Hyperbranched Polylysine and Lipoic Acid Grafted Modification of Polysulfone Hemodialysis Membrane for Treating Hyperbilirubinemia

Abstract Hyperbilirubinemia, a liver disorder characterized by pathological accumulation of free bilirubin, manifests clinically as jaundice, acute bilirubin encephalopathy, or kernicterus, with severe cases proving fatal. In end-stage renal disease (ESRD) patients undergoing chronic hemodialysis, concurrent oxidative stress significantly contributes to cardiovascular complications and increased mortality. In response to the limitations of existing hemodialysis membranes in terms of the synergistic effect of bilirubin clearance efficiency and antioxidant function, this study developed an innovative dual-functional membrane through a partition modification strategy. The membrane design features hyperbranched polylysine (HBPL) grafted onto both surfaces via plasma technology. The outer surface utilizes HBPL for specific bilirubin adsorption through lysine-bilirubin affinity, while the inner surface was further modified with lipoic acid (LA) to shield the positive charge of HBPL and provide antioxidant activity for enhanced hemocompatibility. Performance evaluation showed that the modified membranes had excellent bilirubin adsorption capacity (BSA-bound bilirubin was 65.42 mg/g) and strong antioxidant activity (scavenging DPPH and ABTS+ free radicals >80%). Furthermore, LA modification significantly enhanced hemocompatibility by reducing protein adsorption and platelet adhesion. This dual-functional approach not only effectively addresses both bilirubin toxicity and oxidative stress but also improves membrane biocompatibility, offering a promising therapeutic advancement for ESRD patients requiring hemodialysis.