Biological performance of a new β-TCP/PLLA composite material for applications in spine surgery: In vitro and in vivo studies

• Published in: Journal of biomedical materials research. Part A 2006-08, Vol.78A (2), p.416-422
• Main Authors: Aunoble, Stephane, Clément, Denis, Frayssinet, Patrick, Harmand, Marie Francois, Le Huec, Jean Charles
• Format: Article
• Language: English
• Subjects: Animals; Biocompatible Materials; bone substitutes; Calcium Phosphates - pharmacology; Cell Division - drug effects; Humans; Interleukin-1 - secretion; Lactic Acid - pharmacology; Monocytes - secretion; Osteocytes - cytology; Osteocytes - drug effects; Osteogenesis; Polyesters; Polymers - pharmacology; Prostheses and Implants; Rabbits; Spine - surgery; spine arthrodesis; Surface Properties; tricalcium phosphate
• ISSN: 1549-3296; 1552-4965
• DOI: 10.1002/jbm.a.30749

The objective of this research was to carry out an in vitro and in vivo study of the biological performance of PLLA/β‐TCP composite materials, to estimate the scope of their potential applications in bone surgery. Samples with increasing β‐TCP (0–60% w/w) contents were processed by injection molding. The in vitro study consisted of an evaluation of inflammatory potential by assaying the IL‐1α secreted by monocytes, and then cell proliferation (counting) and phenotype expression (PAL and I collagen) in human osteogenous cells. The in vivo study was carried out using cylindrical implants of composite materials composed of composite materials containing 0 or 60% β‐TCP and pure β‐TCP, respectively. The implants were inserted in femoral sites in rabbits, using the Kathagen protocol. Each animal received a 60% implant, with either a 0 or a 100% implant in the contralateral femur, so that the materials could be compared with one another. Five animals were examined for each material and implantation period, giving a total of 30 animals. This study showed that adding increasing percentages of β‐TCP to a lactic acid polymer matrix stimulated the proliferation of human osteogenous cells and synthesis of the extracellular bone matrix in a dose‐dependent manner. In vivo results indicate that, in comparison with pure PLA, tricalcium phosphate‐containing composite materials had faster degradation kinetics, caused less inflammatory reaction, and promoted contact osteogenesis. The composite material containing 60% β‐TCP demonstrated a similar performance to pure tricalcium phosphate bone grafts in terms of osteogenesis, and is apparently compatible with the production of intra‐osseous implants for situations representing high levels of mechanical strain. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006