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Evaluation of the efficacy of photodynamic antimicrobial therapy using a phenothiazine compound and LED (red-orange) on the interface: macrophage vs S. aureus
Author(s): Fernando José Pires Sampaio; Susana C. P. S. de Oliveira; Juliana S. C. Monteiro; Gustavo M. Pires-Santos; Maria de Fátima M. Gesteira; Antônio L. B. Pinheiro
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Paper Abstract

Antimicrobial Photodynamic therapy is a technique in which microorganisms are exposed to a photosensitizing drug and then irradiated with low-intensity visible light of the appropriate wavelength. The resulting photochemical reaction generates cytotoxic reactive oxygen species, such as singlet oxygen and free radicals, which are able to exert bactericidal effect. Much is already known about the photodynamic inactivation of microorganisms: both antibiotic-sensitive and - resistant strains can be successfully photo inactivated, and there is the additional advantage that repeated photosensitization of bacterial cells does not induce a selection of resistant strains. Recently, a series of studies have shown that it is possible to kill bacteria with a light source after the microorganisms have been sensitized with low concentration of dye, such as phenothiazines. The aim of this study was to evaluate the phagocytic function of macrophages J774 against S. aureus in the presence and absence of AmPDT with phenothiazine compound (12.5 μg/mL) and red-orange LED. Experimental groups: Control Group (L-F-), Phenothiazine group (L-F+) LED group (L+F-), Photodynamic therapy group (L+F+). The tests presented in this study were carried out in triplicate. This study demonstrated that AmPDT is able to increase about twice the phagocytic ability of macrophages; however, the bactericidal capacity of these cells did not show a substantial improvement, probably because the oxidative burst was less intense.

Paper Details

Date Published: 5 March 2015
PDF: 8 pages
Proc. SPIE 9309, Mechanisms for Low-Light Therapy X, 93090Z (5 March 2015); doi: 10.1117/12.2079218
Show Author Affiliations
Fernando José Pires Sampaio, Univ. Federal da Bahia (Brazil)
National Institute of Optics and Photonics (Brazil)
Susana C. P. S. de Oliveira, Univ. Federal da Bahia (Brazil)
National Institute of Optics and Photonics (Brazil)
Juliana S. C. Monteiro, Univ. Federal da Bahia (Brazil)
National Institute of Optics and Photonics (Brazil)
Univ. Estadual de Feira de Santana (Brazil)
Gustavo M. Pires-Santos, Univ. Federal da Bahia (Brazil)
National Institute of Optics and Photonics (Brazil)
Maria de Fátima M. Gesteira, Univ. Federal da Bahia (Brazil)
Antônio L. B. Pinheiro, Univ. Federal da Bahia (Brazil)
National Institute of Optics and Photonics (Brazil)


Published in SPIE Proceedings Vol. 9309:
Mechanisms for Low-Light Therapy X
Michael R. Hamblin; James D. Carroll; Praveen Arany, Editor(s)

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