The company Nanobacterie develops an innovative treatment against cancer using nanoparticles produced by magnetotactic bacteria, called magnetosomes. Magnetosomes are administered in the tumor and then heated under the application of an alternating magnetic field. The heat produced by the magnetosomes induces an anti-tumor effect. This technique of cancer treatment is called magnetic hyperthermia.
The originality of the company Nanobacterie comes from the use of nanoparticles produced by bacteria. Magnetotactic bacteria use the magnetosomes as a compass to swim in the direction of the geomagnetic field. Thus, they can easily move to the areas that are the most appropriate for their survival and development, i. e. essentially regions rich in iron and low in oxygen.
Magnetosomes possess the following advantages for the treatment of tumors:
- They possess efficient heating and magnetization properties. This is due to their large size (40-50 nm on average) which gives them a ferrimagnetic behavior at physiological temperature, i. e. a magnetic moment which is thermally stable. In contrast, chemically synthesized nanoparticles are generally small superparamagnetic nanoparticles with a thermally unstable magnetic moment.
- The magnetosomes are usually organized in chains within magnetotactic bacteria. This arrangement in chains prevents aggregation which is an important advantage for medical applications.
- Magnetosomes are produced by magnetotactic bacteria in a natural environment. The toxicity of the growth medium of magnetotactic bacteria is therefore very low. This contrasts with the toxicity of the chemicals used to synthesize chemically nanoparticles.
Very encouraging results have been obtained with the magnetosomes. It has been shown by several different groups that magnetosomes had low toxicity. This is due to the nature of the main material making the magnetosomes, magnetite or maghemite which is not toxic.
In addition, the company Nanobacterie has carried out several proofs of concept of therapy, including one proof of concept on breast cancer tumors, showing that it was possible to completely eradicate this type of tumor xeno-grafted under the skin of mice. For that, 1 mg of a suspension of magnetosomes was administered into a tumor of breast cancer xeno-grafted under the skin of mice. The mice were exposed to the application of an alternating magnetic field of moderate intensity, 20 mT, and frequency ~198 kHz. This treatment resulted in the total disappearance of the tumor one month after the beginning of the treatment in a number of mice, showing the efficacy of the treatment.
The figure below shows the steps of a protocol of treatment using magnetic hyperthermia to treat breast cancer :
The research of the company Nanobacterie is now focused on :
- the manufacture of an injectable suspension of magnetosomes
- the realization of tests to confirm the absence of toxicity of the injectable suspension
- the proof of concept of the therapy on other cancers than breast cancer
- the fabrication of an electromagnetic coil that could be used in humans.
The objective of the company Nanobacterie is to start clinical trials on a particular cancer within the next 2 to 3 years.