title: Preconditioned 70S30C bioactive glass foams promote osteogenesis in vivo.
abstract: Bioactive glass scaffolds (70S30C; 70% SiO2 and 30% CaO) produced by a sol-gel foaming process are thought to be suitable matrices for bone tissue regeneration. Previous in vitro data showed bone matrix production and active remodelling in the presence of osteogenic cells. Here we report their ability to act as scaffolds for in vivo bone regeneration in a rat tibial defect model, but only when preconditioned. Pretreatment methods (dry, pre-wetted or preconditioned without blood) for the 70S30C scaffolds were compared against commercial synthetic bone grafts (NovaBone® and Actifuse®). Poor bone ingrowth was found for both dry and wetted sol-gel foams, associated with rapid increase in pH within the scaffolds. Bone ingrowth was quantified through histology and novel micro-CT image analysis. The percentage bone ingrowth into dry, wetted and preconditioned 70S30C scaffolds at 11 weeks were 10±1%, 21±2% and 39±4%, respectively. Only the preconditioned sample showed above 60% material-bone contact, which was similar to that in NovaBone and Actifuse. Unlike the commercial products, preconditioned 70S30C scaffolds degraded and were replaced with new bone. The results suggest that bioactive glass compositions should be redesigned if sol-gel scaffolds are to be used without preconditioning to avoid excess calcium release.
authors.affiliation: Centre for Molecular Biosciences, University of Ulster at Coleraine, Coleraine BT52 1SA, UK.
authors.forename: Swati
authors.initials: S
authors.lastname: Midha
authors.forename: Taek Bo
authors.initials: TB
authors.lastname: Kim
authors.forename: Wouter
authors.initials: W
authors.lastname: van den Bergh
authors.forename: Peter D
authors.initials: PD
authors.lastname: Lee
authors.forename: Julian R
authors.initials: JR
authors.lastname: Jones
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Mitchell
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D005898:Glass / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007091:Image Processing, Computer-Assisted; D020007:Implants, Experimental; D008297:Male; D010012:Osteogenesis / Q000187:drug effects*; D016062:Porosity; D051381:Rats; D017208:Rats, Wistar; D013977:Tibia / Q000000981:diagnostic imaging / Q000187:drug effects / Q000473:pathology / Q000601:surgery; D054457:Tissue Scaffolds / Q000737:chemistry; D014945:Wound Healing / Q000187:drug effects; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials; D017077:Culture Media, Conditioned; C588181:SiO2-CaO glass
keywords: 70S30C; Bioactive glass; Bone regeneration; Rat tibia; X-ray computed tomography