Biomimetics in tissue engineering: in vivo validation of hybrid scaffolds

Objectives: The present in vivo animal study aimed at evaluating the osseointegration of biomimetic bone scaffolds made up of an innovative nanocomposite material. Methods: A novel nanocomposite hybrid ceramo-polymeric material was designed and produced to interact with bone tissue at nanoscale interfaces. The chemical, physical and mechanical properties of the material were analyzed and characterized. The highly bioactive material was designed to fabricate three-dimensional bone scaffolds in order to promote osseointegration through the precipitation of hydroxyapatite nanoinclusions in periimplant bone. The biomimetic nanocomposite was fabricated as a foamed hydrogel swelling in contact with biological fluids. The biofidelity of the scaffolded implant system was simulated in a digital environment and the stress and strain distributions assessed using three-dimensional Finite Element Analysis. The biomimetic properties of the nanocomposite material were validated in vivo in an animal model, using three-dimensional scaffolds around dental implants inserted in tibiae of minipigs. After explantation, such tibiae were subjected to micro-computed tomography scannings to evaluate bone-to-implant and bone-to- scaffold contact. Results: The chemical, physical and mechanical laboratory tests showed high biomimetic properties for the innovative hybrid material. Stress and strain distributions within the physiological range of trabecular adaptive organization (2000-3000 με) were noticed in periimplant bone with the Finite Element Analysis. The micro-CT scannings showed comparable percentages of bone contact at level of both the scaffolds and the titanium of the implants. Conclusions: The innovative hybrid ceramo-polymeric nanomaterial proved to promote accelerated osseointegration in post-surgical early healing phases