A novel approach to bone replacement involves the use of in situ crosslinkable biomaterials as scaffolds for cell transplantation and to promote matrix production and tissue growth. Hydrogel/apatite nanocomposites are the ideal biomaterial to mimic the physio-chemical and biologic properties of the bone matrix and to fabricate scaffolds for bone regeneration. The objective of this work was to investigate the effect of a glutamic acid sequence on osteonectin on shear strength of poly(lactide-ethylene oxide-fumarate)/apatite composites. HA nanoparticles were grafted in two steps with hydrophilic unsaturated poly(ethylene glycol) oligomers to improve their suspension stability and interfacial bonding to the hydrogel phase. Poly(lactide-ethylene oxide-fumarate) (PLEOF) unsaturated terpolymer was synthesized by condensation polymerization of low molecular weight PLA and poly(ethylene glycol) (PEG). The 6-glutamic acid sequence derived from osteonectin was synthesized in the solid phase and one end of the chain was functionalized with an acrylate group (Ac-6Glu) in the solid phase. Hydrogel/apatite porous scaffolds were prepared using PLEOF as the degradable macromer, an MMP degradable peptide crosslinker, Ac-6Glu linker, and a neutral redox initiation system. The shear modulus of the samples with Ac-6Glu linker was 2.5 times higher than the sampless crosslinked without Ac-6Glu. These results demonstarte that the 6-mer glutamic acid sequence on osteonectin significantly affects the mechanical properties of the bone matrix.

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