Preparation, Theory, and Biological Applications of Highly Luminescent CdSe/ZnS Quantum Dots in Optical and Electron Microscopy PDF Download

Author: James Christopher Bouwer
Publisher:
ISBN:
Category :
Languages : en
Pages : 366

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Author: Desheng Wang
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
CdSe semiconductor nanocrystals (quantum dots--QDs) with diameters ranging between 1.5 and 8 nm exhibit strong, tunable luminescence [1-5]. They have been widely investigated for their size-dependent optoelectronic properties [6], and for their potential use in optical devices [7], biological labels [8] and sensors [9]. Luminescent quantum dots (QDs) show higher photostability and narrower emission peaks compared to organic fluorophores [8]. The objective of my project was to apply QDs magnetic/luminescent nanoparticle as biological labels in cells. Luminescent CdSe QDs emit bright visible light with high quantum yield and sharp emission peak. The CdSe QDs were capped with a ZnS layer. This increased their emission efficiency and photostability due to the larger band gap of ZnS. The QDs were transferred from organic solvent (e.g. chloroform, hexane) to water by exchanging the capping group (Trioctylphosphine Oxide--TOPO) with mercaptoacetic acid. To develop a separation and detection tool for cells, we combined [gamma]-Fe2O3 magnetic particles with CdSe/ZnS QDs in core-shell composite. The composite nanoparticles showed strong fluorescence emission and high water solubility. Different antibodies were attached to the particles through EDAC coupling. The antibody-coated particles were used to successfully separate and detect breast cancer cells in blood cells. and high water solubility. Different antibodies were attached to the particles through EDAC coupling. The antibody-coated particles were used to successfully separate and detect breast cancer cells in blood cells.

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Category :
Languages : en
Pages :

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Quantum dots (QDs) CdS and CdSe were synthesized in three different media including reverse micelles, aqueous solution, and trioctylphosphine oxide/trioctylphosphine (TOPO/TOP). Transmission electron microscope (TEM), X-ray diffraction (XRD), UV-VIS, fluorescence spectroscopy and microscopy were used to characterize the QDs and their nanoassemblies. CdS QDs synthesized in reverse micelles showed broad emission spectra. CdSe-CdS QDs with core shell structure synthesized in aqueous solution showed more than 30% emission quantum yield. CdSe-CdS QDs of different emission colors were prepared. CdSe and CdSe-ZnS QDs were also synthesized in TOPO/TOP media. This synthesis route produced highly luminescent CdSe QDs with over 50% emission quantum yield. The application of QDs as ions probes and methods to encapsulate QDs in nanospheres including micelles, glyconanospheres and silica nanospheres and the use of these nanospheres in bioassays are described. CdS QDs capped with different ligands such as thioglycerol, cysteine and polyphosphate showed different responses to biological relevant ions. The emission intensity of polyphosphate capped CdS QDs was affected by all the tested ions and did not show a selective response. On the other hand, the emission of thioglycerol capped CdS QDs was selectively quenched by copper ions while the emission of cysteine capped CdS QDs was selectively enhanced by zinc ions. Stern-Volmer equation was applied to correlate the emission intensity of the CdS QDs and the copper ion concentration. A Lagmuir isotherm binding equation was used to describe the relation between the emission intensity of cysteine capped CdS QDs and zinc ion concentration. The possible mechanism to explain the effects of capping ligands on CdS QDs responses to ions is also discussed. CdSe QDs synthesized in TOPO/TOP media were encapsulated in nanospheres for bioassay applications. The glyconanospheres contained a large number of glucose residues on their surface and showed high binding activity towards the lectinic protein Concanavalin A (Con A). Silica nanospheres containing hundreds of CdSe QDs were functionalized with thiol groups to enable the conjugation of streptavidin to the nanospheres. The streptavidin modified silica nanospheres were used as luminescent indicators in a sandwich immunoassay for the detection of antiprotein A antibody. The advantages and disadvantages of the nanospheres based bioassay are discussed.

Author:
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Category : Dissertation abstracts
Languages : en
Pages : 776

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Author: Amin Reza Rajabzadeh
Publisher: CRC Press
ISBN: 1000881032
Category : Technology & Engineering
Languages : en
Pages : 305

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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.

Author: Christian von Borczyskowski
Publisher: CRC Press
ISBN: 9814745251
Category : Science
Languages : en
Pages : 407

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Nanotechnology is one of the growing areas of this century, also opening new horizons for tuning optical properties. This book introduces basic tuning schemes, including those on a single quantum object level, with an emphasis on surface and interface manipulation of semiconducting and metallic quantum dots. There are two opposing demands in current forefront applications of quantum dots as optical labels, namely high luminescence stability (suppression of luminescence intermittency) and controllable intermittency and bleaching on a single-particle level to facilitate super-resolution optical microscopy (for which Eric Betzig, Stefan W. Hell, and William E. Moerner were awarded the 2014 Nobel Prize in Chemistry). The book discusses these contradictory demands with respect to both an understanding of the basic processes and applications. The chapters are a combination of scholarly presentation and comprehensive review and include case studies from the authors’ research, including unpublished results. Special emphasis is on a detailed understanding of spectroscopic and dynamic properties of semiconducting quantum dots. The book is suitable for senior undergraduates and researchers in the fields of optical nanoscience, materials science, and nanotechnology.

Author:
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ISBN:
Category :
Languages : en
Pages : 7

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Biomolecules labeled with luminescent colloidal semiconductor quantum dots (QDs) have potential for use in numerous applications, including fluoro-immunoassays and biological imaging. QD labels exhibit size-tunable narrow-band luminescent emission and high resistance to photodegradation. They also exhibit efficient Fo rster energy transfer between neighboring QDs of different sizes and their emission is readily quenched by bound fluorescent dyes. In this paper, we describe preliminary results aimed at defining conditions for the design and preparation of nanoscale QD-bioconjugate sensors based on fluorescence quenching. We envision building sensor assemblies that employ quantum dots linked with dye-labeled biological receptors that utilize donor acceptor energy transfer between QDs and receptors for conducting recognition-based assays. In particular, we report the effects of varying the concentration of energy acceptors bound to nanocrystal surfaces under both soluble and solid phase conditions on quenching phenomena.

Author: Ameenah Al-Ahmadi
Publisher: BoD – Books on Demand
ISBN: 9535104837
Category : Science
Languages : en
Pages : 294

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Book Description
The book “Quantum dots: A variety of a new applications” provides some collections of practical applications of quantum dots. This book is divided into four sections. In section 1 a review of the thermo-optical characterization of CdSe/ZnS core-shell nanocrystal solutions was performed. The Thermal Lens (TL) technique was used, and the thermal self-phase Modulation (TSPM) technique was adopted as the simplest alternative method. Section 2 includes five chapters where novel optical and lasing application are discussed. In section 3 four examples of quantum dot system for different applications in electronics are given. Section 4 provides three examples of using quantum dot system for biological applications. This is a collaborative book sharing and providing fundamental research such as the one conducted in Physics, Chemistry, Biology, Material Science, Medicine with a base text that could serve as a reference in research by presenting up-to-date research work on the field of quantum dot systems.

Author: Xin Tong
Publisher: Springer Nature
ISBN: 3030465969
Category : Science
Languages : en
Pages : 331

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Book Description
This book outlines various synthetic approaches, tuneable physical properties, and device applications of core/shell quantum dots (QDs). Core/shell QDs have exhibited enhanced quantum yield (QY), suppressed photobleaching/blinking, and significantly improved photochemical/physical stability as compared to conventional bare QDs. The core-shell structure also promotes the easy tuning of QDs’ band structure, leading to their employment as attractive building blocks in various optoelectronic devices. The main objective of this book is to create a platform for knowledge sharing and dissemination of the latest advances in novel areas of core/shell QDs and relevant devices, and to provide a comprehensive introduction and directions for further research in this growing area of nanomaterials research.

Author: Jun-Jie Zhu
Publisher: Springer Science & Business Media
ISBN: 3642449107
Category : Technology & Engineering
Languages : en
Pages : 96

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Book Description
This book provides a broad introduction to all major aspects of quantum dot properties including fluorescence, electrochemical, photochemical and electroluminescence. Such properties have been produced for applications in biosensing, cell tracking, in vivo animal imaging and so on. It focuses on their special applications in DNA biosensing and provides readers with detailed information on the preparation and functionalization of quantum dots and the fabrication of DNA biosensors, using examples to show how these properties can be used in DNA biosensor design and the advantages of quantum dots in DNA biosensing. Further new emerging quantum dots such as metal nanoclusters and graphene dots and their applications in DNA biosensing have also been included.