Photodynamic therapy of antibiotic-resistant biofilms in a maxillary sinus model

Merrill A. Biel, Lisa Pedigo, Aaron Gibbs, Nicolas Loebel

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Background: Chronic rhinosinusitis (CRS) is one of the most common chronic conditions in the United States. There is a significant subpopulation of CRS patients who remain resistant to cure despite rigorous treatment regimens including surgery, allergy therapy, and prolonged antibiotic therapy. Antimicrobial photodynamic therapy (aPDT) is a noninvasive nonantibiotic broad spectrum antimicrobial treatment. Our previous in vitro studies demonstrated that aPDT reduced CRS polymicrobial planktonic bacteria and fungi by >99.9% after a single treatment. However, prior to human treatment, the effectiveness of aPDT to eradicate polymicrobial biofilms in a maxillary sinus cavity must be demonstrated. The objective of this study was to demonstrate the effectiveness of a noninvasive aPDT treatment of antibiotic resistant biofilms known to cause CRS in a novel anatomically correct maxillary sinus in vitro model using an enhanced photosensitizer solution. Methods: Antibiotic resistant polymicrobial biofilms of Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) were grown in an anatomically correct novel maxillary sinus model and treated with a methylene blue/ethylenediamine tetraacetic acid (EDTA) photosensitizer and 670-nm nonthermal activating light. Cultures of the biofilms were obtained before and after light treatment to determine efficacy of biofilm reduction. Results: The in vitro maxillary sinus CRS biofilm study demonstrated that aPDT reduced the CRS polymicrobial biofilm by >99.99% after a single treatment. Conclusion: aPDT can effectively treat CRS polymicrobial antibiotic resistant Pseudomonas aeruginosa and MRSA biofilms in a maxillary sinus cavity model.

Original languageEnglish (US)
Pages (from-to)468-473
Number of pages6
JournalInternational Forum of Allergy and Rhinology
Issue number6
StatePublished - Jun 2013


  • Biofilms
  • Chronic sinusitis
  • MRSA
  • Maxillary sinus model
  • Photodynamic therapy
  • Pseudomonas aeruginosa

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