title: Voltage-sensitive styryl dyes as singlet oxygen targets on the surface of bilayer lipid membrane.
abstract: Photosensitizers are widely used as photodynamic therapeutic agents killing cancer cells by photooxidation of their components. Development of new effective photosensitive molecules requires profound knowledge of possible targets for reactive oxygen species, especially for its singlet form. Here we studied photooxidation of voltage-sensitive styryl dyes (di-4-ANEPPS, di-8-ANEPPS, RH-421 and RH-237) by singlet oxygen on the surface of bilayer lipid membranes commonly used as cell membrane models. Oxidation was induced by irradiation of a photosensitizer (aluminum phthalocyanine tetrasulfonate) and monitored by the change of dipole potential on the surface of the membrane. We studied the drop of the dipole potential both in the case when the dye molecules were adsorbed on the same side of the lipid bilayer as the photosensitizer (cis-configuration) and in the case when they were adsorbed on the opposite side (trans-configuration). Based on a simple model, we determined the rate of oxidation of the dyes from the kinetics of change of the potential during and after irradiation. This rate is proportional to steady-state concentration of singlet oxygen in the membrane under irradiation. Comparison of the oxidation rates of various dyes reveals that compounds of ANEPPS series are more sensitive to singlet oxygen than RH type dyes, indicating that naphthalene group is primarily responsible for their oxidation.
authors.affiliation: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, Moscow, Russia. Electronic address: sokolov.valerij@gmail.com.
authors.forename: V S
authors.initials: VS
authors.lastname: Sokolov
authors.affiliation: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, Moscow, Russia.
authors.forename: A N
authors.initials: AN
authors.lastname: Gavrilchik
authors.affiliation: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, Moscow, Russia.
authors.forename: A O
authors.initials: AO
authors.lastname: Kulagina
authors.affiliation: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, Moscow, Russia.
authors.forename: I N
authors.initials: IN
authors.lastname: Meshkov
authors.affiliation: Institute of Biophysics, Johannes Kepler University Linz, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Pohl
authors.affiliation: A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Science, Moscow, Russia; N.S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Science, Moscow, Russia.
authors.forename: Yu G
authors.initials: YG
authors.lastname: Gorbunova
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004560:Electricity; D007211:Indoles / Q000737:chemistry; D007834:Lasers; D008051:Lipid Bilayers / Q000737:chemistry*; D008956:Models, Chemical; D009942:Organometallic Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D017319:Photosensitizing Agents / Q000737:chemistry; D011726:Pyridinium Compounds / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004396:Coloring Agents; D007211:Indoles; D008051:Lipid Bilayers; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D011726:Pyridinium Compounds; C048577:aluminum tetrasulfophthalocyanine; D026082:Singlet Oxygen; D004121:Dimethyl Sulfoxide
keywords: ANEPPS; Aluminum sulfonated phthalocyanine; Dipole potential; Lipid bilayer; Photosensitizers; Singlet oxygen; Styryl dyes