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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Synthesis and Encapsulation of a New Zinc Phthalocyanine Photosensitizer Into Polymeric Nanoparticles to Enhance Cell Uptake and Phototoxicity

Mehraban, Nahid, Musich, Phillip R., Freeman, Harold S. 24 January 2019 (has links)
Efforts to enhance the utility of photodynamic therapy as a non-invasive method for treating certain cancers have often involved the design of dye sensitizers with increased singlet oxygen efficiency. More recently, however, sensitizers with greater selectivity for tumor cells than surrounding tissue have been targeted. The present study provides an approach to the modification of the known photosensitizer zinc phthalocyanine (ZnPc), to enhance its solubility and delivery to cancer cells. Targeting a photosensitizer to the site of action improves the efficacy of the sensitizer in photodynamic therapy. In this work we used PLGA-b-PEG to encapsulate a new zinc phthalocyanine derivative, 2(3), 9(10), 16(17), 23(24)-tetrakis-(4'-methyl-benzyloxy) phthalocyanine zinc(II) (ZnPcBCH3), to enhance uptake into A549 cells, a human lung cancer cell line. ZnPcBCH3 exhibited the same photochemical properties as the parent compound ZnPc but gave increased solubility in organic solvents, which allowed for efficient encapsulation. In addition, the encapsulated dye showed a near 500-fold increase in phototoxicity for A549 cancer cells compared to free dye.
12

Bimetallic Ruthenium(II) Polypyridyl Complexes Bridged by a Boron Dipyrromethene (BODIPY): Synthesis, Spectroscopic and Plasmid DNA Photoreactions and The Impact of the 515 nm Effect in Photosynthesis: Model System Using β-Carotene Acid Complexes

Wertz, Ashlee Elizabeth 05 June 2019 (has links)
No description available.
13

Method For Determination Of Singlet Oxygen Quantum Yields For New Fluorene-based Photosensitizers In Aqueous Media For The Advancement Of Photodynamic Therapy

Grabow, Wade William 01 January 2004 (has links)
Photodynamic therapy (PDT) has been investigated over the past three decades and is currently an approved therapeutic modality for skin cancer, the treatment of superficial bladder, early lung and advanced esophageal cancers, and age-related macular degeneration in a number of countries. In PDT, the absorption of light by a chromophore generates cytotoxic species such as reactive singlet oxygen, leading to irreversible destruction of the treated tissue. The measurement of the singlet oxygen quantum yield is an important determinant used to evaluate the efficiency of new photodynamic therapy agents developed in the laboratory, to screen potential photosensitizers in aqueous media.The singlet oxygen quantum yield is a quantitative measurement of the efficiency in which photosensitizers are able to use energy, in the form of light, to convert oxygen in the ground state to the reactive species singlet oxygen useful in photodynamic therapy. Singlet oxygen quantum yields of photosensitizers differ when measured in different solvents. The majority of the existing quantum yield values found in literature for various photosensitizers are documented with the sensitizers in organic solvents though values in aqueous media are more valuable for actual applications. Determination of accurate and precise quantum yield values in aqueous solution is a much more difficult problem than in organic media. Problems in aqueous solution arise primarily from the physicochemical properties of singlet oxygen in water. Singlet oxygen has a much shorter lifetime in water than it does in organic solvents, causing challenges with respect to quantitative detection of singlet oxygen.The ensuing pages are an attempt to explore the theory and document the procedures developed to provide the accurate measurement of singlet oxygen in aqueous media. Details of this experimental method and singlet oxygen quantum yield results of new compounds relative to established photosensitizers will be presented.
14

Development of Nanoparticle-based Platforms for Potential Applications in Biosensing and Therapeutics

Wang, Peng January 2017 (has links)
No description available.
15

Supramolecular Ruthenium(II) and Osmium(II) Complexes: Synthesis, Characterization, DNA Binding and DNA Photocleavage

Li, Kaiyu January 2017 (has links)
No description available.
16

Synthesis and characterization of self-assembling polymers using hydrogen bonding or hydrophobic effect

Yu, Xinjun January 2015 (has links)
No description available.
17

Enhanced Singlet Oxygen Production from Metal Nanoparticle Based Hybrid Photosensitizers

Ding, Rui 26 May 2016 (has links)
No description available.
18

Synthesis and Characterization of Indole-Based Zinc Dipyrrin Photosensitizers

Sanza, Jean-Pierre 01 May 2024 (has links) (PDF)
Metal complexes of dipyrromethene (dipyrrins) used as sensitizers in photocatalysis offer a way to harness solar energy in chemical bonds to create new fuels. This offers the dual role of reducing fossil fuel dependence and atmospheric CO2 levels. Traditionally, metal dipyrrin complexes are synthesized using substituted pyrroles, aldehydes, and transition metals. Indoles have a more expanded pi-electron system and their dipyrrin-type complex may exhibit visible light absorption, suggesting that they can act as photosensitizers for CO2 reduction processes. A novel indoledipyrromethene was synthesized using unsubstituted indole and mesitaldehyde. The complex exhibits visible light absorption at 422 nm. Its Zn coordinated complex it likely to exhibit blue-green light absorption making it suitable as a sensitizer for CO2 photoreduction and other applications.
19

Metody výzkumu fotofyziky fotosensibilizátorů s aplikací na thiazolyl-porfyriny / Methods of Study of Photosensitizer-Photophysics with Application on Thiazolyl-porphyrins

Scholz, Marek January 2011 (has links)
Title: Methods of Study of Photosensitizer-photophysics with Application on Thiazolyl-porphyrins Author: Marek Scholz Department: Department of Chemical Physics and Optics Supervisor: RNDr. Roman Dědic, Ph.D. Supervisor's e-mail address: Roman.Dedic@mff.cuni.cz Abstract: Photodynamic therapy for oncologic and various chronic diseases is a rapidly emerging method of treatment. It is based on the production of highly reactive singlet oxygen and free radicals by excitation energy transfer from the molecules of photosensitizers. Photosensitizers are preferentially accumulated in the target tissues and locally illuminated. This way produced reactive species cause apoptosis or necrosis of the cells leading to the desired therapeutic effect. Synthesis and subsequent photophysical characterization of photosensitizing dyes is a fundamental part of the development of photodynamic methods. The main aim of the work is to explain the most widely used methods of photophysical study of photosensitizers and apply them to new synthesized photosensitizers: thiazolyl-porphyrins. Methods of absorption and fluorescence spectroscopy, flash- photolysis, time- and spectral-resolved detection of luminescence, optoacoustic spectroscopy and other spectroscopic methods were used. Thiazolyl-porphyrins proved to be promising new...
20

Nano-objets tout organiques pour la thérapie photodynamique biphotonique / soft organic nanoparticles for two photon photodynamic therapy

Sourdon, Aude 16 December 2013 (has links)
La thérapie photodynamique est fondée sur l’activation sélective par la lumière de médicaments appelés photosensibilisateurs. Non toxique en l’absence d’excitation lumineuse, le photosensibilisateur est capable, une fois excité, de transférer son énergie pour former de l’oxygène singulet qui induit la mort de la cellule. L’utilisation d’une excitation biphotonique offre de nouvelles perspectives pour la thérapie photodynamique du cancer. En effet, la dépendance quadratique de l’absorption à deux photons (ADP) avec l’intensité du laser permet une très grande sélectivité spatiale, ce qui rend possible un traitement plus sélectif des tumeurs, et la lumière infra-rouge utilisée permet le traitement de tumeurs plus profondes. Dans ce travail, nous avons développé une famille de nano-objets tout organiques pour la thérapie photodynamique biphotonique. Ils présentent des sections efficaces d’ADP très élevées dans la gamme spectrale d’intérêt biologique et leur efficacité a été démontrée in vitro. / Photodynamic therapy is based on the selective activation by light of drugs called photosensitizers. Non-toxic in the absence of excitation light, the photosensitizer is able, upon excitation, to transfer energy to produce singlet oxygen, which induces cell death. Two-photon excitation offers new perspectives for photodynamic therapy of cancer. Indeed, the quadratic dependence of two-photon absorption (TPA) with the laser intensity allows high spatial selectivity, which enables a more selective treatment of tumors, and the use of infrared light allows treatment of deeper tumors. In this work, we have developed a family of fully organic nano-objects for two-photon photodynamic therapy. They exhibit very high TPA cross-sections in the biological spectral range of interest and their efficiency has been demonstrated in vitro.

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