关键词: 聚乙烯醇, 海藻酸钠, 复合水凝胶, 载药, 抗菌

Abstract: In recent years, people have paid increasing attention to wound healing, and medical dressings have developed rapidly. Wound dressings can act as a skin protective barrier to prevent wound infection, quickly absorb wound exudate, and guide human tissue regeneration. The ideal dressing material should not only absorb the excess exudation of the wound, but also keep the wound in a proper moist state, effectively avoid the dry necrosis of the wound tissue and prevent secondary infection. Hydrogels, which are a hydrophilic cross-linked polymer network, can maintain a large amount of water by expansion, and perfectly mimic the natural structure of the tissue microenvironment. Due to its porous structure, biodegradability, growth factor incorporation ability and controlled release ability, it is a promising dressing material. In particular, hydrogels can be loaded with antimicrobial materials such as antibiotics, nanoparticles, and natural products to avoid contact with external bacteria and to effectively prevent cross-infection and improve the healing process.
From the perspective of biosafety and anti-infection, we use polyvinyl alcohol (PVA) and sodium alginate (SA) as raw materials to prepare a PVA/SA composite hydrogel with semi-interpenetrating network structure (SIPN) by a green and simple method, namely cyclic freezing-thawing method, to improve the biological characteristics of PVA and the brittleness of SA, and use it as a carrier to better carry Vancomycin hydrochloride (VAN), aiming to achieve a new composite material with excellent biocompatibility, good mechanical properties and antibacterial effect. The morphology and structure were characterized by scanning electron microscope (SEM), infrared spectrometer (FT-IR) and X-ray powder diffractometer (XRD). The swelling degrees, porosities and mechanical properties of PVA/SA@VAN drug-loaded composite hydrogels were analyzed, and their antibacterial properties were explored. The results showed that the PVA/SA@VAN drug-loaded composite hydrogels all showed a three-dimensional porous structure, with uniform pore distribution and a porosity of more than 80%. They swelled rapidly in phosphate buffer solution without dissolution, and the swelling degree could reach 1338%. They had strong water absorption and swelling ability and good mechanical properties. Antibacterial experiments showed that the PVA/SA@VAN drug-loaded composite hydrogel had significant antibacterial effect on Staphylococcus aureus. The results of this study provide a basis for the application of drug-loaded composite hydrogels in wound dressings.
At present, the demand for antibacterial wound dressings that control infection and prevent microbial invasion by releasing fungicides is gradually increasing. The antibacterial composite hydrogel wound dressing prepared in this paper can be used as a short-term dressing candidate for acute wounds. The research results can provide reference for the research of hydrogel wound dressings.

Key words:  , polyvinyl alcohol, sodium alginate, composite hydrogel, drug loaded, antibacterial