Observation of Surface Undulations on the Mesoscopic Length Scale by NMR

Abstract

One of the striking systematic differences between materials “designed by nature” via the processes of evolution and those designed by engineers and physicists using well established principles of condensed matter physics is the predominance of ultra-soft materials in the organization of natural condensed matter structures as compared with hard materials in man-made materials. An example is that the lipid bilayer component of the membranes of virtually all cells, be they procaryotic (bacterial) or eucaryotic (animal, vegetable or fungal), are very compressible “fluids” under physiological conditions^1–3. The word “fluid” here means, to those of the macroscopic-continuum intuitive persuasion (the “MACROS”), that the membrane does not support shear restoring forces. To those having a predominantly microscopic-molecular intuition (the “MICROS”), “fluidity” means that those spectroscopic measurements on molecules in membranes that are sensitive to translational and rotational diffusive molecular motions indicate that the membrane medium has a viscosity of moderately thick oil (≈ 1 poise).