5 Poster 5 . 1 Connected Porous Systems and Multidimensional NMR Approaches P 1 A T 2 D TDNMR Study of Skin

P1 A T2D TDNMR Study of Skin Julian Bent 1, Joanna Lee 1, Nikki Carpenter 1, Tim Benson 2 1 Unilever Research Colworth, 2 Advanced Magnetics Resonance Ltd. T2D TDNMR data is used to improve the assignment of the location of water in in-vitro pig skin. Whilst it is not possible to resolve or uniquely assign water environments in either 1-dimensional T2 or D data, the T2D method clearly resolves the data into two components, considered intraand extra-cellular water. T2D data are presented for whole defatted skin, a dermatomed slice of the top 0.4 mm (mostly epidermis) and the remaining sub layer (dermis). The assignment of intraand extra-cellular water is made by considering the peak intensities in the T2D data from the whole and dermatomed skin sections. The relative proportion of fast relaxing/fast diffusing water is largest in the epidermis section (which has a close packed cellular structure) so this peak is assigned as intra-cellular water. Whilst there is more slowly relaxing/slowly diffusing water in the dermis section (which has fewer cells within a collagen network) so this is assigned as extra-cellular water. The observation that intracellular water is relaxing fastest, suggests that the skin cells contain more exchangeable species, through which the water can relax, than the extra-cellular network. The resolution between intra-cellular and extra-cellular water is lost on repeated freezing (breaking the cell walls) and also on increasing the diffusion time from 50 to 100 and 150 ms, this is likely partly due to relaxation but also due to diffusion through the cell membranes during the experiment. This gives a measure of the cell wall permeability.