Dynamic reflection interference contrast (RIC-) microscopy : a new method to study surface excitations of cells and to measure membrane bending elastic moduli

Imaging optical thicknesses and separation distances of phospholipid vesicles at solid surfaces

“…It can be applied in combination with fluorescence and phase contrast microscopy. It is especially applicable for dynamical studies, as was demonstrated by a recent study of the surface undulation of red blood cells [6] and out of plane Brownian motion of latex beads [7].…”

“…This type of experiment allows the momentaneous height profile of a membrane bound by a weak potential for each video frame to be determined. From the data the füll time-space correlation function of the undulations can be obtained by image processing [6].…”

Red blood cell thermal fluctuations: comparison between experiment and molecular dynamics simulations

“…at small deformations) suggest that the membrane skeleton is essentially stress free with µ ≈ 0, Recent years have seen significant progress in addressing important questions such as the contribution of non-linear elasticity to RBC shapes 1 , the effects of skeleton-induced tension, confinement 10 and spectrin mesh size 11 on the 70 membrane thermal fluctuation spectrum, as well as producing diverging views on the role of ATP-dependent active membrane fluctuations [13][14][15] . Despite these advances, new experimental methods for quantifying erythrocyte membrane elasticity through analysis of membrane fluctuations (besides 75 the pioneering works of Brochard and Lennon 16 and Sackmann's group 2,8,9,12 ) are relatively few 17,18 . Part of the problem is that whilst the λ < R regime is somewhat easier to analyse theoretically (using planar-membrane approximations 10 ), short wavelengths are difficult to access 80 experimentally.…”

Cytoskeleton Influence on Normal and Tangent Fluctuation Modes in the Red Blood Cells

“…The authors of [19] give the fluctuation spectra of RBC as the dependence of −log < |U q | 2 > q 4 on the wave vector q in the wavelength region from 0.25 µm to 2 µm. They stress also that the region of fidelity of their results does not exceed 0.5 µm ≤ λ ≤ 1 µm limits.…”

“…The material constants for these estimations were obtained by a double-step numerical fit of the effective bending rigidity dependence on the wave vector q [19]. The same type of experimental data is frequently used in the theoretical estimations of the RBC mechanical properties [16,17,20].…”