Bioinert Fibrous Polypropylene Membranes via In Situ Polymerization of Zwitterionic Poly(sulfobetaine methacrylate)

This study reports the fabrication of a biocompatible polypropylene (PP) fibrous membrane via an in situ polymerization process, generating a dual network of PP fibers and poly(sulfobetaine methacrylate) (poly(SBMA)). In this method, the synthesis of the polymer and the modification process happen in a single step. Notably, the modification was achieved without the incorporation of hydrophobic groups in the modifying polymer, demonstrating that the physical entanglement of poly(SBMA) and PP was sufficient to produce a stable biocompatible membrane. The presence of the poly(SBMA) coating was confirmed through various characterization techniques. A reduction in the water contact angle indicated increased hydrophilicity, while Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses verified the presence of poly(SBMA) on the PP membrane surface. The PP membranes were modified with varying sulfobetaine methacrylate solid. The physical morphology of the modified membranes was observed via SEM, and it was seen that membranes modified with higher solid content (4.00, 7.50, 15.0, and 30.0 wt %) showed significant polymer aggregates, making the membranes significantly denser than the original PP membrane. Therefore, optimal modification was achieved with 1.00 wt % poly(SBMA), which balanced enhanced hydrophilicity with preservation of the structural integrity of the membrane. This modification resulted in a 70% reduction in bacterial (Escherichia coli) attachment and a 60% reduction in blood cell attachment compared to the unmodified PP membrane.