Rare earth oxides as nanoadditives in 3-D nanocomposite scaffolds for bone regeneration

Nanocomposite scaffolds of bioactive glass foams containing tailor made rare earth oxide (i.e. nanoceria) additives were demonstrated to enhance the production of collagen by HMSCs (Human Mesenchymal Stem Cells) compared to bioactive glass scaffolds without nanoceria. The addition of osteogenic supplements was not required for this to occur. Two different preparations of nanoceria were successfully incorporated in 3-D bioactive glass foam scaffolds and were compared with bioactive scaffolds without nanoceria. The nanoparticles had individual particle sizes of 3-5 nm while the agglomerate size varied from 5-15 nm. Preliminary investigations show that nanoceria is non toxic to the cells. After 10 days of culture, nanoceria containing scaffolds showed enhanced osteoblastic differentiation of HMSCs and collagen production compared to the scaffolds without nanoceria even in the absence of any osteogenic supplements (i.e. ascorbic acid, dexamethasone and β-glycerophosphate). This could be due to the incorporation of nanoceria, which acts as an oxygen buffer thereby regulating the differentiation of HMSCs. Further investigations are currently underway to determine the role of the nanoceria controlled oxygen buffering on the HMSC differentiation. © 2010 The Royal Society of Chemistry.