Combined application of sub-toxic level of silver nanoparticles with low powers of 2450 MHz microwave radiation lead to kill Escherichia coli in a short time

Electromagnetic radiations which have lethal effects on the living cells are currently also considered as a disinfective physical agent. In this investigation, silver nanoparticles were applied to enhance the lethal action of low powers [100 and 180 W] of 2450 MHZ electromagnetic radiation especially against Escherichia coli ATCC 8739. Silver nanoparticles were biologically prepared and used for next experiments. Sterile normal saline solution was prepared and supplemented by silver nanoparticles to reach the sub-inhibitory concentration [6.25microg/mL]. Such diluted silver colloid as well as free-silver nanoparticles solution was inoculated along with test microorganisms, particularly E. coli. These suspensions were separately treated by 2450 MHz electromagnetic radiation for different time intervals in a microwave oven operated at low powers [100 W and 180 W]. The viable counts of bacteria before and after each radiation time were determined by colony-forming unit [CFU] method. Results showed that the addition of silver nanoparticles significantly decreased the required radiation time to kill vegetative forms of microorganisms. However, these nanoparticles had no combined effect with low power electromagnetic radiation when used against Bacillus subtilis spores. The cumulative effect of silver nanoparticles and low powers electromagnetic radiation may be useful in medical centers to reduce contamination in polluted derange and liquid wastes materials and some devices

Effect of oral supplementation of biogenic selenium nanoparticles on white blood cell profile of BALB/c mice and mice exposed to X-ray radiation

Radiation therapy is an effective method used for treatment of many types of cancers. However, this method can cause unwanted side effects such as bone marrow suppression. In this study, the effect of oral administration of biogenic selenium nanoparticles [SeNPs] on total and differentiated white cells profile of BALB/c mice exposed to X-ray radiation was investigated and compared with non-irradiated mice. Sixty female BALB/c mice between six to eight weeks olds were divided into 4 test and control groups in two categories of normal and irradiated mice. In normal mice SeNPs administration was started from the day 0 and followed for a month. Irradiated mice were divided into three groups and were exposed to doses of 2, 4 and 8 Gy. After 72 hr of irradiation, the SeNPs treatment was started and continued for a month. Total and differentiated blood cells counts of both irradiated and non-irradiated groups were monitored during 30 days and the obtained results were compared. Also, the deposition of Se in different tissues and blood serum of normal mice was determined in normal mice after 30 days period of supplementation. In normal mice an increase in the count of neutrophils was observed after 30 days of supplementation. In irradiated mice, SeNPs supplementation led to increase in both lymphocytes and neutrophils counts especially in mice exposed to 2 and 4 Gys radiation. Radiotherapy is categorized as an invasive method which can cause tissue damage and suppress the host immune defense. A restore of lymphocytes which was observed after SeNPs supplementation in irradiated mice can be highly interesting and provide cellular immunity against malignant diseases or other bacterial or fungal infections after radiotherapy