In this paper, iron oxide nanoparticles coated with trisodium citrate were obtained. Nanoparticles self-assembling stable clusters were ~10 and 50–80 nm in size, consisting of NPs 3 nm in size. The stability was controlled by using multi-angle dynamic light scattering and the zeta potential, which was −32 ± 2 mV. Clusters from TSC-IONPs can be destroyed when interacting with a hen egg-white lysozyme. After the destruction of the nanoparticles and proteins, aggregates are formed quickly, within 5–10 min. Their sizes depend on the concentration of the lysozyme and nanoparticles and can reach micron sizes. It is shown that individual protein molecules can be isolated from the formed aggregates under shaking. Such aggregation was observed by several methods: multi-angle dynamic light scattering, optical absorption, fluorescence spectroscopy, TEM, and optical microscopy. It is important to note that the concentrations of NPs at which the protein aggregation took place were also toxic to cells. There was a sharp decrease in the survival of mouse fibroblasts (Fe concentration ~75–100 μM), while the ratio of apoptotic to all dead cells increased. Additionally, at low concentrations of NPs, an increase in cell size was observed.

It has been shown that low-temperature non-equilibrium piezoelectric direct discharge plasma exerts a dose-dependent cytotoxic effect on a HeLa cell culture. Doxorubicin, an antitumor antibiotic, potentiates this effect of cold plasma, while dihydroquercetin, as an antioxidant, attenuates it.

The effect of pH and temperature on the interaction of sodium citrate-coated magnetic iron oxide nanoparticles (IONPs) with the BSA protein was studied using optical methods. The optical properties of aqueous colloids of BSA, IONPs, and BSA with IONPs were studied with pH changes in the range of 2–12 and temperature in the range of 25–85 °C. It was found that at pH 2.0, no significant changes in the optical properties were observed with increasing temperature in aqueous colloids containing a mixture of BSA with IONPs. Temperature affects the optical properties of BSA colloids with IONPs in the pH range from 5.0 to 8.0. Moreover, by increasing the temperature at these pH levels, it is possible to control the particle size in the colloids. In general, both temperature and pH have a significant effect on the properties of the aqueous colloid of BSA with IONPs and allow for the control of interactions between BSA and IONPs, namely, the processes of aggregation, particle reclustering, and protein denaturation.