Poly(Vinyl Alcohol)/Hyaluronic Acid Nanofibers for Biomedical Use Under Physiological Conditions: Electrospinning Fabrication and Stabilization via Solvent-Free Citric Acid Crosslinking

Electrospun polymeric nanofibers have emerged as promising materials for wound management owing to their high surface area, efficient exudate absorption and gas exchange, and extracellular-matrix-like architecture. This study investigates the fabrication of nanofiber dressings from poly(vinyl alcohol) (PVA) and hyaluronic acid (HA), prepared by fully aqueous electrospinning (without organic solvents) for potential wound-care applications. HA incorporation is expected to influence hydration and matrix interactions, properties that have been associated with modulation of wound healing in previous studies. However, the high solubility of PVA-based NFs in aqueous environments limits their use in biological applications. To address this issue, PVA/HA nanofibers were chemically crosslinked through a solid-state esterification process at 150 °C using biocompatible citric acid (CA). The electrospinning parameters were optimized to obtain PVA/HA fibers with diameters ranging from 130 to 200 nm, which were assembled to form mats with different porosity and intersection density. FTIR confirmed the formation of ester bonds, while DSC analysis showed an increase in Tg from 41 °C to about 55 °C and a slight decrease in Tm after crosslinking. Swelling and degradation analyses demonstrated a significant enhancement in hydrolytic stability, as the weight loss of the nanofiber mats decreased from ~90% in the non-crosslinked samples to less than 10% after 2 h of crosslinking. Dynamic mechanical analysis (DMA) showed an increase in Young's modulus from ~70 MPa to 230 MPa after crosslinking. Overall, the results demonstrate the stabilizing effect of citric-acid crosslinking on PVA/HA nanofibers and support their potential use in wound dressings under physiological conditions.