Organic Light‐Emitting Diodes as an Innovative Approach for Treating Cutaneous Leishmaniasis

• Published in: Advanced materials technologies Vol. 6; no. 11
• Main Authors: Cabral, Fernanda V., Lian, Cheng, Persheyev, Saydulla, Smith, Terry K., Ribeiro, Martha S., Samuel, Ifor D. W.
• Format: Journal Article
• Language: English
• Published: 01-11-2021
• Subjects: antimicrobial photodynamic therapy; flexible light sources; Leishmania parasites; low irradiance photodynamic therapy; methylene blue; organic light‐emitting diode; phenothiazine photosensitizer
• ISSN: 2365-709X; 2365-709X
• DOI: 10.1002/admt.202100395

Antimicrobial photodynamic therapy (APDT) has been studied as a noninvasive therapy for treating cutaneous leishmaniasis to overcome challenges with current treatment, such as toxicity, resistance, and need for in‐patient hospital treatment. Organic light‐emitting diodes (OLEDs) have emerged as an attractive technology that can provide wearable light‐emitting materials that are conformable to human skin. This makes OLEDs ideal candidates for APDT by light‐bandages for ambulatory care. In this work, suitable OLEDs are successfully developed to match the absorbance of three photosensitizers: methylene blue, new methylene blue, and 1,9‐dimethyl‐methylene blue to inactivate two Leishmania species in vitro: Leishmania major and Leishmania amazonensis. Parasites are treated either by LED (20 mW cm−2) or OLED (6.5 mW cm−2) at increasing photosensitizer concentrations at a radiant exposure of 50 J cm−2. 1,9‐Dimethyl‐methylene blue is the most potent photosensitizer, killing both strains at nanomolar concentrations. The effect of different intensities from the OLEDs (0.7, 1.5, and 6.5 mW cm−2) are also explored and it is shown that effective killing of Leishmania occurs even at a very low intensity. These findings demonstrate the great potential of OLEDs as a new approach for ambulatory treatment of cutaneous leishmaniasis by APDT.
The growing problem of antimicrobial resistance means new approaches to dealing with infections are needed. Here, organic light‐emitting diodes (OLEDs) are shown to be effective light sources for killing two species of Leishmania parasite by photodynamic therapy. The results illustrate the growing potential of OLEDs as new light sources for medicine with the potential to enable ambulatory treatment.