Fabrication of a surface imprinted hydrogel shell over silica microspheres using bovine serum albumin as a model...

Surface imprinting is an effective approach to improve the template transfer efficiency in applications of molecularly imprinted polymers as biosensors and separation materials. In this paper, we tried to fabricate a surface imprinted hydrogel over silica microspheres for selective recognition of bovine serum albumin by covalent immobilization of a water-soluble UV sensitive initiator onto the surface of silica beads. The polymerization was initiated by UV radiation with N-[3-(dimethylamino)propyl]methacrylamide and N-isopropylacrylamide as the functional monomer and assistant monomer, respectively, and a thin coat of stimuli-responsive hydrogel yielded over the silica gels. The surface imprinted hydrogels exhibited specific affinity toward the template protein with an association constant (K(a)) of 2.2 x 10(5)L mol(-1) and a maximum binding capacity (Q(max)) of 27.3 mgg(-1) in Tris-HCl buffer (pH 7.0). The rebinding and desorption kinetics of the surface imprinted hydrogels were determined and proven to be extremely fast (about 1 min compared to 3h for the previously prepared bulk imprinted hydrogel). Besides, the hydrogel-silica core-shell particles inherit both the stimuli-responsive property of the hydrogel and the good mechanical strength of the silica beads based on the on-line evaluation with high-performance liquid chromatography. The above comprehensive merits of the obtained surface imprinted hydrogel suggest the presented approach an attractive and broadly applicable way of developing biosensors and high-performance protein separation materials.