title: Photodynamic inactivation of Candida albicans biofilm: Influence of the radiant energy and photosensitizer charge.
abstract: BACKGROUND
  The aim of this study is to investigate the photoinactivation of C. albicans biofilm on acrylic resin discs (the standard material for dental prosthesis) using the photosensitizers Methylene Blue and a Protoporphyrin IX.
  
  
  METHODS
  Eighteen thermally activated Methyl Methacrylate Polymers were used for the biofilm growth of Candida albicans ATCC 10231. Two photosensitizers were tested: methylene blue (50μM) and protoporphyrin IX (10μM). Two custom-made LEDs emitting at 660nm and 630nm with approximately 800mW each were used for the irradiation, with duration ranging from 2 to 10min.
  
  
  RESULTS
  This study demonstrates that MB decreased the aPDT CFUs by approximately two orders of magnitude, but the protoporphyrin was ineffective.
  
  
  CONCLUSIONS
  The aPDT with MB significantly reduces (but does not sterilize) the amount of CFU after 10min of irradiation, and it is not dose-dependent. The lack of effect of the protoporphyrin is likely because the negative charges of the proteoglycans present in the extracellular matrix repel the negative charges of the PS, thus preventing its diffusion in the cells.
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Aline Silva
authors.initials: AS
authors.lastname: Sousa
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil. Electronic address: pratesra@uninove.br.
authors.forename: Renato Araujo
authors.initials: RA
authors.lastname: Prates
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Maria Eugênia Simões Onofre
authors.initials: ME
authors.lastname: de Santi
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Rúbia Garcia
authors.initials: RG
authors.lastname: Lopes
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Sandra Kalil
authors.initials: SK
authors.lastname: Bussadori
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Luis Rodolfo
authors.initials: LR
authors.lastname: Ferreira
authors.affiliation: Postgraduate Program in Biophotonics Applied to Health Sciences, Nove de Julho University (UNINOVE), São Paulo, SP, Brazil.
authors.forename: Alessandro Melo
authors.initials: AM
authors.lastname: Deana
mesh_terms: D018441:Biofilms / Q000187:drug effects / Q000528:radiation effects; D002176:Candida albicans / Q000187:drug effects* / Q000528:radiation effects*; D008751:Methylene Blue / Q000627:therapeutic use*; D008855:Microscopy, Electron, Scanning; D017319:Photosensitizing Agents; D011524:Protoporphyrins / Q000627:therapeutic use*
chemical_list: D017319:Photosensitizing Agents; D011524:Protoporphyrins; C028025:protoporphyrin IX; D008751:Methylene Blue
keywords: Antimicrobial; Antimicrobial photodynamic therapy; Methylene blue; Photoinactivation; Protoporphyrin IX; Yeast