Diffusion coefficient in biomembrane critical pores.

Diffusion is fundamental to the random movement of solutes in solution throughout biological systems. Theoretical studies of diffusing solutes across cell membranes confined in a microscopic size of pores have been an interesting subject in life and medical sciences. When a solute is confined in a critical area of membrane pores, which shows a quite different behavior compared to the homogeneous-bulk fluid whose transport is isotropic in all directions. This property has novel features, which are of considerable physiological interest.

Correction to: Diffusion coefficient in biomembrane critical pores.

The original version of this article unfortunately contained two mistakes.

Protein Misfolding Thermodynamics.

It is known that protein misfolding is governed by the hydrophobic effect of solutes at hydrophobic amino acid side chains. The hydrophobic force of nonaqueous solutes acts as a driving force for the spatial rearrangement of protein side chains, whose structural transitions need to be regulated in both time and space. Smaller hydrophobic solutes exert more effect at protein side chains, which involves the clustering of proteins into misfolded shapes. The consequences of misfolding are loss of protein function, gain of toxic function, or both. This is a physical process, whose result has been directly linked to a large number of human diseases.

Stretching of red blood cells using an electro-optics trap.

The stretching stiffness of Red Blood Cells (RBCs) was investigated using a combination of an AC dielectrophoretic apparatus and a single-beam optical tweezer. The experiments were performed at 10 MHz, a frequency high enough to avoid conductivity losses, but below the second turnover point between positive and negative dielectrophoresis. By measuring the geometrical parameters of single healthy human RBCs as a function of the applied voltage, the elastic modulus of RBCs was determined (µ = 1.80 ± 0.5 µN/m) and compared with similar values of the literature got by other techniques. The method is expected to be an easy-to-use, alternative tool to determine the mechano-elastic properties of living cells, and, on this basis, to distinguish healthy and diseased cells.