title: Evaluation of dense polylactic acid/beta-tricalcium phosphate scaffolds for bone tissue engineering.
abstract: Advances in biomaterial fabrication have introduced numerous innovations in designing scaffolds for bone tissue engineering. Often, the focus has been on fabricating scaffolds with high and interconnected porosity that would allow for cellular seeding and tissue ingrowth. However, such scaffolds typically lack the mechanical strength to sustain in vivo ambulatory stresses in models of load bearing cortical bone reconstruction. In this study, we investigated the microstructural and mechanical properties of dense PLA and PLA/beta-TCP (85:15) scaffolds fabricated using a rapid volume expansion phase separation technique, which embeds uncoated beta-TCP particles within the porous polymer. PLA scaffolds had a volumetric porosity in the range of 30 to 40%. With the embedding of beta-TCP mineral particles, the porosity of the scaffolds was reduced in half, whereas the ultimate compressive and torsional strength were significantly increased. We also investigated the properties of the scaffolds as delivery vehicles for growth factors in vitro and in vivo. The low-surface porosity resulted in sub optimal retention efficiency of the growth factors, and burst release kinetics reflecting surface coating rather than volumetric entrapment, regardless of the scaffold used. When loaded with BMP2 and VEGF and implanted in the quadriceps muscle, PLA/beta-TCP scaffolds did not induce ectopic mineralization but induced a significant 1.8-fold increase in neo vessel formation. In conclusion, dense PLA/beta-TCP scaffolds can be engineered with enhanced mechanical properties and potentially be exploited for localized therapeutic factor delivery.
authors: Department of Biomedical Engineering, University of Rochester, Rochester, New York, USA.
authors: Laura
authors: L
authors: Yanoso-Scholl
authors: Justin A
authors: JA
authors: Jacobson
authors: Gino
authors: G
authors: Bradica
authors: Amy L
authors: AL
authors: Lerner
authors: Regis J
authors: RJ
authors: O'Keefe
authors: Edward M
authors: EM
authors: Schwarz
authors: Michael J
authors: MJ
authors: Zuscik
authors: Hani A
authors: HA
authors: Awad
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D002130:Calcium Phosphates / Q000737:chemistry* / Q000378:metabolism; D019245:Compressive Strength; D020007:Implants, Experimental; D019344:Lactic Acid / Q000737:chemistry* / Q000378:metabolism; D008422:Materials Testing; D051379:Mice; D008810:Mice, Inbred C57BL; D018919:Neovascularization, Physiologic; D010012:Osteogenesis; D011091:Polyesters; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D016062:Porosity; D011994:Recombinant Proteins / Q000378:metabolism; D013314:Stress, Mechanical; D013499:Surface Properties; D023822:Tissue Engineering / Q000295:instrumentation / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D002130:Calcium Phosphates; D011091:Polyesters; D011108:Polymers; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A; C485817:beta-tricalcium phosphate; D019344:Lactic Acid; C033616:poly(lactide)