Laser-induced hyperthermia (LH) is a treatment technique researched in multiple medical applications, including the treatment of warts and malignant tumors. Optimal laser energy delivery to target tissue is important to achieve an effective LH with minimal damage to healthy tissue. However, this can be challenging because optical properties may vary depending on tissue type and environmental factors. Therefore, real-time measurement of temperature is as important as dosimetry for a successful and safe LH application. In addition, the temperature measurement must be non-contact to minimize the risk of microbial contamination. In this study, we developed a temperature-controlled 808 nm diode-laser system that eliminates the risk of thermal damage and contamination by performing non-contact, real-time temperature measurements of the irradiated surface. The system is composed of an 808 nm c-mount diode laser, an infrared (IR) array sensor for temperature measurement, a PC, and an electronic control unit (ECU). The system was tested on phantoms and ex vivo tissues. According to the results, the temperature-controlled 808 nm diode-laser system could maintain the surface temperature of samples at the target temperature value.
Exploiting differences in photosensitizer (PS) localization and mechanisms of action with sequential or simultaneous activation protocols has been shown to improve photodynamic therapy (PDT) efficacy. Various sub-cellular, cellular and stromal components can be targeted, causing selective photodamage. Previous reports have shown that rationally targeting non-overlapping tumor compartments or sub-cellular sites considerably enhances outcomes from PDT. The current presentation describes the benefits of simultaneously targeting lysosomes and mitochondria/endoplasmic reticulum using lipid-anchored and entrapped liposomal preparations of benzoporphyrin derivative, respectively, with an emphasis on results in 3D models of ovarian cancer.
Photodynamic therapy is a non-invasive therapeutic modality that has gained much attention in the last few decades. It involves administration of a photoactivatable substance, called photosensitizer (PS) into the body, and this substance, upon receiving light can generate reactive oxygen species (ROS), which could subsequently destroy nearby malignancies. The technique has been widely used for cancer treatment, but is also of significance to fight against infectious diseases. For the purpose of this study, Enterococcus faecalis, a bacterial strain common in oral cavities, gastrointestinal system, and wound infections, was selected and its antimicrobial photodynamic inactivation (aPDI) effect with the phenothiazinium dye Toluidine Blue Ortho (TBO) using a 635 nm diode laser was observed. To investigate the possibility of aPDI enhancement, potassium iodide (KI), an inorganic salt which has been proven to have antimicrobial use in dermatology, was used as a potentiating mediator, in order to give a comparative account of the aPDI effect. Laser power was set at 300 mW with irradiation times of 30, 60, and 180 s. Photosensitizer and inorganic potentiator concentration ranges were selected to be 100 μM(TBO) and 100 mM(KI) respectively. Noticeable potentiation of aPDI effect was observed, especially for 60 and 180 s irradiation groups.
Photobiomodulation (PBM) triggers proliferation of many type of cell, including fibroblasts. Although PBM has positive effects on modulation of ample biological processes, significant contradictions in underlying process has been waiting for gathering and clarifying. This preliminary study evaluated the efficacy of correct combination between different energy densities and intensities of 635 nm laser light. This study aimed to investigate and identify the compatible match of energy and power density to proliferate L929 cell line. Cells were plated at a cell density of 20,000cells per well on 96-well polystyrene plates. The plates were incubated for 24 h and then, the wells were irradiated using power densities of 30 mW/cm2, 50 mW/cm2, 125 mW/cm2, and 200 mW/cm2. Energy densities used in this study were 1 J/cm2, 3 J/cm2, and 5 J/cm2. 1 J/cm2 laser energy density stimulated significantly the proliferation of L929 cells at 30 mW/cm2, 50 mW/cm2, 125 mW/cm2. However, the proliferation at 3 J/cm2 was significantly (p ≤ 0.05) higher than the proliferation at 1 J/cm2 when 200 mW/cm2 of laser power density was used. In conclusion, the results show that the stimulatory effect of PBM depends on both energy density and power density. Thus, the combination of laser energy density and intensity may change the treatment response.
Cancer is one of the main reasons of death in all around the world. The main treatments of cancer include surgical intervention, radiation therapy and chemotherapy. These treatments can be applied separately or in a combined manner. Another therapeutic method that is still being researched and recently has started to be used in clinical applications is Photodynamic Therapy (PDT). Most photosensitizers currently being investigated are sensitive to red light. However, it is known that infrared light has a better penetration into the skin or tissue. Indocyanine Green (ICG), which is used in this study, is sensitive to infrared light. The aim of this in vitro study is to investigate the effect of PDT on breast cancer cells by using different doses of ICG and infrared light irradiation. 25, 50 and 100 μM ICG concentrations and 25 and 50 J/cm2 laser energy doses were applied to MCF-7 cell lines. MTT analyses were performed on 24, 48 and 72 hours following the treatments. As a result, inhibition of cell viability was observed in a time and dose dependent manner. It can be concluded that ICG-PDT application is a good alternative to conventional radiation therapy and chemotherapy for breast cancer treatment.
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