## 3 Results
### Antibacterial Activity  
Because of their large active surface area, which enables them to readily pierce biofilms, these nanoparticles (NPs) are potent antibacterial agents. Certain metals, including copper (Cu) and silver (Ag), were used as antibacterial agents even before the invention of pharmacological antibiotics. A new class of \"nano-metal-antibiotics\" were developed due to continued progress in this area, which involves investigating different NPs for their antibacterial qualities [58]. Medical research has seen a paradigm change concerning the creation of metal-based antibacterial drugs since the 19 th century when it was discovered that the evolution of illnesses and infections was directly linked [58]. _Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae_ and _Escherichia coli_ are Gram-negative bacterial species that often cause hospital infections. Methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus species are often implicated among Gram-positive bacteria [27]. For our study, we chose to test the sample's efficiency on _Escherichia coli_. For all concentrations of _Escherichia coli_, inoculations were carried out by the flooding method on the culture medium specific for _Escherichia coli_. The method of making bacterial suspensions of different concentrations was carried out by the serial dilution technique, a fact demonstrated by the differentiation of the number of colonies. To demonstrate that the bacterium can grow according to and under the deposited material, _Escherichia coli_ being an aerobic, facultatively anaerobic bacterium [59; 60], a sample was placed with the non-deposited side in contact with the bacterial suspension. Using ImageJ version 2021 software, the zones of the inhibition of _Escherichia coli_ growth were determined, and the diameters in Table 1 were calculated. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Concentration of _Escherichia coli_** & **Sample** & **Bacterial Growth Inhibition Diameter (cm)** \\
**(CFU/mL)** & **Sample** & **(Average \(\pm\) stdev)** \\ \hline \(10^{7}\) & TiO\({}_{2}\)+Ag & 1.21 \(\pm\) 0.032 \\  & SiO\({}_{2}\)+Ag & 0.90 \(\pm\) 0.037 \\ \hline \(2\times 10^{6}\) & TiO\({}_{2}\)+Ag & 1.39 \(\pm\) 0.020 \\  & SiO\({}_{2}\)+Ag & 1.08 \(\pm\) 0.111 \\ \hline \(10^{6}\) & TiO\({}_{2}\)+Ag & 1.26 \(\pm\) 0.0110 \\  & SiO\({}_{2}\)+Ag & 0.97 \(\pm\) 0.025 \\ \hline \(2\times 10^{5}\) & TiO\({}_{2}\)+Ag & 1.55 \(\pm\) 0.004 \\  & SiO\({}_{2}\)+Ag & 1.59 \(\pm\) 0.013 \\ \hline \(10^{5}\) & TiO\({}_{2}\)+Ag & 1.54 \(\pm\) 0.020 \\  & SiO\({}_{2}\)+Ag & 1.51 \(\pm\) 0.104 \\ \hline \(2\times 10^{4}\) & TiO\({}_{2}\)+Ag & 1.71 \(\pm\) 0.033 \\  & SiO\({}_{2}\)+Ag & 1.60 \(\pm\) 0.092 \\ \hline \(10^{4}\) & TiO\({}_{2}\)+Ag & 1.79 \(\pm\) 0.101 \\  & SiO\({}_{2}\)+Ag & 1.84 \(\pm\) 0.004 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Escherichia coli_ growth inhibition diameters under the conditions of different concentrations \(10^{7}\)-\(10^{4}\) CFU/mL, at 37 \({}^{\circ}\)C for 24 h, using films deposited with TiO\({}_{2}\)+Ag and SiO\({}_{2}\)+Ag. From the concentration of \(10^{5}\) CFU/mL to the concentration of \(10^{7}\) CFU/mL, the colonies become uncountable. From concentrations higher than \(10^{6}\) CFU/mL, the high consumption of \(\beta\)-galactosidaseos (compound incorporated in the culture medium) is observed, the medium becoming a green-blue color. The following samples deposited with TiO\({}_{2}\)+Ag, SiO\({}_{2}\)+Ag were tested for the same bacteria concentrations, as well as non-deposited samples to have the original material as a reference. In the case of concentrations higher than \(10^{6}\) CFU/mL, it is observed that the bacterium continues to develop under the deposited film so the composition of the films partially inhibits (only in the central area of the film) the development of _Escherichia coli_. From the concentration of \(2\times 10^{5}\) CFU/mL to \(10^{4}\) CFU/mL, the area where the foil was highlighted--under _Escherichia coli_--did not develop.