Aims: In recent years, magnetotactic bacteria and their magnetic nanoparticles (magnetosomes) were considered in different fields of science, including medicine, biotechnology, and nanobiotechnology due to their novel and unique magnetic properties. The present study was performed with the aim of evaluating the effect of temperature and reducing agent on labeling of magnetosomes with 188Re and biodistribution of labeled magnetic nanoparticles. Materials & Methods: In this experimental study, Alphaproteobacterium MTBKTN90 and sonication extraction method were used for the extraction of magnetic nanoparticles. After bacterial lysis, the magnetic nanoparticles produced by electron microscope were investigated and tin (II) chloride, as reducing agent, was used to check the labeling efficiency and rats were used to examine the biodistribution of the labeled magnetosomes. Findings: The highest efficiency in magnetosome labeling experiments was 11100kBq in the initial activity, which decreased with increasing activity. The increase in temperature did not have much effect on increasing the labeling efficiency. The labeling value in the absence of a reducing agent was 721. 5kBq, while at a concentration of 2mg of this agent, the labeling value increased to 10745. 91kBq. After the injection of magnetosomes through the sublingual vein of the rat, the magnetosomes accumulated in the liver. Conclusion: Magnetosomes extracted from Alphaproteobacterium MTB-KTN90 have a high potential for labeling by 188Re. Increasing temperature does not affect the labeling efficiency, but tin (II) chloride is a very important factor in optimizing the labeling efficiency, and the highest accumulation of magnetosomes labeled with 188Re after injection is in the liver of the rat.

Aim: The aim of this study was purification of magnetosomes of Magnetospirillum gryphiswaldense and investigation cytotoxicity effect of the purified particles of this bacterium on the breast cancer cell lines. Material and Methods: In this study, the standard strain of bacteria was cultured on DSMZ broth at temperature of 28° C for seven to ten days and incubated under the microaeraphilic conditions. To ensure phenotype tests, the PCR reactions were performed using specific primers (MT1166), associated with scanning electron microscope imaging. The influence of purified magnetosome from Magnetospirillum gryphiswaldense in various concentrations was investigated on the breast cancer cell lines. Kruskalwalis test was performed for statistical analysis. Results: Gram staining results showed that the bacterium was gram negative spirillum. Electronic micrographs indicated that the magnetosome of this bacterium was 60 nanometer in size. Purified magnetosome from Magnetospirillum gryphiswaldense did not show considerable cytotoxic properties on the breast cancer cell lines. The percentage of living cells against magnetosomes purified from the bacterium Magnetospirillum gryphiswaldense was 85% (p=0. 04). Conclusion: Magnetospirillum gryphiswaldense magnetosomes killed 15% of the cancer cells. The size and structure of magnetosomes of Magnetotactic bacteria are great importance in the elimination of the breast cancer cells.

Magentotactic bacteria are the types of bacteria capable of orientation in an external magnetic field because of the ability to produce structures called magnetosomes. Magnetosomes, nanometer-scale structures, are present in most of the magnetotactice bacteria. They are intracellular organelles composed of magnetic iron mineral crystals individually surrounded by a phospholipid layer. Because of the unique features of magnetosomes, magentotactic bacteria have become the fascinating subject of research in many research and applied fields of study, including robotics, medicine, biology, environment and geology. In this review, we have tried to introduce magentotactic bacteria, the formation of magnetosomes and their structures, in order to highlight the importance of these bacteria. Finally, some applications of these bacteria in different areas of research, e. g. targeted drug delivery, cancer treatment and removal of heavy metals from water, were described in order that a better understanding of their applications could be obtained.