Mechanistic insight of the photodynamic effect induced by a dicationic fullerene C60 derivative on microorganisms

MARIANA B. SPESIA, M. PAULA CORMICK, M. ELISA MILANESIO, EDGARDO N. DURANTINI

Córdoba

Encuentro; XI Encuentro Latinoamericano de Fotoquímica y Fotobiología; 2012

According with its photochemical properties, fullerene derivatives have been used as efficient agents to mediate photodynamic inactivation (PDI) of various classes of microbial cells. Under aerobic conditions, the 3C60* can interact with ground state molecular oxygen to form reactive oxygen species. This process can occur by energy transfer from the 3C60* to produce singlet molecular oxygen, O2(1Dg), or by electron transfer to form superoxide anion radical (O2–-). In contrast to O2(1Dg) generation, the electron transfer type of reaction preferentially occurs in polar solvents, particularly in the presence of reducing agents such as NADH.These pathways are analogous to the two main photochemical reaction types known as type II and type I photochemical mechanisms, respectively. In previous studies, we have investigated the photodynamic activity of fullerene derivatives with different number of cationic charges as agents to eradicate Gram-negative bacteria. In the present work, the photodynamic mechanism of action induced by N,N-dimethyl-2-(4’-N,N,N-trimethylaminophenyl)fulleropyrrolidinium iodide (DTC602+) was investigated on Candida albicans and Escherichia coli cells.