Degradable biocomposite of nano calcium- deficient hydroxyapatite-multi(amino acid) copolymer

Hong Li¹, Min Gong¹, Aiping Yang¹, Jian Ma², Xiangde Li³, Yonggang Yan<sup>1

1</sup>School of Physical Science and Technology, Sichuan University, Chengdu People’s Republic of China; ²Hospital of Stomatology, Tongji University, ShanghaiPeople’s Republic of China; ³Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China

Background and methods: A nano calcium-deficient hydroxyapatite (n-CDHA)-multi(amino acid) copolymer (MAC) composite bone substitute biomaterial was prepared using an in situ polymerization method. The composition, structure, and compressive strength of the composite was characterized, and the in vitro degradability in phosphate-buffered solution and preliminary cell responses to the composite were investigated.
Results: The composite comprised n-CDHA and an amide linkage copolymer. The compressive strength of the composite was in the range of 88–129 MPa, varying with the amount of n-CDHA in the MAC (ranging from 10 wt% to 50 wt%). Weight loss from the composite increased (from 32.2 wt% to 44.3 wt%) with increasing n-CDHA content (from 10 wt% to 40 wt%) in the MAC after the composite was soaked in phosphate-buffered solution for 12 weeks. The pH of the soaking medium varied from 6.9 to 7.5. MG-63 cells with an osteogenic phenotype were well adhered and spread on the composite surface. Viability and differentiation increased with time, indicating that the composite had no negative effects on MG-63 cells.
Conclusion: The n-CDHA-MAC composite had good cytocompatibility and has potential to be used as a bone substitute.

Keywords: calcium deficient hydroxyapatite, multi(amino acid) copolymer, biocomposite, degradability, cytocompatibility