Download or read book Design Synthesis and Characterization of New Two photon Absorbing 2PA Fluorescent Dyes and Bioconjugates and Their Applications in Bioimaging written by Carolina D. Andrade and published by . This book was released on 2010 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of new multiphoton absorbing materials has attracted the attention of researchers for the last two decades. The advantages that multiphoton absorbing materials offer, versus their one-photon absorbing counterparts, rely on the nature of the nonlinearity of the absorption process, where two photons are absorbed simultaneously offering increased 3D resolution, deeper penetration, and less photobleaching and photodamage as a result of a more confined excitation. The applications of efficient two-photon absorbing materials have been extensively expanding into the fields of photodynamic therapy, microscopy, and optical data storage. One of the fields where an increased interest in multiphoton absorbing materials has been most evident is in bioimaging, in particular, when different cellular processes and organelles need to be studied by fluorescence microscopy. The goal of this research was to develop efficient two-photon absorption (2PA) compounds to be used in fluorescence bioimaging, meaning that such compounds need to posses good optical properties, such as high fluorescence quantum yield, 2PA cross section, and photostability. In the first chapter of this dissertation, we describe the synthesis and structural characterization of a new series of fluorescent donor-acceptor and acceptor-acceptor molecules based on the fluorenyl ring system that incorporated functionalities such as alkynes and thiophene rings, through efficient Pd-catalyzed Sonogashira and Stille coupling reactions, in order to increase the length of the conjugation in our systems. These new molecules proved to have high two-photon absorption (2PA), and the effect of these functionalities on their 2PA cross section values was evaluated. Finally, their use in two-photon fluorescence microscopy (2PFM) imaging was demonstrated. One of the limitations of the compounds described in Chapter 1 was their poor water solubility; this issue was addressed in Chapter 2. The use of micelles in drug delivery has been shown to be an area of increasing interest over the last decade. In the bioimaging field, it is key to have dye molecules with a high degree of water solubility to enable cells to uptake the dye. By enclosing a hydrophobic dye in Pluronic® F-127 micelles, we developed a system that facilitates the use of 2PA molecules (typically hydrophobic) in biological systems for nonlinear biophotonic applications, specifically to image the lysosomes. Furthermore, we report in this chapter the efficient microwave-assisted synthesis of the dye used in this study. In addition, linear photophysical and photochemical parameters, two-photon absorption (2PA), and superfluorescence properties of the dye studied in Chapter 2, were investigated in Chapter 3. The steady-state absorption, fluorescence, and excitation anisotropy spectra of this dye were measured in several organic solvents and aqueous media. In Chapter 4, we describe the preparation and the use of an efficient and novel two-photon absorbing fluorescent probe conjugated to an antibody that confers selectivity towards the vascular endothelial growth factor receptor 2 (VEGFR-2) in porcine aortic endothelial cells that express this receptor (PAE-KDR). It is known that this receptor is overexpressed in certain cancer processes. Thus, targeting of this receptor will be useful to image the tumor vasculature. It was observed that when the dye was incubated with cells that do not express the receptor, no effective binding between the bioconjugate and the cells took place, resulting in very poor, nonspecific fluorescence images by both one and two-photon excitation. On the other hand, when the dye was incubated with cells that expressed VEGFR-2, efficient imaging of the cells was obtained, even at very low concentrations (0.4[micrometer]). Moreover, incubation of the bioconjugate with tissue facilitated successful imaging of vasculature in mouse embryonic tissue.

Download or read book Enhanced Two photon Absorption in a Squaraine fluorene squaraine Dye written by William V. Moreshead and published by . This book was released on 2013 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: The discovery of any new technology is usually accompanied by a need for new or improved materials which make that technology useful in practical applications. In the case of two-photon absorption (2PA) this has truly been the case. Since its first demonstration in 1961, there has been an ever increasing quest to understand the relationships between two-photon absorption and the structure of two-photon absorbing materials. This quest has been motivated by the many applications for 2PA which have been reported, including fluorescence bioimaging, 3D microfabrication, 3D optical data storage, upconverted lasing, and photodynamic therapy. The work presented in this dissertation represents another step in the effort to better understand the structure/property relationships of 2PA. In this work a new, squaraine-fluorene-squaraine molecule, proposed through a joint effort of quantum and synthetic chemists, was synthesized and its photophysical properties were measured. The measurements included linear and two-photon photophysical properties, as well as solvatochromic behavior. Quantum calculations were done to aid in understanding those photophysical and solvatochromic properties. A single squaraine dye was also synthesized and used as a model compound to assist in understanding this new structure. In Chapter 1 an introduction to 2PA and several of its applications is given. Chapter 2 gives a background of 2PA structure/property relationships that have been reported to date, based on work done with polymethine dyes. Chapter 3 gives a full account of the synthesis, characterization, and detailed quantum chemical analyses of this new squaraine-fluorene-squaraine molecule and the corresponding model compound squaraine dye. Chapter 4 gives some additional work and suggested future directions.

Download or read book Synthesis Characterization and Evaluation of New Reactive Two photon Absorbing Dyes for Two photon Excited Fluorescence Imaging Applications written by Katherine J. Schafer and published by . This book was released on 2005 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent, cooperative advances in chemistry, biology, computing, photophysics, optics, and microelectronics have resulted in extraordinary developments in the biological sciences, resulting in the emergence of a novel area termed ‘biophotonics’. The integrative and interdisciplinary nature of biophotonics cuts across virtually all disciplines, extending the frontiers of basic cellular, molecular, and biology research through the clinical and pharmaceutical industries. This holds true for the development and application of the novel imaging modality utilizing multiphoton absorption and its extraordinary contribution to recent advances in bioimaging. Intimately involved in the revolution of nonlinear bioimaging has been the development of optical probes for probing biological function and activity.

Download or read book Design Synthesis and Characterization of Mechanosensitive Dual Fluorescent Dyes as Potential Probes for Biological Applications written by Susantha Ganegamage and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 3 of this dissertation explores a hypothesis that leverages the seesaw photophysical model for N-aryl (2,3- and 1,8-) naphthalimides. The Heagy group initially developed this model to understand the dual fluorescence effect concerning the electron donor or electron-withdrawing substituents. This study envisions the design and synthesis of novel dual fluorescence molecules for a new class of N-aryl-phenanthridinone dyes. The applied photophysical model further investigates these dyes with a substitution pattern opposite naphthalimide systems. Interestingly, predictive computational modeling shows that the substituent pattern, used previously for 2,3-naphthalimides, relies on these groups getting placed on rings in opposite positions for N-aryl-phenanthridinones. Chapter 4, provides an overall conclusion of the and future directions for both parts of the research. In chapter 5, a complete description of experimental data is provided for the characterization of all the dye systems presented. This data includes a detailed synthesis procedure, characterization, purity analysis by HPLC, absorptivity calculation, fluorescence lifetime measurements, quantum yield determination, biological evaluation and fluorescence titration.

Download or read book Synthesis of Fluorene based Derivatives Characterization of Optical Properties and Their Applications in Two photon Fluorescence Imaging and Photocatalysis written by Grace Wairimu Githaiga and published by . This book was released on 2015 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two-photon absorption (2PA) phenomenon has attracted attention from various fields ranging from chemistry and biology to optics and engineering. Two of the common NLO applications in which organic materials have been used are three-dimensional (3D) fluorescence imaging and optical power limiting. Two-photon absorbing materials are, therefore, in great demand to meet the needs of emerging technologies. Organic molecules show great promise to meet this need as they can be customized through molecular engineering, and as the development of two-photon materials that suit practical application intensifies, so does research to meet this need. However, there remains some uncertainty in the particulars of design criteria for molecules with large 2PA cross sections at desired wavelengths, as such research to understand structure-property relationships is matter of significant importance. As a result, the full potential of 2PA materials has not been fully exploited. Several strategies to enhance the magnitude and tune the wavelength of 2PA have been reported for [pi]conjugated organic molecules. On this account, we have designed novel fluorophores using the fluorene moiety and modified it to tune the properties of the compounds.

Download or read book written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Synthesis and Characterization of Organic and Polymeric Two photon Absorbing Materials written by Lixin Zheng and published by . This book was released on 2003 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Two and Three Photon Pumped Lasing Dyes Design Synthesis and Characterization written by and published by . This book was released on 2006 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this proposed research project, efforts have been focused on the synthesis and optical properties characterization of some multi-photon absorbing chromophores especially with frequency up-converted stimulated emission behavior. This research project was originally aimed to study some structural parameters that may affect the multi-photon pumped stimulated emission properties in dye molecules. The structural parameters that was attempted to investigate include the substituent effects (types and/or positions) and chromophoric unit number density effect. Significant amount of time and man-power was spent to accomplish the synthesis and characterization of some of the designed model compounds. Most of these compounds possess strong two- and three-photon absorption (2PA & 3PA) induced up-converted emission covering various spectral regions. One of the synthesized stibazolium-type chromophore also shows strong 2PA-induced stimulated emission when pumped by femtosecond laser pulses at ~775 nm. Specifically, four stilbazolium chromophores have been stabilized for 2PP stimulated emission property studies. Only one of the synthesized compounds possesses 2PP-induced up-converted cavityless lasing when pumped by femtosecond laser pulses. To the best of author's knowledge, this compound is so far the only stilbazolium salt with symmetrical di-substitution in its molecular structure that exhibits 2PP-induced stimulated emission in femtosecond regime. Although the currently collected data could not provide any clear picture of the relationship between molecular structure and stimulated emission property, using thiophene unit(s) as part of pi-bridge in designing symmetrically di-substituted two-photon lasing dyes might be a direction that worthy to explore. On the other hand, the blueshifted forward lasing is an interesting phenomenon that worth to put more efforts on studying its origin.

Download or read book Self assembly and Photophysics of Selected Organic Materials and Two photon Bioimaging with Profluorescent Nitroxides Polyelectrolyte Nanoparticles and Squaraine Probes written by Hyo-Yang Ahn and published by . This book was released on 2011 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-photon absorption and upconverted fluorescence has been utilized in a variety of applications in pure science and engineering. Multiphoton-based techniques were used in this research in order to understand photophysical and chemical characteristics of several fluorescent dyes and to demonstrate some of their key applications. Two-photon fluorescence microscopy (2PFM) has become a powerful technique in bio-photonics for non-invasive imaging in the near-infrared (NIR) region (700~1000 nm) that often results in less photobleaching. In Chapter 1, there is a brief introduction to fluorescence, examples of fluorescence materials, and a discussion of the advantages of two-photon absorption. 2PFM imaging was utilized in Chapters 2 to 4 for various applications. In Chapter 2, a new squaraine dye is introduced and its linear and nonlinear photophysical properties are characterized. This compound has very high two-photon absorption (2PA) cross sections and high photostability both in an organic solvent and when encapsulated in micelles. Based on these properties, this dye was demonstrated as a near-infrared (NIR) probe in in vitro 2PFM imaging with excitation over 800 nm wavelength. In Chapter 3, new profluorescent nitroxides are introduced. Nitroxide radicals are utilized for electron paramagnetic resonance (EPR) spectroscopy and in biological systems as some are known, in some manner, to mimic the behavior of superoxide dismutase (SOD) that detoxifies or mitigates oxidative stress by trapping free radicals. Here, two profluorescent nitroxides investigated for use as a two-photon fluorescent oxidative stress indicator in in vitro two-photon fluorescence microscopy (2PFM) imaging. In Chapter 4, two-photon excited (2PE) fluorescence of a conjugated polyelectrolyte (CPE), PPESO3, was studied in methanol and in water. The results of CPE quenching studies were comparable under both one-photon excitation conditions and two-photon excitation. CPE coated silica nanoparticles were incubated in HeLa cells and 2PFM imaging was demonstrated for this new class of fluorescent probe. Supramolecular structures based on organized assemblies/aggregation of chromophores have attracted widespread interest as molecular devices with potential applications in molecular electronics, artificial light harvesting, and pharmacology. In Chapter 5, J-aggregate formation was investigated for two porphyrin-based dyes, 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS, 4) and an amino tris-sulfonate analog (5) in water via UV-vis, fluorescence, and lifetime decay studies. The effect of aggregation on two-photon absorption properties was also investigated. A functionalized norbornene-based homopolymer, synthesized by the ring opening metathesis polymerization technique was used as a J-aggregation enhancement template and had a role of polymer-templating to facilitate porphyrin aggregation and modulate 2PA. In Chapter 6, squaraine dye aggregates templated with single wall carbon nanotubes (SWCNTs) that were atomically clean were studied by using optical absorption spectroscopy, atomic force microscopy (AFM), and photoconductivity measurements. SWCNTs selectively promote the formation of squaraine dye aggregates with a head-to-head stacking arrangement, and these dye aggregates effectively photosensitize SWCNTs, demonstrating that this novel approach can yield highly photosensitized devices.

Download or read book Design Synthesis and Spectral Property Studies of Novel Two photon Absorbing Chromophores written by Tzu-Chau Lin and published by . This book was released on 2002 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Two photon Fluorescent Chromophores for Biological Imaging MS written by Judith M. Lavin and published by . This book was released on with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Synthesis and Characterization of Conjugated Polymers as Fluorescent Sensors written by Yan Zhang and published by . This book was released on 2003 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applications and Synthesis of Two photon Absorption Materials for Biological Imaging written by Xiaopeng Wang and published by . This book was released on 2000 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Synthesis and Application of Ultrastable Rylene Dyes for Fluorescent Labeling of Biomolecules written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of organic fluorescent dyes are experiencing a renaissance related to the increasing demands posed by new microscopy techniques for high resolution and high sensitivity. While in the last decade single molecule equipment and methodology has significantly advanced and in some cases reached theoretical limits (e.g. detectors approaching unity quantum yields) unstable emission from chromophores and photobleaching become more and more the bottleneck of the advancement and spreading of single-molecule fluorescence studies. The main goal of this work was the synthesis of fluorophores that are water-soluble, highly fluorescent in an aqueous environment, have a reactive group for attachment to a biomolecule and posses exceptional photostability. An approach towards highly fluorescent, water-soluble and monofunctional perylene-3,4,9,10-tetracarboxdiimide and terrylene-3,4:11,12-tetra carboxidiimide chromophores was presented. A new synthetic strategy for the desymmetrization of perylenetetracarboximides was elaborated; water-solubility was accomplished by introducing sulfonyl substituents in the phenoxy ring. Two strategies have been followed relying on either non-specific or site specific labeling. For this purpose a series of new water-soluble monofunctional perylene and terrylene dyes, bearing amine or carboxy group were prepared. The reactivity and photophysical properties of these new chromophores were studied in aqueous medium. The most suitable chromophores were further derivatized with amine or thiol reactive groups, suitable for chemical modification of proteins. The performance of the new fluorescent probes was assessed by single molecule enzyme tracking, in this case phospholipase acting on phospholipid supported layers. Phospholipase-1 (PLA-1) was labeled with N-hydroxysuccinimide ester functionalized perylene and terrylene derivatives. The purification of the conjugates was accomplished by novel convenient procedure for the removal of unreacted dye from.

Download or read book The Design Synthesis and Use of Photoreactive Fluorescent Reagents in Biochemical Studies with Specific Reference to 4 benzoyl benzamidofluorescein a New Fluorescent Photocrosslinking Probe for Adenine Nucleotide Binding Site on Enzymes written by Jane E. Rosen and published by . This book was released on 1985 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design Syntheses and Applications of Fluorescent Dyes written by Liangxing Wu and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New methodologies for the efficient syntheses of 4,4-difluoro-4-bora-3a,4adiaza- s-indacenes (BODIPYs) and rosamines were developed. A serendipitous discovery led to a new reaction which afforded BODIPYs in high yields. Systematic studies of the kinetics and mechanisms of the new reaction were performed. A series of BODIPYs were successfully prepared using the new approach. A simple and efficient synthesis of rosamines with cyclic-amine substituents was devised. These new rosamines showed interesting anti-tumor activities. Several types of novel fluorescent compounds were prepared. Highly fluorescent GFP-chromophore analogs were designed and synthesized. The correlation between the optical properties and the structures was investigated. New pyronin dyes with mesoheteroatom substituents were efficiently prepared. The fluorescence properties of these compounds were highly dependent on the nature of the meso-substituents. A set of BODIPY dyes that fluoresce brightly above 600 nm were made. They were then used as acceptors to prepare water-soluble through-bond energy transfer cassettes. All the cassettes had complete energy transfer and high quantum yields in MeOH. A few also had good fluorescence properties in aqueous media and even on proteins. The through-bond energy transfer cassettes were used to monitor protein-protein interactions. In order to test our hypothesis, an artificial protein interaction system was built by utilizing the biotin/(strept)avidin interactions. Thus Atto425-BSA-biotin, streptavidin-cassette1 and avidin-cassette2 were prepared. The interactions between Atto425-BSA-biotin and cassette labeled (strept)avidin were successfully detected in vitro and in living cells by fluorescence techniques.

Download or read book Two photon Induced Photochemistry written by Jing Wang and published by . This book was released on 2007 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-photon absorption is the process in which a molecule absorbs two photons simultaneously. The two key advantages of two-photon processes over one-photon processes are the possibility of excitation of materials with high three-dimensional spatial resolution and deep light-penetration into absorbing materials. Based on bond-cleavage reactions activated by photon-induced intramolecular electron transfer, two-photon activatable acid and radical initiators and two-photon removable protecting groups have been successfully designed and synthesized for photopolymerization and three-dimensional microfabrication and for biomedical photo-triggers. The optical and chemical properties of synthesized molecules, such as quantum yield of acid generation, initiation efficiency of photopolymerization, and photolysis efficiency, have been studied by using a variety of physical and analytical techniques under one-photon conditions. The two-photon characteristics and applications of these molecules are being investigated in collaboration with other groups.