Effect of crosslinking degree and thickness of thermosensitive imprinted layers on recognition and elution efficiency of protein imprinted magnetic microspheres

Crosslinking degree is difficult to determine on the premise of simultaneously considering response performance and recognition capability in the thermosensitive imprinted materials due to their mutually contradictory relationship. In addition, the effect of thickness of thermosensitive imprinted layers on the recognition of target protein is also difficult to evaluate quantitatively. To solve these two problems, a series of thermosensitive magnetic imprinted microspheres with different crosslinking degree and imprinted layer thickness were fabricated. The adsorption results showed that imprinted layer thickness of 17 nm was the most appropriate for BSA imprinting. Crosslinking degree of 20% was determined as the balance point by simultaneously considering response performance and recognition capability. Under such conditions, the elution efficiency after once washing process was up to 78.60%, which guaranteed the satisfactory regeneration capability. The adsorption capacity and the imprinting factor could reach 42.01 mg/g and 3.41, respectively, which were greatly increased compared to those imprinted materials reported previously. Furthermore, the practical separation performance of the imprinted microspheres was investigated by separating BSA from the protein mixture sample, and the results were exciting. All these results indicated that these imprinted microspheres were expected to be applied to the rapid isolation and purification of BSA.