Photodynamic effect of light-emitting diode light on cell growth inhibition induced by methylene blue

Abstract

The aim of this study was to propose the use of red light-emitting diode (LED) as an alternative light source for methylene blue (MB) photosensitizing effect in photodynamic therapy (PDT). Its effectiveness was tested against Staphylococcus aureus (ATCC 26923), Escherichia coli (ATCC 26922), Candida albicans (ATCC 90028) and Artemia salina. The maximum absorption of the LED lamps was at a wavelength of 663 nm, at intensities of 2,4,6 and 12 J.cm-2 for 10, 20, 30 and 60 min of exposure, respectively. Assays with and without LED exposure were carried out in plates containing MB at concentrations of 7 to 140.8 (micro) M for microorganisms and 13.35 to 668.5 (micro) M for microorganisms or microcrustaceans. The LED exposure induced more than 93.05%, 93.7% and 93.33% of growth inhibition for concentrations of 42.2 (micro)M for S.aureus (D-value=12.05 min) and 35.2 (micro)M for E.coli (D-value=11.51 min) and C.albicans (D-value=12.18 min), respectively after 20 min of exposure. LED exposure for 1 h increased the cytotoxic effect of MB against A.salina from 27% to 75%. Red LED is a promising light device for PDT that can effectively inhibit bacteria, yeast and microcrustacean growth.

Susceptibility of Candida albicans to photodynamic therapy in a murine model of oral candidosis

“…Recently, alternative light sources, such as LED, have been successfully used in PDT. 25,26,44 In the present investigation, LED was used as a light source because of its ability to irradiate larger areas than is possible with collimated laser light. Moreover, LED technology is simpler and has a lower cost than laser.…”

“…However, light sources with simpler technology and lower cost than lasers, such as light-emitting diodes (LED), have been successfully applied in PDT. 25,26 In addition, there are different colors of LED light, with radiations covering almost the entire visible electromagnetic spectrum. Investigations with the aim of confirming the effectiveness of antimicrobial PDT in animal models are scarce.…”

Photodynamic Therapy As a Promising Method Used in the Treatment of Oral Diseases

“…Diode lasers are small, portable and inexpensive, which makes them more commonly used in PDT therapy. Light emitting diodes have similar advantages (lightweight, flexible and less expensive) and are also successfully applied during photodynamic treatment [9].…”

Avaliação in vitro da resistência de união de diferentes tratamentos de superfície para reparos em resina composta

“…A odontologia também está começando a incorporar a fotodesinfecção no tratamento da cavidade oral. As propriedades antibacterianas e fungicidas do fotossensibilizador têm sido utilizadas para obter melhores resultados no tratamento do canal radicular, na terapia periodontal e na erradicação da candidíase em prótese [6][7][8][9][10][11][12][13][14][15] . Atualmente, o uso de PDT na terapia endodôn-tica foi testado em termos de redução da carga bacteriana 1,[16][17][18][19][20] .…”