| Abstrakt: |
Summary Flash illumination alters the voltage across bilayer lipid membranes in the presence of certain cyanine dyes. The waveforms of the photo-voltage vary systematically with dye structure and imposed transmembrane voltage. Experimental results are reported for 27 positively charged cyanine dyes, primarily oxazole derivatives, using lecithin/oxidized cholesterol bilayer membranes and 10-mm sodium chloride solutions. Several dyes do not induce any photo-voltages. Examples are 3,3' diethyl 9 ethyl 2,2' oxacarbocyanine iodide, 3,3' diethyl 2 oxa 2' thiacyanine iodide, and 3,3' dimethyl 2,2' indocarbocyanine iodide. Several dyes, when added to one side of the membranes, induce monophasic waveforms. Examples are 3,3' dimethyl 2,2' oxacarbocyanine chloride, and 3,4,3',4' tetramethyl 2,2' oxazalinocarbocyanine iodide. Other dyes induce a photo-voltage only if transmembrane voltages are imposed. These waveforms are biphasic with some dyes (3,3' diethyl 2,2' oxacarbocyanine iodide, for example) and monophasic with other dyes (3,3' dibutyl 2,2' oxacarbocyanine iodide, for example). |
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