Preparation of Temperature-Sensitive Molecularly Imprinted Cryogel for Specific Recognition of Proteins

In order to maintain the stability of the structure of protein molecules and improve the recognition during the separation process, molecular imprinting technology is combined with freeze polymerization to synthesize molecular imprinting cryogels (MICs). This study uses bovine serum albumin (BSA) as a template protein, low critical cosolubility temperature (LCST)-type ionic liquids as temperature-sensitive functional monomers, imidazole ionic liquids, and acrylamides as auxiliary functional monomers to prepare MICs with specific recognition, temperature sensitivity, interpenetrating macroporous structure, and large specific surface area. The MICs prepared at freezing temperature have uniform macroporous structures and good mechanical properties, which is conducive to the improvement of the mass transfer and adsorption capacities. Due to the advantages, the MIC reaches the adsorption equilibrium within 125 min with a saturated adsorption capacity of 741.5 mg g^-1 and an imprinting factor of 1.65. Their static and dynamic adsorption behaviors are more in line with the Langmuir model and the quasi-secondary kinetic model, respectively. In addition, the MIC has obvious temperature sensitivity, and the maximum adsorption amount is reached at 37 °C. The separation factor (relative to cytochrome <i>c</i>, bovine blood hemoglobin, and lysozyme) of the MICs for BSA is up to 1.39. Repeatability experiments reveal that the adsorption capacity of molecularly imprinted cryogels is retained at 87% after five adsorption-desorption cycles, indicating excellent recyclability and potential for practical application.