Synthesis and characterization of a collagen based biodegradable polymer initiated by hydroxyapatite nanoparticle for bone regeneration

Synthetic bone graft biomaterials are considered as a potential alternative to the conventional use of bone grafts, due to their limitless supply and lack of disease transmission. Current synthetic bone graft materials generally lack the necessary combination of biological and mechanical properties for use as a bone graft substitute. Bone is a dynamic tissue that serves biological, chemical and mechanical purpose in the body and it is unlikely that a single component synthetic biomaterial can provide the appropriate combination of mechanical integrity and biological stimulation to replace bone. Multicomponent biomaterials need chemical bonding between the components to prevent phase separation after implantation. To obtain covalently bound multicomponent biomaterial with improved biological and mechanical properties, the synthesis of the novel nano hydroxyapatite-poly(lactide-co-glycolide)-collagen (abbreviated as nHAP-PLGA-collagen) biomaterial is described in this dissertation. Biomaterial synthesis was carried out in several steps and spectroscopic and thermal characterization techniques were used to demonstrate the chemical bonding between the components. Physical and mechanical characterization techniques were used to demonstrate the suitability of nHAP-PLGA-collagen in bone regeneration applications. nHAP-PLGA-collagen showed mechanical integrity comparable to human cancellous bone. Human mesenchymal stem cells secreted minerals and matrices on nHAP-PLGA-collagen after culturing for 5 weeks to mitigate strength lost during hydrolytic degradation of the polymer phase. 3D scaffolds of nHAP-PLGA-collagen with appropriate pore size were favorable for hMSC attachment, migration and osteogenic differentiation. Results from biological characterization demonstrated the efficacy of the nHAP-PLGA-collagen to support bone formation. The combination of mechanical integrity and osteogenic bioactivity makes nHAP-PLGA-collagen a promising biomaterial for future use as synthetic substitute for bone grafts.