title: Effects of designed PLLA and 50:50 PLGA scaffold architectures on bone formation in vivo.
abstract: Biodegradable porous scaffolds have been investigated as an alternative approach to current metal, ceramic, and polymer bone graft substitutes for lost or damaged bone tissues. Although there have been many studies investigating the effects of scaffold architecture on bone formation, many of these scaffolds were fabricated using conventional methods such as salt leaching and phase separation, and were constructed without designed architecture. To study the effects of both designed architecture and material on bone formation, this study designed and fabricated three types of porous scaffold architecture from two biodegradable materials, poly (L-lactic acid) (PLLA) and 50:50 Poly(lactic-co-glycolic acid) (PLGA), using image based design and indirect solid freeform fabrication techniques, seeded them with bone morphogenetic protein-7 transduced human gingival fibroblasts, and implanted them subcutaneously into mice for 4 and 8 weeks. Micro-computed tomography data confirmed that the fabricated porous scaffolds replicated the designed architectures. Histological analysis revealed that the 50:50 PLGA scaffolds degraded but did not maintain their architecture after 4 weeks implantation. However, PLLA scaffolds maintained their architecture at both time points and showed improved bone ingrowth, which followed the internal architecture of the scaffolds. Mechanical properties of both PLLA and 50:50 PLGA scaffolds decreased but PLLA scaffolds maintained greater mechanical properties than 50:50 PLGA after implantation. The increase of mineralized tissue helped support the mechanical properties of bone tissue and scaffold constructs between 4-8 weeks. The results indicate the importance of choice of scaffold materials and computationally designed scaffolds to control tissue formation and mechanical properties for desired bone tissue regeneration.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2099, USA.
authors.forename: Eiji
authors.initials: E
authors.lastname: Saito
authors.forename: Elly E
authors.initials: EE
authors.lastname: Liao
authors.forename: Wei-Wen
authors.initials: WW
authors.lastname: Hu
authors.forename: Paul H
authors.initials: PH
authors.lastname: Krebsbach
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Hollister
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000187:drug effects; D055119:Elastic Modulus / Q000187:drug effects; D006801:Humans; D020007:Implants, Experimental; D019344:Lactic Acid / Q000494:pharmacology*; D051379:Mice; D009929:Organ Size / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D011100:Polyglycolic Acid / Q000494:pharmacology*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*; D055114:X-Ray Microtomography
chemical_list: D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid