Cells are able to deform, migrate or integrate external mechanical cues such as forces or rigidity of the environment. These capabilities are essential all along the life of an organism starting from development to pathologies. My team developed during the last years a new approach to access to these properties at the scale of in vitro networks, subcellular structures in vitro or in cellulo, isolated cells and cell monolayer. We use dipolar forces that develop in superparamagnetic colloids in an homogenous magnetic field to follow the deformation of biological structures under controlled forces (applied and tuned by the intensity of the magnetic field). In addition, the self-assembly of the colloids into chains allow high throughput of the measurements to be obtained. Based on this technique we have studied the link between architecture and mechanics of dense branched networks resembling the ones found in the leading edge of a moving cell (Arp2/3 machinery) (Pujol et al. 2015), we followed the assembly of actin network when facing a loading forces (Tavacoli et al 2013, Pierre Bauër, PhD, 2015). We are now working closer to cellular context by using cell extract instead of purified proteins thanks to our collaboration with Alphée Michelot (IBDM, Marseille). Our approach is also applicable to intra-cellular organelles as well as the cell scale isolated or within a monolayer.