Antibacterial wound coating based on chitosan and povidone, obtained by 3D printing

The objective of this study was to develop a method for forming an antimicrobial wound coating based on chitosan and polyvinylpyrrolidone using 3D printing technology. The properties of the coating were then studied in vitro and in vivo to improve the treatment outcomes of deep burns. The resulting coating was a 4% hydrogel of medium molecular weight chitosan with the addition of 1% povidone iodine and dermal fibroblasts. After transplantation, the coating was covered with “Foliderm” film. The coating was formed using an extrusion 3D bioprinter, with printing parameters determined experimentally. The samples were first studied in vitro. Scanning electron microscopy was used to evaluate the coating’s microarchitecture and its interaction with dermal fibroblasts. A colorimetric test was conducted to assess cell metabolic activity and cytotoxicity, and antimicrobial activity against reference strains of Staphylococcus aureus was analyzed. An experiment was conducted to evaluate the in vivo properties of the coating. Nineteen male Wistar rats were used in the study. An injury was inflicted that resulted in a deep thermal contact burn, affecting all layers of skin and subcutaneous fatty tissue, with an area of approximately 20 cm2. The animals were divided into three groups: experimental (with the application of the developed coating), comparative (using the traditional and widespread method of treatment with Levomekol ointment) and control (without treatment). The study lasted for 38 days and found that the developed coating is highly biocompatible, atraumatic, elastic, and adheres well to wounds. Chitosan was used to create a porous structure with channels running parallel to each other. The coating cells are evenly distributed on the surface of the matrix, specifically on the walls of the pores. The inclusion of 1% povidone iodine in the polymer resulted in high antimicrobial activity without significantly affecting the activity of the cells in the composition. The experiment on applying a coating for treating deep thermal burns demonstrated that the developed coating had a positive effect on the wound healing process. This effect was characterized by a higher rate of epithelization and a significantly lower incidence of infectious complications compared to other experimental groups. In the histological study, the experimental group outperformed the control and comparison groups in the quality of the formed granulation tissue, the number of newly formed capillaries, and the severity of the local inflammatory process.