Photodynamic therapy used to reduce microbial contamination and disinfection on solid surfaces of diverse materials ...!!!

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The Photodynamic Therapy is based on the association of a nontoxic photosensitizer and post-irradiation with a proper wavelength light source proper for the formation of reactive species oxygen. PDT may be an option for decontamination of surfaces of various materials that are based on the interaction between a nontoxic photosensitizer (PS) and irradiation with a wavelength light source suitable for the formation of reactive oxygen species with antimicrobial effects. These photoreactions have been used since the beginning of the 20th century as a tool to disable numerous pathogens and were established as a therapeutic platform commonly referred to as PDT. With help of powerful and well controlled light sources, such as lasers and light emitting diode (LED), great advances were made in photochemical and photobiotic studies the low-intensity light can also be associated with the administration of nontoxic PS to locally promote photochemical reactions that might induce cell death. In short, when the PS absorbs a photon, it is upgraded to an excitable state and can transfer charges or energy to molecular oxygen of the fundamental state inducing the formation of reactive species of oxygen. The by-products of phenothiazine, such as toluidine blue and methylene blue (MB) are amongst the most studied PS for the antimicrobial photodynamic therapy (aPDT) and have been tested in the last decades in association with the red light to promote the bactericidal effect in vitro and in vivo.