Development of soluble glasses for biomedical use Part II: The biological response of human osteoblast cell lines to phosphate-based soluble glasses

Soluble glasses are considered to be of potential clinical value in orthopa edic and dental surgery. However, the biological response to these material s is not well understood. To determine the effects of these glasses, two hu man osteoblast cell lines, MG63 and HOS (TE85), were incubated in vitro in the presence of increasing concentrations of extracts of the glasses. The e ffects of the extracts on cell growth was measured using the MTT assay and an ELISA assay was used to measure the expression of bone sialoprotein (BSP ), osteonectin (ON) and fibronectin (FN), antigens which play a fundamental part in the integrity and function of hard connective tissue. The results showed that the proliferation of the cells was adversely affected only by t he more soluble glasses, which also down-regulated the expression of the bo ne-associated proteins. In contrast, the extract of the glass with the lowe st dissolution rate, which contains relatively elevated levels of Ca2+, was found to enhance bone cell growth and antigen expression. These findings s uggest that the compositions of these glasses at least partly determine the response of cells and thus, that the glasses could be modified to elicit a more optimal biological response and clinical efficacy. (C) 2000 Kluwer Ac ademic Publishers.