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Photodynamic Therapy With Bengal Rose and Derivatives Against Leishmania amazonensis
摘要： Introduction: The treatment of cutaneous leishmaniasis (CL) is based primarily on the use of pentavalent antimonials, which may lead to many side effects limiting their use. Photodynamic therapy (PDT) is an alternative for the treatment of CL, and some xanthene dyes have the potential for use in PDT. Methods: The xanthenes rose bengal B (RB) and its derivatives rose bengal methyl ester (RBMET), and butyl ester (RBBUT) were analyzed for leishmanicidal activity against promastigotes and intracellular amastigotes of Leishmania amazonensis. Cytotoxicity was assessed in J774.A1 macrophages. Results: RB derivates RBMET (IC50 9.83 μM), and RBBUT (IC50 45.08 μM) showed leishmanicidal activity, however, were toxic to J774.A1 macrophages, resulting in low selectivity index. Conclusion: The RBMET and RBBUT showed to be effective against the L. amazonensis and the low selectivity index presented may not be a limitation for their use in PDT to CL treatment.
关键词： Photodynamic therapy,Xanthenes,Rose Bengal B,Leishmania amazonensis,Cutaneous leishmaniasis
更新于2025-09-23 15:22:29
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Response surface methodology can be used to predict photoinactivation of foodborne pathogens using Rose Bengal excited by 530?nm LED
摘要： In this work, the photodynamic bactericidal effect of Rose Bengal (RB), combined with green LED light, against Staphylococcus aureus and Salmonella Typhimurium, was investigated. The interaction of RB concentration and illumination time was evaluated using a response surface methodology, and a second-order polynomial empirical model was adjusted to the experimental data. The derived model predicted the combined influences of these factors on S. aureus and S. Typhimurium counts, in accordance with predictions and experimental observations (R2 = 0.8483 and p = .0013 for S. aureus; R2 = 0.9191 and p = .0001 for S. Typhimurium). Total inhibition of S. aureus and S. Typhimurium was observed when applying a light dose of 0.125 J cm?2 and 152.0 J cm?2, respectively. The treatments also showed loss of membrane integrity, morphological changes, and internal cell structural alterations. In sum, the polynomial model developed could provide accurate information on the combined influences of RB and green LED light in aPDT treatment and, that this combination was able to inactivate S. aureus and S. Typhimurium.
关键词： Rose Bengal,green LED light,Salmonella Typhimurium,response surface methodology,Staphylococcus aureus,photodynamic bactericidal effect
更新于2025-09-11 14:15:04
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Rose Bengal Incorporated to α-Cyclodextrin Microparticles for Photodynamic Therapy against the cariogenic microorganism Streptococcus mutans
摘要： Rose Bengal@α-cyclodextrin (RB@α-CD) microparticles (μPs) were prepared and the RB inclusion in α-CD was experimentally demonstrated through infrared, UV-VIS absorption spectroscopy and cyclic voltammetry. The RB inclusion in α-CD was theoretically investigated using classical molecular mechanics calculations, the simulation results showing that RB can be included in both the narrow and wide apertures of the α-cyclodextrin ring with configurations exhibiting average binding energies of about 27 kcal.mol-1. The prepared RB@α-CD microparticles were characterized through Scanning Electron Microscopy (SEM) and it was demonstrated that they are highly efficient in the photodynamic therapy against a Streptococcus mutans (the main bacteria of cariogenic dental plaque) suspension, as a concentration of RB@α-CD μPs 10 times smaller than the usual concentration of pure RB is still capable to produce significant antibacterial activity.
关键词： antibacterial activity,molecular interaction simulations,Rose Bengal,photodynamic therapy,α-cyclodextrin microparticles
更新于2025-09-10 09:29:36
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Transformation of Commercial TiO <sub/>2</sub> into Anatase with Improved Activity of Fe, Cu and Cu–Fe Oxides Loaded TiO <sub/>2</sub>
摘要： In the present study copper and iron oxides loaded TiO2 catalysts are prepared by the deposition-precipitation method (DP) and the photocatalytic efficiency of these catalysts are tested for the degradation of Rose Bengal dye (Acid Red 94) under sunlight. The catalysts are characterized by XRD, TEM and UV-vis diffuse reflectance spectral analysis. It is interesting to note that the rutile form of commercial TiO2 is competently converted into anatase after loading oxides of Cu, Fe and Cu–Fe on TiO2 as evident from XRD analysis. This result is consistence with the result obtained in UV-vis diffuse reflectance spectra. TEM analysis confirms the nano particles of Cu and Fe deposited on TiO2. Photocatalytic studies were performed in a batch reactor under solar radiation. Preliminary studies are performed to understand the photocatalytic degradability of the dye and optimization of catalyst weight and dye concentration. Kinetic studies were done at different dye concentrations and it was found that the rate equation followed first order kinetics and obeyed Langmuir–Hinshelwood model. The comparison of the activity of blank TiO2, copper or/and iron oxides loaded TiO2 catalysts showed that the Cu and Fe oxide loaded catalysts are more active than pure TiO2 and also the Cu–Fe oxides co-loaded TiO2 catalysts showed much best activity. The order of activity of the catalysts is in the following order: Cu–Fe/TiO2 > Cu/TiO2 > Fe/TiO2 > TiO2. The enhanced activity of metal oxide loaded TiO2 is attributed to the presence of TiO2 in anatase form after loading, which enhanced the charge transfer from the TiO2 to adsorbed molecules for reaction.
关键词： Sunlight,TiO2,Rutile into Anatase,Photocatalyisis,Cu/Fe Loading,Rose Bengal Dye
更新于2025-09-09 09:28:46
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Hybrid Silver Nanocubes for Improved Plasmon-Enhanced Singlet Oxygen Production and Inactivation of Bacteria
摘要： Plasmonic nanoparticles can strongly interact with adjacent photosensitizer molecules, resulting in significant alteration of their singlet oxygen (1O2) production. In this work, we report the next generation of metal-enhanced 1O2 nanoplatforms exploiting the lightning rod effect, or plasmon hot spots, in anisotropic (non-spherical) metal nanoparticles. We describe the synthesis of Rose Bengal decorated silica-coated silver nanocubes (Ag@SiO2-RB NCs) with silica shell thicknesses ranging from 5 to 50 nm based on an optimized protocol yielding highly homogeneous Ag NCs. Steady-state and time-resolve 1O2 measurements demonstrate not only the silica shell thickness dependence on the metal-enhanced 1O2 production phenomenon, but also the superiority of this next generation of nanoplatforms. A maximum enhancement of 1O2 of approximately 12-fold is observed with a 10 nm silica-shell, which is amongst the largest 1O2 production metal enhancement factor ever reported for a colloidal suspension of nanoparticles. Finally, the Ag@SiO2-RB NCs were benchmarked against Ag@SiO2-RB nanospheres previously reported by our group, and the superior 1O2 production of Ag@SiO2-RB NCs resulted in improved antimicrobial activities in photodynamic inactivation experiments using both gram-positive and -negative bacteria model strains.
关键词： Plasmonic nanoparticles,photodynamic inactivation,singlet oxygen,Rose Bengal,silver nanocubes,bacteria
更新于2025-09-04 15:30:14
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - A Quantitative Model for Estimating the Scale of Photochemically Induced Ischemic Stroke
摘要： Photothrombosis is a technique that can induce ischemic cortical infarcts using the photodynamic effect of anionic xanthene dyes, typically Rose Bengal, to cause occlusion of cerebral blood circulation. The ability to quantitatively predict the scale of the lesion in photothrombotic procedures can offer crucial insight in the development and implementation of light-induced stroke models in animals. In this article, we introduced a quantitative model that could estimate the normalized light intensity distribution in tissue which scatters photons from a collimated beam. We simulated the penetration and scattering profile of light of Rose Bengal’s characteristic absorption wavelengths in mouse cortex. We further illustrated that our model could estimate the spatial extent of effective region under photothrombotic protocols, and how this model can be used to titrate the intensity and geometry of light beams used to generate infarcts of desired dimensional characteristics.
关键词： Rose Bengal,ischemic stroke,Photothrombosis,quantitative model,light scattering
更新于2025-09-04 15:30:14