Directional-Freezing Multimodal Hemostat For Oral And Cutaneous Wounds

To address clinical limitations of traditional hemostatic materials, this study developed a PVA-DOPA/CS composite biomaterial through directional-freeze-drying technology. The PVA-DOPA/CS polymer was synthesized by blending DOPA-modified polyvinyl alcohol (PVA) with chitosan followed by directional freezing, with material characterization including FTIR, SEM, ¹H-NMR, and rheological analysis. Hemostatic performance was evaluated through citrated porcine whole blood coagulation assays (n=3), adhesion strength measurements on porcine oral mucosa (n=3 independent specimens), and in vitro sealing stability tests using a porcine tooth extraction model. For the latter, citrated porcine blood was infused into extraction sockets sealed with PVA/CS sponges, compared with untreated controls. Animal studies encompassed SD rats (n=36, 8-week-old males) subjected to incisor extraction and liver hemorrhage models. Histological (H&E, Masson's trichrome) and immunohistochemical (CD31, VEGF) analyses were performed alongside cytotoxicity assessment via CCK-8 assay. Statistical significance was determined by ANOVA (p<0.05). Directionally frozen PVA-DOPA/CS sponges achieved rapid hemostasis within 30 seconds in alveolar sockets, with 80.9% wound closure at day 6 and 99.5% socket healing by day 8. New bone formation reached 49.5% at 4 weeks. The powdered formulation maintained 85% adhesion efficiency on moist wounds and achieved 78% complete hemostasis in hepatic hemorrhage models. This multimodal biomaterial system establishes a novel clinical paradigm for precision hemostasis through rational design and multi-model validation, demonstrating significant translational potential via its multifunctional properties.