Visualizing dynamics of membrane rafts on live cells

Membrane rafts are cellular portals to external stimuli that trigger signaling cascades for sophisticated yet remarkable biochemical activities. Visualization of the topographic evolution of membrane rafts remains unreported on live cells due to the nanosized and dynamic nature. Here, an imaging strategy involving atomic force microscopy and Hadamard product is developed to unveil membrane-raft features. Michigan Cancer Foundation-7 (MCF-7) cells were subjected to fibrinogen or manganese(II) (Mn²⁺)/resveratrol, both of which are ligands of integrin α_Vβ₃ embedded within membrane rafts; the former promotes metastasis, and the latter enables apoptosis. MCF-7 cellular membranes responded to the two stimulants markedly different. The size, height, spatiotemporal trajectory, and persistent time of ligand-activated nanodomains are revealed. This approach opens up a visualized platform toward the understanding of activation-associated signaling cascades.