Abstract

This work reports chemically cross-linked poly(vinyl alcohol) (PVA) hydrogels cofunctionalized with graphene oxide (GO <= 0.2 wt %) and vitamin A palmitate (VAP <= 0.2 wt %) as a single platform wound dressing that couples multiple functionalities: mechanical reinforcement, photoprotection, tunable swelling and retinoid delivery. The GO/VAP loading significantly enhances the mechanical properties of neat PVA (E-c = 15.8 +/- 0.5 kPa; failure strain 0.51), transforming it into highly compressible networks with E-c up to 57.4 +/- 1.0 kPa, compressive stresses up to 327 kPa and strains of 0.64-0.76 without fracture, and tensile strains up to 2.6 at 68 kPa, outperforming previously reported PVA/GO hydrogels. The equilibrium swelling ratio was tuned from 120 to 222% by varying GO and VAP contents, which correlates with a transition from mixed diffusion/relaxation to predominantly diffusion-controlled VAP release (as described by Peppas-Sahlin fits, R-2 = 0.998-0.999). A key finding of this system is the marked extension of VAP photostability upon incorporation into GO-containing PVA matrices: the characteristic UV-C photodegradation time increases from 3.6 x 10(2) min for free VAP to 1.2 x 10(3) min in GO/VAP formulations (3.3-fold increase), while still retaining 71-86% of the initial absorbance at 330 nm after 1 week versus 59% for VAP alone. PVA-GO(0.1%)/VAP(0.2%) and PVA-GO(0.2%)/VAP(0.2%) release 55 and 44% of VAP within 150 min, and their cumulative release at 58 h reaches 89 and 72%, respectively. In contrast, the sample without GO (PVA-VAP(0.2%)) release only 35%. All hydrogels are noncytotoxic to human dermal fibroblasts (HDF) (viability >= 86%, up to 122%), nonhemolytic (HR < 2%) and nonirritant in vivo (PII = 0). The PVA-GO(0.2%)/VAP(0.2%) formulation promotes near-complete closure (in a scratch test at 48 h) and organized collagen in a porcine full-thickness wound model, thus underscoring the originality of integrating GO and VAP within a single PVA matrix for multifunctional wound care.