Fig. 4

Structural arrangement of VIMs and dependence on temperature. a Lack of diffusion of membrane-embedded Rh-PE between vesicle compartments suggests that the vesicle interfaces are composed of two adherent membranes as opposed to a hemifused diaphragm. b This is reinforced by a fluorescence intensity profile across a two-vesicle network (inset; dotted line) showing the fluorescence of the interface membrane being double that of the external vesicle membrane. c Cartoon showing the characteristic parameters of a symmetric vesicle pair including vesicle radius (r), contact angle (θ) and interface length (l). d Turning on the optical tweezers to trap a vesicle (950 mW at trap; bottom vesicle trapped) triggered a change in both interface length and contact angle. e Network morphology could be dynamically alternated by sequential application and removal of the trap. This is demonstrated by the graph showing the change in interface length over time as the trap is tuned on and off, where the interface length is normalised with respect to vesicle radius. Lower applied powers resulted in smaller changes to interface lengths. Scale bars = 10 µm for all images