## 4 Discussion  
The XRD analysis, Figure 2, revealed that the phase compositions of the MBG specimens treated with varying concentrations (un-doped, Ag-doped, Ce-doped, and Ag-Ce co-doped MBG), HCl acid catalysts, and Pluronic F-127 surfactant were all characterized as amorphous except for the 5.75 mol% Ag-doped MBG. These findings suggest that the MBG specimens were successfully synthesized and that the concentration treatments had no effect on the chemical or phase composition of the spray-pyrolyzed MBG specimens, except for 5.75 mol% Ag-doped MBG. Furthermore, according to the FE-SEM morphology figures (Figure 3), all MBG specimens have a smoothed sphere morphology with no irregular shapes and nanosized particles (less than 100 nm) formed, indicating that un-doped, Ag-doped, Ce-doped, and Ag-Ce co-doped MBG specimens went through the \"gas-to-particle\" conversion rather than the \"one-particle-per-droplet\" conversion [64]. Table 2 shows the surface area, pore volume, and pore size statistics. At high relative pressures, all MBG samples display type IV isotherms, indicative of a mesoporous structure, with type H1 hysteresis loops and a strong capillary condensation step, as shown in Figure 6. As a result of the produced Si-O-Ag or Ce bonds taking up more space in the mesoporous channels, the pore volume and specific surface area decreased (the addition of silver and cerium disrupted the structure of the mesoporous silica) [65] when we increased the concentration of Ag and Ce ions. However, the mesoporous materials' distinctive textural features imply that the surface properties, particularly the ultrahigh specific surface area, play a significant role in enhancing the apatite-forming ability [2]. The formation of apatite is significantly accelerated by ultrahigh-specific surface area (over 100 m\({}^{2}\)/g [66]), and this material has unique features that make it particularly appealing for biomedical applications. As a result, all MBGs exhibited remarkably high specific surface areas, with the exception of the 5.75 mol% Ce-doped MBG, which demonstrated a considerably lower specific surface area, approximately one-third of the other samples. The remaining MBGs were specifically developed for applications involving bone defects. Besides the specific surface area, the concentration of the dopant played an essential role in influencing the surface characteristics  
Figure 11: Cell Viability test of un-doped MBG, 2.87 mol% Ag-doped, 5.75 mol% Ag-doped, 2.87 mol% Ce-doped, 5.75 mol% Ce-doped, and 2.87 mol% Ag/2.87 mol% Ce co-doped MBG during 72 h (\(n=3\), \({}^{*}\)\(p<0.05\) and \({}^{**}\)\(p<0.001\)). and the surface chemistry, which, consequently, exerted a substantial influence on bacterial activity and in vitro bioactivity. Significantly, the results of our study emphasize the antibacterial effectiveness of dopants, which is dependent on their concentration. The un-doped MBG demonstrated the least effectiveness, with a reduction of only 3%. This emphasizes the importance of doping in enhancing the potential for antibacterial activity. Moving up the scale, the MBG doped with 2.87 mol% of cerium displayed limited bactericidal activity at 6.67%, suggesting that cerium ions alone may not be as effective against _E. coli_. In contrast, the MBG doped with 5.75 mol% of cerium exhibited moderate antibacterial effects with a reduction of 63.33%, indicating the potential of cerium ions. Additionally, the MBG doped with 2.87 mol% of silver demonstrated significant efficacy, eliminating 86.6% of _E. coli_, thereby emphasizing the role of silver ions. The most impressive bactericidal performance was observed in the MBG doped with 5.75 mol% of silver and the MBG co-doped with 2.87 mol% of silver and 2.87 mol% of cerium, as they completely eradicated _E. coli_ within 24 h. This can be attributed to the strong antibacterial properties of silver ions. Importantly, the results of our study emphasize the effectiveness of dopants in preventing bacterial growth, which is dependent on their concentration.