The aim of this study was to evaluate genotoxicity and oxidative stress in workers who formulate organophosphorus (OP) pesticides. In this survey, blood leukocytes and erythrocytes of a group of 21 pesticide formulating workers and an equal number of control subjects were examined for genotoxicity and oxidative stress parameters. The mean comet tail length and mean comet length were used to measure DNA damage. Lipid peroxidation level, catalase, superoxide dismutase (SOD) and glutathione peroxidase activities in erythrocytes were analysed as biomarkers of oxidative stress. In addition, the acetylcholinesterase activity was measured as a biomarker of toxicity. The average duration of employment of workers in the factory was 97 months. Results indicated that chronic exposure (multiple5dose, greater than or equal to 6 months duration) to OP pesticides was associated with increased activities of catalase, SOD and glutathione peroxidase in erythrocytes. The level of lipid peroxidation and acetylcholinesterase activity did not show any significant differences between the two groups. The results also indicated that chronic exposure to OP pesticides was associated with increased DNA damage. It is concluded that human chronic exposure to OP pesticides may result in stimulated antioxidant enzymes and increased DNA damage in the absence of depressed acetylcholinesterase levels. Routine genotoxicity monitoring concomitant to acetylcholinesterase activity in workers occupationally exposed to OP insecticides is suggested.

A magneto-photothermal therapy for cancer (in vitro photothermal therapy of prostate cancer cells and in vivo photothermal therapy of human glioblastoma tumors in the presence of an external magnetic field) was developed using superparamagnetic zinc ferrite spinel (ZnFe₂O₄)–reduced graphene oxide (rGO) nanostructures (with various graphene contents). In vitro application of a low concentration (10 μg mL⁻¹) of the ZnFe₂O₄–rGO (20 wt%) nanostructures under a short time period (∼1 min) of near-infrared (NIR) irradiation (with a laser power of 7.5 W cm⁻²) resulted in an excellent destruction of the prostate cancer cells, in the presence of a magnetic field (∼1 Tesla) used for localizing the nanomaterials at the laser spot. However, in the absence of a magnetic field, ZnFe₂O₄–rGO and also rGO alone (10 μg mL⁻¹) resulted in only ∼50% cell destruction at the most in the short photothermal therapy and also in a typical radiotherapy (∼2 min gamma irradiation with a dose of 2 Gy). The minimum concentrations required for the successful application of the nanostructures in the photothermal and radiotherapeutic methods were found to be ∼100 and 1000 μg mL⁻¹, while in the proposed magneto-photothermal therapy it was only ∼10 μg mL⁻¹. The in vivo feasibility of this method was also examined on mice bearing glioblastoma tumors. Furthermore, the localization of the magnetic nanomaterials injected into the tumors was studied in the presence and absence of an external magnetic field. These results will stimulate more applications of magnetic graphene-containing composites in highly efficient photothermal therapy.

To examine the radiosensitizing effects of iron oxide nanoparticles in the presence of 6 MV (megavoltage) X-ray radiation. Iron oxide nanoparticles with two different modifications - dextran coating (plain) and amino-group dextran coating - were used. The rate of iron oxide penetration was monitored using Prussian blue staining, magnetic resonance imaging and atomic adsorption spectroscopy. The effect of iron oxide on the viability of cells was determined using trypan blue dye exclusion assay followed by evaluating the cytotoxicity effect of amino-group iron oxide nanoparticles and ionizing radiation. Radiation dose enhancement studies were carried out on DU145 human prostate carcinoma cell line with 1 mg/ml amino-group iron oxide nanoparticles and different doses of 6 MV X-ray radiation. The uptake of amino-group coated nanoparticles by DU145 cells was significantly more than the plain nanoparticles. In addition, cell viability was decreased with the increase of iron oxide concentration. The dose enhancement factor (DEF) is approximately 1.2 at different doses in the range of 2-8 Gy of 6 MV X-ray radiation. It was demonstrated that iron oxide nanoparticles with the appropriate surface modifications can enter the DU145 cells and it can be used as a cell sensitizer to megavoltage ionizing radiations in radiation therapy.