Photosensitizers in antibacterial photodynamic therapy: an overview

Abstract

Phototherapy began in ancient Egypt. Ancient Egyptians treated some skin diseases with herbs and sunlight. They applied natural photosensitizers such as psoralens (extracted from particular plants such as Parsley and Stjohn's-wort) for treatment of leprosy lesions 1, 2). Osar Raab, a medical student who worked in Munich was the first one to notice that dyes like acrydine along with light can kill paramecia. He discovered that the incubation of paramecium with acridine and consequent exposure to light potentially kills paramecium. However, the mere application of acridine without light exposure was not effective 3). In following years, Von Tappeiner coined the term "photodynamic action" and attested that the presence of oxygen is essential in photodynamic action. The first PDT was performed on a patient with skin carcinoma. It was carried out by T. Appaeiner and H. Jesionek in 1904. They used Eosin as PS along with white light. In recent years, more advances have been made in anticancer photodynamic therapy and different PSs are discovered 1, 2, 4, 5). Antibacterial Photodynamic Therapy (APDT) was first introduced in 1960. Macmillan used toluidine blue against microorganisms like bacteria, algae, and yeast. It was observed that 99% of bacteria were killed within 30 min of irradiation with 21-30 mW of light at 632 nm from

In the Right Light: Photodynamic Inactivation of Microorganisms Using a LED-Based Illumination Device Tailored for the Antimicrobial Application

“…For proof of the principle of the applicability of the Repuls7PDI, we tested two photosensitizers and three different microbial model systems. Phenothiazinium dyes, such as MB [4], are widely used in PDT, and applications range from the treatment of diabetic leg ulcers [22], of infected burn wounds [23] and antibacterial fabrics [24], to environmental applications such as the treatment of plant pathogens [16]. Our results using red light activation prove the photoantimicrobial activity of MB against all bacteria and fungi employed in this study.…”

“…Other compounds with properties optimized for fighting bacteria and fungi were synthesized. As a result, a wide spectrum of photosensitizers readily exist from the classes of phenothiazinium dyes [4], porphyrins [5], chlorins, phthalocyanines and even natural substances, such as chlorophyllin [6], curcumin or hypericin [4], are ready for their testing in clinical trials.…”

“…A cooling fan prevents heating up of the device, which is required for application in human medicine. Two different photosensitizers are tested here: The phenothiazinium dye Methylene blue (MB), which is widely used in PDI [4] and which can be photoactivated with the Repuls7PDI-red, and the natural compound Sodium Magnesium chlorophyllin (CHL), which holds approval as food additive E100. This chlorin e6 derivative was photoactivated with both, that is, the Repuls7PDI-blue and Repuls7PDI-red.…”

Antimicrobial Photoinactivation Approach Based on Natural Agents for Control of Bacteria Biofilms in Spacecraft

“…A wide range of compounds of different structures can be applied, and the efficacy of some PSs has already been evaluated for the eradication of biofilms. Generally, phenothiazinium dyes (e.g., Methylene Blue, Toluidine Blue), porphyrins (e.g., TMPyP), and xanthene dyes (e.g., Erythrosine and Rose Bengal) have been used for API applications [18,19]. There are several advantages of the API method for the control of bacteria biofilms in specific, confined spacecraft environments: (1) API belongs to a multitarget process, so no development of bacterial resistance occurs; (2) microbial killing is rapid (occurs within seconds); and (3) broad-spectrum action removes the need to identify the particular pathogen (identification is difficult to perform in the space environment).…”

Low Dosed Curcumin Combined with Visible Light Exposure Inhibits Renal Cell Carcinoma Metastatic Behavior in Vitros

“…The Type 1 reaction produces free radicals and, due to an interaction with oxygen, reactive oxygen species (ROS). The Type 2 reaction results in singlet oxygen that can interact with specific intracellular molecules [27]. Whether this mechanism also holds true for curcumin is not yet clear.…”