Fig. 2.

A–C) Examples of micropipette aspiration of vesicles at low-suction to determine excess area. Three vesicles are shown for each of the different pattern types: A) vesicle-encompassing quasi-lattice; B) dynamic disordered state; and C) closely associated configurations. The images show the greatest membrane projections into the pipette for the vesicle-encompassing lattice pattern. The scale bars apply to all images. D) The relationship between the excess area and the coefficient of variation from the limited Delaunay triangulation measured for each vesicle. The error in measuring domain positions, producing error in the reported CVs, as described in the Supplementary material, would contribute error in CV, increasing its upward by an amount of 0.02 for the black and blue data points. For the red data points, curvature effects and other measurement error contribute no more than an increase of 0.03 to the CV values in the worst case. Vesicles featured in (A–C) are starred in (D). E) Time variation in the measured CVs for each category of pattern. The solid symbols indicate vesicles which are featured in parts (A–C). Typically, vesicles were viewed for a few seconds at different focal planes to ensure a lack of tethers before being selected for micropipette study, and so for some vesicles, the video time for a given focal plane was limited. Therefore, two additional vesicles of each pattern type, represented by hollow symbols, were included also, in some cases interruptions in measurements corresponded to different focal planes or optical adjustments; however, the persistent patterns typically are unaltered on the timescale of minutes.