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Jean-Michel Siaugue

Maître de conférences Sorbonne Université 32ème section

Barre 32-42, 3ème étage, bureau 312

Sorbonne Université - Case courrier 51- 4, place Jussieu - 75252 Paris Cedex 05

Tel : 33 (0) 1 44 27 43 09 / Fax : 33 (0) 1 44 27 32 28

Research topic

My research is dedicated to the biomedical applications of magnetic nanoparticles.

I have developed the synthesis of a nanometric composite system, made of a core of magnetic nanoparticles and a shell of functionalized silica, and its use for applications in therapy, multimodal imaging, magnetogenetics as well as in vitro diagnostic.

Coating the magnetic nanoparticles with a silica shell, instead of a coating with organic ligands, offers several advantages. The silica surface can be easily functionalized with commercial organosilanes. The silica layer can be doped with fluorophores to obtain nanoparticles magnetic and fluorescent. Finally, silica is known for its affinity with biological membranes.

Silica coated magnetic nanoparticles are obtained thanks to a two steps protocol. The first step is dedicated to the synthesis of a well cross-linked silica shell, doped with fluorophores (rhodamin, fluorescein, cyanin…). The second step consists in the simultaneous condensation of two functionalized organosilanes, one with PEG chains, to ensure colloidal stabiliy, the second one with amino groups, to allow further biofunctionalization.

Over the years, classical coupling protocols were used to graft various biochemical entities, like anticancerous drugs for drug delivery, antigens or DNA for in vitro diagnostic in lab on chip. In the context of the MAGNEURON project (FET - Open research projects (H2020)), copper free click chemistry was used to graft ligands of proteins at the surface. The nanoparticles, once injected in the cell cytoplasm, can recruit proteins at their surface thus creating accumulation of proteins when a magnetic field is applied close to the cell membrane (magnetogenetics).

My research effort is now directed towards anisotropic magnetic nanoparticles, as their magnetic properties and biological activity can be improved by controlling their shape. Indeed, some researchers have reported that tuning the anisotropy, by modifying the shape of the nanoparticles, leads to higher specific adsorption rate and better performance as contrast agent in MRI. Moreover, enhanced blood circulation time and prolonged retention in tumors have also been observed for anisotropic nanoparticles.

Main scientific collaborations

2018 - now : Thanh Duc Mai, Claire Smadja (Institut Gallien, Université Paris Saclay), magnetic nanoparticles for pre-concentration and detection of alzheimer’s biomarkers in capillary electrophoresis.

2018 - now : Guenaelle Jasmin (Service de Physique de l’Etat Condensé, CEA-Saclay) : magnetic nanoparticles for the detection of cancer cells in microfluidic chips.

2017 - now : Emilie Secret (PHENIX, Sorbonne Université) : anisotropic magnetic nanoparticles for biomedical applications.

2014 - now : Jean Gamby (Centre de Nanosciences et de Nanotechnologies, Université Paris Saclay) : Magnetic nanoparticles for the detection of microRNAs in microfluidic chips (ANR DIMELEC).

2005 - now : Christine Ménager (PHENIX, Sorbonne Université) : magnetic hybrid nanomaterials for biomedical applications.