Synergism between Electrolysis and Methylene Blue Photodynamic Action inEscherichia Coli

Abstract

There is interest in the use of photodynamic therapy for the treatment of certain diseases, including cancer. However, weak penetration of visible light in tissues has restricted its use. In this study the possibility of enhancing photodynamic effects by the use of energies that penetrate more deeply in tissues was investigated. Weak electric currents (1.0 mA) applied to Escherichia coli cells for short periods, producing little or no lethal damage, was found to act synergistically with the photodynamic action of methylene blue, significantly enhancing the effects of this treatment. This synergism exists also between electrolysis and X-rays but not between electrolysis and UV-254 nm. It is suggested that this synergism might eventually be used to improve the results obtained in therapeutic practice based on the utilization of photodynamic action.

Cellular damage and altered carbohydrate expression in P815 tumor cells induced by direct electric current: An in vitro analysis

“…In previous studies, we have demonstrated that treatment of bacterial and tumoral cells in a single chamber can induce several cellular effects, such as alterations in cell surface composition and cell viability [Capella and Menezes, 1992;Holandino et al, 1998;2000]. In previous studies, we have demonstrated that treatment of bacterial and tumoral cells in a single chamber can induce several cellular effects, such as alterations in cell surface composition and cell viability [Capella and Menezes, 1992;Holandino et al, 1998;2000].…”

“…In previous studies, Capella and Menezes [1992] used the cationized ferritin technique and determination of the zeta potential to demonstrate that treatment of Escherichia coli with electricity also promoted loss of membrane negative charges. Ruthenium staining showed that cathodic treatment caused loss of anionogenic sites in parallel with the occurrence of cell lysis.…”

“…Prior studies suggest that cell membrane is a key target for the effects caused by electric treatment [Capella and Menezes, 1992;Holandino et al, 1998]. Cell membrane alterations induced by DC were evaluated by cationic ligand ruthenium red [Luft, 1971a,b], which binds to the cellular surface membrane, a highly negatively charged compartment.…”

Crossed and Linked Histories of Tetrapyrrolic Macrocycles and Their Use for Engineering Pores within Sol-Gel Matrices

“…At present, scientists are searching for ways of increasing the selectivity and accumulation of photosensitizers in infectious agents, according to the general concept of PDT treatment of tumors. In this way, increased PDT effects over in vivo Escherichia coli , were observed when methylene-blue-based was employed in combination with a 1-mA electric current [ 169 ] or when a previous laser irradiation was applied. Similarly, the antimicrobial PDT efficiency was increased by employing photosensitizers conjugated with antibodies, such as chlorin e6 linked to poly-L-lysine, which showed a high in vitro efficiency against the pathogenic microflora of the oral cavity [ 170 ].…”

Computational simulation of low energy x-ray source for photodynamic therapy: a preliminary study

“…Although previous xPDT studies can be found in the literature [10][11][12][13][14][15][16][17][18][19][20], evaluating the role played by the photosensitizers in the presented results -specially the experimental ones -is a far from trivial task. Since information about the physical interactions between the x-rays and photosensitizers is sparse, and results in the absence of these photosensitizing agents are not always presented, numerically modelling and evaluating such interactions may provide useful information for optimizing the xPDT.…”