In order to improve the mechanical strength and imprinting efficiency, a novel bovine serum albumin (BSA) molecularly imprinted poly(ionic liquid)/calcium alginate composite cryogel membrane (MICM) was prepared. The results of the tensile test indicated that the MICM had excellent mechanical strength which could reach up to 90.00 KPa, 30.30 times higher than the poly (ionic liquid) membrane without calcium alginate; the elongation of it could reach up to 93.70%, 8.28 times higher than the poly (ionic liquid) membrane without calcium alginate. The MICM had a very high welling ratio of 1026.56% and macropore porosity of 62.29%, which can provide effective mass transport of proteins. More remarkably, it had a very high adsorption capacity of 485.87 mg g−1 at 20 °C and 0.66 mg mL−1 of the initial concentration of BSA. Moreover, MICM also had good selective and competitive recognition toward BSA, exhibiting potential utility in protein separation. This work can provide a potential method to prepare the protein-imprinted cryogel membrane with both high mechanical strength and imprinting efficiency.

Bio‐macromolecule hemoglobin (Hb) is a kind of iron‐rich metalloprotein that abundant in erythrocytes with various physiological properties. Separating Hb from bio‐matrix with high efficacy is crucial to Hb application but quite challenging. In this study, a supermacroporous molecularly imprinted membrane (MIM) was prepared with high performance on recognizing bovine hemoglobin (BHb). By using the silk fibroin and calcium alginate as mechanical modifiers, the mechanical strength of the prepared membrane was significantly improved to at around 0.25 MPa, and the supermacroporous structure in MIM was also formed. The MIM adsorption capacity of BHb was as high as 121.8 mg g−1 at the initial concentration of 0.5 mg mL−1. The MIM separation factor of BHb from BHb/BSA mixtures was as high as 7.34, and the relative imprinting factor was at around 4.0. The prepared MIM demonstrated the superiority and the valuable application prospect on specific separation of BHb.