Introduction: Magnetosomes are natural nanoparticles with a nucleus of iron oxide or iron sulfide derived from magnetotactic bacteria. This structure causes the ability of bacteria to move in the direction of the magnetic field. Since they are between 20 and 100 nanometers in size; and due to the membrane that exists around this iron nucleus, it creates a property for them to bind drugs and therapeutic agents, therefore by attaching the markers to their surface, the ability to precisely identify the target cell can be created in them; So, their use will be very effective in treating diseases such as cancer. This treatment can be by hyperthermia, drug delivery, gene therapy, or antibody delivery. Here is a summary of magnetosomes and a brief overview of the drug delivery using them as a method to treat cancer.
Methods: PubMed, Google Scholar, and Scopus were used for a comprehensive search for articles published up to 2020. Keywords were included magnetotactic bacteria, magnetosome, nanoparticles, cancer, and drug delivery. We chose the articles based on their title and abstract. Finally, we have found 61 Articles with our study criteria of selection.
Results: The use of MTBs and their characterization for biotechnological applications require a pure culture in vitro. This is not easy to achieve because MTBs prefer a low oxygen system. Their replication time is very long, which puts them at risk of contamination by fast-growing bacteria. Magnetococcus marinus strain MC-1 is used to transport drugs loaded on nanoliposomes in hypoxic regions of colorectal tumors in mice. The results show that when these nanocarriers are combined with bacterial magnetosomes, they improve treatment. The unexpected conclusion reached by scientist Felfoul and colleagues was that these bacteria were clinically safe; this discovery was surprising because safety features for a Gram-negative bacterium with a particular wall were not expected to be safe. In several studies, a set of DOX antitumor drugs and magnetosomes isolated from the MSR-1 strain using glutaraldehyde as a cross-transporter used in this set of one milligram of pure magnetosomes could be limited to 87 mg DOX. The relationship between magnetosome levels and DOX appears to be very stable, leading to more prolonged drug release. The activity of this complex against HLG0 and EMT-6 cell lines was evaluated in human leukemia and rat breast cancer, respectively. After 48 hours, it showed that 80% of the drug was bound to the magnetosome, and the drug was not destroyed; In the systemic circulation, most DOX is not released before reaching the target, and it also showed potent antitumor activity. In another study, antitumor drugs cytarabine and daunorubicin were attached to magnetosomes using geaipin and polylactic glutamic acid. The prolonged-release time of these drugs indicates that they are used less for treatment.
Conclusion: The only problem with using magnetosomes is that they are limited compared to synthetic nanomagnets because synthetic nanomagnets can be made as much as needed, but magnetosomes are natural and depend on bacteria and their growth. Resolving this problem can be a turning point in the treatment of many diseases, especially cancer. Given that the growth of magnetotactic bacteria is long-term and grows better in low oxygen conditions, the use of appropriate antibiotics to prevent the growth of infectious microorganisms, as well as methods to accelerate the growth of bacteria, can be the first step to address these problems; Therefore, the use of artificial bacterial primary ecosystem can be a good option for a large-scale pure culture of these bacteria and increase growth efficiency.
It is suggested that magnetosome technology be used to deliver high-dose drugs, such as antibiotics; As we see today that many antibiotics are ineffective due to uncontrolled use, then we can hope that the effective antibiotics will be able to neutralize the function of bacteria for a more extended period and be effective in specific diseases.
It is worth mentioning that the use of magnetosomes to deliver drugs with severe side effects such as chemotherapy drugs and iodine therapy in various cancers, can reduce their negative effects rather, it can reduce the chance of recurrence of the disease and the numerous injections that make the condition difficult for the patient, both financially and in terms of health.
Keywords: Magnetotactic bacteria, Magnetosomes, Nanoparticles, Cancer, Drug delivery