Figure 4

Different mechanisms for mechanical stimulation using magnetic particles. Magnetic twisting cytometry: actin filaments are stimulated by the attachment of large (1 μm) magnetic nanoparticles (MNPs) to integrin receptors on the cell membrane. A magnetic pulse is applied, followed by a torque being applied to the particle, resulting in a twisting motion. Mechano-sensitive (MS) ion channel activation: large MNPs are attached to the integrin. The magnetic force causes the particle to be pulled towards the field, thus deforming the membrane and activating the adjacent MS ion channel. Targeted ion channel activation: MNPs (100 nm to 2.7 μm) are attached to certain MS ion channels via corresponding antibodies. Applying a magnetic force forces the channel to open. Receptor clustering: MNPs (30 nm) are bound to receptor complexes along the membrane, and once a force is applied with a magnetic needle the receptors are pulled towards the field source, thus initiating receptor clustering. Adapted from [3].