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.

The effect of serum proteins on apatite growth for 45S5 Bioglass and common sol-gel derived glass in SBF

“…This verified that calcium in TG was depleted after immersion in pSBF, leaving a network of silica. This supports in vivo results on porous scaffolds of the same sol-gel derived bioactive glass (70 mol% SiO 2 and 30 mol% CaO), that calcium release is too rapid from that composition [28]. The in vivo results showed that, while the scaffolds were not toxic, the calcium dissolution inside the pore structure caused a pH rise that promoted bone growth around the scaffold, rather than through it.…”

Addition of WEEE Glass to Metakaolin-Based Geopolymeric Binder: A Cytotoxicity Study

“…Those materials are able to stimulate osteogenesis via both their dissolution and degradation products. Soluble silica ions activate and stimulate osteoprogenitor cells at the implant site, promoting bone tissue growth [29,30].…”

Controlling particle size in the Stöber process and incorporation of calcium

“…The objectives of this paper were to: i) Revisit the original Stöber process to provide a comprehensive understanding of how to reliably control particle size, whilst maintaining monodispersed particles; ii) Investigate the subsequent incorporation of calcium with complete quantitative characterisation of the nanoparticles to prove the incorporation of calcium, with the 70S30C composition (70 mol% SiO2, 30 mol% CaO) [32][33][34] as the target value; iii) Assess the dissolution of the particles in artificial lysosomal fluid (ALF) and Simulated Body Fluid (SBF) to determine how they might degrade in the body.…”