Water confined in reverse micelles--probe tool in biomedical informatics

Water pools caged in reverse micelles have sizes comparable to the typical dimensions of aqueous cavities in cells and tissues. Therefore, these models of confined water can be extremely helpful in biomedical informatics. Here, we present a practical approach that facilitates the use of such models to interpreting data from measurements of the spectral density of water caged in cells and tissues. We start from the observation that water molecules confined in microscopic pools display both bulk-like and rotationally constrained dynamics. We show that the fraction of structured water molecules in a pool and the frequency of the orientational relaxation of these water molecules can be derived from basic molecular principles in terms of the geometrical dimension of the water pool. Then, we employ these equations to relate the dielectric and magnetic responses of confined water to the size of the water pool. The present study provides the basis of a mathematical model that can relate the magnetic and dielectric signals of water in cavities of cells and tissues to the dimensions of these cavities. The approach can be used to assess the degree of structural alteration of injured and pathological tissues from the patterns of the dielectric and magnetic relaxation of water in these tissues.