Imaging Cell Surface Macromolecular Distribution by Mapping Intermolecular Interactions with an Atomic Force Microscope

Extract

An atomic force microscope (AFM) can image real-time intermolecular interactions between complementary macromolecules, such as receptor-ligand and antigen-antibody with nanometer resolution in hydrated state. Recent developments in AFM imaging allow mapping of such interaction forces over a large surface area such that local as well as global distribution of complementary biomolecules could be ascertained simultaneously. Using the force-volume maps and AFM probe conjugated with antibody, we have mapped the reorganization of specific receptors on the cell surface as well as the resultant changes in cellular micromechanical properties, such as elasticity and cytoskeletal reorganization of the cell (Figure 1).

In present study, we have mapped vascular endothelial growth factor receptor (VEGF-R) in the plasma membrane of cultured endothelial cells using anti-VEGFR - antibody conjugated to AFM probe. VEGF induced changes in cytoskeleton reorganization in endothelial cells were observed by real-time AFM imaging.