Preparation of pH and temperature dual-sensitive molecularly imprinted polymers based on chitosan and N-isopropylacrylamide for recognition of bovine serum albumin

pH and temperature dual-sensitive protein imprinted microspheres with high absorption capacity have been successfully synthesized on the surface of SiO ₂ using chitosan grafted N-isopropylacrylamide (CS-g-NIPAM) as the pH and temperature sensitive monomer, with acrylamide as comonomer, N,N′-methylenebisacrylamide as the crosslinking agent and bovine serum albumin (BSA) as the template protein. The pH and temperature dual-sensitivity was also investigated. The results showed that the adsorption capacity and imprinting factor improved slowly with increasing incubation pH from 4.6 to 7.0, and then decreased sharply in alkaline conditions due to the reduction of non-specific binding from electrostatic and hydrogen bonding interactions. Fourier transform infrared spectroscopy, thermogravimetric analysis and transmission electron microscopy were used to characterize the polymers. The as-prepared SiO ₂ @BSA molecularly imprinted polymers were also found to have high adsorption capacity (119.88 mg g ⁻¹ ) within 2 h, an excellent imprinting factor (α = 2.25), specific selectivity and good reusability.