• Molecular & Cellular Toxicology
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• v.2 no.1
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• pp.1-6
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• 2006

Photodynamic therapy (PDT), a newly established treatment for solid tumors, involves the systemic administration of a tumor localizing photosensitizer that is only activated when exposed to light of appropriate wavelength. Photoactivation of photosensitizer in the presence of oxygen results in the formation of highly cytotoxic molecular species, which precipitates necrosis. PDT has now become a promising means for the treatment of cancer due to its specificity, relatively minimal side effects, and inexpensive. However, the application of PDT has been restricted to the treatment of superficial lesions or the use of interstitial light delivery. A single photon generally activates the photochemical reaction in traditional PDT. However the use of multi photon excitation, where two or more photons simultaneously excite a photosensitizer, allows for the use of wavelengths twice as long. Such wavelengths exhibit better transmittance through tissue and thereby deeper penetration is achieved. This paper will review theoretical principles of multi photon excitation, challenges associated with multi photon PDT and update the current and future role of multi photon PDT in cancer.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.188-190
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• 2006

In this study, a newly-synthesized metalloporphyrin, Gd-chlorin (PB Chlorin), was investigated by using a simple tissue phantom to test its efficacy as an MRI contrast agent. This study demonstrated the potential activity of Gd-chlorin as not only a MRI contrast agent, but also as a PDT photosensitizer by using a simple tissue phantom and conducting a very brief MRI experiment.

• Journal of Gastric Cancer
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• v.20 no.4
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• pp.355-375
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• 2020

Selective accumulation of a photosensitizer and the subsequent response in only the light-irradiated target are advantages of photodynamic diagnosis and therapy. The limited depth of the therapeutic effect is a positive characteristic when treating surface malignancies, such as peritoneal carcinomatosis. For photodynamic diagnosis (PDD), adjunctive use of aminolevulinic acid- protoporphyrin IX-guided fluorescence imaging detects cancer nodules, which would have been missed during assessment using white light visualization only. Furthermore, since few side effects have been reported, this has the potential to become a vital component of diagnostic laparoscopy. A variety of photosensitizers have been examined for photodynamic therapy (PDT), and treatment protocols are heterogeneous in terms of photosensitizer type and dose, photosensitizer-light time interval, and light source wavelength, dose, and dose rate. Although several studies have suggested that PDT has favorable effects in peritoneal carcinomatosis, clinical trials in more homogenous patient groups are required to identify the true benefits. In addition, major complications, such as bowel perforation and capillary leak syndrome, need to be reduced. In the long term, PDD and PDT are likely to be successful therapeutic options for patients with peritoneal carcinomatosis, with several options to optimize the photosensitizer and light delivery parameters to improve safety and efficacy.

• Journal of the korean academy of Pediatric Dentistry
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• v.51 no.1
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• pp.32-39
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• 2024

This study evaluated the additive impact of ethylenediamine tetraacetic acid (EDTA) on erythrosine-mediated photodynamic therapy (PDT) against Streptococcus mutans (S. mutans) biofilm by measuring colony-forming units and applying confocal laser scanning microscopy. Fifty-six bovine incisors, free from dental caries or structural defects, were utilized in this study. Dentin specimens were created by cutting with a low-speed diamond disk under a continuous flow of water, resulting in dimensions of 6.0 mm × 3.0 mm × 2.0 mm. The specimens were categorized into 4 groups: Control, EDTA, PDT, and EDTA + PDT. S. mutans ATCC 25175 was employed to establish biofilm on the dentin specimens. A 17% EDTA solution was applied for 1 min. For PDT, erythrosine served as the photosensitizer. Finally, a light-emitting diode source (385 - 515 nm) was employed in this study. The PDT group exhibited a significantly lower bacterial count than both the control and EDTA groups (p < 0.001). The EDTA + PDT group demonstrated a significantly reduced bacterial count compared to the other 3 groups (p < 0.001). This study demonstrated that EDTA enhances the antimicrobial efficacy of PDT on S. mutans biofilm. Even at a low concentration of photosensitizer, the combination of EDTA and PDT yields a significant antibacterial effect.

• Biomedical Science Letters
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• v.15 no.3
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• pp.233-239
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• 2009

The aim of this study was to evaluate the photodynamic effect of various photosensitizing agents against methicillin-resistant Staphylococcus aureus (MRSA). MRSA was exposed to light from a 632 urn diode laser (15 J/$cm^2$) in the presence of various photosensitizer, such as photofrin, photogem, radachlorine and ALA. In vivo study was performed using ICR mice. Twenty eight mice had a standard wound ($100\;mm^2$) created on the dorsum, and MRSA was inoculated into the wound region. The four groups were classified as follows: (1) the untreated control group (bacteria alone), (2) the bacteria plus light group (15 J/$cm^2$), (3) the bacteria plus photofrin group (kept in the dark), and (4) the photodynamic therapy (PDT) group (bacteria, photofrin, and light). After photofrin (dose 1 mg/kg) injection, the experimental group was irradiated with 632 urn diode laser (15 J/$cm^2$) for 30 minutes after In vitro results of PDT showed the complete killing of MRSA at the photofrin, radachlorine, and photogem However, ALA-PDT was ineffective on MRSA viability. In vivo results showed that photofrin has therapeutic effect on the wound infection. These results demonstrate that selective lethal photosensitization of MRSA can be achieved using phofrin, photogem and radachlorin. Thus, PDT can inactivate MRSA survival.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2465-2468
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• 2011

• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2505-2508
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• 2008

• Biomedical Science Letters
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• v.15 no.1
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• pp.87-91
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• 2009

In photodynamic therapy (PDT), oxygen plays important role. Because of singlet oxygen which is produced by activated photosensitizer after laser irradiation of specific wavelength. The aim of this study is to find how oxygen concentration affects anticancer effect in PDT. Groups were divided into PDT with oxygen applied group and only PDT applied group. PDT with oxygen applied group supplied oxygen for 15 minute before laser irradiation. In vitro, CT-26 cell was incubated with various concentration of photofrin $(50.0{\sim}0.05{\mu}g/ml)$ and was irradiated with 632nm diode laser 6hr after application of photofrin. The cell viability of two groups was assessed by MTT assay. In vivo, CT-26 cell line was transplanted into the subcutaneous tissue of BALB/c mouse. The anticancer effect of two groups was measured by tumor volume change. In vitro study, the cell viability was significantly decreased at $1.56{\sim}3.13{\mu}g/ml$ in PDT with oxygen applied group. In vivo study, the PDT with oxygen applied group significantly higher reduction rate of tumor volume 7 days after PDT compared to PDT only group. The high oxygen concentration might enhance the anticancer effect of the photodynamic therapy.

• KSBB Journal
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• v.22 no.5
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• pp.318-321
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• 2007

Photodynamic therapy (PDT) is a targeted-tumor treatment system using a photosensitizer, light and oxygen to treat malignant tumor. We have investigated the cytotoxicity of 4 types of phthalocyanine derivative (silver phthalocyanine, iron (III) phthalocyanine, copper (II) phthalocyanine, nickel (II) phthalocyanine) against lung and breast cancers based on photodynamic therapy. As a result, phthalocyanine derivatives indicated a higher anticancer activity on a breast cancer cell line. Among the tested phthalocyanines, silver phthalocyanine (AgPc) showed a lower cytotoxicity against a normal cell line. In addition AgPc gave a good color characteristic when it is solubilized in water. Finally AgPc was selected as a potential antitumor agent for breast cancer.

• Tuberculosis and Respiratory Diseases
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• v.57 no.4
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• pp.358-363
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• 2004

Background : Photodynamic therapy (PDT) involves the use of photosensitizing agents for treatment of malignant disease. PDT is approved by the U.S. Food and Drug Administration for the endobronchial microinvasive nonsmall cell lung cancer and for palliation in patients with obstructing tumors. We report our experience and results of PDT in lung cancer. Method : Ten patients with lung cancer who were diagnosed in Chosun university hospital by histologic confirm through bronchoscopy were included between August 2002 and May 2003. The photosensitizer (Photogem$^{(R)}$, Lomonosov institute of Fine Chemical, Russia/dose 2.0 mg/kg body weight) was injected 48 hours prior to the PDT session. For PDT with the photosensitizer (Photogem$^{(R)}$), Diode LASER system (Biolitec Inc., Germany, wavelength; 633nm) were used. PDTs were done at 48-72 hours after photogem injection. Follow up bronchoscopy and chest X-ray or thorax computerized tomography were done for evaluate PDT response. Results : 9 of 10 patients with endobronchial obstruction showed partial remission with bronchus opening after PDT. Direct reaction of the tumor to PDT was similar in despite of its localization. It was as follows; edema, hyperemia, in-situ bleeding, fibrin film occurrence. Any other complications such as sunburns of skin, inflammation within the PDT zone were not occurred by the end of the fourth week. Conclusion : In the advanced endobronchial disease, PDT has been shown to be useful in treating endobronchial tumors that are causing clinically significant dyspnea or are likely to progress and lead to further clinical complications, such as postobstructive pneumonia.