Biocatalytic nanofibrous membranes with enhanced self-cleaning properties through an in-situ ZIF-8 anchoring and trypsin incorporation strategy

Membranes are extensively utilized for protein separation and purification; however, fouling is a significant challenge and limits further practical application. Biocatalytic membranes have attracted much attention due to their potential anti-fouling and self-cleaning properties. Herein, biocatalytic nanofibrous porous membranes were fabricated through an in-situ zeolitic imidazolate frameworks (ZIF-8) anchored and trypsin incorporation strategy. Ethylene vinyl alcohol copolymer (EVAL) nanofibers, doped with Zn(Ⅱ) or ZIF-8, were fabricated via electrospinning, and then ZIF-8 layers were anchored onto the surface of the nanofibers via in-situ growth. Continuous ZIF-8 layers were observed and almost completely covered the surface of the nanofibers, providing 2.7-fold trypsin loading than ZIF-8 crystals in solution. For the biocatalytic nanofibrous membranes, the trypsin loading were both exceeded 270 µg cm −2 and the maximum reaction rate values of membranes during filtration increased by 120 % than that of free trypsin. Enhanced hydrophilicity and protein-digestive functionality contributed to high self-cleaning properties of the membranes. The biocatalytic nanofibrous membranes demonstrated 2-fold flux recovery and improved BSA resistance compared to the pristine membrane after BSA filtration. Moreover, the membranes retained high anti-fouling properties after five reuse cycles, utilizing only a simple and cost-effective washing operation. Such biocatalytic nanofibrous membranes hold great promise for enhanced anti-fouling and self-cleaning performance in water applications.