Multicellular aggregates are model systems of tremendous interest for tissue mechanics, embryogenesis, or tumorogenesis. A first technical challenge is to design aggregates with controlled size, shape and composition.
By inserting nanoparticles in cells, they endow magnetic properties allowing to remotely manipulate them. Multicellular aggregates formation requires to put cells together, magnetic forces will drive cells together close to them or in wells of controlled shape. Thus we are able to create multicellular assemblies of unprecedented size (from 100 µm to 1mm radius) and shape (spheroids, cylinders or cuboids) . The content is also controlled during the formation process.
Magnetic multicellular aggregates can be used as 3D model tissues systems in the context of tumoral transition [2,3] or cell differentiation.