Physical properties contrasted in PVP- based hydrogels wound dressing crosslinked by electron beam and gamma radiation

Abstract

The synthesis of hydrogels using ionizing radiation is an environmentally friendly technique that has seen significant advancement in recent decades. Among ionizing technologies, electron beam (EB) and gamma radiation (GA) are the most commonly employed for the production of hydrogel-based wound dressings. However, the influence of dose rate on the properties of hydrogels synthesized via these methods remains insufficiently explored. This study investigates polyvinylpyrrolidone (PVP)-based hydrogels crosslinked using EB and GA at varying doses (25 kGy, 30 kGy, and 40 kGy), with particular emphasis on dose rate effects. Hydrogels synthesized via EB consistently demonstrated greater swelling capacity compared to those produced using GA. This is likely attributable to EB's higher dose rate and superficial penetration, which promote network heterogeneity and localized regions of reduced crosslink density. In contrast, GA irradiation resulted in more homogeneous and tightly crosslinked networks, thereby limiting water uptake and reducing thermal stability due to oxidative degradation at elevated doses. X-ray diffraction analysis confirmed predominantly amorphous structures, with EB hydrogels at higher doses exhibiting slight structural reorganization, while GA hydrogels displayed increased structural disorder. Overall, the physical properties of PVP-based hydrogels are influenced by the dose rate of ionizing radiation, resulting in distinct differences in microstructure, swelling behaviour, and thermal stability. EB irradiation favours enhanced swelling capacity, minor structural reorganization at higher doses, and preservation of thermal stability. Conversely, GA irradiation yields more uniform crosslinking but induces oxidative degradation at elevated doses. These distinctions should be carefully considered in the context of industrial-scale hydrogel manufacturing.