Determination of the self-diffusion coefficient of intracellular water using PGSE NMR with variable gradient pulse length.
A new pulsed-gradient spin-echo NMR protocol for assessing the local self-diffusion coefficient D(0) of water confined within living cells is proposed. Equations for the apparent mean-square displacement <Z(2)> as a function of the effective diffusion time t(d) and the duration of the displacement-encoding gradient pulses delta are derived. The standard method of estimating D(0)--reducing t(d) until the influence of collisions between the water molecules and the plasma membrane can be neglected--often fails because of the small size of typical cells. As demonstrated here, the decrease of the apparent <Z(2)> with increasing delta at constant t(d) can be utilized to measure D(0).
Slund
Ingrid
I
Physical Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden.
Topgaard
Daniel
D
D000465:Algorithms; D004058:Diffusion; D007424:Intracellular Fluid / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D012815:Signal Processing, Computer-Assisted; D014867:Water / Q000032:analysis* / Q000737:chemistry*
D014867:Water