Download or read book Development of Fluorescent Semi conductor Nanocrystal Conjugates for in Vitro and in Vivo Imaging Applications written by Hee-Sun Han (Ph. D.) and published by . This book was released on 2012 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor nanocrystals, also known as quantum dots (QDs), are promising imaging probes with characteristic optical properties: tunable bandgap from visible to infrared, narrow and symmetric emission features, broad absorption, high quantum yield (QY), excellent photostability, and a large two-photon absorption cross section. However, unlike other imaging probes, the surface ligands determine the solubility, stability, quantum yield (QY), biocompatibility, and derivatizability of QDs. Therefore, to use QDs for in vitro and in vivo imaging, QD ligands need to be elaborately engineered for each experiment. Single cell labeling in vivo requires extremely strict criteria for the QD conjugates to be used such as minimal nonspecific cell/serum binding, maintenance of high QY in complex in vivo environments, and compact size. The focus of this thesis is the synthesis of high quality QD conjugates that can be used for single molecule imaging in vivo and in vivo imaging studies that demonstrate the broad and powerful applicability of our new methods. We incorporated novel conjugation methods employing highly strained cycloolefins and a serum stable tetrazine derivative into newly developed polymeric imidazole ligands (PILs) to efficiently couple biomolecules on QDs. Unlike traditional conjugation methods, tetrazine-norbornene cycloaddition benefits from the non-interacting properties of the functional groups to the QD surface, and yields the high conjugation efficiencies on QDs. In addition, the rapid kinetics, absence of catalyst, and bio-orthogonality of the cycloaddition allowed us to achieve in situ conjugation of the norbornene-bearing QDs to tetrazine-bearing epidermal growth factor (EGF) proteins on the HeLa cell surface. On the in vivo front, we accomplished single endogenous cell imaging in live mice. The ability to target single cells using multiple biomarkers and track them for the extended periods of time allowed us to study the microenvironment of the endogenous hematopoietic stem cells (HSCs), which was not possible using conventional techniques engaging dye conjugated antibodies. Lastly, a new class of QD ligands containing betaine moieties was developed to reduce the size of QD conjugates, which we expect will be greatly beneficial for in vitro and in vivo targeting in dense environments. We successfully demonstrated functionalization of the sulfonate betaine poly imidazole ligands (SBPILs) with biomolecules, and the biocompatibility of SBPIL QDs both in vitro and in vivo.

Download or read book Semiconductor Quantum Dots And Rods For In Vivo Imaging And Cancer Phototherapy written by Maoquan Chu and published by #N/A. This book was released on 2017-06-19 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cancer is fast becoming one of the main causes of death worldwide. Unfortunately many cases are diagnosed at an advanced incurable stage, and these lives are usually lost. Early diagnosis and treatment are very important for increasing disease curability. In recent years, novel techniques for cancer diagnosis and therapy have been developed, and nanobiomedicine appears to show the most promising results.The application of nanotechnology to biology and medicine in cancer diagnosis is termed nanobiomedicine. Nanoparticles 1-100 nm in size usually have unique physical and/or chemical properties, and this has attracted great attention in the cancer research. Preparation and biomedical applications of the nanoparticles are key components in nanobiomedicine. Semiconductor nanocrystals, including quantum dots (QDs) and quantum rods (QRs), have been extensively investigated for drug delivery, biomedical imaging and tumor target therapy.In Semiconductor Quantum Dots and Rods for In Vivo Imaging and Cancer Phototherapy, the QD and QR optical properties, sentinel lymph node mapping, in vivo tumor target imaging, self-illuminating QDs for in vivo imaging, in vivo cancer photothermal therapy and photodynamic therapy, QD-graphene nanosheet, and QD-magnetic hybrid nanocomposites for bioimaging and cancer therapy are discussed. This book may interest under- and postgraduate students in the field of bioengineering (especially cancer phototherapy) and medical professions alike.

Download or read book Design and Synthesis of Biocompatible Fluorescent Semi conductor Nanocrystals for In vivo and In vitro Imaging sensing Applications written by Wenhao Liu (Ph. D.) and published by . This book was released on 2010 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dots (QD) are unique materials in which their optical properties are decoupled from their solution properties via the tunability of surface ligands. The primary focus of this thesis is the design and synthesis of new ligand coatings to render QDs water soluble, pushing the boundaries of QD applications in biology both in-vivo and in-vitro. On the in-vivo front, ultrasmall QDs ( -5 nm hydrodynamic diameter) were synthesized via the use of Cysteine as a zwitterionic ligand coating to generate the smallest biocompatible QDs known to date, allowing for the first time collection of quantitative in-vivo renal clearance data of inorganic nanoparticles in a mouse as a model for design of future clearable nanoparticle in-vivo probes and drug delivery vehicles. On the in-vitro front, a suite of multifunctional ligands were synthesized to produce QDs that exhibit low non-specific binding to cells, small hydrodynamic diameter (HD), tunable surface charge, high quantum yield, and good solution stability across a wide pH range. These ligands feature dihydrolipoic acid for tight binding to the QD surface, a short poly(ethylene glycol) (PEG) spacer for water solubility and biocompatibility, and an amine or carboxylate terminus for covalent derivatization. We successfully demonstrated covalent attachment of energy acceptor dyes to enable sensing applications via Forster Resonance Energy Transfer (FRET), and attachment of proteins to enable high-affinity cell labeling and single particle tracking. In addition, QDs solubilized with these ligands could be derivatized via metal-affinity driven conjugation chemistry with polyhistidine-tagged proteins, which facilitated the purification of monovalent QDs for the first time via gel electrophoresis. Further improvement on ligand stability focused on addressing the problem of thiol oxidation, and a new class of multifunctional polymer ligands were developed featuring multiple imidazole moieties for multidentate interactions with the QD surface. The polymers are synthesized via reversible addition-fragmentation chain transfer (RAFT)-mediated polymerization to produce molecular weight controlled monodisperse random copolymers from three types of monomers that feature imidazole groups for QD binding, polyethylene glycol (PEG) groups for water solubilization, and either primary amines or biotin groups for derivatization.

Download or read book Smart Biocompatible Semi conductor Nanocrystal Constructs Designed for In vitro Imaging Applications written by Jungmin Lee (Ph. D.) and published by . This book was released on 2013 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dots (QDs) have unique optical properties that complement fluorescent proteins and organic fluorophores. Despite the widespread use as a fluorescent label in biological imaging studies, the types of biological questions answered by utilizing QDs have been limited due to crucial shortcomings. This thesis focuses on pushing the boundaries of QD applications in vitro, exploring improvements in construct design and methodology to overcome these shortcomings. First, the issues of non-specific binding and reactivity are alleviated by exploring a new method to conjugate molecules onto the QD surface. The improvements that were made enabled a collaborator situated across the country to conjugate biomolecules in a one-step process without performing the usual amine/N-hydroxysuccinimide coupling, thereby diminishing non-specific binding. The utility of QDs in biological applications is further demonstrated by incorporating the nanocrystals into a dynamic sensor construct and taking measurements in a bioenvironment. A dye construct that can act as a Fluorescent Resonant Energy Transfer (FRET) acceptor is conjugated to the FRET donor QD through a molecular linker whose conformation changes depending on the analyte in the microenvironment. As a proof-of-concept, pH is chosen as the environmental factor and the QD-dye FRET sensor is used to track the pH in subcellular compartments along the endocytosis pathway. Lastly, a new microfluidic device is used to deliver QDs into the cell cytosol with high viability and high throughput. QDs delivered this way are shown to be nonaggregated and to interact with the cytosolic environment, opening up the possibility of single molecule tracking of a specific protein of interest inside the cytosol.

Download or read book Fluorescent Semiconductor Nanocrystals for Biological Applications written by Elizabeth L. Bentzen and published by . This book was released on 2007 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Engineering Semiconductor Nanocrystals for Molecular Cellular and in Vivo Imaging written by Andrew Michael Smith and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomedicine has recently exploited many nanotechnology platforms for the detection and treatment of disease as well as for the fundamental study of cellular biology. A prime example of these successes is the implementation of semiconductor quantum dots in a wide range of biological and medical applications, from in vitro biosensing to in vivo cancer imaging. Quantum dots are nearly spherical nanocrystals composed of semiconductor materials that can emit fluorescent light with high intensity and a strong resistance to degradation. The aim of this thesis is to understand the fundamental physics of colloidal quantum dots, to engineer their optical and structural properties for applications in biology and medicine, and to examine the interaction of these particles with biomolecules and living cells. Toward these goals, new synthetic strategies for colloidal nanocrystals have been developed, implementing a cation exchange method for independent tuning of size and fluorescence, and a bandgap engineering technique that utilizes mechanical strain imposed by coherent shell growth. In addition, stable nanocrystals have been prepared with ultrathin coatings (

Download or read book Photoactive Semiconductor Nanocrystal Quantum Dots written by Alberto Credi and published by Springer. This book was released on 2017-01-20 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.

Download or read book Bionanotechnology written by David E. Reisner and published by CRC Press. This book was released on 2008-07-30 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the impact and importance of nanotechnology continues to grow, nanomedicine and biotechnology have become areas of increased development. Drug delivery by nanoparticulates and nanocoatings for medicial devices are among the many new techniques on the horizon. Years from now we will laugh at the approaches to treating disease we currently conside

Download or read book Semiconductor Nanocrystal Quantum Dots written by Andrey Rogach and published by Springer Science & Business Media. This book was released on 2008-09-02 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to specifically focus on semiconductor nanocrystals, and address their synthesis and assembly, optical properties and spectroscopy, and potential areas of nanocrystal-based devices. The enormous potential of nanoscience to impact on industrial output is now clear. Over the next two decades, much of the science will transfer into new products and processes. One emerging area where this challenge will be very successfully met is the field of semiconductor nanocrystals. Also known as colloidal quantum dots, their unique properties have attracted much attention in the last twenty years.

Download or read book Fluorescent Silicon Nanocrystals for Bioimaging written by Dorothy Ann Silbaugh and published by . This book was released on 2017 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dots have been used as alternatives to organic dyes for fluorescence imaging because they are resistant to photobleaching, exhibit strong response to two-photon excitation, and can be conjugated to a wide variety of targeting molecules. Silicon (Si) nanocrystal quantum dots in particular exhibit bright, size-dependent emission with visible to near infrared wavelengths and are biocompatible, making them potentially interesting for in vitro and in vivo bioimaging. Here, Si nanocrystals are studied for imaging applications. The stability of Si nanocrystal dispersibility and photoluminescence (PL) in aqueous solutions was studied. Hydrophobic Si nanocrystals were dispersed with surfactants to produce colloidally stable and brightly fluorescent dispersions, with PL quantum yields in the range of 3.2% - 6.6%. Hydrophilic Si nanocrystals capped with a ligand containing a terminal carboxylic acid group could be directly dispersed in aqueous environments with quantum yields of up to 9.1% in water. The nanocrystal PL was stable in water for at least one week, however there was a significant loss of PL when the particles were dispersed in biological solutions. The drop in PL was accompanied by surface oxidation and degradation of the nanocrystals. Si nanocrystals incubated with mouse macrophage cells were actively taken up by endocytosis. Cell viability assays indicated that the nanocrystals were not toxic to the macrophages. The Si nanocrystals were bright enough to be imaged within the cells by one-photon and two-photon microscopy. Hydrophilic Si nanocrystals that emit in the near infrared (900-1000 nm) could also be dispersed directly into water, however the emission quantum yields were prohibitively low for imaging applications. Time gated imaging of cells labeled with Si nanocrystals enabled multiplex imaging using optical probes with spectral overlap by separating the PL of organic dyes with short nanosecond lifetimes and Si nanocrystals with long microsecond lifetimes. Finally, biotin bioconjugation was accomplished to Si nanocrystal surfaces, though the conjugation reaction efficiencies were relatively low

Download or read book Semiconductor Nanomaterials written by Challa S. S. R. Kumar and published by John Wiley & Sons. This book was released on 2010-04-05 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book series Nanomaterials for the Life Sciences, provides an in-depth overview of all nanomaterial types and their uses in the life sciences. Each volume is dedicated to a specific material class and covers fundamentals, synthesis and characterization strategies, structure-property relationships and biomedical applications. The series brings nanomaterials to the Life Scientists and life science to the Materials Scientists so that synergies are seen and developed to the fullest. Written by international experts of various facets of this exciting field of research, the series is aimed at scientists of the following disciplines: biology, chemistry, materials science, physics, bioengineering, and medicine, together with cell biology, biomedical engineering, pharmaceutical chemistry, and toxicology, both in academia and fundamental research as well as in pharmaceutical companies. VOLUME 6 - Semiconductor Nanomaterials

Download or read book Comprehensive Biomaterials II written by Kevin Healy and published by Elsevier. This book was released on 2017-05-18 with total page 4865 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Biomaterials II, Second Edition, Seven Volume Set brings together the myriad facets of biomaterials into one expertly-written series of edited volumes. Articles address the current status of nearly all biomaterials in the field, their strengths and weaknesses, their future prospects, appropriate analytical methods and testing, device applications and performance, emerging candidate materials as competitors and disruptive technologies, research and development, regulatory management, commercial aspects, and applications, including medical applications. Detailed coverage is given to both new and emerging areas and the latest research in more traditional areas of the field. Particular attention is given to those areas in which major recent developments have taken place. This new edition, with 75% new or updated articles, will provide biomedical scientists in industry, government, academia, and research organizations with an accurate perspective on the field in a manner that is both accessible and thorough. Reviews the current status of nearly all biomaterials in the field by analyzing their strengths and weaknesses, performance, and future prospects Covers all significant emerging technologies in areas such as 3D printing of tissues, organs and scaffolds, cell encapsulation; multimodal delivery, cancer/vaccine - biomaterial applications, neural interface understanding, materials used for in situ imaging, and infection prevention and treatment Effectively describes the many modern aspects of biomaterials from basic science, to clinical applications

Download or read book Nanomaterials for Luminescent Devices Sensors and Bio imaging Applications written by Swapna S. Nair and published by Springer Nature. This book was released on 2021-09-15 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights the synthesis/fabrication of novel materials for different kinds of optical applications. It covers all aspects of optical applications starting from LED/Lasers, SERS, bio-sensing, bio-imaging and non-linear optical applications such as optical limiting, saturable absorbers etc. The book describes the development of novel materials and geometry as well as engineering of their size and shape for harvesting better optical properties. Nonconventional plasmonic materials and their fabrication are discussed apart from the conventionally employed noble metal based nanosystems. In addition, development of Novel materials/structures for biosensing /bioimaging /optical limiting are also covered.

Download or read book Fluorescent Materials for Short wave Infrared Imaging written by Daniel Franke and published by . This book was released on 2018 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our understanding of the fundamental processes that drive biology and medicine is, in large part, based on our ability to visualize biological structures and monitor their transformations over time. Fluorescence imaging is one of the most transformative technologies of modern biomedical imaging as it provides a low cost, high sensitivity method for real-time molecular imaging in vivo. As the scattering and absorption of light through biological tissue impose significant restrictions on imaging penetration depth, acquisition speed, and spatial resolution, the development of novel optical imaging technologies has increasingly shifted toward the use of light of longer wavelengths. Fluorescence imaging in the shortwave infrared (SWIR, 1000 - 2000 nm) spectral region mitigates the negative effects of light attenuation and benefits from a general lack of tissue autofluorescence. As a result, SWIR imaging promises higher contrast, sensitivity, and penetration depths compared to conventional visible and near-infrared (NIR) fluorescence imaging. However, the lack of versatile and functional SWIR emitters has prevented the general adoption of SWIR imaging both in academic and clinical settings. Here, we will present progress toward the synthesis of a new generation of SWIR-emissive materials and discuss their use in enabling biomedical imaging applications. In the first part of this thesis, we will examine the synthesis of SWIR-emissive indium arsenide (InAs) quantum dots (QDs). To address existing challenges in the synthesis of these semiconductor nanocrystals, we will investigate the processes that govern nanoparticle formation and growth. Combining experimental and theoretical methods, we demonstrate that the synthesis of large nanocrystals is hindered by slow growth rates for large particles, as well as the formation and persistence of small cluster intermediates throughout nanocrystal growth. Based on these insights, we design a novel, rational synthesis for large InAs QDs with high brightness across the SWIR spectral region. Second, we will discuss the use of InAs-based QDs in functional SWIR imaging applications in pre-clinical settings. We will present three QD surface functionalizations that enable the non-invasive real-time imaging of hemorrhagic stroke, the quantification of metabolic activity in genetically-engineered animals, and the measurement of hemodynamics in the brain vasculature of mice. In addition, we will present preliminary results for the synthesis of SWIR-emissive QD probes for the molecular targeting of biological entities and for advanced particle tracking applications. Using a QD-based broadband SWIR emitter, we will further investigate the e↵ect of SWIR imaging wavelength on image contrast and tissue penetration depth. While it was previously assumed that reduced scattering of light at longer wavelengths is the primary cause for increased image contrast, our results indicate that for imaging scenarios with strong fluorescent background signals, image contrast and penetration depth correlate closely with the absorptive properties of biological tissue. As a result, deliberate selection of imaging wavelengths at which biological tissue is highly absorptive can help to overcome contrast-limited imaging scenarios. In the last part of this thesis, we will take a closer look at SWIR emitters with the potential for translation into clinical settings. We will demonstrate that the FDA-approved NIR dye indocyanine green (ICG) exhibits an unexpectedly high SWIR brightness that arises from a large absorption cross-section and a vibronic shoulder in its fluorescence spectrum that extends well into the SWIR spectral region. We expand on this finding by showing that ICG outperforms commercial SWIR dyes during in vivo imaging, and additionally by demonstrating a variety of high-contrast and high-speed imaging applications in small animals. These results suggest that ICG enables the direct translation of SWIR imaging into the clinic. In summary, this thesis will paint a comprehensive picture of the current state of SWIR-emissive materials, present the synthesis of novel versatile SWIR probes, and show their application in unprecedented functional SWIR imaging applications.

Download or read book Quantitative Evaluation of Semiconductor Nanocrystals as Contrast Agents for Fluorescence Molecular Imaging written by Mathieu Roy and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Luminescent Semiconductor Nanocrystals intermittent Behavior and Use as Fluorescent Biological Probes written by Marcel Pierre Bruchez and published by . This book was released on 1998 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book IN VITRO IMAGING USING STABLE WATER DISPERSIBLE LUMINESCENT SI QUANTUM DOTS CAPPED WITH VARIOUS CELLULAR TARGETING AGENTS written by Chen-An Tien and published by . This book was released on 2010 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents research on the synthesis, functionalization, and biological applications of silicon nanocrystals, also called silicon quantum dots (Si QDs). Over the past 20 years, semiconductor nanocrystals (also known as quantum dots or QDs) have been investigated for applications ranging from electronic materials science to biological imaging. The outstanding optical properties of QDs, which include stable luminescence, tunable luminescence color, modifiable surface characteristics, and the potential to interface with biologically relevant molecules, have made QDs a good replacement for organic dyes in many applications. Silicon nanocrystals show many of the same useful optical properties but lower toxicity than cadmium based quantum dots for biological applications.^In this thesis, I focus on the biological applications of silicon nanocrystals in fluorescent biosensing and cellular labeling applications. Conventional quantum dots have great potential in cancer-related imaging and diagnostic applications; however, these applications are limited by concerns about the inherent toxicity of their core materials (e.g. cadmium, lead). Virtually all imaging applications require conjugation of the imaging agent to a biologically active molecule to achieve selective uptake or binding. Here, we report a study of biocompatible silicon quantum dots covalently attached to biomolecules including lysine, folate, anti-mesothelin, and transferrin. The particles possess desirable physical properties, surface chemistry, and optical properties. Folate- and anti-mesothelin-conjugated silicon quantum dots show selective uptake into Panc-1 cells.^This study contributes to the preclinical evaluation of silicon quantum dots and further demonstrates their potential as an imaging agent for cancer applications. Major bionanotechnology research issues in quantum dot synthesis include the stabilization of their optical properties using various coating and encapsulation strategies, and advancing the rational design of constructs containing them to optimize overall size, surface chemistry, and composition in order to minimize potential toxicity and overcome biological barriers. Conventional cadmium- and lead-based quantum dots are normally coated, because their degradation may result in the release of toxic heavy metal ions. For in vivo use, they must be cleared from the body without degradation. Freestanding silicon quantum dots are expected to biodegrade to non-toxic products (e.g. silicic acid); however they have not been evaluated in biodegradable nanocarriers.^Previous work from our group has encapsulated them with non-toxic, but non-biodegradable phospholipid-polyethylene glycol surfactants. Here, we report the development of chitosan-coated silicon nanoparticles (CSi QDs). Evaluation of the physicochemical and optical properties of the CSi QDs shows that they remain optically active in aqueous media. The chitosan coating renders silicon quantum dots stable in aqueous biological media and useful for biological applications such as cellular imaging with single and two photon excitation. The particles are also degradable when incubated at physiological temperature. These results open the door for a new generation of silicon quantum dots that may have a wide variety of applications derived from the flexibility of chitosan.