Bio-based tannic acid-assisted engineering of Au NP-enriched PES membranes for potential hemodialysis applications

: The development of advanced hemodialysis membranes with improved hemocompatibility and antibacterial functionality remains a significant challenge in biomedical engineering. In this work, polyethersulfone (PES) mixed-matrix membranes enriched with gold nanoparticles (Au NPs) were fabricated using a solvent-nonsolvent phase inversion method combined with in situ nanoparticle synthesis. Tannic acid (TA), a naturally occurring polyphenol, was incorporated into the casting solution to act as a multifunctional bio-based modifier, enabling strong interactions with both the PES matrix and Au nanoparticles. This strategy was designed to enhance nanoparticle immobilization, reduce potential nanoparticle leaching, and simultaneously introduce antioxidant properties. The resulting membranes were comprehensively characterized using a range of complementary techniques. Filtration performance was evaluated in terms of pure water flux, bovine serum albumin (BSA) rejection, and the removal of low- and middle-molecular-weight model uremic toxins, including creatinine, uric acid, and lysozyme. In addition, protein adsorption from human blood plasma, antioxidant activity, hemocompatibility, whole blood clotting, cytotoxicity using HUVEC cells, and antibiofilm activity against Staphylococcus aureus and Pseudomonas aeruginosa were investigated. Structural analyses confirmed the successful in situ formation and distribution of Au nanoparticles within the membrane matrix, with tannic acid playing a key role in their stabilization and retention. The incorporation of Au NPs improved the membrane hydrophilicity and significantly increased pure water flux while maintaining high creatinine and uric acid clearance and enhanced BSA rejection. Au-containing membranes also demonstrated increased lysozyme clearance, reaching approximately 39% for the 50Au membrane, indicating enhanced transport of middle-molecular-weight solutes. Furthermore, Au incorporation significantly reduced protein adsorption from human plasma and decreased whole blood clot formation compared with the TA-containing control membrane. The membranes exhibited strong antioxidant activity, excellent hemocompatibility with hemolysis ratios below 1.5%, and no cytotoxic effects toward endothelial cells. Furthermore, Au-containing membranes demonstrated effective inhibition of bacterial biofilm formation, particularly against P. aeruginosa. Overall, the developed PES/TA-Au nanocomposite membranes combine high filtration efficiency with multifunctional biological properties, including antioxidant, hemocompatibility, antifouling, and antibiofilm activities. These results highlight their potential as advanced materials for hemodialysis applications.