Increasing the Potential of Bioactive Glass as a Scaffold for Bone Tissue Engineering

Bioactive glass is known for its potential as a bone scaffold due to its ability to stimulate osteogenesis and differentiation of stem cells into bone cells. In an attempt to investigate if we can increase these potentials, we decorated the structure of the bioactive glass made by the sol-gel technique with 3 peptides sequences from different proteins known for their potentials to stimulate the osteogensis process (fibronectin, BMP-2 and protein kinase CKI). This material was tested with Human Mesenchymal Stem Cells (hMSCs) and MC-3T3 preosteoblasts to see the difference in the effect on uncommitted and committed cells. The bioactive glass sol with and without the peptides was dip coated onto glass cover slips, leading to a film of the material, surface decorated with the peptides of choice. The two cell types were seeded onto the materials in standard proliferation medium without additives for differentiation induction. Cells were also grown on tissue culture treated cover slips with and without differentiation induction media as positive and negative controls, respectively. The cells were grown on the materials for a total of five weeks, and were tested at four time points (weekly from week two) by immunocytochemical assays to investigate the levels of different osteogenic markers (osteopontin, osteocalcin and osteonectin) and by qRT-PCR to investigate the mRNA potential of the same proteins. On the native bioactive glass samples, the hMSCs and the MC-3T3s adhered poorly. On peptide- decorated samples, the hMSC adhered poorly, however, the MC-3T3 cells appear to differentiate at a rate that is equal to or faster than the positive control, indicating that the peptide effect is similar to that achieved by traditional BMP-2 soluble protein techniques. This supports our hypothesis that adding specific peptide sequences known for their effects in cells adhesion, proliferation and differentiation can increase the potential of the bioactive glass as a scaffold for bone tissue engineering. The data, however, leads to some questions regarding the MC-3T3 cell model for use in further studies