Molecular imprinting of doxorubicin by refolding thermally denatured bovine serum albumin and cross-linking with hydrogel network

Abstract

In this work, we demonstrate a novel molecular imprinting method by unfolding and refolding an auxiliary protein in the presence of a small-molecular template, followed by fixation of the resultant protein/template assembly via polymerization of additional functional monomers. Employing doxorubicin (DOX) as a model template and bovine serum albumin (BSA) as an auxiliary binding protein, we optimized the conformation of BSA through thermal denaturation and renaturation process in the presence of template DOX. Then, in-situ polymerization of isopropylacrylamide, N-[3-(dimethylamino)propyl]methacrylamide and acrylamide was carried out to form imprinted hydrogels of the dBSA&DOX complex. The conformation of BSA in the resultant polymer was further fixed via formaldehyde cross-linking with the hydrogel network. The obtained imprinted hydrogel showed much higher affinity and selectivity to DOX than both native BSA and the control hydrogel prepared by using native BSA instead of unfolded/refolded BSA. The method may be further extended to prepare water compatible imprinted hydrogel against other small molecules by using easily accessible proteins as auxiliary ligands.