## 3 Results
The pH value of BG dramatically changed after soaking in SBF for 7 days, and the pH value increased to 8.0. This can be due to the basic ions being released in great amounts. The pH value of SiO2 was stable and decreased slightly after soaking in SBF for 7 days, according to the HA deposition on the samples. The pH value of BG_Ti100 obviously increased to 7.8 at the first stage due to the basic ions being released. For BG_Ti25, BG_Ti50, and BG_Ti75, pH values were very close to this, ranging from 7.4 to 7.6, after 7 days soaking in SBF. Figure 4 shows several types of ion released in SBF after the immersion of bioceramics composed of silica and titanium oxide with various concentrations of titanium oxide for 7 days, measured using ICP-MS. As shown in Figure 4a, BG released no titanium ions. The BG_Ti25 sample released very  
Figure 3: The pH value of SBF after the immersion of bioceramics composed of silica and titanium oxide with various concentrations of titanium oxide for 7 days. Figure 2: Phase identification by XRD of bioceramics composed of silica and titanium oxide with various concentrations of titanium oxide soaking in SBF for (**a**) 0 days and (**b**) 7 days. little titanium ions (approximately 0.07 ppm) after 7 days of soaking; BG_Ti50, BG_Ti75, and BG_Ti100 released approximately similar concentrations of titanium ions after 7 days soaking. As shown in Figure 4b, BG and BG_Ti25 released the highest concentration of silica ion after 7 days, and BG_Ti50, BG_Ti75, and BG_Ti100 released a similar amount of silica ions at 7 days, and it was worth noting that the concentration of silica of BG_Ti100 varied drastically from time to time. As shown in Figure 4c, BG released the most calcium ion at 7 days. The other bioceramics composed of titanium oxide and silica released similar amounts of calcium ion at 7 days, except BG_Ti100, which released calcium concentrations that varied drastically. The others had a released calcium concentration that remained stable after 1 day. As shown in Figure 4d, BG_Ti25, BG_Ti75, and BG_Ti100 released approximately similar concentrations of phosphate ion. In this regard, the sample that released the lowest concentration was BG_Ti50, followed by BG, at 7 days. Figure 5 shows the morphology of MG63 cells incubating for 1 day in each type of extraction. Cells incubating in DMEM (Figure 5a) and PBS (Figure 5c) grew normally. In DMSO (Figure 5b), for BG (Figure 5d) and BG_Ti25 (Figure 5e), almost all the cells died and changed their shape. Cells incubating in BG_Ti50 (Figure 5f), BG_Ti75 (Figure 5g), and BG_Ti100 (Figure 5h) were alive and showed similar cell morphology. Figure 4: The ions released into SBF after the immersion of bioceramics composed of silica and titanium oxide with various concentrations of titanium oxide for 7 days, measured using ICP-MS. (**a**) Ti ion concentrations; (**b**) Si ion concentrations; (**c**) Ca ion concentrations; and (**d**) P ion concentrations. Figure 6 shows the cell toxicity test results of MG63 cells incubating for 1 day in each type extraction. The OD value of PBS did not show an evident difference with DMEM, and this means that PBS was a successful negative control group. Whereas the OD value of BG_Ti75 was higher than DMEM in one deviation, but the OD value of the other extractions were far lower than DMEM. Figure 5: The cell morphology of MG63 cells incubating for 1 day in **(a)** [PERSON]’s modified Eagle medium (DMEM); **(b)** dimethyl sulfoxide (DMSO); **(c)** phosphate buffered saline (PBS), **(d)** the extraction of bioglass; and **(e–h)** the extractions of biocercamics composed of silica and titanium oxide with various concentrations of titanium oxide.