title: Effect of 5-aminolevulinic acid photodynamic therapy on Candida albicans biofilms: An in vitro study.
abstract: BACKGROUND
  In this study, the photoinactivation of 5-aminolevulinic acid (ALA) has been investigated on Candida albicans biofilms in vitro.
  
  
  METHODS
  After culture and proliferation of Candida albicans biofilms in vitro, the metabolic activity was confirmed using XTT reduction assay. Then, the suitable incubation time and concentration of ALA were determined by measuring PpIX accumulation quantities. Photosensitivity of the biofilms treated with ALA solution was studied in optical doses of 50, 100, 200 and 300J/cm(2) while light irradiation was applied by a red light semiconductor. Finally, rapid immunofluorescence staining method using the LIVE/DEAD FungaLight Yeast Viability Kit and XTT assay were conducted to visualize and quantify the antifungal effect of ALA-PDT on Candida albicans biofilms.
  
  
  RESULTS
  A 5h incubation time and 15mM ALA concentration were determined for this study. Photoinactivation of ALA-PDT on Candida albicans biofilms showed a significant increase of protoporphyrin IX (PpIX) in the biofilms. The metabolic activity of Candida albicans biofilms tread with ALA-PDT confirmed the inhibition efficacy compared with control groups. Upon radiation at 300J/cm(2), cells in Candida albicans biofilms were 74.45% inhibited.
  
  
  CONCLUSIONS
  PpIX can be absorbed in biofilm-grown Candida albicans in vitro and under appropriate parameters, photochemistry can be triggered by light in combination with ALA and inhibits Candida albicans biofilms effectively.
authors.affiliation: Department of Stomatology, Huashan Hospital, Fudan University, No. 12, Rd Wulumuqi, Huahan Hospital, Shanghai, China. Electronic address: shihang1016@hotmail.com.
authors.forename: Hang
authors.initials: H
authors.lastname: Shi
authors.affiliation: School of Pharmacy, Fudan University, No. 826, Rd Zhangheng Shanghai, China. Electronic address: lijiyang@fudan.edu.cn.
authors.forename: Jiyang
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Stomatology, Huashan Hospital, Fudan University, No. 12, Rd Wulumuqi, Huahan Hospital, Shanghai, China. Electronic address: huihui_8507@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Huashan Hospital, Fudan University, No. 12, Rd Wulumuqi, Huahan Hospital, Shanghai, China. Electronic address: fdhszhangjie@163.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Huashan Hospital, Fudan University, No. 12, Rd Wulumuqi, Huahan Hospital, Shanghai, China. Electronic address: huashan110926@163.com.
authors.forename: Hongying
authors.initials: H
authors.lastname: Sun
mesh_terms: D000622:Aminolevulinic Acid / Q000008:administration & dosage*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects*; D002176:Candida albicans / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects*; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004203:Disinfection / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008027:Light; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage
chemical_list: D017319:Photosensitizing Agents; D000622:Aminolevulinic Acid
keywords: 5-Aminolevulinic acid; Antifungal therapy; Biofilm; Candida albicans; Photodynamic therapy