Magnetosomes, a New Class of Highly Sensitive Superparamagnetic Contrast Agents for MR Molecular Imaging

Benjamin Marty¹, Nicolas Ginet², Christopher Lefevre², Daniel Garcia², Franck Lethimonnier¹, Denis Le Bihan¹, Sbastien Mriaux¹, David Pignol²

In this study we present a new class of superparamagnetic nano-particles, produced naturally by magnetotactic bacteria, and which regroup different characteristics of interest for biomedical applications: a perfectly crystalline and regular nanocrystal of magnetite, a natural lipid bilayer coating the nanoparticles, ensuring their solubilization and a possible functionalization of the lipid surface with biological functions for cellular targeting or in situ enzymatic catalysis. Transverse relaxivity of magnetosomes was measured at high magnetic field (17.2T) and preliminary experiments were performed on mice demonstrating the high in vivo sensivity of such contrast agents.