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Moldable, Resorbable, Composite Bone Grafts Consisting of Calcium Phosphate Cement and Polymeric Microspheres: Mechanical Properties, Degradation Kinetics and Release of Bioactive Molecules

Published

Author(s)

Francis W. Wang, C A. Khatri, J F. Hsii, S Hirayama, Shozo Takagi

Abstract

We have developed new moldable, resorbable, composite bone grafts made of calcium phosphate cement (CPC) and poly(d,l-lactide-co-glycolide) [PLGA] microspheres or other porogens that allow control release of growth factors. The mass of the PLGA/CPC composite containing 60 % by volume of PLGA microspheres (170 - 360 mm) did not decrease rapidly until four weeks after the composite was immersed in a saliva-like solution at 37 oC. However, the mass loss of the composite due to the degradation of PLGA microspheres was complete in seven weeks. Two types of PLGA/CPC composite bone grafts that contained 60 % by volume of PLGA microspheres were used to measure the release of Protein A, a model for growth factors. In the first type, all the microspheres contained Protein A, while in the second type, 35 % of the microspheres contained Protein A and 65 % did not. For both composites, approximately half of the extractable Protein A was released in 170 h. Protein A was also directly added to the liquid component of the CPC modified with 60% by volume of poly(d,l-lactide) [PLA] microspheres. In this case, approximately half of the extractable Protein A was released in 140 h. The release patterns of Protein A from composites that contained, respectively, 0 %, 35 % and 60 % by volume of mannitol crystals were different. Thus, the release patterns of Protein A from the new composite bone grafts can be modulated by varying the types of porogens and their volume fractions.
Citation
Journal of Biomedical Materials Research

Keywords

biocompatible, biodegradable polymers, bone graft composite, calcium phosphate

Citation

Wang, F. , Khatri, C. , Hsii, J. , Hirayama, S. and Takagi, S. (2008), Moldable, Resorbable, Composite Bone Grafts Consisting of Calcium Phosphate Cement and Polymeric Microspheres: Mechanical Properties, Degradation Kinetics and Release of Bioactive Molecules, Journal of Biomedical Materials Research (Accessed May 20, 2024)

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Created October 16, 2008