2025 年 133 巻 1 号 p. 25-33
We have successfully developed a new bioactive borosilicate (4-4) glass fibers with increased silicon content and decreased boron content, fibers of which were prepared by a melt-blow method. In the present study, we evaluated the in vitro degradation and conversion behavior of 4-4 glass fibers using simulated body fluid (SBF) and compared the behavior with those of borate (13-93B3; B3) glass fibers. In addition, to evaluate the effects of 4-4 glass fibers on cellular activity, we compared the effects of 4-4 and B3 glass fibers on cell proliferation and osteogenic differentiation, as assessed using the mouse preosteoblastic cell line MC3T3-E1. Glass fibers were incubated in SBF at 36.5 °C. Weight loss by the 4-4 glass fibers was attenuated compared to that by the B3 glass fibers. Additionally, SBF incubated with the 4-4 glass fibers showed slightly higher pH values than did SBF incubated with the B3 fibers. An analysis of changes in the concentrations of various ions in SBF during these incubations suggested that the precipitates contained calcium and phosphorus. X-ray diffraction analysis detected the presence of apatite peaks at 7 days for both B3 and 4-4 glass fibers. Scanning electron microscope images showed hemispherical structures (heterogeneous nucleation) covering the entire surface of the 4-4 glass fibers after 3 days. Therefore, the formation of apatite on 4-4 glass fibers was superior to that on B3 glass fibers. Moreover, the cell proliferation and osteogenic differentiation of MC3T3-E1 cells in the presence of 4-4 glass fibers was enhanced compared to that in the presence of B3 glass fibers. Together, these results suggested that 4-4 glass fibers might be superior to B3 glass fibers for use as a bone substitute to address bone defects.
