Anti-biofouling microfiltration membranes based on 1-vinyl-3-butylimidazolium chloride grafted PVDF with improved bactericidal properties and vitro biocompatibility

Polyvinylidene fluoride (PVDF) porous membranes have been widely used as the filtration and separation industry. Herein, novel microfiltration membranes based on 1-vinyl-3-butylimidazolium chloride ([VBIm][Cl]) grafted PVDF (PVDF-g-[VBIm][Cl]) were prepared via the non-solvent induced phase separation method. The chemical composition and microstructure of PVDF-g-[VBIm][Cl] membranes were characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Scanning electron microscopy and Water contact angle measurements. The results showed that an increasing in [VBIm][Cl] grafting content leads to the increasing hydrophilicity and wetting capacity of the PVDF-g-[VBIm][Cl] porous membranes. The anti-biofouling properties of membranes were evaluated by measuring the water flux before and after Bovine serum albumin solution treatment. It was found that the modified membranes presented a good anti-biofouling property. The degree of irreversible flux loss caused by protein adsorption dramatically reduced from 42.1% to 2.9% compared with the pristine hydrophobic PVDF membranes. Meanwhile, these PVDF-g-[VBIm][Cl] membranes also exhibited excellent bactericidal properties against both gram-positive bacteria Staphylococcus saureus and gram-negative bacteria Escherichia coli, while PVDF membranes did not show any antibacterial activity. The vitro biocompatibility of the modified membranes was studied by hemolysis analysis, the platelet adhesion observation, thromboelastography assay and cytotoxicity assay. It was found that the incorporation of [VBIm][Cl] into PVDF membranes has less effect on the hemolysis and cytotoxicity of PVDF membranes. Furthermore, both hydrophilicity and charges of the membrane surface played important role in the adhesion and activation of platelet cells, which consequently affected the clotting process of whole blood. The membrane with appropriate [VBIm][Cl] grafting ratio (2.94 wt.%) exhibited good hemocompatibility with less blood coagulation effect. As an ultrafiltration membrane, PVDF-g-[VBIm][Cl] membranes have potential applications in the biomedical field due to the improved antibacterial property and biocompatibility.