Potassium iodide potentiates antimicrobial photodynamic inactivation mediated by Rose Bengal: In vitro and in vivo studies

Xiang Wen, Xiaoshen Zhang, Grzegorz Szewczyk, Ahmed Elhussien, Ying Ying Huang, Tadeusz Sarna, Michael R. Hamblin

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Rose Bengal (RB) is a halogenated xanthene dye that has been used to mediate antimicrobial photodynamic inactivation. While highly active against Gram-positive bacteria, RB is largely inactive in killing Gram-negative bacteria. We have discovered that addition of the non-toxic salt potassium iodide (100mM) potentiates green light (540nm)-mediated killing by up to six extra logs with Gramnegative bacteria Escherichia coli and Pseudomonas aeruginosa,Gram-positive methicillin resistant Staphylococcus aureus, and fungal yeast Candida albicans. The mechanism is proposed to be singlet oxygen addition to iodide anion to form peroxyiodide, which decomposes into radicals, finally forms hydrogen peroxide and molecular iodine. The effects of these different bactericidal species can be teased apart by comparing killing in three different scenarios: (1) cells+RB+KI are mixed together then illuminated with green light; (2) cells+RB are centrifuged then KI added then green light; (3) RB+KI+green light then cells added after light. We showed that KI could potentiate RBPDT in a mouse model of skin abrasions infected with bioluminescent P.aeruginosa.

Original languageEnglish
Title of host publicationLight-Based Diagnosis and Treatment of Infectious Diseases
EditorsTianhong Dai
ISBN (Electronic)9781510614437
Publication statusPublished - 2018
Externally publishedYes
EventLight-Based Diagnosis and Treatment of Infectious Diseases 2018 - San Francisco, United States
Duration: 29 Jan 201831 Jan 2018

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


ConferenceLight-Based Diagnosis and Treatment of Infectious Diseases 2018
Country/TerritoryUnited States
CitySan Francisco


  • Pseudomonas aeruginosa mouse infection
  • Rose Bengal
  • antimicrobial photodynamic inactivation
  • potassium iodide
  • reactive iodine species
  • singlet oxygen

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology, Nuclear Medicine and Imaging


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