Temperature dependence of water self-diffusion through lipid bilayers assessed by NMR

Effect of intercompartmental water exchange on the apparent myelin water fraction in multiexponential T2 measurements of rat spinal cord

“…In this work, D m is the myelin water ADC normal to the myelin membranes, since it is in the normal direction that water must diffuse to enter or leave the myelin compartment. The value of D m estimated in this work (0.005–0.0012 μm 2 /ms) corresponds reasonably with the diffusion coefficient of water measured through stacks of synthetic lipid bilayer near body temperature, ≈ 0.0017 μm 2 /ms (35). …”

“…Extending the formula given of Tanner (36) used to calculate the effective diffusion coefficient across permeable barriers to one that accounts for a finite barrier thickness (35), one gets…”

Simulations on the influence of myelin water in diffusion-weighted imaging

“…To explain the discrepancy between f my and histologic myelin volume fraction, a computational model estimated a myelin water diffusion coefficient of D mr ≈ 10 −3 μm 2 /ms (Harkins et al 2012). While this value of D mr generally agrees with measurements of water diffusion through synthetic myelin (Khakimova et al 2008), a couple studies have indirectly estimated that water exchange through myelin is much slower than this value would suggest (Laule et al 2004, Kalantari et al 2011). Within the context of these previous studies, the physiologic value of D mr is estimated to be between 0 and 10 −3 μm 2 /ms.…”

“…Experiments in synthetic myelin have measured very slow diffusion orthogonal to the lipid bilayer surface (represented as D mr in the present work) and faster diffusion along the lipid bilayer surface (i.e. D mc ) (Khakimov et al 2008). In other experiments, combined multi-exponential T 2 and diffusion experiments have been used to measure D app of the myelin water T 2 component, which was estimated to be > 0.1 μm 2 /ms (Andrews et al 2006, Stanisz and Henkelman 1998).…”

Dielectrophoretic Characterisation of Mammalian Cells above 100 MHz

“…The linear fit of the data gives an activation energy of ~44 kJ/mol for the underlying process leading to the temporal behaviour of the high frequency DEP cross-over. We note that the temperature dependence of the coefficient of water self-diffusion through lipid multilayers is also described by the Arrhenius law, with an apparent activation energy of ~41 kJ/mol [17], a coincidence which requires further study.…”