Moldable Composite Bone Grafts Consisting of Calcium Phosphate Cement and Biodegradable Polymer Microspheres: Mechanical Properties and Controlled Release of Bioactive Molecules
C A. Khatri, J F. Hsii, Francis W. Wang
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 mm to 360 mm) did not decrease rapidly until four weeks after the composite was immersed in a saliva-like solution at 37 degrees C. 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.
biocompatible, biodegradable polymers, bone graft composite, calcium phosphate
, Hsii, J.
and Wang, F.
Moldable Composite Bone Grafts Consisting of Calcium Phosphate Cement and Biodegradable Polymer Microspheres: Mechanical Properties and Controlled Release of Bioactive Molecules, Society for Biomaterials Meeting, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=851971
(Accessed December 5, 2023)