John G Albright
Dr. Albright has, in his laboratory, a unique optical interferometric diffusiometer that has drawn scientists from around the world to TCU. His research has recently become centered on using this instrument to measure diffusion coefficients of components in protein salt mixtures. The motivation for this work is that diffusion of proteins in salt mixtures is important in many in vivo, laboratory, medical, and manufacturing applications. Examples include centrifugation and other separations, dialysis, and crystallization. Effective modeling, prediction, and design of these processes requires accurate descriptions of protein transport. The complete description of diffusion transport in an n-solute system requires an n x n matrix of diffusion coefficients relating the flux of each species to the gradients of all species.
A specific example of research that is being performed at TCU is the measurement of the four diffusion coefficients that describe diffusion in systems containing: lysozyme chloride + metal ion chloride + water. The metal ions so far have included sodium, potassium, and magnesium. This will soon expand to other cases that will also include other anions. The experiments have extended into composition regions where the lysozyme is supersaturated. Lysozyme has been the model protein that most researchers have used to experimentally investigate protein nucleation (initiation of a protein crystal) and the crystal growth of a protein in solution. The highly unique data that Dr. Albright’s group are now generating will greatly benefit the community of scientists working on nucleation and crystal growth theory.
Dr. Albright continues to have an interest in the measurement and interpretation of multicomponent diffusion coefficients in systems that are models for sea water, salt lakes, and subterranean brines. The ion constituents of greatest concentration in sea water are Na+, Mg2+, Cl-, and SO42-. The study of the ternary system NaCl+MgCl2+H2O at 25 degreesC has been the focus of an international collaboration and he was involved in the ternary diffusion measurement over the full concentration range of this system. He is now in the process of examining NaCl + Na2SO4 + H2O at 25 degrees C. Research in this area will continue.
In a third area of research, Dr. Albright has been involved in the measurement and interpretation of activity coefficients of salts measured by the isopiestic method.