Estimation of Membrane Permeability and Intracellular Diffusion Coefficients

We propose a method for estimating membrane permeability and the intracellular diffusion coefficient using pulsed-gradient spin-echo measurement in combination with numerical simulation. The diffusion signal attenuation of leukocytes was measured with 4π2q2(Δ−δ/3) values up to 6000 s/mm2. For numerical simulations, the cell was modeled as a 15×15 μm2 square with various membrane permeabilities and intracellular diffusion coefficients. Minimization of the difference in signal attenuations between the measurement and the simulation enabled estimations of these unknown parameters for the leukocytes. A cell sample of 2.17×108 cells/mL had a membrane permeability and an intracellular diffusion coefficient of 23 μm/s and 8.9×10-4 mm2/s, respectively.