In vitro photodynamic inactivation of Candida albicans by phenothiazine dye (New methylene blue) and Indocyanine green (EmunDo®)

Background: The application of a new generation of photosensitizers to increase the efficacyof antifungal photodynamic therapy (aPDT) is an important aspect of PDT. Thus, this in vitrostudy is aimed to evaluate the antifungal efficacy of the photo-elimination of Candida albicanswith photothermal and antifungal photodynamic therapy.Method and material: aPDT with new methylene blue and photothermal therapy with EmunDo®were applied to a fungal suspension, which was then subcultured in Sabouraud dextrose agar(SDA). The C. albicans colonies were counted and are expressed as colony-forming unit permilliliter (CFU/ml).Results: aPDT with either EmunDo®or new methylene blue (NMB) considerably diminished theviability of inoculated C. albicans (P < 0.001) by log reduction of 1.9 and 3.37, respectively,compared with the control group respectively, compared with the control group. The antifungalpotency or dark toxicity of the two photosensitizers alone did not significantly differ (P = 0.70).The same trend was observed for the light sources (�: 810 nm vs. �: 630 nm), which also did notsignificantly differ (P = 0.78).Conclusion: The photo-elimination of C. albicans with either new methylene blue or EmunDo®as a photosensitizer can reduce the viability of fungal cells. Although the result of this study isencouraging, further investigations are warranted to determine clear protocols for the reliableand safe application of this method in clinical practice.© 2015 Elsevier B.V. All rights reserved