Hexagonally Packed Macroporous Molecularly Imprinted Polymers for Chemosensing of Follicle-Stimulating Hormone Protein.

Abstract

Homogenous nanostructuration of molecularly imprinted polymer (MIP) films for follicle-stimulating hormone (FSH) sensing was achieved by using optimized colloidal crystals as a hard mold. Introduction of heating step after assembling colloidal crystals of silica beads promoted their adhesion. Thus precise assembling of beads was not disturbed during further multistep of surface imprinting, and crack free hexagonal packing was maintained. SEM imaging confirmed hexagonal packing of silica colloidal crys-tals as well as homogenous nanostructurization in MIP films. FSH immobilization over silica beads and later its derivatization with electroactive functional monomers was confirmed by XPS analysis. The nanostructured molecular recognition films prepared in this way were combined with an electrochemical transducer in order to design a capacitive impedimetry (CI) based chemosensing system. It was tested for the determination of FSH in the range from 0.1 fM to 100 pM in 10 mM MES buffer (pH = 4.2). The detection limit of the chemosensor was 0.1 fM showing a high selectivity with respect to common protein interferences as well as other protein hormones of the gonadotropin family.