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Updated: Jun 23, 2025
An In Vitro Approach to Photodynamic Therapy
Published on: August 17, 2018
Anticandidal effect of multiple sessions of erythrosine and potassium iodide-mediated photodynamic therapy
Pran Pitaksanurat1, Nirawat Mayeah1, Pattranun Saithong1
1Division of Oral Diagnosis, Department of Oral Biomedical Sciences, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
Background:
Erythrosine+potassium iodide-mediated photodynamic therapy has shown an anticandidal effect. Single session, however, has inadequate fungal inhibition.
Objectives:
We aimed to examine the effects of multiple aPDT sessions on Candida albicans inhibition and singlet oxygen formation.
Methods:
220 μM erythrosine +/-100 mM potassium iodide was applied to C. albicans biofilms for 1 min prior to irradiation at 530±10 nm using a 250 mW/cm2 light-emitting diode. Negative and positive controls were phosphate buffer saline and nystatin, respectively. Single, double and triple irradiation sessions with a 5 min resting time between sessions were performed. Post-treatment candidal counts were done at 0, 1 6 and 24 hr while log10 colony forming unit/ml was calculated and compared using a Kruskal-Wallis with Dunn's post hoc test at a p<0.05 - Singlet oxygen amount was compared using one-way ANOVA with a post hoc test at a p< 0.05.
Results:
Two and three irradiation sessions to erythrosine+potassium iodide could inhibit Candida albicans at 7.92 log10CFU/ml (p < 0.001) . Singlet oxygen from a combination groups was significantly higher than for erythrosine (positive control). Moreover, the correlation coefficient (r) between singlet oxygen production and decreased Candida albicans counts was equal to 1.
Conclusion:
Multiple sessions PDT of 220 μM erythrosine+100 mM potassium iodide effectively inhibited a Candida biofilm.
Insights
Multiple sessions of photodynamic therapy (PDT) using erythrosine and potassium iodide effectively inhibited Candida albicans biofilms. This approach significantly reduced fungal counts and increased singlet oxygen production, demonstrating its anticandidal potential.
Area of Science:
- Biochemistry
- Microbiology
- Photomedicine
Background:
- Photodynamic therapy (PDT) using erythrosine and potassium iodide has demonstrated anticandidal properties.
- A single PDT session provides insufficient inhibition of Candida albicans.
Purpose of the Study:
- To evaluate the efficacy of multiple PDT sessions in inhibiting Candida albicans.
- To assess the impact of repeated PDT sessions on singlet oxygen formation.
Main Methods:
- Candida albicans biofilms were treated with erythrosine and potassium iodide, followed by irradiation.
- Single, double, and triple irradiation sessions were performed with resting periods in between.
- Fungal inhibition was quantified by colony-forming unit counts, and singlet oxygen production was measured.
Main Results:
- Two and three PDT sessions significantly inhibited Candida albicans, reducing counts to 7.92 log10 CFU/ml (p < 0.001).
- The combination of erythrosine and potassium iodide generated significantly higher singlet oxygen levels compared to erythrosine alone.
- A strong positive correlation (r=1) was observed between singlet oxygen production and the reduction in Candida albicans counts.
Conclusions:
- Multiple PDT sessions utilizing erythrosine and potassium iodide are effective in inhibiting Candida biofilms.
- The enhanced anticandidal effect is linked to increased singlet oxygen generation.
- This multi-session PDT approach offers a promising strategy for managing Candida infections.
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