microspheres for surface enhanc24 June 2013ed Raman scattering applications

A simple route for the synthesis of core-shell Ag-molecularly imprinted polymer (Ag@MIP) hybrid was proposed. Silver microspheres were first fabricated by the acid-directed self-assembly technique, and then they were modified using coupling agent, core-shell Ag@MIP hybrid were finally obtained through surface molecular imprinting technique. The morphology and structure of the resulting hybrid were characterized by X-ray diffraction, energy dispersive spectroscopy, transmission and scanning electron microscopy, and Fourier transform infrared spectroscopy. The obtained Ag@MIP substrate is extremely high surface enhanced Raman scattering (SERS) activity toward the target molecule 4-mercaptobenzoic acid (4-MBA)，and exhibits a 10-15 M detection limit. The SERS signals of 4-MBA show good reproducibility and selectivity. A possible mechanism for our SERS enhancement was briefly discussed using a molecularly imprinting “gate effect” model. Our experimental results show that the Ag@MIP hybrid as SERS platform is potential for ultrasensitive sensing and analytical applications.