Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Scientific result | Biotechnology | Cell and molecular imaging | MRI | Diagnosis | Nanomedicine
The CEA-IBEB has partnered with the CEA-I2BM to develop original MRI contrast agents. Nano-magnets produced by bacteria may reveal targets at the molecular level.
Detecting diseases in their very early stages, particularly cancers, requires highly sensitive and specific diagnostic imaging tools. For this purpose,
MRI  uses
functionalized contrast agents, which are molecules that can target biomarkers of disease. In addition to their efficiency in precisely locating these biomarkers, these agents must be biocompatible and non-toxic. Even though they are the most used agents today in clinical examinations, some gadolinium chelates exhibit high toxicity risks to patients.
A new generation of contrast agents has been created through a multidisciplinary approach combining biologists, chemists and physicists from the CEA-IBEB and CEA-I2BM. It uses
magnetotactic bacteria that naturally produce
magnetosomes, which are nano-magnets surrounded by a biological membrane that is soluble in aqueous media.
“These nano-magnets are non-toxic”, explains Nicolas Ginet, researcher at the CEA-IBEB.
“And we have demonstrated that they are highly effective as a contrast agent in a rodent brain tumor model.” Another advantage: their production is simple.
“You just need to compress the bacteria and collect the magnetosomes with a magnet”, adds the biologist.
How do these nano-magnets precisely reveal the biomarkers to be detected? “By functionalizing them”, says Nicolas Ginet. “In our experiments with rodents, we have ‘attached’ to the nano-magnets a protein  capable of identifying the cells of blood vessels that feed the brain tumor.” In the long term, the researchers want to genetically modify the magnetotactic bacteria so as to customize the functionalization of magnetosome surfaces. “A therapeutic tool can be added to the diagnostic tool”, continues the researcher. “You just need to add a therapeutic molecule to the surface of the nano-magnet, which will specifically target the diseased area.
This work is funded by the National Research Agency (ANR) under the MEFISTO project, in the amount of 1.5 million euros.
 Magnetic resonance imagering
 This is the RGD peptide, which targets certain integrin receptors overexpressed on the surface of cells in the angiogenic network of the tumor.
Magnetosomes, Biogenic Magnetic Nanomaterials for Brain Molecular Imaging with 17.2 T MRI Scanner | Advanced healthcare materials
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.