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