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 Inorganic Nanoprobes for Biological Sensing and Imaging written by Hedi Mattoussi and published by Artech House. This book was released on 2009 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: This groundbreaking resource offers you an up-to-date account of the pioneering activity pushing new boundaries in the emerging area of inorganic nanoprobes and their use in biology and medicine. Written and edited by leading experts in the field, this unique book places particular emphasis nanoprobes made of luminescent semiconductor nanocrystals (quantum dots or QDs) and magnetic nanoparticles (MNPs). You find an insightful discussion on the synthesis, characterization, and analysis of the unique properties of luminescent QDs and MNPs.

Download or read book Fluorescent Organic Nanoparticles written by Waseem A. Wani and published by Springer. This book was released on 2018-09-27 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a critical review of recent advances in the development of fluorescent organic nanoparticles as materials of choice for the design and fabrication of sensors, bioimaging agents and drug delivery systems. The properties and functions of nanoparticles differ significantly from those of their parent entities or their bulk phases. Two of their most important features are their increased surface-to volume ratio, and the formation of surface structures differing from those in their bulk phases. In addition, the book discusses the synthesis of fluorescent conjugated polymers, self-assembled fluorescent nanoparticles, polydopamine nanoparticles, and aggregation-induced-emission or aggregation-induced-emission enhancement nanomaterials. In closing, the book provides an outlook on future research and development in fluorescent organic nanoparticles as smart materials with an impressive range of potential applications.

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 Syntheses of Biocompatible Luminescent Nanocrystals for Visible and Short wave Infrared Imaging Applications written by Yue Chen (Ph. D.) and published by . This book was released on 2018 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary focus of this thesis is to synthesize biocompatible luminescent nanocrystals for visible and short-wave infrared (1-2 [mu]m, SWIR) imaging applications. Quantum dots (QDs) have been promising fluorescent probes for biomedical imaging due to their high quantum yield (QY), narrow photoluminescence spectra, and excellent photostability. However, challenges remain to be solved to transfer the as-synthesized hydrophobic QD to aqueous solutions while maintaining the high QY and a compact size. This study involves the design and synthesis of a novel ligand that can be introduced to the established QD synthesis, producing norbornene functionalized QDs that can be readily phase transferred into water via norbornene/tetrazine click chemistry, meanwhile allowing flexible functionalization of the QDs by incorporating a functional group on the hydrophilic chain. This ligand system can be applied to a variety of carboxylic-ligand-stabilized QDs, with emission spectra spanning the visible and the SWIR region. The resulting water-soluble QDs exhibit a high QY, a small hydrodynamic diameter (HD), and excellent colloidal stability and pH stability. Further in vitro cell labeling experiments using azido-functionalized QDs demonstrates their potential for cell targeting applications. As in vivo imaging in the SWIR range has further reduced background noise from tissue scattering compared to traditional visible and near infrared (0.7-1 tm, NIR) imaging, images of higher contrast and better resolution can be readily obtained. The next challenge is to develop SWIR emitters that have high quantum efficiency and minimal toxicity, which is of critical importance in order to promote this technology for clinical applications. Our study found that the emission of luminescent gold nanoclusters can be tuned from the visible to the SWIR region by proper selection of ligands and post ligand modifications. The SWIR-emitting gold nanoclusters have a good QY, a HD that is small enough that they exhibit a rapid renal clearance, and images taken in the SWIR region show better resolution of the blood vessels than in the NIR region.

Download or read book Design and Synthesis of Ultra bright Organic Nanoparticles ONPs for Bioimaging written by Paolo Pagano and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nowadays the use of bright luminescent nano-objects in biological environment is a topic that is gaining more and more importance, especially for biomedical applications such as imaging, the rapyand diagnostic. So far, numerous studies have been conducted with gold nanoparticles, silica nanoparticles (doped or functionalized with organic molecules), as well as semiconductor nanoparticles (quantum dots, i.e., QDs). However, most of these nanoparticles suffer from drawbacks (in terms of stability, biocompatibility, eco-toxicity or degradability). On the other hand, several nontoxic fluorescent molecular probes have been widely used, but most of the time their brightness remain modest in biological environments compared to QDs. Our idea is to engineer new organicchromophores with tunable emission wavelength (from visible to near infrared) for further preparation of organic fluorescent nanoparticles (so called FONs) that display giant one-photon and two-photonbrightness, as well as good colloidal and chemical stability, and suitable photostability for in vitro andin vivo imaging. As such, these FONs would represent interesting alternatives to QDs for use in bioimaging. This manuscript describes the synthesis and characterization of new classes of fluorescent molecules specifically engineered as building blocks for the fast preparation of such nanoparticles byself-aggregation in water. The FONs were fully characterized from both morphological and photophysical points of view and further used in bioimaging.

Download or read book Semiconductor Nanocrystals for Biological Imaging written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

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 Semiconductor and Metal Nanocrystals written by Victor I. Klimov and published by CRC Press. This book was released on 2003-11-07 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vast technological potential of nanocrystalline materials, as well as current intense interest in the physics and chemistry of nanoscale phenomena, has led to explosive growth in research on semiconductor nanocrystals, also known as nanocrystal quantum dots, and metal nanoparticles. Semiconductor and Metal Nanocrystals addresses current topics impacting the field including synthesis and assembly of nanocrystals, theory and spectroscopy of interband and intraband optical transitions, single-nanocrystal optical and tunneling spectroscopies, electrical transport in nanocrystal assemblies, and physical and engineering aspects of nanocrystal-based devices. Written by experts who have contributed pioneering research, this reference comprises key advances in the field of semiconductor nanocrystal quantum dots and metal nanoparticles over the past several years. Focusing specifically on nanocrystals generated through chemical techniques, Semiconductor and Metal Nanocrystals Merges investigative frontiers in physics, chemistry, and engineering Documents advances in nanocrystal synthesis and assembly Explores the theory of electronic excitations in nanoscale particles Presents comprehensive information on optical spectroscopy of interband and intraband optical transitions Reviews data on single-nanocrystal optical and tunneling spectroscopies Weighs controversies related to carrier relaxation dynamics in ultrasmall nanoparticles Discusses charge carrier transport in nanocrystal assemblies Provides examples of lasing and photovoltaic nanocrystal-based devices Semiconductor and Metal Nanocrystals is a must read for scientists, engineers, and upper-level undergraduate and graduate students interested in the physics and chemistry of nanoscale semiconductor and metal particles, as well as general nanoscale science.

Download or read book Nanocrystals written by Sudheer Neralla and published by BoD – Books on Demand. This book was released on 2012-08-29 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocrystals research has been an area of significant interest lately, due to the wide variety of potential applications in semiconductor, optical and biomedical fields. This book consists of a collection of research work on nanocrystals processing and characterization of their structural, optical, electronic, magnetic and mechanical properties. Various methods for nanocrystals synthesis are discussed in the book. Size-dependent properties such as quantum confinement, superparamagnetism have been observed in semiconductor and magnetic nanoparticles. Nanocrystals incorporated into different material systems have proven to possess improved properties. A review of the exciting outcomes nanoparticles study has provided indicates further accomplishments in the near future.

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 Colloidal Semiconductor Nanocrystals Synthesis Properties and Applications written by Vladimir Lesnyak and published by Frontiers Media SA. This book was released on 2020-01-06 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Quantum Dots for Bioimaging written by Amin Reza Rajabzadeh and published by CRC Press. This book was released on 2023-06-05 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioimaging is a sophisticated, non-invasive, and non-destructive technique for the direct visualization of biological processes. Highly luminescent quantum dots combined with magnetic nanoparticles or ions form an exciting class of new materials for bioimaging. These materials can be prepared in cost-effective ways and show unique optical behaviors. Magnetic Quantum Dots for Bioimaging explores leading research in the fabrication, characterization, properties, and application of magnetic quantum dots in bioimaging. Covers synthesis, properties, and bioimaging techniques Discusses modern manufacturing technologies and purification of magnetic quantum dots Explores thoroughly the properties and extent of magnetization to various imaging techniques Describes the biocompatibility, suitability, and toxic effects of magnetic quantum dots Reviews recent innovations, applications, opportunities, and future directions in magnetic quantum dots and their surface-decorated nanomaterials This comprehensive reference offers a road map of the use of these innovative materials for researchers, academics, technologists, and advanced students working in materials engineering and sensor technology.

Download or read book written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Semiconductor Nanocrystal Quantum Dots written by Andrey Rogach and published by Springer Verlag. This book was released on 2008-07-03 with total page 372 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 SYNTHESIS AND BIOLOGICAL APPLICATIONS OF HEAVY METAL FREE SEMICONDUCTOR NANOCRYSTALS written by Ying Qi and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor nanocrystals, also called quantum dots (QDs), are an interesting class of materials exhibiting size-tunable optical properties. QDs are attractive for a variety of applications, such as biological sensing and imaging, high color definition display technologies, and photovoltaics. The most widely studied QDs are compound semiconductors of the type CdX and PbX (with X= S, Se, and Te). The absorption and fluorescence emission wavelengths of these QDs span the visible and near infrared (NIR) regions of the electromagnetic spectrum. However, the highly toxic heavy metals Cd and Pb contained in these materials are problematic for their widespread use in commercial applications. Substitution of the heavy metals with Zn and Sn can yield QDs that are less toxic and more environmentally friendly. ZnSe QDs are highly luminescent in the UV-blue region of the spectrum and can be engineered to emit at longer wavelengths by doping them with transition metals, such as Mn or Cu. Encapsulation of ZnSe QDs with an inorganic shell, such as ZnS, has been shown to increase their stability and fluorescence intensity (quantum yield). However, the thermodynamic stability of such core/shell particles must be studied to understand the feasibility and long-term stability of atomically-abrupt interfaces between the core and the shell. The thermodynamic stability of ZnSe/ZnTe and ZnTe/ZnSe core/shell QDs was explored in this study. It was found that ZnSe/ZnTe core/shell QDs are thermodynamically more stable than ZnTe/ZnSe core/shell QDs. Functionalization of the surface of the QDs with biomolecules enables their use in biological sensing and imaging applications. A ZnSe-based QD-DNA biosensor was fabricated and characterized using a novel portable time-domain LED fluorimeter that enables nanosecond fluorescence lifetime measurements. SnSe QDs that absorb near-infrared (NIR) radiation are attractive nano-materials for applications in photovoltaics, photodetectors and photothermal therapy. A new synthesis method for small-size (