Incorporation of ZnO nanoparticles into heparinised polyvinyl alcohol/chitosan hydrogels for wound dressing application.

Available wound dressings have some major deficiencies including low water vapor transmission rate (WVTR), low absorption of wound fluids, and not providing a suitable and moist environment for wound healing. The main advantage of hydrogels is giving aid to the creation of a moist and cool environment for wound healing and providing high water vapor permeability along with preventing penetration of microbes into the wound surface. Therefore, hydrogels of heparinized polyvinyl alcohol (PVA)/chitosan (CS)/nano zinc oxide (nZnO) were prepared to be used as wound dressing. Samples were characterized via infrared spectrometry (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). In addition, other properties including swelling ratio, water vapor transmission rate, the size of pores, mechanical and thermal properties, cell viability, and antibacterial efficiency were investigated. Water vapor permeability, porosity, and swelling ratio showed a wide range of numerical values that facilitate the use of provided samples as ideal wound dressings. Besides, investigating mechanical and thermal properties exhibited the improvement of mentioned properties by adding nano zinc oxide. Furthermore, Heparin loading was conducted on optimum samples. Heparin release rate decreased and was more sustained by adding nanoparticles compared to hydrogel wound dressings without nZnO. Cell viability of bionanocomposite samples showed no toxicity after loading nanoparticles and this value was >70% for all samples. Antibacterial properties of hydrogel samples can effectively protect wounds especially with an increase nZnO content. Hence, these hydrogels were found applicable as robust wound dressings.