Poly(α-Hydroxy Ester)/Short Fiber Hydroxyapatite Composite Foams for Orthopedic Application

Abstract

AbstractA process has been developed to manufacture biodegradable composite foams of poly(DL-lactic- co-glycolic acid) (PLGA) and hydroxyapatite short fibers for use in bone regeneration. The processing technique allows the manufacture of three-dimensional foam scaffolds and involves the formation of a composite material consisting of a porogen material (either gelatin microspheres or salt particles) and hydroxyapatite short fibers embedded in a PLGA matrix. After the porogen is leached out, an open-cell composite foam remains which has a pore size and morphology defined by the porogen. The foam porosity can be controlled by altering the volume fraction of porogen used to make the composite material. Foams made using NaCl particles as a porogen were manufactured with porosities as high as 0.84±0.01 (n=3). The short hydroxyapatite fibers served to reinforce the PLGA. The compressive yield strength of foams manufactured using gelatin microspheres as a porogen was found to increase with fiber content. Foams with compressive yield strengths up to 2.82±0.63 MPa (n=3) with porosities of 0.47±0.01 (n=3) were manufactured using 30% by weight hydroxyapatite fibers in the initial composite prior to leaching. These composite foams with improved mechanical properties may also be expected to have enhanced osteoconductivity and hence provide a novel material which may prove useful in the field of bone regeneration.