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Nanotechnology-based fabricated wound dressings are known as appropriate substrates to enhance healing in both acute and chronic wounds. These types of materials have the ability to deliver therapeutic agents. In this study, a wound dressing including heparinized zinc oxide nanoparticles in combination with chitosan and poly(vinyl alcohol) was developed to investigate its antibacterial and regenerative properties in a rat model of full thickness skin wounds. By adding nanoparticles, the mechanical strength increased up to twice as compared to the sample without nanoparticles. In addition, heparin release profile follows the Hixson-Crowell release kinetic. Protein adsorption enhanced by adding nanoparticles in hydrogels and the prepared wound dressings were completely biocompatible. In terms of antibacterial activity, the minimum inhibitory concentration decreased by conjugation of heparin on the surface of zinc oxide nanoparticles compared to the non-functionalized nanoparticles, and, this shows the increased antibacterial synergistic effect by adding heparin to nanoparticles. Furthermore, it was found that the heparinized zinc oxide nanoparticles effectively accelerate wound closure, re-epithelialization and decrease collagen deposition compared to other groups after implantation. Hence, the prepared wound dressings have the capacity to significantly enhance healing of acute wounds.

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.