Fig. 2
a AFM topographic image of non-extruded DOPC liposomes adsorbed on a functionalized planar gold substrate. b Cross-section topographic (black line) and capacitance gradient (red line) profiles along the dashed line in a and e, respectively. The green dashed line represents the adjustment of the profile to a spherical cap geometry. c (symbols) Height, h, versus width, D, of the liposomes in a. The continuous line is a linear fit to the data, which gives a slope (aspect ratio) ~ 0.14. d Distribution of equivalent spherical radii of the liposomes in a assuming that the surface area remains constant during the absorption process. e Constant height SDM image acquired at a distance z ~ 270 nm from the substrate and at a frequency fel = 5 MHz. f Capacitance gradient at the centre of each detected liposome in the SDM images measured at four tip-substrate distances. Each colour represents the same liposome (N = 81). For the largest liposomes (h > 200 nm) data for z = 190 nm is not available. Experimental parameters: σsol = 0.2 µF/m, σlip = 0.8 S/m, fmod = 6 kHz, v0 = 0.7 V, k = 0.43 N/m, f0 = 30 kHz (in air)