Biomimetically Modified Microspheres for Bone Augmentation 3 Biomimetically Modified Poly (2-Hydroxy Ethyl Methacrylate-Co-Methyl

Poly (methyl methacrylate), (PMMA) microspheres are widely used for many orthopaedic and dental infrabony defect filling applications with or without drug loading. However, PMMA microspheres are biologically inert and unable to take part actively in bone bonding or regeneration. In the present study a copolymer of methyl methacrylate, poly(2-hydroxy ethyl methacrylate-co-methyl methacrylate) microspheres of 50-250μm, was prepared by suspension polymerization and crosslinked with ethylene glycol di methacrylate (EGDMA). The microspheres were biomimetically modified by phosphorylation using a phosphorylating medium containing phosphoric acid and urea. The phosphorylated microspheres on immersion in simulated body fluid (SBF), with ionic concentration nearly equal to human blood plasma, induced nucleation of calcium phosphate over the microspheres. The SEM analysis shows that primary coating was complete within 3 days and the Ca/P ratio of the coating increased with increase in immersion time near to that of hydroxyapatite as observed by EDS analysis. The in vitro cell adhesion behaviour of HOS cells on the polymer substrate was performed by seeding the cells on the polymer substrate for one week. The cells adhered and covered the substrate by forming a network, keeping their typical morphology. The phosphorylated microspheres, due to their unique ability to induce in vitro mineralization of bone-like apatite and cell adhesion behaviour could be a potential candidate for bone augmentation. increased bioactivity of the nanoapatite that lead