GP/CPC Of Different Gelatin Particle Size And Ratio In Repairing Critical-size Bone Defects

Background:Gelatin particles/calcium phosphate cement (GP/CPC), a new bone substitute, is superior to pure CPC for its higher porosity and larger micropores. However, it is unclear whether and, if yes, how the size of GP and the ratio of GP to CPC affect the physical and chemical properties of GP/CPC as well as bone repairing.Purpose:To investigate different influences on GP/CPC repairing critical-size bone defect by making a comparison based on two factors, GP size and GP ratio, focused on their physicochemical and biological properties, as well as their repairing potency for critical-size cranial bone defect.Methods:Four groups of GP/CPC, different in GP size (100-200μm v.s.200-300μm) and ratio (5%v.s.10%), were manufactured and paired. Comparisons were made between these four groups to investigate the differences in physicochemical and biological properties, such as porosity, resistance to compression, ultrastructure, and biocompatibility. Furthermore, a comparison was made between groups in bone histology and newly formed bone inside scaffolds (nBIS) to investigate the repairing potency for critical-size cranial bone defect in the rabbit model.Results:GP ratio made an important role in porosity, as a higher porosity in10%GP group compared with5%GP group. While the factor of GP size made no influence on porosity significantly. Both of GP size and ratio made an effect on resistance to compression, with a highest level in group of100-200μm&5%GP. There was good biocompatibility for these four groups, with no significant difference. As for repairing potency, apart from time, which might be an important factor to achieving better bone histology and nBIS, group of200-300μm&10%GP made a better repairing results compared with other groups. What’s more,10%GP ratio was prior in nBIS compared with5%GP ratio.Conclusion:Both the particle size of GP and its ratio in the GP/CPC affect the properties of the composite biomaterials and their role in bone reparation. In particular, the GP/CPC containing10%GP of200-300μm in size is most suitable to repair critical-size cranial bone defect.