EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Bone is a complex living tissue with significant metabolic and regenerative activities which are disrupted when the tissue is damaged. Bone non-union and infection are the leading causes of compromised bone healing, resulting in poor vasculature, decreased cell growth, and the scaffolds' inability to integrate with bone. We have developed multilayered osteoconductive and antibacterial scaffolds, which mimic the natural structure of bone. The synthetic cortical (Type-1) and trabecular (Type-2) bone biomaterials were fabricated from porous titanium embedded with iron-doped brushite minerals and freeze-dried porous chitosan embedded with brushite and cerium oxide nanoparticles, respectively. The biomaterials were combined via a freeze-drying approach.
Type-1 biomaterials were prepared by mixing different ratios of titanium powder with 10% iron-doped brushite mineral. Appropriate quantities of potassium chloride powder (0, 20, 40 (v)%) were added as space holders to create porous structures, and the mixtures were pressed into pellets. Cerium oxide nanoparticles were synthesised by adding 0.3 M aqueous sodium hydroxide solution dropwise to 0.1 M aqueous cerium nitrate hexahydrate solution at 25 °C. The nanoparticles were collected by filtration and washed several times with distilled water, frozen at -80 °C for 24 h, then freeze-dried for 24 h.
Type-2 biomaterials were prepared by dissolving 6g of chitosan flakes in a 2 (v/v)% aqueous acetic acid solution, after which different quantities of brushite minerals (i.e. 20, 30, 40 and 50 (w/v)%) and 5 (w/v)% cerium oxide nanoparticles were added. The mixtures were frozen for 24 h, then freeze-dried at -100 ºC, and 43 millitorrs for 24 h. The synthesised minerals, nanoparticles and multilayered scaffolds were characterised using light-based techniques. The osteoconductivity was investigated via cytotoxicity and osteoblast (cell line G292) proliferation experiments. The antibacterial properties of the scaffolds were investigated against common bone-infection related bacteria, i.e., Escherichia coli, Staphylococcus epidermis and Pseudomonas aeruginosa.