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Updated: Sep 27, 2026
An In Vitro Approach to Photodynamic Therapy
Published on: August 17, 2018
Antimicrobial photodynamic therapy: assessment of genotoxic effects on keratinocytes in vitro
1Dermatology Department of Teshreen Hospital, Damascus, Syria.
Background:
Work has shown that cutaneous microbial species associated with skin conditions of microbial aetiology are susceptible to killing by antimicrobial photodynamic therapy (APDT) using visible light and methylene blue.
Objectives:
To evaluate immediate and delayed genotoxicity of APDT on keratinocytes in vitro.
Methods:
A combination of methylene blue (100 microg mL(-1)) and visible light (42 mW cm(-2)), as used in studies of microbe and keratinocyte cytotoxicity, was employed to test a human keratinocyte cell line (H103) for genotoxic damage by comet assay.
Results:
The comet assay was able to detect genotoxic damage in H2O2-treated keratinocytes (positive control). APDT did not cause either immediate or delayed genotoxic damage in keratinocytes following APDT of up to 180 min.
Conclusions:
APDT sufficient to reduce microbes by seven log cycles showed no detectable genotoxic effects on keratinocytes. APDT applied in vivo may represent a useful low-risk alternative to conventional antimicrobial treatment in dermatology.
