Magnetic bacteria show promise as efficient vehicle for delivering tumor-fighting drugs

Researchers funded by the National Institute of Biomedical Imaging and Bioengineering (NIBIB) have found that magnetic bacteria can act as a possible tool for efficiently transporting drugs to tumors in the human body.

One of the largest issues in cancer treatment is being able to deliver a sufficient amount of chemotherapy drugs to tumors without damaging healthy cells in the process. Researchers have tried using nanocarriers, extremely small particles packed with drugs, which are specifically designed so that only cancer cells absorb them (1). While they do a good job of protecting healthy tissue, only a small amount of drugs actually reach centers of tumor activity, characterized by low oxygen content.

Attempting to create nanocarriers that would travel to areas of the human body where cancerous cells typically develop, researchers discovered nature might have the solution. A bacteria named magnetococcus marinus thrives in deep waters where oxygen is scarce by using system of sensors to help detect changes in oxygen levels and also possess a chain of magnetic nanocrystals that direct the bacteria to swim north using Earth’s magnetic fields. Dr. Martel believes the bacteria’s unique navigation system could be capitalized on to easily deliver drugs to tumors (1).

Using mice as test subjects, researchers injected bacteria tagged with cancer-killing drugs into living tissue next to tumor cells (1). They exposed the mice to a magnetic field, aiming to direct the cells into the tumor. Results indicated that live bacterial cells were found deep within the tumor, especially in regions with low oxygen content (2).

Later trials demonstrate that the rate of drug intake in tumor cells increases significantly compared to standard nanocarriers. Researchers estimate that on average, 55% of injected bacterial cells with attached vesicles when exposed to the magnet make it to tumor cells, versus standard nanocarriers that deliver about 2% of the drug load (2). The bacteria harmlessly die within 30 minutes of being injected, suggesting that they be safe in humans.

Dr. Martel’s next goal is to determine the drug-loaded bacterial cells’ effects on shrinking tumor size in the body. They are also interested in examining whether the bacteria can deliver other types of cancer-killing medicines.


  1. National Institute of Biomedical Imaging and Bioengineering. (2016, September 22). Swarms of magnetic bacteria could be used to deliver drugs to tumors. ScienceDaily. Retrieved September 25, 2016 from
  2. Felfoul, O., Mohammadi, M., Taherkhani, S., de Lanauze, D., Zhong Xu, Y., & Loghin, D. et al. (2016). Magneto-aerotactic bacteria deliver drug-containing nanoliposomes to tumour hypoxic regions. Nature Nanotechnology.

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