The role of the methylene blue and toluidine blue monomers and dimers in the photoinactivation of bacteria

Усачева, М. Н.; Teichert, Matthew C.; Biel, Merrill A.

doi:10.1016/j.jphotobiol.2003.06.002

Cited by 196 publications

(119 citation statements)

References 19 publications

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“…This may be related to the ability of phenothiazinium dyes to form dimers and oligomers. Usacheva et al (48)(49)(50) showed that TBO was a better antimicrobial PS than MB partly because it was able to self-associate into dimers that were supposed to preferentially interact with lipopolysaccharide and other components of bacterial membranes.…”

Section: Discussionmentioning

confidence: 99%

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Demidova

Hamblin

2005

Appl Environ Microbiol

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Spore formation is a sophisticated mechanism by which some bacteria survive conditions of stress and starvation by producing a multilayered protective capsule enclosing their condensed DNA. Spores are highly resistant to damage by heat, radiation, and commonly employed antibacterial agents. Previously, spores have also been shown to be resistant to photodynamic inactivation using dyes and light that easily destroy the corresponding vegetative bacteria. We have discovered that Bacillus spores are susceptible to photoinactivation by phenothiazinium dyes and low doses of red light. Dimethylmethylene blue, methylene blue, new methylene blue, and toluidine blue O are all effective, while alternative photosensitizers such as Rose Bengal, polylysine chlorin(e6) conjugate, a tricationic porphyrin, and a benzoporphyrin derivative, which easily kill vegetative cells, are ineffective. Spores of Bacillus cereus and B. thuringiensis are most susceptible, B. subtilis and B. atrophaeus are also killed, and B. megaterium is resistant. Photoinactivation is most effective when excess dye is washed from the spores, showing that the dye binds to the spores and that excess dye in solution can quench light delivery. The relatively mild conditions needed for spore killing could have applications for treating wounds contaminated by anthrax spores, for which conventional sporicides would have unacceptable tissue toxicity.

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Section: Discussionmentioning

confidence: 99%

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Demidova

Hamblin

2005

Appl Environ Microbiol

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“…As the chromophore concerned is established as a planar moiety, this infers that neither the auxochromic dimethylamino-or amino-groups, nor the methyl at position 2 of the ring system cause any deviation from this. Aggregates can be observed in the visible spectrum of aqueous TBO -and similarly for other phenothiazinium cations -as a broad shoulder to lower wavelengths extending from the  max [6].…”

Section: Introductionmentioning

confidence: 86%

“…More recently TBO has been widely examined as a photoantimicrobial agent aimed at oral disinfection [3,4], and is a lead compound in azine photosensitiser research and development [5]. Where comparative testing of the photoantimicrobial efficacies of MB and TBO have been carried out, little overall difference has been reported [6]. However, as the principal lead compound for photoantimicrobial research, MB has a significantly fuller pedigree in terms of the range of bacterial, fungal, viral and protozoal challenges reported [7].…”

Section: Introductionmentioning

confidence: 99%

Phenothiazinium photosensitisers XI. Improved toluidine blue photoantimicrobials

Wainwright

O'Kane

Rawthore

2016

Journal of Photochemistry and Photobiology B: Biology

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The phenothiazinium derivative toluidine blue O (TBO) is widely employed as a photoantimicrobial agent in clinical trialling, particularly in dentistry. However, its activity against a range of pathogenic microbial species is not significantly different to that of the standard photoantimicrobial methylene blue. In the current study, derivatives of TBO with varying hydrocarbon substitution in chromophore position 2 were synthesised via the established anilinethiosulphonic route, using the mild oxidant silver(II) carbonate to allow substituent preservation.The resulting series of analogues demonstrated the expected increases in visible absorption wavelength and lipophilicity with increasing hydrocarbon content, as well as decreased aggregation for derivatives with bulkier substituents, and all produced singlet oxygen on illumination in vitro. Screening against a range of bacterial and fungal pathogens relevant to infection control showed remarkable increases in activity relative to the parent compound, particularly against the clinically important Gram-negative bacterium Pseudomonas aeruginosa. In addition, in order to demonstrate clinical relevance, the photoactivities of the new derivatives against microbial targets were compared to conventional antibacterial and antifungal drugs, as well as biocides commonly used for local disinfection. Activity here was also generally greater than that of the conventional agents used for comparison, considerably so relative to the local disinfectant agents.

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“…[18][19][20] Due to its planar structure, which is similar to acridine dyes, MB can interact easily with DNA and has been used as a stain agent for DNA. 21 The interaction of methylene blue with DNA has been studied with various methods.…”

Section: Introductionmentioning

confidence: 99%

Study on the interaction between doxorubicin and Deoxyribonucleic acid with the use of methylene blue as a probe

Hajian

Shams

Mohagheghian

2009

J. Braz. Chem. Soc.

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Neste trabalho, a interação de doxorrubicina com DNA (obtido de timo de bezerro) em fita dupla foi investigada através de técnicas de espectrofotometria UV-Vis, voltametria e espectrofluorometria, usando azul de metrileno (MB) como marcador. O comportamento voltamétrico da doxorrubicina foi investigado em eletrodo de carbono vítreo usando voltametria de pulso diferencial. A doxorrubicina é reduzida, produzindo um pico de redução. Os dois estudos, espectrofotometria UV-Vis e voltametria de pulso diferencial, confirmam a reação de intercalação. Os resultados mostraram que a doxorrubicina e a molécula de MB foram intercaladas na dupla hélice do DNA. A constante de ligação aparente de doxorrubicina com DNA foi 3,2 × 10 4 L mol -1 . O sinal de fluorescência da doxorrubicina e azul de metileno é suprimido com a adição de DNA. A equação de Stern-Volmer baseou-se na supressão do sinal de fluorescência da doxorrubicina.In this work, the interaction of doxorubicin with calf thymus double strand Deoxyribonucleic acid (ds-DNA) has been investigated with the use of Methylene Blue (MB) dye as a probe by the application of UV-Vis spectrophotometry, voltammetry and spectrofluorometry. The voltammetric behavior of doxorubicin has been investigated at glassy carbon electrode using differential pulse voltammetry. Doxorubicin is reduced, yielding one reduction peak. Both UV-Vis spectrophotometry and differential pulse voltammetry studies confirm the intercalation reaction. The results showed that both doxorubicin and the MB molecule could intercalate into the double helix of the DNA. The apparent binding constant of doxorubicin with DNA has been found to be 3.2 × 10 4 L mol -1 . The fluorescence signal of doxorubicin and methylene blue was quenched with DNA addition. The Stern-Volmer equation was plotted based on quenching fluorescence signal of doxorubicin.Keywords: doxorubicin, DNA, chemotherapy, spectrophotometry, voltammetry, spectrofluorometry IntroductionStudy of interactions between drugs and DNA is very interesting and significant not only in understanding the mechanism of interaction, but also for the design of new drugs. 1,2 However mechanism of interactions between drug molecules and DNA is still relatively little known. It is necessary to introduce more simple methods for investigating the mechanism of interaction. By understanding the mechanism of interaction, designing of new DNA-targeted drugs and the screening of these in vitro will be possible.A great variety of substances, including several agents of importance in cancer chemotherapy, 3 are known to bind to DNA by intercalation. 4 Attention has been concentrated on the classical intercalating drugs, acridines and ethidium bromide. [4][5][6] Studies on the binding of various dyes, drugs and antibiotics to DNA and chromatin have contributed to the understanding of the structure of these macromolecules, 6-14 and have suggested possible mechanisms of the biological activity of some drugs. 3 Molecular models of the intercalation of some drugs into DNA have been describ...

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The role of the methylene blue and toluidine blue monomers and dimers in the photoinactivation of bacteria

Cited by 196 publications

References 19 publications

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Photodynamic Inactivation of Bacillus Spores, Mediated by Phenothiazinium Dyes

Phenothiazinium photosensitisers XI. Improved toluidine blue photoantimicrobials

Study on the interaction between doxorubicin and Deoxyribonucleic acid with the use of methylene blue as a probe

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