## 3 Results and Discussion
### Biological Assessments
#### 3.3.3 Cytotoxic Activity  
The cytotoxic activity of the biosynthesized Ag-NPs, the Ag-TiO\({}_{2}\) bmNPs, Ag-SeO\({}_{2}\) bmNP nanoparticles, and _Beta vulgaris_ aqueous extract was evaluated in vitro, applying the MTT assay (Figure 8 and Table S4). WI38 was used as a normal cell line, and HepG2 and MCF-7 were applied as tumor cell lines. The results specified that _Beta vulgaris_ extract revealed the least cytotoxic potency against the tumor cell lines, specifically HepG2 with IC\({}_{50}\) = 67.96 \(\pm\) 3.7 \(\mu\)g/mL and MCF-7 cell lines with IC\({}_{50}\) = 59.20 \(\pm\) 3.3 \(\mu\)g/mL. It was significant to emphasize that the formation of metallic/bimetallic nanoparticles improved the cytotoxicity against the inhibition of cell line growth. Particularly, the Ag NPs revealed improved cytotoxicity against the HepG2 (IC\({}_{50}\) = 39.69 \(\pm\) 2.3 \(\mu\)g/mL) and MCF-7 (IC\({}_{50}\) = 45.40 \(\pm\) 2.5 \(\mu\)g/mL) cell lines in comparison with the results of the plant \begin{table}
\begin{tabular}{c c c} \hline \hline
**Bacterium** & **Nanoparticle** & **Hallow Zone Diameter (mm)** \\ \hline \multirow{3}{*}{_S. aureus_} & Ag-NPs & \(16.7\pm 1.1\) \\ \cline{2-3}  & Ag-SeO\({}_{2}\)-NPs & \(37.7\pm 2.1\) \\ \cline{2-3}  & Ag-TiO\({}_{2}\)-NPs & \(21.3\pm 0.6\) \\ \hline \multirow{3}{*}{_E. faecalis_} & Ag-NPs & \(14.0\pm 1.3\) \\ \cline{2-3}  & Ag-SeO\({}_{2}\)-NPs & \(34.7\pm 1.6\) \\ \cline{2-3}  & Ag-TiO\({}_{2}\)-NPs & \(20.0\pm 2.6\) \\ \hline \multirow{3}{*}{_E. coli_} & Ag-NPs & \(16.7\pm 0.8\) \\ \cline{2-3}  & Ag-SeO\({}_{2}\)-NPs & \(11.7\pm 0.6\) \\ \cline{2-3}  & Ag-TiO\({}_{2}\)-NPs & \(11.0\pm 1.0\) \\ \hline \multirow{3}{*}{_S. enterica_} & Ag-NPs & \(19.7\pm 2.1\) \\ \cline{2-3}  & Ag-SeO\({}_{2}\)-NPs & \(32.7\pm 1.2\) \\ \cline{2-3}  & Ag-TiO\({}_{2}\)-NPs & \(25.0\pm 1.0\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Antibacterial activity of mono- and bimetallic silver-based nanoparticles against some human pathogenic bacteria (average \(\pm\) SD, \(n\) = 3). The aqueous _Beta vulgaris_ L. extract showed no antibacterial activity. extract. Furthermore, the formation of bimetallic nanoparticles improved the cytotoxicity against the tumor cell lines in comparison to the cytotoxic effects of silver nanoparticles. Thus, the Ag-TiO\({}_{2}\) bmNPs revealed strong cytotoxicity against the HepG2 cell line (IC\({}_{50}\) = 18.18 \(\pm\) 1.5 \(\mu\)g/mL). In addition, the Ag-SeO\({}_{2}\) bmNPs displayed a strong cytotoxic effect against the MCF-7 cell line (IC\({}_{50}\) = 17.92 \(\pm\) 1.4 \(\mu\)g/mL). In comparison with the results with doxorubicin, it was noted that the Ag-TiO\({}_{2}\) bmNPs and Ag-SeO\({}_{2}\) bmNPs were the most effective cytotoxic agents acquired from a bio-source, with fewer side effects on the growth of the normal cell line (WI38). Ag-TiO\({}_{2}\) bmNPs are the most appropriate cytotoxic agent against the WI38 cell line, with IC\({}_{50}\) = 83.39 \(\pm\) 4.1 \(\mu\)g/mL; this led to the highest percentage of cell viability. Figures 9 and S2 and Table S5 introduce the percentages of cell viability at different concentrations (1.56-100 \(\mu\)g/mL). The high dose of the samples led to the improved % inhibition against the cell growth in line with the least cell viability. At 100 \(\mu\)g/mL, the Ag-SeO\({}_{2}\) bmNPs displayed the most reduced % of cell viability against both types of tumor cell lines. It still remains that doxorubicin has a great impact on the growth of tumors and normal cell lines. The Ag-TiO\({}_{2}\) bmNPs displayed the most improved cytotoxicity against WI38 cells, with 48.2% viability; at the same time, this nano-solution has good cytotoxicity against the following tumor cell lines: HepG2: 21.4% and MCF-7: 28.3%. The decrease in the dose concentration resulted in increased cell viability percentages. Silver nanoparticles have the most potent cytotoxic effect against WI38 cells at 12.5 \(\mu\)g/mL (93.5%) and have no cytotoxic action at 6.25 and 3.125 \(\mu\)g/mL.