Design of a biodegradable UV-irradiated gelatin-chitosan/nanocomposed membrane with osteogenic ability for application in bone regeneration

Guided bone regeneration membranes are used in oral surgery to protect the site of a lesion exposed to connective tissue invasion which, in turn, prevents new bone formation. Although non-degradable and degradable materials have been applied in clinical treatments, biodegradable membranes have the advantage that they do not require a secondary surgical procedure to be removed. However, they have a very low mechanical strength. As biodegradable membranes, biomaterials based on gelatin-chitosan have gained importance in clinical applications due to their unique properties. Gelatin contains RGD-like sequences, promoting cell adhesion/migration, and it can be blended with chitosan, which allows the immobilization of nanoparticles. In this work, we designed a new gelatin-chitosan polymeric membrane which contains hydroxyapatite and titania nanoparticles as two very well-documented osteoconductive materials. UV radiation was used as a non-toxic cross-linking agent to improve the thermophysical/mechanical characteristics and to control the biodegradability of the nanocomposed membrane. The microstructure, thermophysical and mechanical properties of the UV-irradiated material were studied by scanning electron microscopy, differential scanning calorimetry and Young's modulus, respectively. The in vitro biocompatibility of the new nanocomposite was evaluated by cell adhesion and proliferation assays. The osteoconductive ability was determined by an alkaline phosphatase production assay using mouse embryonic fibroblast (MEF) cells. The results show a homogeneous material with an appropriate distribution of nanoparticles. Cross-linking by UV radiation improved the mechanical and biological performance of the membrane. The presence of two osteoconductive nanoparticles, such as titania and hydroxyapatite, increased the osteogenic potential of the gelatin-based material in vitro, which confers a biological function, in addition to functioning as a physical barrier. The material obtained herein represents a good alternative to current guided bone regeneration membranes, with high potential for use in oral/orthopaedic applications in patients.