Poly(alpha-hydroxyl acids)/hydroxyapatite porous composites for bone-tissue engineering. I. Preparation and morphology.
Tissue engineering has shown great promise for creating biological alternatives for implants. In this approach, scaffolding plays a pivotal role. Hydroxyapatite mimics the natural bone mineral and has shown good bone-bonding properties. This paper describes the preparation and morphologies of three-dimensional porous composites from poly(L-lactic acid) (PLLA) or poly(D,L-lactic acid-co-glycolic acid) (PLGA) solution and hydroxyapatite (HAP). A thermally induced phase separation technique was used to create the highly porous composite scaffolds for bone-tissue engineering. Freeze drying of the phase-separated polymer/HAP/solvent mixtures produced hard and tough foams with a co-continuous structure of interconnected pores and a polymer/HAP composite skeleton. The microstructure of the pores and the walls was controlled by varying the polymer concentration, HAP content, quenching temperature, polymer, and solvent utilized. The porosity increased with decreasing polymer concentration and HAP content. Foams with porosity as high as 95% were achieved. Pore sizes ranging from several microns to a few hundred microns were obtained. The composite foams showed a significant improvement in mechanical properties over pure polymer foams. They are promising scaffolds for bone-tissue engineering.
Department of Biologic and Materials Sciences, The University of Michigan, Ann Arbor 48109-1078, USA.
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D000268:Adhesiveness; D001672:Biocompatible Materials / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D017886:Durapatite / Q000737:chemistry*; D005612:Freeze Drying; D019344:Lactic Acid / Q000138:chemical synthesis / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009994:Osmolar Concentration; D011091:Polyesters; D011100:Polyglycolic Acid / Q000138:chemical synthesis / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D016062:Porosity; D012997:Solvents; D013696:Temperature
D001672:Biocompatible Materials; D018786:Bone Substitutes; D011091:Polyesters; D011108:Polymers; D012997:Solvents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; C033616:poly(lactide); D017886:Durapatite