Pressure Induced Hydration Dynamics of Membranes

TL;DR

This study uses pressure-jump time-resolved x-ray diffraction to investigate hydration dynamics in biological membranes, revealing non-exponential relaxation and homogeneous swelling behavior characterized by power law kinetics.

Contribution

It provides new insights into membrane hydration by demonstrating non-diffusion-limited, homogeneous swelling with specific power law kinetics.

Findings

Relaxation of unit cell spacing is non-exponential.

Bragg peaks shift smoothly without broadening.

Hydration occurs via homogeneous swelling, not diffusion.

Abstract

Pressure-jump initiated time-resolved x-ray diffraction studies of dynamics of the hydration of the hexagonal phase in biological membranes show that (i) the relaxation of the unit cell spacing is non-exponential in time; (ii) the Bragg peaks shift smoothly to their final positions without significant broadening or loss in crystalline order. This suggests that the hydration is not diffusion limited but occurs via a rather homogeneous swelling of the whole lattice, described by power law kinetics with an exponent $ \beta = 1.3 \pm 0.2$.