title: Bone regeneration in rat calvarial defects implanted with fibrous scaffolds composed of a mixture of silicate and borate bioactive glasses.
abstract: Previous studies have evaluated the capacity of porous scaffolds composed of a single bioactive glass to regenerate bone. In the present study, scaffolds composed of a mixture of two different bioactive glasses (silicate 13-93 and borate 13-93B3) were created and evaluated for their response to osteogenic MLO-A5 cells in vitro and their capacity to regenerate bone in rat calvarial defects in vivo. The scaffolds, which have similar microstructures (porosity=58-67%) and contain 0, 25, 50 and 100 wt.% 13-93B3 glass, were fabricated by thermally bonding randomly oriented short fibers. The silicate 13-93 scaffolds showed a better capacity to support cell proliferation and alkaline phosphatase activity than the scaffolds containing borate 13-93B3 fibers. The amount of new bone formed in the defects implanted with the 13-93 scaffolds at 12 weeks was 31%, compared to values of 25, 17 and 20%, respectively, for the scaffolds containing 25, 50 and 100% 13-93B3 glass. The amount of new bone formed in the 13-93 scaffolds was significantly higher than in the scaffolds containing 50 and 100% 13-93B3 glass. While the 13-93 fibers were only partially converted to hydroxyapatite at 12 weeks, the 13-93B3 fibers were fully converted and formed a tubular morphology. Scaffolds composed of an optimized mixture of silicate and borate bioactive glasses could provide the requisite architecture to guide bone regeneration combined with a controllable degradation rate that could be beneficial for bone and tissue healing.
authors.affiliation: School of Materials Science and Engineering, Tongji University, Shanghai 200092, People's Republic of China.
authors.forename: Yifei
authors.initials: Y
authors.lastname: Gu
authors.forename: Wenhai
authors.initials: W
authors.lastname: Huang
authors.forename: Mohamed N
authors.initials: MN
authors.lastname: Rahaman
authors.forename: Delbert E
authors.initials: DE
authors.lastname: Day
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D001881:Borates / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects; D002460:Cell Line; D017886:Durapatite / Q000737:chemistry; D005898:Glass / Q000737:chemistry*; D020007:Implants, Experimental; D008297:Male; D051379:Mice; D008855:Microscopy, Electron, Scanning; D008970:Molecular Weight; D010012:Osteogenesis / Q000187:drug effects; D016062:Porosity; D051381:Rats; D017207:Rats, Sprague-Dawley; D017640:Silicates / Q000494:pharmacology*; D012886:Skull / Q000187:drug effects / Q000473:pathology*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001881:Borates; D017640:Silicates; D017886:Durapatite; D000469:Alkaline Phosphatase
keywords: Bioactive glass; Bone regeneration; Mineralization; Rat calvarial defect model; Scaffold