title: Time-resolved studies of singlet-oxygen emission from L1210 leukemia cells labeled with 5-(N-hexadecanoyl)amino eosin. A comparison with a one-dimensional model of singlet-oxygen diffusion and quenching.
abstract: Time-resolved measurements were made of near-infrared emission from 5-(N-hexadecanoyl)amino-eosin-labeled L1210 leukemia cells following pulsed-laser excitation. The cells were suspended in phosphate-buffered saline made with deuterium oxide solvent. A significant fraction of the emission occurring 10-80 microseconds after the laser pulse was due to singlet oxygen. This singlet-oxygen emission is believed to result from singlet oxygen generated near the cell-membrane surface, where 5-(N-hexadecanoyl)amino eosin is known to concentrate, and then diffusing out into the buffer. The intensity and the kinetics of the experimentally observed singlet-oxygen emission were in excellent agreement with the predictions of a theoretical one-dimensional model of singlet-oxygen diffusion and quenching. During the 10-80 microseconds time period studied, most of the singlet oxygen was located in the buffer. Thus, the use of water-soluble singlet-oxygen quenchers, such as histidine, provide one means of separating the singlet-oxygen emission from other sources of light during this time interval.
authors.affiliation: Research Service, Edward Hines, Jr., Department of Veterans Affairs Hospital, Hines, IL 60141.
authors.forename: A
authors.initials: A
authors.lastname: Baker
authors.forename: J R
authors.initials: JR
authors.lastname: Kanofsky
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002336:Carnosine / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D004058:Diffusion; D004801:Eosine Yellowish-(YS) / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D006639:Histidine / Q000494:pharmacology; D007700:Kinetics; D007939:Leukemia L1210 / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D010100:Oxygen / Q000378:metabolism*; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000494:pharmacology*; D026082:Singlet Oxygen; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D017319:Photosensitizing Agents; C081505:5-(N-hexadecanoyl)aminoeosin; D026082:Singlet Oxygen; D006639:Histidine; D002336:Carnosine; D001205:Ascorbic Acid; D010100:Oxygen; D004801:Eosine Yellowish-(YS)