title: Effect of different pre-irradiation times on curcumin-mediated photodynamic therapy against planktonic cultures and biofilms of Candida spp.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of pre-irradiation time (PIT) on curcumin (Cur)-mediated photodynamic therapy (PDT) against planktonic and biofilm cultures of reference strains of Candida albicans, Candida glabrata and Candida dubliniensis.
  
  
  METHODS
  Suspensions and biofilms of Candida species were maintained in contact with different concentrations of Cur for time intervals of 1, 5, 10 and 20min before irradiation and LED (light emitting diode) activation. Additional samples were treated only with Cur, without illumination, or only with light, without Cur. Control samples received neither light nor Cur. After PDT, suspensions were plated on Sabouraud Dextrose Agar, while biofilm results were obtained using the XTT-salt reduction method. Confocal Laser Scanning Microscopy (CLSM) observations were performed to supply a better understanding of Cur penetration through the biofilms after 5 and 20min of contact with the cultures.
  
  
  RESULTS
  Different PITs showed no statistical differences in Cur-mediated PDT of Candida spp. cell suspensions. There was complete inactivation of the three Candida species with the association of 20.0μM Cur after 5, 10 and 20min of PIT. Biofilm cultures showed significant reduction in cell viability after PDT. In general, the three Candida species evaluated in this study suffered higher reductions in cell viability with the association of 40.0μM Cur and 20min of PIT. Additionally, CLSM observations showed different intensities of fluorescence emissions after 5 and 20min of incubation.
  
  
  CONCLUSIONS
  Photoinactivation of planktonic cultures was not PIT-dependent. PIT-dependence of the biofilm cultures differed among the species evaluated. Also, CLSM observations confirmed the need of higher time intervals for the Cur to penetrate biofilm structures.
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil.
authors.forename: Mariana Carvalho
authors.initials: MC
authors.lastname: Andrade
authors.affiliation: Department of Operative Dentistry, University of Brasília - UnB, Brasília, DF, Brazil.
authors.forename: Ana Paula Dias
authors.initials: AP
authors.lastname: Ribeiro
authors.affiliation: Department of Social Dentistry, Araraquara Dental School, UNESP - Univ Estadual Paulista, Araraquara, Araraquara, SP, Brazil.
authors.forename: Lívia Nordi
authors.initials: LN
authors.lastname: Dovigo
authors.affiliation: Department of Clinical Analysis, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil.
authors.forename: Iguatemy Lourenço
authors.initials: IL
authors.lastname: Brunetti
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil.
authors.forename: Eunice Teresinha
authors.initials: ET
authors.lastname: Giampaolo
authors.affiliation: Physics Institute of São Carlos, University of São Paulo - USP, São Carlos, SP, Brazil.
authors.forename: Vanderlei Salvador
authors.initials: VS
authors.lastname: Bagnato
authors.affiliation: Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP - Univ Estadual Paulista, Araraquara, SP, Brazil. Electronic address: pavarina@foar.unesp.br.
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Pavarina
mesh_terms: D018441:Biofilms / Q000187:drug effects*; D002175:Candida / Q000187:drug effects*; D018929:Cell Culture Techniques; D003474:Curcumin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D018613:Microscopy, Confocal; D010778:Photochemotherapy / Q000379:methods*; D013535:Suspensions; D013997:Time Factors
chemical_list: D013535:Suspensions; D003474:Curcumin