Research Equipment: Pulsed Field Gradient NMR Diffusion Probe

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9905569BungeThis project supports acquisition of a pulsed field gradient (PFG) diffusion probe for the state-of-the-art nuclear magnetic resonance (NMR) spectrometer at the Colorado School of Mines (CSM) NMR Facility. The experimental capabilities provided by this probe will greatly enhance research and educational opportunities to CSM's faculty and students. Six separate research programs housed in four different departments will initially use the PFG probe to produce significant new scientific and engineering knowledge. In addition, graduate and undergraduate students will be able to learn about and use this modern tool for investigating composite media and complex materials through measurements of diffusion and boundaries to diffusion. This probe will be particularly valuable to the principal investigator's (PI's) studies of composite membrane materials, specifically mammalian epidermis (skin). Chemical penetration in composite materials can proceed by one or more pathways. For composite materials, diffusion cell measurements, the traditional method of quantifying chemical transport through membranes, provide information on overall transport, but no insights into the actual pathways or the local diffusion coefficients in those paths. Using the PFG diffusion probe, the PI will measure self-diffusion coefficients of selected chemical tracers (those that include 19F) in stratum corneum (SC) excised from human and animal subjects. The SC is the outermost layer of skin and the main barrier to passage of most chemicals into and out of the body. The aim of these diffusion probe studies is to understand the mechanisms of epidermal barrier function. This understanding will then be used in developing methods to predict, enhance, and control dermal penetration and in developing materials to replace skin samples for estimating dermal absorption. The investigative strategies used to study the SC composite membrane will also be useful in the study of other complex membranes, either biological or non-biological. In addition to the PI's program, five other members of the CSM faculty (auxiliary users) from three departments (Chemical Engineering and Petroleum Refining, Engineering, and Geophysics) have proposed research investigations utilizing the PFG diffusion probe. The NMR-PFG method has been demonstrated for all of the research projects described in this proposal, although the number of measurements is extremely small and there is a great opportunity to produce new knowledge with this device.