OBJECTIVETo investigate the influence of gelatin particle (GP) size and gelatin/calcium phosphate cement (GP/CPC) ratio on repairing potency of comparison artificial bone material.

METHODSComposite GP/CPC materials with different GP size (100~200 μm vs. 200~300 μm) and ratio(5% vs. 10%) were prepared. Physiochemical and biological properties, including porosity, resistance to compression, ultrastructure and biocompatibility were compared among 4 groups of GP/CPC materials. Different GP/CPC materials were used to repair the critical-size cranial bone defect in rabbit model, and the histology and newly formed bone inside scaffolds (nBIS) were examined and compared among different groups.

RESULTSGP/CPC with GP of 200~300 μm possessed larger micropores than that with GP of 100~200 μm (P<0.05). The GP/CPC containing 10% GP had higher porosity than that containing 5% GP (P<0.05). The animal model study showed that more new bone formed in those defects filled with GP/CPC containing 10% GP with 200~300 μm in size compared with GP/CPC containing 5% GP with 100~200 μm in size (P<0.05). While GP/CPC containing 5% GP with 100~200 μm in size showed a higher level of resistance to compression.

CONCLUSIONBoth the particle size of GP and its ratio in the GP/CPC affect the properties of the composite biomaterials and their role in bone repairing. In particular, the GP/CPC containing 10% GP with 200~300 μm in size is most suitable for repairing critical-size cranial bone defect in animal model.