Polyviniyl alcohol mats crosslinked with citric acid for regenerative medicine applications

Abstract

Introduction: Currently, biomaterials have stood out in the medical field, seeking innovative solutions for wound healing. Papain, an enzyme with remarkable healing properties, shows promise in this context. However, its activity is compromised when in contact with water and at high temperatures. To overcome this challenge, this project has considered the use of polyvinyl alcohol (PVA) membranes, a low-toxicity, costeffective and hydrophilic polymer, offering an effective and safe approach to promote wound healing. However, the solubility of this polymer restrains its use, thus the aim of this project is to crosslink PVA fibers directly during solution blow spinning procedure. Methodology: Mats were produced using a Solution Blow Spinning (SBS) device with a rotary collector. The SBS device was 40 cm away from the collector and the solution was supplied with a pump at 3mL/h through a syringe using air at 6 psi of pressure. Mats were prepared using a 14 wt% PVA (65% high molecular weight/35% low molecular weight) solution in water and compared with solutions containing different concentrations of citric acid. The mechanical and rheological characterizations were done by tensile strength and viscosity tests, while infrared spectroscopy and scanning electron microscopy were employed to analyze fibers structure and morphology. Results and discussion: The mats produced in this study were consistently white, irrespective of citric acid presence. With increasing citric acid concentration, the mats showed improved resistance, making them more durable for various applications. The addition of citric acid also reduced mats water solubility, enhancing their long-term stability in different environments, notably biological fluids as exudate. Infrared spectroscopy analysis confirmed the crosslinking, while scanning electron microscopy revealed mats were composed by ultrafine fibers. These improved properties obtained by crosslinking make the mats highly suitable for practical applications of wound dressing, mainly by the use of safe crosslinking agent. The PVA solutions presented a higher viscosity with increasing citric acid content, presenting viscosity values of 0.9 ± 0.03 Pa s and 1.19 ± 0.07 Pa s for 0 wt% and 10 wt% of citric acid (in reference to the PVA mass) at 21,5 s-1. These findings hold significant promise for expanding crosslinked PVA mats usage in various types of wounds. Conclusions: Based on our results, it is possible to assert that with the addition of citric acid, which promoted polymer crosslinking, we obtained PVA dressings with ideal properties for wound use. Since the dressings are in perfect condition to withstand wound moisture, we can now consider the inclusion of papain in the mats, that can be stored dry and hydrated just in the moment of use, an attempt to preserve the hydrolysis of these enzyme.