SBIR Phase I: Nanostructured Calcium Phosphate Injectable Cements for Treatment of Osteoporosis

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This Small Business Innovative Research (SBIR) Phase I project aims to develop an injectable orthopedic cement made from oligomers containing cross-linkable functional groups and a reinforcing phase of calcium phosphate nanocrystals that can be injected into low strength bone to provide mechanical strength and bioactivity. This system will have excellent handling properties, remain localized at the injection site, and rapidly harden at body temperature without chemical initiators and with a minimal heat generation, unlike current bone cements. The research will investigate the chemistry of these novel oligomer systems and the effect of calcium phosphate nanocrystal morphology, surface chemistry, and loading by examining properties such as cure time, cure temperature, heat of reaction, rheological behavior, chemical structure, strength and in vitro bioactivity. Commercially, the application provides an alternative surgical cement to what is in current use (in situ polymerization of methylmethacrylate) for total joint replacement. While current methods have been used safely, as the need for a surgical has spread to more sensitive tissues, such as the spine, and new procedures are developed, numerous safety and efficacy issues need to be addressed. About 700,000 vertebral fractures occur annually; patients not responsive to conservative treatment are potential candidates for minimally invasive procedures that use current bone cements off-label to treat vertebral compression fractures. However, leakage of liquid from low viscosity bone cements can result in soft tissue damage as well as nerve root pain and compression. Other reported complications, generally associated with the use of bone cements in the spine, include pulmonary embolism, respiratory and cardiac failure, abdominal intrusions/ileus, and death. The proposed project will alleviate many of these issues and open new methods and mechanisms for the treatment of osteoporosis.