Related Experiment Video
Updated: Mar 28, 2026
Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers
Published on: October 28, 2015
Functional Polymeric Systems as Delivery Vehicles for Methylene Blue in Photodynamic Therapy
Mariana V Junqueira1, Fernanda B Borghi-Pangoni1, Sabrina B S Ferreira1
1Postgraduate Program in Pharmaceutical Sciences, Laboratory of Research and Development of Drug Delivery Systems, Department of Pharmacy, and ‡Postgraduate Program in Chemistry, Department of Chemistry, State University of Maringá , Maringá, Paraná, Brazil.
Abstract:
Antibiotic-resistant microorganisms have become a global concern, and the search for alternative therapies is very important. Photodynamic therapy (PDT) consists of the use of a nontoxic photosensitizer (PS), light, and oxygen. This combination produces reactive oxygen species and singlet oxygen, which can alter cellular structures. Methylene blue (MB) is a substance from the phenothiazine class often used as a PS. In this work, to facilitate the PS contact within the wounds, we have used Design of Experiments 2(3) plus central point to develop functional polymeric systems. The formulations were composed by poloxamer 407 [15.0, 17.5, or 20.0% (w/w)], Carbopol 934P [0.15, 0.20, or 0.25% (w/w)], and MB [0.25, 0.50, or 0.75% (w/w)]. The sol-gel transition temperature, flow rheometry, in vitro MB release, and ex vivo study of MB cutaneous permeation and retention were investigated. Moreover, the evaluation of photodynamic activity was also analyzed by in vitro degradation of tryptophan by singlet oxygen and using Artemia salina. The determination of the gelation temperature displayed values within the range of 25-37 °C, and the systems with better characteristics were subjected to rheological analysis and in vitro release profiling. The 20/0.15/0.25 formulation showed the best release profile (42.57% at 24 h). This system displayed no significant skin permeation (0.38% at 24 h), and the photooxidation of tryptophan test showed the production of reactive species of oxygen. The toxicity test using A. salina revealed that the MB associated with the light increased the mortality rate by 61.29%. Therefore, investigating the PDT efficacy of the functional polymeric system containing MB will be necessary in the future.
Insights
This study developed functional polymeric systems containing methylene blue (MB) for photodynamic therapy (PDT) to combat antibiotic resistance. The optimized gel formulation showed good MB release and produced reactive oxygen species, indicating potential for wound treatment.
Area of Science:
- Pharmaceutical Sciences
- Biomaterials Engineering
- Photomedicine
Background:
- Antibiotic-resistant microorganisms pose a significant global health threat, necessitating novel therapeutic strategies.
- Photodynamic therapy (PDT), utilizing a photosensitizer, light, and oxygen, offers a promising alternative by generating cytotoxic reactive oxygen species.
- Methylene blue (MB), a phenothiazine photosensitizer, is explored for its therapeutic potential.
Purpose of the Study:
- To develop functional polymeric systems for enhanced topical delivery of methylene blue (MB) for photodynamic therapy (PDT).
- To optimize MB-loaded poloxamer/Carbopol gels using Design of Experiments for wound applications.
- To evaluate the physicochemical, release, permeation, and photodynamic efficacy of the developed MB-loaded gels.
Main Methods:
- Formulation of poloxamer 407 and Carbopol 934P gels with varying MB concentrations using Design of Experiments (2(3) + central point).
- Characterization of sol-gel transition temperature, rheological properties, and in vitro MB release kinetics.
- Ex vivo skin permeation and retention studies, in vitro photodynamic activity assessment (tryptophan degradation), and Artemia salina toxicity testing.
Main Results:
- Optimized MB-loaded gels exhibited gelation temperatures between 25-37 °C, suitable for physiological application.
- The formulation containing 20% poloxamer 407, 0.15% Carbopol 934P, and 0.25% MB demonstrated the most favorable in vitro release profile (42.57% at 24 h).
- This optimized system showed minimal skin permeation (0.38% at 24 h), effective reactive oxygen species generation, and a significant increase in Artemia salina mortality (61.29%) when exposed to light, indicating photodynamic efficacy.
Conclusions:
- Functional polymeric systems containing methylene blue were successfully developed for potential topical photodynamic therapy.
- The optimized gel formulation exhibits desirable release characteristics and demonstrates photodynamic activity, suggesting its potential as an alternative to antibiotics.
- Further investigation into the in vivo efficacy of this MB-loaded polymeric system for treating infections caused by antibiotic-resistant microorganisms is warranted.
Related Concept Videos
01:24Site-Targeted Drug Delivery Systems: Polymeric Carriers
01:24Modified-Release Drug Delivery Systems: Site-Targeted