The resolution of images acquired by MALDI mass spectrometry is influenced by laser spot size, matrix crystal size, and the method of matrix deposition. The potential for the spreading of molecules in tissue sections when applying matrix by any technique for MALDI-MSI is a chronic concern that increases as imaging technology reaches towards ever finer resolution. This concern looms great when imaging small lipid molecules that have partial to full solubility in organic solvents used to apply matrix by spray techniques. Ozone at high levels as an environmental pollutant has been correlated to health problems and diminished lung function (1). Lung surfactant lines the surface of the alveolar sacs of the lung and reduces the surface tension on the cellular surface leaving the lung pliable and spongy. This lipid-abundant component is hypothesized to have a protective function by reacting with ozone at first contact when the gas enters the lung. Studies of isolated lung surfactant with ozone have demonstrated transformation of specific lipid components (16:0a/16:1-glycerophosphocholine and cholesterol) to bio-active compounds 16:0a/9al glycerophosphocholine and cholestan-6-oxo-3,5 diol (2,3). We would like to apply mass spectrometric imaging (MSI) to record the anatomical distribution of these biologically active molecules as a function of ozone exposure.
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