Photodynamic action of merocyanine 540 in artificial bilayers and natural membranes: action spectra and quantum yields. Photochem Photobiol 1991 Apr;53(4):493-500
Date
04/01/1991Pubmed ID
1857744DOI
10.1111/j.1751-1097.1991.tb03661.xScopus ID
2-s2.0-0026149992 (requires institutional sign-in at Scopus site) 37 CitationsAbstract
The action spectra and quantum yields for singlet oxygen (1O2) generation by merocyanine 540 (MC540) in liposomes and isolated erythrocyte membranes were obtained using electron spin resonance techniques. Oxygen consumption was measured by spin label oximetry in the presence of histidine for fully-saturated dimyristoylphosphatidylcholine vesicles, mono-unsaturated 1-palmitoyl-2-oleoylphosphatidylcholine vesicles and erythrocyte membranes. The quantum yield for the photogeneration of 1O2 by membrane-bound MC540 in aqueous buffer was determined to be 0.065 +/- 0.005, which is approx. 1/10 of the value determined for Rose Bengal under similar conditions. Using unilamellar liposomes and isolated erythrocyte membranes containing MC540 at different monomer/dimer ratios, we have observed that the action spectra of 1O2 generation closely overlap the absorption spectra of the monomeric dye in these systems. It is likely that factors which affect the monomer-dimer equilibrium of MC540 will influence the production of 1O2. These findings have important implications for the phototherapeutic efficacy of MC540.
Author List
Singh RJ, Feix JB, Pintar TJ, Girotti AW, Kalyanaraman BAuthors
Jimmy B. Feix PhD Professor in the Biophysics department at Medical College of WisconsinAlbert W. Girotti PhD Adjunct Professor in the Biochemistry department at Medical College of Wisconsin
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
Cell MembraneErythrocyte Membrane
Humans
In Vitro Techniques
Liposomes
Oxygen Consumption
Photochemistry
Photochemotherapy
Pyrimidinones
Radiation-Sensitizing Agents
