Zwitterionic electrospun PVDF fibrous membranes with a well-controlled hydration for diabetic wound recovery

This works describes the formation of nanofibers made of poly(vinylidene fluoride) (PVDF) and a zwitterionic copolymer prepared from the reaction of 3-iodopropionic acid with a polymer of polystyrene and poly(4-vinylpyridine), zP(S-r-4VP). After presenting the copolymer, we move onto the characterization of nanofibers. It is proven that zP(S-r-4VP) is well distributed, from mapping FT-IR images, and that its concentration at the surface gradually increases with the initial copolymer content in solution. The PVDF/zP(S-r-4VP) nanofibers hydration capacity is enhanced, compared to virgin PVDF, leading to improved resistance to fibrinogen (75% reduction), Pseudomonas aeruginosa (>90% reduction), Staphylococcus aureus (>80% reduction) and Escherischia coli (>95% reduction), cells from whole blood (>95% reduction), but also L929 cells (85% reduction). Besides, steam sterilization does not negatively impact the antibiofouling properties of the membranes. Given their highly porous nature, ability to remain hydrated, antibiofouling property, nonsticky property and improved hemo-compatibility, these nanofibers were applied onto diabetic wounds (type 2), leading to faster wound recovery than commercial DuoDerm (TM) bandage (14 days vs. 17 days), while histological analysis unveiled a complete remodeling of the skin tissue. Faster water transport though the zwitterionic nanofibrous membrane than through the commercial dressing suggests faster removal of exudates away from the wound bed, which is necessary in the case of highly exuding wounds.