Advanced red blood cell thermal fluctuation analysis: a new method to quantify membrane elasticity

We propose a new experimental technique for red blood cell thermal

fluctuation analysis, which makes it possible to quantify the

cell membrane elastic moduli. The method is based on the comparison

of the mean-square fluctuations in the shape of cell equatorial

contours as observed using phase contrast microscopy to the equivalent

fluctuation spectrum acquired in a coarse grained molecular

dynamics simulation. The simulation is based on a network of virtual

particles which interact via a harmonic potential and a dihedral

angle potential and are subject to a constant volume and area constraints,

which gives rise to finite values for the membrane bending

and shear elastic moduli. Using this method, the elastic properties

of individual red blood cells can be measured and their changes can

be easily monitored in response to changing environmental conditions

(temperature, solute concentration, osmotic pressure changes).

We also present evidence of increased bending rigidity in red blood

cells from diabetic individuals.