QCM sensing of bisphenol A using molecularly imprinted hydrogelconducting polymer matrix

Molecular imprinting is a well-known fabrication technique for designing artificial receptors and molecular sensors. The technique resembles a lock and key mechanism and utilizes shape-complementary cavities within polymeric materials as molecular recognition sites for various relevant molecules. In this study, we prepared molecularly imprinted polypeptide gel layers based on cyclodextrin-modified poly(L-lysine) (CD-PLL) on quartz crystal microbalance (QCM) sensor chips and investigated their molecular recognition behaviors for bisphenol A (BPA) using the QCM technique. With BPA as the template and CD as its ligand, the BPA-imprinted CD-PLL gel layers were prepared on electropolymerized polyterthiophene films, which were formed using electrochemical QCM (EQCM). The BPA-imprinted CD-PLL gel layer chip exhibited a much greater QCM response than the non-imprinted gel layer chip in an aqueous BPA solution. The greater response of the BPA-imprinted CD-PLL gel layer chip means that molecular imprinting enabled CD ligands to be arranged at optimal positions for forming molecular recognition sites. The combination of in situ electropolymerization using EQCM and molecular imprinting provides useful methods for fabricating highly selective and sensitive sensor devices for monitoring minute amounts of BPA in water. Polymer Journal (2016) 48, 525–532; doi:10.1038/pj.2016.23; published online 17 February 2016