Electrospun polyvinylpyrrolidone (PVP) hydrogels containing hydroxycinnamic acid derivatives as potential wound dressings

Polyvinylpyrrolidone (commonly known as povidone or PVP) rapidly dissolves in water. This significantly hinders its use in sustained release formulations developed for the biomedical field. Electrospun fibers of PVP dissolve even faster due to larger surface to volume ratio. In this work, we propose a way to circumvent this problem by developing and using functional fibrous materials in hydrogel form. In particular, we demonstrate that ethanolic solutions of PVP containing two hydroxycinnamic acid derivatives, namely p-coumaric and ferulic acids could be electrospun into functional hydrogel fiber mats. After electrospinning, the formed composite mats were first thermally treated at 130 °C for 20 h and subsequently were immersed in aqueous media, where they turned into hydrogels. Thermal annealing did not degrade hydroxycinnamic acid derivatives, preserving their functionality. We propose these hydrogel fiber mats as potential wound dressings and to that end, in vitro tests showed up to 8 days of antioxidants' release, and consequent protection of A549 epithelial cells against oxidative stresses. Biocompatibility tests using human red blood cells, A549 and HaCaT cell lines indicated no adverse effects. Model studies of mice skin burns induced by UV-B radiation showed that the hydrogel fiber dressings significantly reduced the levels of matrix metallopeptidase, (MMP-9), and glutathione peroxidase 1 (GPX-1), which are usually upregulated by reactive oxidative species on burnt skin. Finally, ex-vivo human skin investigations demonstrated skin regeneration and control of the inflammatory phase as indicated by low levels of pro-inflammatory cytokines (IL-6 and IL-8). Therefore, our outcomes indicate that the developed PVP-based fiber hydrogels, produced using a simple protocol, are promising candidates for active wound dressings.