Layered composite sponges with rapid blood clotting and antioxidant functions

Abstract

To address the clinical challenges of conventional hemostatic dressings in the treatment of complex wounds, including insufficient hemostatic efficiency and difficulties in modulating the oxidative stress level in the wound microenvironment, a drug‑loaded composite sponge dressing with an alternating hydrophobic‑hydrophilic‑hydrophobic layered structure was constructed in this study. The hydrophilic layer was fabricated using carboxymethylated cellulose nanofibrils (CMCNF), polyvinyl alcohol (PVA) and phenylboronic acid‑grafted gelatin (Gt‑PBA), which were loaded with the natural flavonoid quercetin. The hydrophobic layer consisted of electrospun poly(lactic‑co‑glycolic acid) (PLGA) fibrous membranes. By using layer‑by‑layer assembly and freeze‑drying, a layered composite sponge dressing with ordered channels was successfully constructed. It was found that the fibrous membranes and sponge layers are tightly integrated at the interface. The water contact angle analysis demonstrated the hydrophobic property of the PLGA fibrous membranes and the superior hydrophilic property of the cross-section of the layered composite sponge. Moreover, the composite sponge with a layered structure exhibited faster water transport than the uniform sponge, indicating improved directional fluid transport capability. Furthermore, the blood clotting index (BCI) of the quercetin‑loaded layered composite sponge reached 22.3%, showing better blood‑clotting capability compared to commercially available gelatin sponge. In addition, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays showed that the quercetin-loaded layered composite sponge exhibited a DPPH scavenging rate of 95.5%, which was primarily attributed to the introduction of the flavonoid quercetin. This work may offer a potential approach to the construction of multifunctional wound dressings.