Immunoaffinity membrane for specific removal of hepatitis B virus from plasma

The high global prevalence of hepatitis B virus (HBV) poses a significant threat to transfusion safety. In this study, we proposed a rationally designed immunoaffinity membrane for specific removal of HBV from plasma. A single-chain variable fragment (scFv-1) targeting the HBV surface antigen (HBsAg) with high affinity was selected as the functional ligand for specific HBV capture. The scFv-1 was expressed in an E. coli Shuffle T7 system (yield: 125 ± 6 mg/L), purified to high monomeric purity, and covalently immobilized onto cellulose acetate membranes, obtaining the scFv-1 functionalized immunoaffinity membrane of CA-scFv-1. The CA-scFv-1 membrane exhibited Langmuir-type adsorption against HBsAg with a maximum static binding capacity of 10.3 mg/g (K_D = 2.11 ×10^-7 mol/L). Under dynamic flow conditions, stacked CA-scFv-1 membranes (25 mm in diameter, 1.0 mm in thickness) achieved complete removal of HBsAg from plasma (20 mL, HBsAg concentration: 300 kIU/mL) at 100 L/m²·h. Further study demonstrated that the CA-scFv-1 membrane could reduce HBV in clinical HBV-positive plasma effectively from 1 to 82 kIU/mL to undetectable levels, while normal plasma components and their biological function were well preserved. These results highlight the potential of our CA-scFv-1 immunoaffinity membrane in specific HBV removal for plasma purification.