Membrane mediated attraction and ordered aggregation of colloidal particles bound to giant phospholipid vesicles

We report a light microscopy study of interactions between colloidal particles either chemically bound or physisorbed onto flexible giant vesicle fluid membranes. The particles induce pinched shape deformations of the membrane and are driven to negative curvature regions on nonspherical vesicles. The membrane distortions were found to induce interparticle attraction with a range approximately equal to the particle diameter. Multiple particles decorating fluid membranes aggregate into finite-sized two-dimensional close packed aggregates or, unexpectedly, one-dimensional ringlike aggregates.