Bioglass-derived glass-ceramic scaffolds: study of cell proliferation and scaffold degradation in vitro

Cell support function as well as cell proliferation on highly porous Bioglass(R)-derived glass-ceramic scaffolds (designed for bone tissue engineering) have been assessed in vitro using osteoblast-like cells (MG 63) cultured for up to 6 days. The biodegradation and mechanical stability of the scaffolds in the cell-culture medium have also been investigated. It was found that the scaffolds had excellent cell supporting ability, with cells effectively infiltrating into and surviving at the center of the scaffolds. A quantitative study using the AlamarBlue assay revealed that the proliferation of cells on the glass-ceramic materials was comparable to that on the noncrystallized Bioglass. While the crystalline phase in the glass-ceramic scaffolds transformed into a biodegradable amorphous calcium phosphate phase during cell culture, the mechanical strength of the scaffolds was maintained when compared with that of scaffolds incubated in simulated body fluid or immersed in cell-free culture medium. It is believed that the attached cells and collagen secreted by cells could fill the micropores and microcracks on the surface of the foam struts, thus contributing to the mechanical stability of the degrading scaffolds. In summary, the developed glass-ceramic scaffolds possess the most essential features of a scaffold for bone tissue engineering: they are capable to support and foster relevant cells, able to provide temporary mechanical function, and biodegradable.