Application of photothermal techniques in photosensitizer studies ...
Dr. Vinicius Granatto (Physics Institute - UFU) March 25, 2021 Photodynamic therapy (PDT) is a series of methods and procedures that can be used on humans and animals to treat epidermal disease, cancer, and other diseases. In PDT, light triggers a light-sensitive compound (FS), which creates reactive oxygen species that attack particular targets. Consequently, understanding the physical and chemical properties of FS, as well as its photodegradation mechanism, is important in order to achieve better applicability and technical results. Because of its sensitive and almost non-destructive nature and the capacity to reach, extremely low detection limits like at low concentration intervals where commercial techniques are ineffective. This presentation will consist of three parts of my research related to the PDT. In the first part of the research, we used the TL technique in combination with an absorption spectrum analysis to investigate the photoconversion of protohypericin into hypericin, a dye used in PDT. The TL technique was combined with other techniques (absorption spectrum,emission, and transmittance variation) in the second part to investigate the mechanisms of erythrosine photodegradation in the presence of various suppressors. Finally, the pulsed excitation TL technique was used to look at the various effects that make up a transient on the nanosecond and microsecond scales. For nanosecond scale transients, acoustic wave effects induced by the laser pulse were observed and identified. For FS instances, it was discovered that excited state absorption contributes to the TL transient on a microsecond scale, and that this effect is proportional to the triplet state lifetime. These findings allow us to apply the TL technique to the study of a variety of physicochemical properties in liquid samples. Download slides of the talk here: https://drive.google.com/file/d/1nKx1xkcujPWtWMT-zAeb1J6rNnRvQADM/view?usp=sharing
Dr. Vinicius Granatto (Physics Institute - UFU) March 25, 2021 Photodynamic therapy (PDT) is a series of methods and procedures that can be used on humans and animals to treat epidermal disease, cancer, and other diseases. In PDT, light triggers a light-sensitive compound (FS), which creates reactive oxygen species that attack particular targets. Consequently, understanding the physical and chemical properties of FS, as well as its photodegradation mechanism, is important in order to achieve better applicability and technical results. Because of its sensitive and almost non-destructive nature and the capacity to reach, extremely low detection limits like at low concentration intervals where commercial techniques are ineffective. This presentation will consist of three parts of my research related to the PDT. In the first part of the research, we used the TL technique in combination with an absorption spectrum analysis to investigate the photoconversion of protohypericin into hypericin, a dye used in PDT. The TL technique was combined with other techniques (absorption spectrum,emission, and transmittance variation) in the second part to investigate the mechanisms of erythrosine photodegradation in the presence of various suppressors. Finally, the pulsed excitation TL technique was used to look at the various effects that make up a transient on the nanosecond and microsecond scales. For nanosecond scale transients, acoustic wave effects induced by the laser pulse were observed and identified. For FS instances, it was discovered that excited state absorption contributes to the TL transient on a microsecond scale, and that this effect is proportional to the triplet state lifetime. These findings allow us to apply the TL technique to the study of a variety of physicochemical properties in liquid samples. Download slides of the talk here: https://drive.google.com/file/d/1nKx1xkcujPWtWMT-zAeb1J6rNnRvQADM/view?usp=sharing