title: Mechanistic studies on the photodynamic effect induced by a dicationic fullerene C60 derivative on Escherichia coli and Candida albicans cells.
abstract: The photodynamic mechanism of action induced by N,N-dimethyl-2-(4'-N,N,N-trimethylaminophenyl)fulleropyrrolidinium iodide (DTC60(2+)) was investigated on Candida albicans and Escherichia coli cells. First, photogeneration of superoxide anion radical by DTC60(2+) in the presence of NADH was detected using nitro blue tetrazolium method in reverse micelles. In C. albicans suspensions, 10 μM DTC60(2+) was an effective photosensitizer, producing a ∼5log decrease of cell survival when the cultures were irradiated for 30 min with visible light. Also, C. albicans cells growth was not detected in the presence of 10 μM DTC60(2+) and irradiation. Photodynamic mechanism investigations were compared in both C. albicans and E. coli cells. Studies under anoxic conditions indicated that oxygen was required for the photodynamic inactivation of these microorganisms. The photocytotoxicity induced by DTC60(2+) was similar in D2O than in water cell suspensions. Furthermore, photoinactivation of microbial cells was negligible in the presence of azide ion, while the addition of mannitol produced a photoprotective effect on the cellular survival. These results indicate that DTC60(2+) has potential as agent to the photodynamic inactivation of microbial cells. Also, the photocytotoxicity activity induced by this cationic fullerene derivative can involve the intermediacy of both superoxide anion radical and singlet molecular oxygen.
authors.affiliation: Departamento de Química, Facultad de Ciencias Exactas Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Agencia Postal Nro 3, X5804BYA Río Cuarto, Córdoba, Argentina.
authors.forename: M Elisa
authors.initials: ME
authors.lastname: Milanesio
authors.forename: Mariana B
authors.initials: MB
authors.lastname: Spesia
authors.forename: M Paula
authors.initials: MP
authors.lastname: Cormick
authors.forename: Edgardo N
authors.initials: EN
authors.lastname: Durantini
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D058491:Bacterial Load / Q000187:drug effects / Q000528:radiation effects; D002176:Candida albicans / Q000166:cytology* / Q000187:drug effects* / Q000528:radiation effects; D002264:Carboxylic Acids / Q000737:chemistry / Q000494:pharmacology*; D002413:Cations, Divalent; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000166:cytology* / Q000187:drug effects* / Q000528:radiation effects; D037741:Fullerenes / Q000737:chemistry / Q000494:pharmacology*; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000494:pharmacology*; D011829:Radiation Dosage
chemical_list: C416673:C60 carboxyfullerene; D002264:Carboxylic Acids; D002413:Cations, Divalent; D037741:Fullerenes; D017319:Photosensitizing Agents
keywords: Candida albicans; Escherichia coli; Fullerene; Photodynamic inactivation; Photosensitizer