• Biomedical Science Letters
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• v.15 no.2
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• pp.153-160
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• 2009

Photodynamic therapy(PDT) is a treatment utilizing the generation of singlet oxygen and other reactive oxygen species(ROS), which selectively accumulate in target cells. The aim of present work is to investigate the photodynamic therapy mechanism of 9-HpbD-a-mediated PDT in HeLa cell lines. We studied the general reactive oxygen species(G-ROS) activation after 9-HpbD-a PDT using fluorescence stain with $H_2DCF-DA$. G-ROS activation observed after 9-HpbD-a PDT and higher activation condition was 1 hour after PDT at 0.5 ${\mu}g/ml$ 9-HpbD-a concentration. Sodium azide and reduced glutathione(the singlet oxygen quencher) could protect HeLa cells from cell death induced by 9-HpbD-a PDT. But D-mannitol(the hydroxyl radical scavenger) could not protect cell death. Singlet oxygen played a decisive role in 9-HpbD-a PDT induced HeLa cell death. Type II reaction was the main type of ROS formation at 9-HpbD-a PDT.

• Journal of Photoscience
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• v.9 no.2
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• pp.524-526
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• 2002

Hypericin was found to exhibit the highest antitumoral activity in treating EAT by photodynamic therapy (PDT): Hypericin>HPde>PII>TPPS$_4$>ALA. Moreover, 25% of mice after Hyp-based PDT survived 4 months, if compare with control group. Antitumor activity of these photosensitizers was in rather clear correlation with accumulation potential.

• Biomedical Science Letters
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• v.16 no.4
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• pp.331-339
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• 2010

This study aims to evaluate the effect of Photodynamic Therapy (PDT) against methicillin-resistant Staphylococcus aureus with high-level mupirocin resistance (Hi-Mup MRSA). To examine the antimicrobial effect of photogem-mediated PDT against Hi-Mup MRSA, CFU quantifications, bacteria cell viability tests, and disk diffusion antimicrobial susceptibility tests were evaluated. In addition, one of PDT mechanisms was investigated by accumulating photogem ($10\;{\mu}g/ml$) in Hi-Mup MRSA. Photogem-mediated PDT properly inhibited the colony formation of Hi-Mup MRSA. Viable bacteria decreased greatly after a PDT application with photogem $10\;{\mu}g/ml$ at energy density $15\;J/cm^2$. The diameter of the inhibition zone around susceptible disks increased after PDT. In addition, we confirmed the accumulation of photogem in bacteria through fluorescent images. These results demonstrated that excellent photosensitization of Hi-Mup MRSA can be achieved using photogem with 630 nm LED irradiation. Thus, PDT may make survival Hi-Mup MRSA inactive.

• Biomedical Science Letters
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• v.14 no.2
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• pp.83-89
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• 2008

We have compared the antitumor effect of photodynamic therapy (PDT), using 5-aminolevulinic acid (ALA) as the photosensitizer, combined with cisplatin (CDDP) on AMC-HN3 human squamous cell carcinoma. AMC-HN3 cells were cultured and then incubated with various concentrations of CDDP and ALA. 632 nm diode laser was given at $6.0J/cm^2$ followed by incubation for 24 hours. The evaluation of cell viability was done by MTT assay. In vivo CDDP was injected intraperitoneally 24 hours prior to PDT. The anti-tumor effects of each treatment were measured by tumor volume change. Cell viability were 44.29% for the cisplatin-mediated chemotherapy group $(6.25{\mu}g/ml)$, 77.22% for ALA-PDT group, and 15.06% for the Combination therapy group. In vivo, the antitumor effect of photodynamic therapy was enhanced by combination of Cisplatin-mediated chemotherapy. Photodynamic therapy combined with administration of Cisplatin appears to enhance antitumor effect and to be a useful treatment modality.

• Journal of Veterinary Clinics
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• v.31 no.1
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• pp.66-69
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• 2014

Photodynamic therapy (PDT) is an effective method for infectious disease, but as yet, no clinical trial on otitis externa has been conducted in animals. This report describes 4 cases of PDT treatment on severe otitis externa in canine. Four canines were treated with various concentrations of 5-aminolevulinic acid hydrochloride (5-ALA) and with various J (second ${\times}$ power) and irradiated by light-emitting diode light source at 635 nm, respectively. After the PDT applications, canines incubated in the dark for 5 or 6 hr. All patients showed clinical resolution of otitis externa after PDT treatment at the dose of 0.16~0.3 g ALA and J (54~162 $J/cm^2$). On the basis of these findings, PDT can be considered to be a new therapeutic approach to severe otitis externa in canine.

• Korean Journal of Clinical Laboratory Science
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• v.43 no.3
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• pp.124-132
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• 2011

The aim of this study was to evaluate the effects of the photosensitizer photogem with light-emitting diode (LED) on vancomycin-resistant enterococci (VRE). Two VRE strains isolated from the feces of patients. that was identificated Enterococcus faecium (vanA) and Enterococcus gallinarum (vanC1) using traditional biochemical tests and confirmed VRE genotyping from using polymerase chain reaction. In addition, three strains were used Enterococcus. faecalis CDC-286 (vanA), E. faecalis CDC-583 (vanB) and E. gallinarum CDC-42 (vanC1). To examine the antimicrobial effect of photogem mediated photodynamic therapy (PDT) against, CFU quantification and Disk diffusion antimicrobial susceptibility test were evaluated. The effects of Photodynamic therapy was not associated with genotype. Photogem mediated PDT perfectly inhibited the colony formation of E. faecalis CDC-286. The number of viable bacteria decreased greatly after PDT application with photogem $50{\mu}g/mL$ and energy density of $15J/cm^2$. The diameter of inhibition zone was increased to after PDT more than before PDT. The case of vancomycin disc on E. faecalis CDC-583 and E. galinanum-Patient were changed from resistant to intermediate resistant, from intermediate resistant to susceptable. These results demonstrate that lethal photosensitization of VRE can be achieved using photogem plus 630 nm LED irradiation.

• 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.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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.467-469
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• 2021

The dendritic molecule has focused on the target material for photodynamic therapy, and used as the energy harvesting molecule for the application of medicinal field. Those molecules have also researched on the molecule design for the preparation of new dendritic material on PDD and PDT. In this presentation, new dendritic molecules are introduced on the development of DPPZ dendritic molecule for PDT and the efficient synthetic process.

• International Journal of Oral Biology
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• v.41 no.1
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• pp.39-43
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• 2016

Dental caries, the most common oral disease, is a multifactorial disease caused by interactions among bacteria within the dental plaque, food, and saliva, resulting in tooth destruction. Streptococcus mutans has been strongly implicated as the causative organism in dental caries and is frequently isolated from human dental plaque. Photodynamic therapy (PDT) is a technique that involves the activation of photosensitizer by light in the presence of tissue oxygen, resulting in the production of reactive radicals capable of inducing cell death. Postantibiotic effect (PAE) is defined as the duration of suppressed bacterial growth following brief exposure to an antibiotic. In this study, the in vitro PAE of PDT using erythrosine and light emitting diode on S. mutans ATCC 25175 was investigated. The PAE of PDT for 1 s irradiation and 3 s irradiation were 1.65 h and 2.1 h, respectively. The present study thus confirmed PAE of PDT using erythrosine on S. mutans.