Poly(vinyl alcohol)/Pullulan Composite Hydrogels as a Potential Platform for Wound Dressing Applications

Abstract

Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on physical hydrogels obtained from poly(vinyl alcohol) (PVA) and pullulan (PULL) mixtures in different weight ratios by using the freezing/thawing method. Hybrid hydrogels of similar polymer compositions were prepared in the presence of 0.5% Laponite® RD. The influence of polysaccharide and clay addition on the properties of PVA hydrogels was investigated. Scanning electron microscopy showed evidence of the inner porous structure. The viscoelastic properties were investigated in different shear conditions and revealed the influence of the hydrogel composition on the network strength. The swelling behavior was followed in physiological saline solutions at 37 °C and pH = 7.4. For all samples, a quasi-Fickian diffusion mechanism was found. The delivery of neomycin sulfate was studied in similar conditions as for the swelling tests (0.15 M NaCl solutions; 37 °C; pH = 7.4) and different kinetic models were used to determine the release mechanism. The Peppas–Sahlin approach described very well the in vitro drug release mechanism from the polymeric hydrogels in the absence of clay. However, the hybrid polymer/clay hydrogels showed the best fit with the Korsmeyer–Peppas model. According to the present study, the porous membranes containing 40–60% PULL (in absence of clay) are suitable for the release of therapeutic agents at wound sites in physiological conditions.

Recent Insights into Glucose-Responsive Concanavalin A-Based Smart Hydrogels for Controlled Insulin Delivery

“…The attractive interactions between pullulan and negatively charged macromolecules (polyanions [131] or proteins [132]), mediated by Na + ions, determine the formation of a complex structure with implications in hydrogel stability and drug delivery in physiological conditions [133]. The oxidation applied to pullulan determines the conversion of the -OH groups into carboxylic ones and transforms the neutral macromolecules into valuable products with polyelectrolyte behavior, opening the route for a wide range of biomedical applications [134].…”

A Novel Fabrication of Heterogeneous Saponified Poly(Vinyl Alcohol)/Pullulan Blend Film for Improved Wound Healing Application

“…In order to maintain the proper moisture levels in the injured area and thereby speed up the healing process, the hydrophilicity of the polymer is increased by mixing it with hydrophilic polymers [12]. In this study, blending PULL with poly(vinyl alcohol) (PVA) can improve surface properties and hydrophilic characteristics that support the absorption of excess wound exudates and retention of moisture at wound sites [13].…”

“…Additionally, the saponification method can be used to prepare hydrophobic-hydrophilic PVA blend films [22], which are typically challenging to fabricate due to variations in cosolvent solubility, poor compatibility between the hydrophobic matrix and hydrophilic polymer, and the possibility of phase separation during the film production process [23,24]. PVA and PULL blending generally exhibit immiscibility [13], which can be resolved by applying the suggested saponification method.…”

Poly(vinyl alcohol)/Pullulan/NaCl Conductive Hydrogels with High Strength and Sensitivity for Wearable Strain Sensors

“…Unlike other polysaccharides, pullulan has a higher water solubility without further modification, which enables pullulan to be easily processed in hydrogel preparation. For instance, the composite hydrogels made from PVA/Pullulan were used as a platform for drug delivery, tissue engineering, and wound dressing, but the mechanical properties were not significantly studied. − Teramoto et al found that the blends of Pullulan/PVA films cross-linked with glyoxal showed high tensile strength, yet the Pullulan/PVA composites were in the form of dried films and the potential as wearable sensors has not been explored . Thus, it is indispensable to study the relevant mechanical properties of PVA/Pullulan hydrogels and broaden the scenarios in wearable sensors.…”