Modern radiotherapy utilizes a broad range of sources of ionizing radiation, both low-dose-rate (LDR) and high-dose-rate (HDR). However, the mechanisms underlying specific dose-rate effects remain unclear, especially for corpuscular radiation. To address this issue, we have irradiated human epidermoid carcinoma A431 cells under LDR and HDR regimes. Reducing the dose rate has lower lethality at equal doses with HDR irradiation. The half-lethal dose after HDR irradiation was three times less than after LDR irradiation. The study of mechanisms showed that under HDR irradiation, the radiation-induced halt of mitosis with the accompanying emergence of giant cells was recorded. No such changes were recorded after LDR irradiation. The level of DNA damage is significantly greater after HDR irradiation, which may be the main reason for the different mechanisms of action of HDR and LDR irradiations. Comparing the mechanisms of cell response to LDR and HDR irradiations may shed light on the mechanisms of tumor cell response to ionizing radiation and answer the question of whether different dose rates within the same dose range can cause different clinical effects.

Nanotechnology currently offers two approaches to tumor therapy. The first involves coating the surface of nanoparticles with high-affinity molecules for targeted delivery. The second involves directing the nanoparticles to the desired area of the body using an external magnetic field. Such nanoparticles are often made of magnetic metals (iron, nickel, cobalt, etc.), but in living systems, the main problem with such nanoparticles is their toxicity. To address the toxicity issue, various barriers and coatings are primarily used. In this work, a laser technology for producing multifunctional nanocomposites based on graphene-coated iron nanoparticles decorated with gold nanoparticles was developed. Graphene-coated iron nanoparticles (200 nm) were synthesized using laser ablation in isopropanol. The presence of a graphene coating on the surface of the iron nanoparticles was confirmed by TEM, Raman spectroscopy, and luminescence analysis. A technology for depositing gold nanoparticles approximately 10 nm in size onto the graphene shell of the resulting iron nanoparticles was invented. The essence of the technology lies in creating critical conditions in a nanoparticle colloid, leading to intense aggregation with each other. Multifunctional nanocomposites based on graphene-coated iron nanoparticles decorated with gold nanoparticles did not exhibit acute toxicity to cell cultures under normal conditions. Moreover, under the combined influence of an alternating magnetic field and laser radiation, nanocomposites damaged 96% of neuroblastoma cells in culture.

One of the promising methods for generating low-temperature plasma to address oncological issues is a spark discharge initiated by a piezotransformer. This is attributed to its relative simplicity and versatility in application, both in the direct treatment of biological objects in vitro and in vivo, as well as indirectly through the production of plasma-activated solutions. The study presents the results of a comprehensive study of the effect of spark discharge initiated by a piezotransformer in argon flow on the metabolic activity and survival rate of cancer HEp-2 cells. For this purpose, adhesive cells cultured in DMEM were subjected to plasma exposure of different duration (from 10 to 120 s). The produced effect was assessed by studying the spark discharge optical emission spectra, as well as by measuring the concentrations of reactive oxygen and nitrogen species in the liquid medium. Cell viability and metabolic rate were determined by MTT test and fluorescence microscopy using propidium iodide (PI) and Hoechst dyes. The metabolic activity of cells is reduced by half after 20 s of treatment, cell viability reduced after 150 s of treatment. The concentration of hydrogen peroxide H₂O₂ reaches a value of ~50 μM, and the concentration of nitrite ion NO₂⁻ reaches a value of ~20 μM.