## 3 Results and Discussion
In our studies, we limited cell observations to less than 4 h because the ESR signal disappeared after that. The purpose of our research was also not to verify the influence of a magnetic field on  
Figure 5: Decrease in free radical concentration with time after incubation of yeast cells with TEMPOL-functionalized magnetite nanoparticles without a magnetic field (control sample) and on a neodymium magnet (red line for samples taken from the focusing point and green line from the edge of a Petri dish). The data for each point are shown as the mean value \(\pm\) 5% of ESR accuracy. The results exhibit statistically significant differences (one-way ANOVA test, significance level 0.05). biological effects in yeast cells. In the future, microscopic observations could be repeated by extending the time and changing the culture conditions with additional biological tests. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Time** & **Control** & **YC + MNPs 1** & **YC + MNPs + NM 2** \\
**(h)** & **Sample (\(\times\)10\({}^{6}\)/mL)** & **(\(\times\)10\({}^{6}\)/mL)** & **(\(\times\)10\({}^{6}\)/mL)** \\ \hline
0 N & 305 \(\pm\) 46 & 255 \(\pm\) 38 & 282 \(\pm\) 42 \\
0.75 N & 349 \(\pm\) 52 & 327 \(\pm\) 49 & 262 \(\pm\) 39 \\
1.5 N & 355 \(\pm\) 53 & 274 \(\pm\) 41 & 373 \(\pm\) 56 \\
2.25 N & 269 \(\pm\) 40 & 390 \(\pm\) 59 & 383 \(\pm\) 58 \\
3 N & 343 \(\pm\) 52 & 380 \(\pm\) 57 & 363 \(\pm\) 55 \\
3.75 N & 326 \(\pm\) 49 & 385 \(\pm\) 58 & 339 \(\pm\) 51 \\ \hline \hline \end{tabular} 1
[FOOTNOTE:1]Footnote 1: Yeast cells with TEMPOL-functionalized magnetite nanoparticles kept in a rotating magnetic field during 15 min before incubation. 3  
\end{table} 
Table 1: The number of yeast cells in individual samples for the experiment with a neodymium magnet (mean value \(\pm\) SD). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Time** & **Control** & **YC + MNPs 1** & **YC + MNPs + 15 2** & **YC + MNPs + 30 3** \\
**(h)** & **Sample (\(\times\)10\({}^{6}\)/mL)** & **(\(\times\)10\({}^{6}\)/mL)** & **(\(\times\)10\({}^{6}\)/mL)** & **(\(\times\)10\({}^{6}\)/mL)** \\ \hline
0 N & 359 \(\pm\) 54 & 332 \(\pm\) 49 & 336 \(\pm\) 50 & 270 \(\pm\) 40 \\
0.75 Y & 354 \(\pm\) 53 & 424 \(\pm\) 64 & 271 \(\pm\) 41 & 273 \(\pm\) 40 \\
1.5 Y & 391 \(\pm\) 59 & 396 \(\pm\) 59 & 396 \(\pm\) 61 & 260 \(\pm\) 39 \\
2.25 N & 332 \(\pm\) 50 & 360 \(\pm\) 54 & 332 \(\pm\) 50 & 322 \(\pm\) 48 \\
3 N & 400 \(\pm\) 60 & 352 \(\pm\) 53 & 357 \(\pm\) 54 & 347 \(\pm\) 52 \\
3.75 N & 376 \(\pm\) 56 & 321 \(\pm\) 48 & 452 \(\pm\) 68 & 340 \(\pm\) 51 \\ \hline \hline \end{tabular} 1
[FOOTNOTE:1]Footnote 1: footnotetext: Yeast cells with TEMPOL-functionalized magnetite nanoparticles. 2 Yeast cells with TEMPOL-functionalized magnetite nanoparticles kept in a rotating magnetic field during 15 min before incubation. 3  
\end{table} 
Table 2: The number of yeast cells in individual samples for the experiment with a rotating magnetic field (mean value \(\pm\) SD). Figure 6: Decrease in free radical concentration with time after incubation of yeast cells with TEMPOL functionalized magnetite nanoparticles incubated without a magnetic field (control sample): (**a**) samples kept in a rotating magnetic field for 15 and 30 min; (**b**) samples kept in a rotating magnetic field for 15 min. The data for each point are shown as the mean value \(\pm\) 5% of ESR accuracy. The results exhibit statistically significant differences after 1.5 h and 2.25 h (**a**), and 0.75 h and 1.5 h (**b**) (one-way ANOVA test, significance level 0.05). The toxic effects of nanoparticles, including iron oxide nanoparticles, are described in the literature [60]. The studies cover both mammalian cells and yeast cells. In the study with yeast cells, uncoated nanoparticles were used, and mainly no negative impact on cell growth was observed. However, there are also studies in which the negative effects of such nanoparticles on yeast cell viability, apoptosis, and ROS generation were noticed.