Biocomposite films based on chitosan and cerium oxide nanoparticles with promising regenerative potential

Polymeric nanocomposite materials have great potential in the development of tissue-engineered scaffolds because they affect the structure and properties of polymeric materials and regulate cell proliferation and differentiation. In this work, cerium oxide nanoparticles (CeONPs) were incorporated into a chitosan (CS) film to improve the proliferation of multipotent mesenchymal stem cells (MSCs). The citrate-stabilized CeONPs with a negative ζ-potential (−25.0 mV) were precoated with CS to obtain positively charged particles (+20.3 mV) and to prevent their aggregation in the composite solution. The composite CS–CeONP films were prepared in the salt and basic forms using a dry-cast process. The films obtained in both forms were characterized by a uniform distribution of CeONPs. The incorporation of CeONPs into the salt form of CS increased the stiffness of the CS–CeONP film, while the subsequent conversion of the film to the basic form resulted in a decrease in both the Young's modulus and the yield stress. The redox activity (Ce4+ ⇌ Ce3+) of cerium oxide in the CS–CeONP film was confirmed by thermal oxidative degradation. In vitro culture of MSCs showed that the CS–CeONP film has good biocompatibility, and in vivo experiments demonstrated its substantial regenerative potential.