Preparation and characterization of a novel polysialic acid/gelatin composite hydrogels cross-linked by tannic acid to improve wound healing after cesarean section dressing.

The infections and delayed wound healing after cesarean delivery is one of the most complicated issues in surgical medicinal field. In the present investigation, designed novel polysialic acid loaded gelatin (PSA-Gel) composite hydrogels cross-linked by tannic acid (TA) has been developed and used as a facile wound dressing to improve cesarean wound healing ability with prevent bactericidal infections. The cross-linking effect was predominant when the TA content was lower, resulting in the formation of a cross-linked network. An effective TA cross-linking effect on the PSA-Gel hydrogel matrix was achieved when the amount of TA was around 15 wt %. The morphology of as-fabricated hydrogels was characterized using scanning electron microscopy (SEM) with an average pore sizes of PSA-Gel, PSA-Gel-TA-5%, PSA-Gel-TA-10%, and PSA-Gel-TA-15% hydrogels were 95.4 ± 12.6 μm, 120.4 ± 8.2 μm, 165.3 ± 21.6 μm, and 270.2 ± 32.5 μm, respectively. The effects of hydrogels on the swelling ratio, in vitro degradation, and mechanical properties were systemically evaluated. The TA cross-linked PSA-Gel hydrogels display strong antimicrobial behavior against gram-positive (Staphylococcus aureus) gram-negative (Escherichia coli) bacteria strains. Moreover, PSA-Gel-TA hydrogels also displayed favorable cytotoxicity toward L929 fibroblast cell lines. Finally, the therapeutic and wound healing potential of the PSA-Gel-TA hydrogels has been studied in vivo using the excision wound model in rats. The results indicate that the PSA-Gel-TA hydrogels have a greater and significant effect on wound closure and increased the wound healing rate compared with native PSA-Gel hydrogels and untreated control group at 94%, 73% and 65% on day 21. The findings suggest that PSA-Gel-TA hydrogels are promising dressing materials for the treatment of wound healing. TA-reinforced PSA-Gel hydrogels with cross-linked network were developed. PSA-Gel-TA hydrogels exhibited enhanced mechanical properties. PSA-Gel-TA hydrogels had excellent antibacterial activity against E. coli and S. aureus. PSA-Gel hydrogels ell viability properties were improved by TA treatment. TA-reinforced PSA-Gel hydrogels significantly accelerated the wound healing process. [ABSTRACT FROM AUTHOR]