Exploration of BSA imprinting mechanism by fluorescence anchoring and host–guest interactions

For protein imprinting, template molecule anchoring and imprinting site recognition are very important processes. Herein, we have proposed for the first time to use photo-switchable host–guest interactions between α-cyclodextrin (α-CD)-modified bovine serum albumin (BSA) and azobenzene coated organic covalent framework (COF) to immobilize and elute proteins. A novel surface labeled polymer microspheres (COF-MIPs) were constructed, which could reduce the mass transfer resistance and accelerate the adsorption process, resulting in the adsorption equilibrium reaching 60 min and the saturated adsorption amount of 563.86 mg/g. Additionally, using guest molecules (azobenzene) to label the imprinted sites allows the correlation of the relationship between the fluorescence intensity and the protein adsorption process. The fluorescence analyses show that the material exhibits excellent adsorption specificity, with imprinting factors greater than 4. This work extended the application of the host–guest interaction between cyclodextrin and azobenzene and provides a new approach for developing protein-imprinting materials.