title: Enhanced bone regeneration in rat calvarial defects implanted with surface-modified and BMP-loaded bioactive glass (13-93) scaffolds.
abstract: The repair of large bone defects, such as segmental defects in the long bones of the limbs, is a challenging clinical problem. Our recent work has shown the ability to create porous scaffolds of silicate 13-93 bioactive glass by robocasting which have compressive strengths comparable to human cortical bone. The objective of this study was to evaluate the capacity of those strong porous scaffolds with a grid-like microstructure (porosity=50%; filament width=330μm; pore width=300μm) to regenerate bone in a rat calvarial defect model. Six weeks post-implantation, the amount of new bone formed within the implants was evaluated using histomorphometric analysis. The amount of new bone formed in implants composed of the as-fabricated scaffolds was 32% of the available pore space (area). Pretreating the as-fabricated scaffolds in an aqueous phosphate solution for 1, 3 and 6days to convert a surface layer to hydroxyapatite prior to implantation enhanced new bone formation to 46%, 57% and 45%, respectively. New bone formation in scaffolds pretreated for 1, 3 and 6days and loaded with bone morphogenetic protein-2 (BMP-2) (1μg per defect) was 65%, 61% and 64%, respectively. The results show that converting a surface layer of the glass to hydroxyapatite or loading the surface-treated scaffolds with BMP-2 can significantly improve the capacity of 13-93 bioactive glass scaffolds to regenerate bone in an osseous defect. Based on their mechanical properties evaluated previously and their capacity to regenerate bone found in this study, these 13-93 bioactive glass scaffolds, pretreated or loaded with BMP-2, are promising in structural bone repair.
authors.affiliation: Department of Materials Science and Engineering and Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, Rolla, MO 65409, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.forename: Mohamed N
authors.initials: MN
authors.lastname: Rahaman
authors.forename: Yongxing
authors.initials: Y
authors.lastname: Liu
authors.forename: B Sonny
authors.initials: BS
authors.lastname: Bal
authors.forename: Lynda F
authors.initials: LF
authors.lastname: Bonewald
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage* / Q000737:chemistry; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology*; D003131:Combined Modality Therapy / Q000295:instrumentation / Q000379:methods; D004343:Drug Implants / Q000008:administration & dosage* / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005898:Glass / Q000737:chemistry*; D008297:Male; D008422:Materials Testing; D051381:Rats; D017207:Rats, Sprague-Dawley; D012887:Skull Fractures / Q000473:pathology / Q000503:physiopathology* / Q000628:therapy*; D013499:Surface Properties; D054457:Tissue Scaffolds; D016896:Treatment Outcome
chemical_list: C553965:13-93 bioactive glass; D019485:Bone Morphogenetic Proteins; D004343:Drug Implants