Related Experiment Video
Updated: Jun 7, 2026
Investigation of a Blue Light LED Device to Suppress Wound Pathogens Using a Collagen-Based Synthetic Skin Model
Published on: February 24, 2026
Photodynamic therapy mediated by methylene blue dye in wound healing
Felipe Fornias Sperandio1, Alyne Simões, Ana Cecília Corrêa Aranha
1Department of Oral Pathology, School of Dentistry, University of São Paulo, Brazil. sperandio@usp.br
Objective:
We sought to investigate the wound-healing process after photodynamic therapy (PDT) mediated by methylene blue dye (MB).
Background Data:
Few scientific studies show the PDT roles in wound healing.
Materials And Methods:
One hundred rats were given a circular wound on the back, inflicted with a 6-mm-diameter punch. The animals were divided into four groups: control (no treatment); dye (topical application of MB); laser (InGaAlP, 117.85 J/cm(2), 100 mW, 660 nm, single point); and PDT (topical application of MB followed by laser irradiation). After 1, 3, 5, 7, and 14 days, the cutaneous wounds were photographed and assessed with histopathologic examination by using light microscope. Changes seen in edema, necrosis, inflammation, granulation tissue, re-epithelialization, and number of young fibroblasts were semiquantitatively evaluated. The wound-area changes were measured with special software and submitted to statistical analysis.
Results:
The laser group demonstrated the smallest wound area at 14 days after the surgical procedure (p < 0.01). Concerning complete re-epithelialization, the laser group showed it at 5-7 days after surgery, whereas the PDT and the other groups showed it at 14 days.
Conclusions:
Laser interaction with tissue is somehow changed when exposed to the MB. PDT mediated by MB was not prejudicial to wound healing, as no delay occurred compared with the control group.
Insights
Photodynamic therapy (PDT) using methylene blue dye (MB) did not delay wound healing in rats. The laser-only group showed faster wound closure and re-epithelialization compared to other groups.
Area of Science:
- Biomedical research
- Tissue regeneration
- Photomedicine
Background:
- Limited research exists on photodynamic therapy's (PDT) role in wound healing.
- Methylene blue dye (MB) is a photosensitizer with potential therapeutic applications.
Purpose of the Study:
- To investigate the effects of MB-mediated PDT on the cutaneous wound healing process.
- To compare wound healing outcomes between PDT, laser-only, dye-only, and control groups.
Main Methods:
- A standardized 6-mm punch wound model was used in 100 rats.
- Animals were divided into control, dye (MB), laser, and PDT groups.
- Wound healing was assessed via photography, histopathology, and software analysis over 14 days.
Main Results:
- The laser-only group exhibited the smallest wound area and fastest re-epithelialization (5-7 days).
- The PDT group showed no delay in wound healing compared to the control group.
- Histopathological analysis evaluated edema, necrosis, inflammation, granulation tissue, and fibroblast proliferation.
Conclusions:
- MB-mediated PDT is not detrimental to wound healing, showing comparable results to the control group.
- Laser irradiation alone accelerated wound healing and re-epithelialization.
- MB potentially alters laser-tissue interactions during PDT.
More Related Videos
05:13LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation
Published on: January 24, 2025
11:04An In-House-Built and Light-Emitting-Diode-Based Photodynamic Therapy Device for Enhancing Verteporfin Cytotoxicity in a 2D Cell Culture Model
Published on: January 13, 2023