Mechanical properties of a biodegradable bone regeneration scaffold

Poly (Propylene Fumarate) (PFF), a novel, bulk erosion, biodegradable polym er, has been shown to have osteoconductive effect in vivo when used as a bo ne regeneration scaffold (Peter, S. J., Suggs, L. J., Yaszemski, M. J., Eng el, P. S., and Mikos, A. J., 1999, J. Biomater. Sci. Polym. Ed., 10, pp. 36 3-373). The material properties of the polymer allow it to be injected into irregularly shaped voids in vivo and provide mechanical stability as well as function as a bone regeneration scaffold. We fabricated a series of biom aterial composites, comprised of varying quantities of PPF, NaCl and beta - tricalcium phosphate (beta -TCP), into the shape of right circular cylinder s and tested the mechanical properties in four-point bending and compressio n. The mean modulus of elasticity in compression (E-c) was 1204.2 MPa (SD 3 2.2) and the mean modulus of elasticity in bending (E-b) was 1274.7 MPa (SD 125.7). All of the moduli were on the order of magnitude of trabecular bon e. Changing the level of NaCl from 20 to 40 percent, by mass, did not decre ase E-c and E-b significantly, but did decrease bending and compressive str ength significantly. Increasing the beta -TCP from 0.25 g/g PPF to 0.5 g/g PPF increase all of the measured mechanical properties of PPF/NVP camposite s. These results indicate that this biodegradable polymer composite is an a ttractive candidate for use as a replacement scaffold for trabecular bone.