SPR Sensing of Bisphenol A Using Molecularly Imprinted Nanoparticles Immobilized on Slab Optical Waveguide with Consecutive Parallel Au and Ag Deposition Bands Coexistent with Bisphenol A-Immobilized Au Nanoparticles

摘要

A slab-type optical waveguide (s_OWG)-basednmicrofluidic SPR measurement system for bisphenol A wasndeveloped. This s_OWG possesses consecutive parallel goldnand silver deposition bands in the line of plasmon flow,nallowing two individual SPR signals to be independentlynobtained as a result of the difference in resonant reflectionnspectra of these metals. As a molecular recognition element,nmolecularly imprinted polymer nanoparticles (MIP-Np) werenemployed and immobilized on the surface of each of the gold and silver deposition bands. The resonant reflection spectra werenmeasured on the MIP-Np-immobilized consecutive parallel gold and silver deposition bands coexistent with BPA-AuNp. The AgbasednSPR spectra showed a red shift (0.7 nm) when free BPA (0.1 mM) was passed over the BPA-AuNp/immobilized MIP-Npncomplexes formed on the s_OWG, unlike the case for the Au deposition band, while a large excess of BPA induced a blue shiftndue to the competitive desorption of BPA-AuNp from the immobilized MIP-Np on the s_OWG. By using the proposedndetection system, binding events of other small molecules could be monitored in conjunction with the use of MIP-Np andnlabeled-AuNp.