Metal Oxide Substituted Polyurethane foams for enhanced craniofacial bone repair: Exploring the properties of Cerium, Zirconium and Copper doped Zinc oxide nanoparticles as potential additive for bone regeneration and angiogenesis.

Zinc oxide containing bone regenerative scaffolds have great potential in bone tissue
engineering since zinc oxide has multifunctional properties and is one of the most researched
metal oxide. Zinc oxide have been synthesized via different methods and in different
morphologies such as nanowires, rods and nanoparticles. It is a known antibacterial agent
and can promote cell growth, differentiation, and angiogenesis. Within this thesis, cerium,
zirconium and copper doped zinc oxides were synthesized using eco-friendly continuous
hydrothermal flow system. The nanoparticles were characterized and change in particle size
and morphology was seen. The zirconium doping resulted in smallest particle size i.e. from
83 nm (ZnO_2) to 45 nm (ZrZnO5). The porous polyurethane-hydroxyapatite scaffolds
containing doped zinc oxides were fabricated using freeze extraction salt leaching process.
The 1% CeZnO5, ZrZnO5 and CuZnO5 was added to polyurethane-hydroxyapatite scaffold.
The cell seeding efficiency data revealed 60% cell adhesion for PU-HA-CeZnO5 scaffold, 45%
cell adhesion for PU-HA-ZrZnO5 and 80% for PU-HA-CuZnO5 scaffolds when compared with
PU only or PU-HA and PU-HA-ZnO_2. The cell metabolic activity assay revealed highest cell
metabolic activity for scaffolds incorporated with doped zinc oxide nanoparticles. The raised
ALP levels were also detected with doped zinc oxide incorporated scaffolds which is an early
marker for bone regeneration. The current data suggested that the doped zinc oxide
nanoparticles can be used as additives for bone regenerative applications and angiogenesis.