title: Fabrication and characterization of poly(DL-lactic-co-glycolic acid)/zirconia-hybridized amorphous calcium phosphate composites.
abstract: Several minerals, such as hydroxyapatite and beta-tricalcium phosphate, have been incorporated into bioresorbable polyester bone scaffolds to increase the osteoconductivity both in vitro and in vivo. More soluble forms of calcium phosphate that release calcium and phosphate ions have been postulated as factors that increase osteoblast differentiation and mineralization. Recently, a zirconia-hybridized pyrophosphate-stabilized amorphous calcium phosphate (Zr-ACP) has been synthesized allowing controlled release of calcium and phosphate ions. When incorporated into bioresorbable scaffolds, Zr-ACP has the potential to induce osteoconductivity. In this study, 80-90% (w/v) porous poly(DL-lactic-co-glycolic acid) (PLGA) scaffolds were formed by thermal phase separation from dioxane while incorporating Zr-ACP. Scanning electron microscopy revealed a highly porous structure with a pore size ranging from a few microm to about 100 microm, smaller than we had hoped for. Zr-ACP particles were evenly dispersed in the composite structure and incorporated into the pore walls. The amorphous structure of the Zr-ACP was maintained during composite fabrication, as found by X-ray diffraction. Composite scaffolds had larger compressive yield strengths and moduli compared to pure polymer scaffolds. These initial efforts demonstrate that PLGA/Zr-ACP composites can be formed in ways that ultimately serve as promising bone scaffolds in tissue engineering.
authors.affiliation: School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0298, USA.
authors.forename: Bryce M
authors.initials: BM
authors.lastname: Whited
authors.forename: Aaron S
authors.initials: AS
authors.lastname: Goldstein
authors.forename: Drago
authors.initials: D
authors.lastname: Skrtic
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Love
mesh_terms: D018786:Bone Substitutes / Q000138:chemical synthesis* / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D019245:Compressive Strength; D019344:Lactic Acid / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry*; D016062:Porosity; D012997:Solvents / Q000737:chemistry; D023822:Tissue Engineering; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D002712:Chlorides; D011108:Polymers; D012997:Solvents; C519480:amorphous calcium phosphate; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C020243:calcium phosphate; D015040:Zirconium; C429984:zirconium chloride