GROWTH OF MC3T3-El PRE-OSTEOBLASTS ON BORATE CONTAINING GLASSES & GROWTH OF OSTEOBLASTIC CELLS ON 13-93 GLASS SCAFFOLDS

Three borate-based glasses, compositions designated 1B, 2B, and 3B, with B203 levels of 15, 31, and 46 mole percent (Table 1), respectively, were tested for their effects on the growth of MC3T3-El mouse pre-osteoblastic cells under physiological fluid conditions. Silicate type 45S5 glass was used as a control for comparison. Independently, the biocompatibility of recently developed silicate-based porous 13-93 bioactive glass scaffolds was tested; Saos-2 human osteosarcoma cell line was used. Tests performed for the two studies included: contact assays of cell growth at the glass interface, chemical analysis of borate released into the culture medium, quantitative fluorescence DNA assay of cell proliferation in the presence of the test glasses and scanning electron microscope imaging. The results obtained suggest that 1 B and 2B glasses permit a satisfactory level of MC3T3-El cell growth while the porous 13-93 bioactive glass scaffolds appear highly promising for possible use in bone tissue engineering

Effect of Borate Glass Composition on Its Conversion to Hydroxyapatite and on the Proliferation of MC3T3-E1 Cells

Glasses containing varying amounts of B2O3 were prepared by partially or fully replacing the SiO2 in silicate 45S5 bioactive glass with B2O3. The effects of the B2O3 content of the glass on its conversion to hydroxyapatite (HA) and on the proliferation of MC3T3-E1 cells were investigated in vitro. Conversion of the glasses to HA in dilute (20 mM) K2HPO4 solution was monitored using weight loss and pH measurements. Proliferation of MC3T3-E1 cells was determined qualitatively by assay of cell density at the glass interface after incubation for 1 day and 3 days, and quantitatively by fluorescent measurements of total DNA in cultures incubated for 4 days. Higher B2O3 content of the glass increased the conversion rate to HA, but also resulted in a greater inhibition of cell proliferation under static culture conditions. For a given mass of glass in the culture medium, the inhibition of cell proliferation was alleviated by using glasses with lower B2O3 content, by incubating the cell cultures under dynamic rather than static conditions, or by partially converting the glass to HA prior to cell culture