title: Hydroxyapatite fiber reinforced poly(alpha-hydroxy ester) foams for bone regeneration.
abstract: A 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. By changing the weight fraction of the leachable component it was possible to produce composite foams with controlled porosities ranging from 0.47 +/- 0.02 to 0.85 +/- 0.01 (n = 3). Up to a polymer:fiber ratio of 7:6, short hydroxyapatite fibers served to reinforce low-porosity PLGA foams manufactured using gelatin microspheres as a porogen. Foams with a compressive yield strength up to 2.82 +/- 0.63 MPa (n = 3) and a porosity of 0.47 +/- 0.02 (n = 3) were manufactured using a polymer:fiber weight ratio of 7:6. In contrast, high-porosity composite foams (up to 0.81 +/- 0.02, n = 3) suitable for cell seeding were not reinforced by the introduction of increasing quantities of hydroxyapatite short fibers. We were therefore able to manufacture high-porosity foams which may be seeded with cells but which have minimal compressive yield strength, or low porosity foams with enhanced osteoconductivity and compressive yield strength.
authors.affiliation: Institute of Biosciences and Bioengineering and Department of Chemical Engineering, Rice University, Houston, TX 77005-1892, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Thomson
authors.forename: M J
authors.initials: MJ
authors.lastname: Yaszemski
authors.forename: J M
authors.initials: JM
authors.lastname: Powers
authors.forename: A G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D001861:Bone Regeneration; D019245:Compressive Strength; D017886:Durapatite / Q000737:chemistry*; D048091:Guided Tissue Regeneration / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry*; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D016062:Porosity
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D017886:Durapatite