Degradability and cytocompatibility of tricalcium phosphate/poly(amino acid) composite as bone tissue implants in orthopaedic surgery

Abstract

In this study, a tricalcium phosphate (TCP) and poly (amino acid) copolymer (PAA) biocomposite were fabricated for bone repair and characterized. The results show that the compressive strength of the TCP/PAA composites increased with an increase in the TCP content at TCP contents less than 40 w%. The weight loss of the composite after soaking in phosphate buffered saline for 12 weeks significantly increased with an increase in the TCP content, revealing its good degradability. In addition, the composite maintained adequate mechanical strength during the degradation period because it underwent a surface erosion process. In vitro MG63 cell culture experiments showed that the composite is non-cytotoxic and thus allows cells to adhere, proliferate and differentiate. Osteoid formation was evidenced on the composite surfaces 12 weeks after its implantation into the femoral bone of dogs. Furthermore, the composite combined directly with the host bone tissue without fibrous capsule tissue, and no inflammatory responses were found, showing the good biocompatibility of the composite. It is expected that the composite may be used for the development of bone implants for orthopaedic surgery.

Keywords:

• poly (amino acid)
• biocomposite
• degradation
• biocompatibility
• implantation

Funding

The authors are grateful for the financial support provided by the Scientific Research Starting Foundation for Young Teachers of Sichuan University [grant number 2013SCU11019]; the International Cooperation Project of the Ministry of Science and Technology of China [2013DFB50280]; the National Natural Science Foundation of China [grant number 81271705], [grant number 83171383], [grant number 51173041]; the Major Program of Natural Science Foundation of Shanghai, China [grant number 12JC1416302]; the Key Medical Program of Science and Technology Development of Shanghai [grant number 12nm0500400], [grant number 12441903600].

Acknowledgements

We would also like to acknowledge Dr Huipin Yuan for his assistance with the animal experiments.