Molecularly imprinted polymer grafted on polysaccharide microsphere surface by the sol–gel process for protein recognition

An interfacial organic-inorganic hybridization concept was applied to the preparation of a new spherical imprinted material for protein recognition. The functional biopolymer chitosan (CS), shaped as microsphere and high-density cross-linked, constituted of the polysaccharide core for surface imprinting. After the model template protein, bovine serum albumin, was covalently immobilized by forming imine bonds with the functional amine groups of CS, two kinds of organic siloxane (3-aminopropyltrimethoxysiloxane: APTMS, and tetraethoxysiloxane: TEOS) assembled and polymerized on the polysaccharide-protein surface via sol-gel process in aqueous solution at room temperature. After template removal, the protein-imprinted sol-gel surface exhibited a prevalent preference for the template protein in adsorption experiments, as compared with four contrastive proteins. Bioinformatics methods were also employed to investigate the imprinting process and the recognition effect. The influence of siloxane type, pH, siloxane/water ratio on template removal and recognition selectivity was assessed. Under optimized imprinting conditions, a large quantity of well-distributed pores was observed on the immobilized-template imprinted surface. The surface-imprinted adsorbent offered a fast kinetics for template re-adsorption and could be reused. Compared with the imprinted material prepared with free-template, material prepared with immobilized-template possessed higher adsorption capacity towards template protein. Easy preparation of the described imprinted material, high affinity and good reusability make this approach attractive and broadly applicable in biotechnology for down-stream processing and biosensor.