Influence of surface morphology of chitosan films modified by chitin nanofibrils on their biological properties

•Chitosan-chitin composite film are characterized by their oriented structure.•Chitosan macromolecules self-organize on the chitin nanofibrils surface.•Chitin nanofibrils enhances mechanical properties, specific conductivity, proliferative activity of fibroblasts on the composite surface.•Optimal concentration of chitin nanofibrils in the composite film is 5 wt.%. The paper is devoted to the study of influence of chitin nanofibrils on the structure, surface morphology, mechanical properties, and electrical conductivity of chitosan-based composite films intended for use in biomedical technologies. It was demonstrated that the optimal concentration of chitin nanofibrils in the composite film is 5 wt.%. For the films of this composition, we observed orientation of structural elements on film surface, enhanced mechanical properties as well as an increase in both specific conductivity and proliferative activity of skin fibroblasts on film surface. These results are related to the appearance of oriented structure in nanocomposites and to self-organization of chitosan macromolecules on the surface of chitin nanofibrils. It was revealed that increase in surface energy and surface hydrophilicity did not facilitate effective adhesion, viability and proliferative activity of cells during cultivation on the surface of composite films.