Injectable photocrosslinkable nanocomposite based on poly(glycerol sebacate) fumarate and hydroxyapatite: development, biocompatibility and bone regeneration in a rat calvarial bone defect model

Aim: An injectable, photocrosslinkable nanocomposite was prepared using a fumarate derivative of poly(glycerol sebacate) and nanohydroxyapatite. Materials & methods: Polymers with varying physical and mechanical properties were synthesized. Furthermore, nanocomposites were developed using a homogenization process by combining nanohydroxyapatite within poly(glycerol sebacate) matrix via photocrosslinking and evaluated both in vitro and in vivo. Results & discussion: The nanocomposites were injectable, highly bioactive and biocompatible. Addition of nanohydroxyapatite led to enhanced mechanical properties with an ultimate strength of 8 MPa. The optimized nanocomposite showed good in vitro cell attachment, proliferation and differentiation of rat bone marrow-derived mesenchymal stem cells. The in vivo evaluation in a rat calvarial bone defect model showed significantly high alkaline phosphatase activity and bone regeneration. Conclusion: This injectable, biocompatible and bioactive in situ hardening composite graft was found to be suitable for load-bearing bone regeneration applications using minimally invasive surgery. Original submitted 17 April 2012; Revised submitted 26 October 2012; Published online 5 February 2013