DYNAMICS OF WATER MOLECULES IN POLYETHYLENE GLYCOL SOLUTIONS. STUDY OF THE LONGITUDINAL RELAXATION TIME (T1) IN 2D AND 1H NMR.

E.M. CLOP; M.A. PERILLO; A. K. CHATTAH

Alta Gracia

Workshop; Magnetic Resonance in a Cordubensis Perspective; 2011

FaMAF - UNC e ISMAR

Liquid water is a network of molecules microscopically connected by hydrogen bonds, in constant topological reshaping . In solution, ions and hydrophilic residues can immobilize water molecules. This interaction can describe the water in solutions as a set of dynamic subsystems defined by the pattern of water adsorption energies to the different binding sites. Measurements of relaxation times T1 and T2 in magnetic resonance, provides information about the time evolution of water distributions, and help to distinguish between the free liquid fractions and structured water in the presence of solutes. In this work, the dynamics of H2O in solutions of polyethylene glycol (PEG) of molecular weight of 6000 Da, is studied by analyzing the proton (1H) or deuterium (2D) spin-lattice relaxation times (T1). The PEG concentrations ([PEG]) ranged between 0 and 70 % W/V, from dilute to highly concentrated systems, simulating the conditions of molecular crowding characteristics of cell cytoplasm. The temperature was set to 37 C in all the experiments, in order to extend the analysis to real physiological systems.