Download or read book Monitoring Cellular Interactions During T Cell Activation at the Single Molecule Level Using Semiconductor Quantum Dots written by and published by . This book was released on 2005 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced peptide-coated quantum dots (with high brightness and high saturation intensity) were developed. Two high-affinity targeting "velcro-pairs" based on avidin-biotin and fluorescine-antibody interactions were demonstrated and used to specifically target single proteins in membranes of live cells. Single molecule spectroscopy and imaging of individual quantum dot-labeled lipid rafts receptors were performed. Software tools were developed to analyze individual diffusion and trafficking trajectories. These studies provide strong support for the lipid raft hypothesis. Cloning and fusion of avidin to four immune synapse components were achieved. These mutants are being characterized by flow cytometry and fluorescence microscopy. This report provides information on the following new findings: (1) hybrid approach to the synthesis of highly luminescent infrared CdTe/ZnS and CdHgTe/ZnS quantum dots; (2) bioactivation and cell targeting of semiconductor CdSe/ZnS quantum dots with phytochelatin-related peptides; (3) development of bright Cd+ rich peptide-coated quantum dots; (4) comparison of the photophysical and colloidal properties of biocompatible quantum dots using fluorescence correlation spectroscopy (FCS); (5) testing the lipid raft hypothesis by single molecule imaging of targeted peptide-coated quantum dots; and (6) molecular cloning and fusion of avidin to immunological synapse (IS) components.

Download or read book Study of T Cell Activation and Migration at the Single cell and Single molecule Level written by Irene Yin-Ting Chang and published by . This book was released on 2011 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: T cells are required by their immunological roles to recirculate in the body and migrate to tissue sites, a journey that exposes them to distorting forces and physical obstacles that hinder their movement. Therefore, they must possess appropriate deformability to accommodate and adapt to these mechanical stimuli to migrate unimpeded. Since T cells alter their physical properties and migration routes upon activation, they may possess dissimilar mechanical properties as a result of this process. This hypothesis was tested using the techniques micropipette aspiration and atomic force microscopy, which allow the investigation of the elastic and viscous responses of single T cells. It was discovered that the activation process reduced T cell stiffness by more than three folds, a finding that agrees with the motility gain observed in activated T cells. The same testing procedure was applied to Wiskott-Aldrich syndrome protein (WASp)-deficient T cells that exhibit abnormal morphology and impaired chemotaxis. The stiffness of the diseased cells in the naive state was 1.5 times less than that of the non-diseased cells, a result that may be due to the disrupted polymerization and cross-linking of the actin cytoskeleton in the absence of WASp, a regulator of actin growth and organization. Furthermore, the viscous response of the diseased cells in the activated state was found to be impaired. Chemokines were found to dramatically reduce the stiffness of naive T cells that were induced to migrate. These findings suggest that WASp plays an important role in maintaining cell mechanical property and facilitating T cell extravasation by tailoring the cells' deformability. At the molecular level, activation of T cells is triggered by the binding of their surface receptors to antigens, a mechanism that is also key in T cell development. In both cases, the bond strength, conventionally measured by the affinity (KD) or the dissociation rate (koff) of the interacting pair, dictates the biological outcome. Since a few weak interactions may nudge a sub-threshold signal over the threshold strength, and observing that the current methods for measuring KD and koff lack the resolution to detect very weak bonds, this work explored the possibility of utilizing dynamic force spectroscopy (DFS) to study very weak binding strengths. Preliminary results confirm this capability.

Download or read book Semiconductor Quantum Dots written by Y. Masumoto and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor quantum dots represent one of the fields of solid state physics that have experienced the greatest progress in the last decade. Recent years have witnessed the discovery of many striking new aspects of the optical response and electronic transport phenomena. This book surveys this progress in the physics, optical spectroscopy and application-oriented research of semiconductor quantum dots. It focuses especially on excitons, multi-excitons, their dynamical relaxation behaviour and their interactions with the surroundings of a semiconductor quantum dot. Recent developments in fabrication techniques are reviewed and potential applications discussed. This book will serve not only as an introductory textbook for graduate students but also as a concise guide for active researchers.

Download or read book Alchemical Libraries Almanack written by and published by . This book was released on 2006 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biomolecule Conjugated Quantum Dot Nanosensors as Probes for Cellular Dynamic Events in Living Cells written by Jung Y. Huang and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A single-molecule tracking/imaging technique with semiconductor quantum dot (QD) nanosensors conjugated with appropriate peptides or antibodies is appealing for probing cellular dynamic events in living cells. We developed a 2D analysis of single-molecule trajectories using normalized variance versus mean square displacement (MSD) to provide high-quality statistics sampled by nanosensors while preserving single-molecule sensitivity. This plot can be more informative than MSD alone to reflect the diffusive dynamics of a protein in its cellular environment. We illustrate the performance of this technique with selected examples, which are designed to expose the functionalities and importance in live cells. Our findings suggest that biomolecule-conjugated QD nanosensors can be used to reveal interactions, stoichiometries, and conformations of proteins, and provide an understanding of the mode of the interaction, stable states, and dynamical pathways of biomolecules in live cells.

Download or read book Co signal Molecules in T Cell Activation written by Miyuki Azuma and published by Springer Nature. This book was released on 2019-11-22 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book equips young immunologists and health professionals with a clear understanding of the fundamental concepts and roles of co-signal molecules and in addition presents the latest information on co-stimulation. The first part of the book is devoted to co-signal molecules and the regulation of T cells. Following an initial overview, subsequent chapters examine each co-signal molecule in turn and discuss the mechanisms by which co-signal molecules regulate the different types of T cell. The second part covers various clinical applications, including in autoimmune disease, neurological disorders, transplantation, graft-versus-host disease, and cancer immunotherapy. To date, co-stimulation blockade and co-inhibition blockade have shown beneficial effects and many additional clinical trials targeting co-signal molecules are ongoing. The mechanisms underlying these successful treatments are explained and the future therapeutic potential in the aforementioned diseases is evaluated. Co-signal Molecules in T Cell Activation will be a valuable reference guide to co-stimulation for basic and clinical researchers in the fields of both immunology and pharmaceutical science.

Download or read book Plasma Membrane Dynamics and Pattern Formation During T Cell Activation written by Adam D. Douglass and published by . This book was released on 2006 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: T cell activation entails a complex series of signal transduction events that begin with ligation of the T cell receptor by a cognate antigen, displayed on the surface of an antigen presenting cell. During T cell signaling proteins in the cell surface partition from one another into large, stereotyped molecular pattern that is known as the immunological synapse. This thesis attempts to understand the mechanisms by which this segregation occurs, and uses a number of fluorescence imaging techniques---in particular, single molecule microscopy---to this end. Contrary to reports that suggest a role for lipid raft domains in patterning the synapse, we find that protein-protein interactions, and not putative lipid raft associations, are a strong driving force in synapse formation. We also develop a method for reconstituting synapse formation in an immortalized T cell line that allows us to perform single molecule imaging on a fluid substrate of a defined composition. A common finding is that both passive mechanisms, involving diffusional trapping and exclusion, as well as active mechanisms, involving actin-driven transport, can act in concert to shape the immunological synapse.

Download or read book Toxicological Studies of Semiconductor Quantum Dots on Immune Cells written by and published by . This book was released on 2008 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoengineered materials hold a vast promise of enabling revolutionary technologies, but also pose an emerging and potentially serious threat to human and environmental health. While there is increasing knowledge concerning the risks posed by engineered nanomaterials, significant inconsistencies exist within the current data based on the high degree of variability in the materials (e.g., synthesis method, coatings, etc) and biological test systems (e.g., cell lines, whole organism, etc). In this project, we evaluated the uptake and response of two immune cell lines (RAW macrophage and RBL mast cells) to nanocrystal quantum dots (Qdots) with different sizes and surface chemistries, and at different concentrations. The basic experimental design followed a 2 x 2 x 3 factorial model: two Qdot sizes (Qdot 520 and 620), two surface chemistries (amine 'NH2' and carboxylic acid 'COOH'), and three concentrations (0, 1 nM, and 1 [mu]M). Based on this design, the following Qdots from Evident Technologies were used for all experiments: Qdot 520-COOH, Qdot 520-NH2, Qdot 620-COOH, and Qdot 620-NH2. Fluorescence and confocal imaging demonstrated that Qdot 620-COOH and Qdot 620-NH2 nanoparticles had a greater level of internalization and cell membrane association in RAW and RBL cells, respectively. From these data, a two-way interaction between Qdot size and concentration was observed in relation to the level of cellular uptake in RAW cells, and association with RBL cell membranes. Toxicity of both RBL and RAW cells was also significantly dependent on the interaction of Qdot size and concentration; the 1 [mu]M concentrations of the larger, Qdot 620 nanoparticles induced a greater toxic effect on both cell lines. The RBL data also demonstrate that Qdot exposure can induce significant toxicity independent of cellular uptake. A significant increase in TNF-[alpha] and decrease in IL-10 release was observed in RAW cells, and suggested that Qdot exposure induced a pro-inflammatory response. In contrast, significant decreases in both TNF-[alpha] and IL-4 releases were observed in RBL cells, which is indicative of a suppressed inflammatory response. The changes in cytokine release observed in RAW and RBL cells were primarily dependent on Qdot concentration and independent of size and surface chemistry. Changes in the activity of superoxide dismutase were observed in RAW, but not RBL cells, suggesting that RAW cells were experiencing oxidative stress induced by Qdot exposure. Overall, our results demonstrate that the uptake/association and biomolecular response of macrophage and mast cells is primarily driven by an interaction between Qdot size and concentration. Based on these findings, a more detailed understanding of how size directly impacts cellular interactions and response will be critical to developing predictive models of Qdot toxicity.

Download or read book Investigating the Interaction of Semiconductor Quantum Dots with in Vivo and Cellular Environments to Determine Disposition and Risk written by Hans Christian Fischer and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tuning Semiconducting and Metallic Quantum Dots written by Christian von Borczyskowski and published by CRC Press. This book was released on 2017-03-27 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book T Cell Receptor Signaling written by Chaohong Liu and published by . This book was released on 2020 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides current and new advanced methods and protocols to study T cells. Chapters guide readers through T cell diversity using mass cytometry, analyzing T cells from single cell level, CRISPR/Cas9 techniques to study the T cell activation, techniques to study subsets of Tcell's, procedures to study artificial antigen presentosomes for T cell activation, techniques to study the T cell development, two-photon microscopy, and MAIT cells. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, T-Cell Receptor Signaling: Methods and Protocols aims to provide a wide range of approaches and be an invaluable resource for present and future generations of T cell researchers.

Download or read book Single Semiconductor Quantum Dots written by Peter Michler and published by Springer Science & Business Media. This book was released on 2009-06-13 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews recent advances in the field of semiconductor quantum dots via contributions from prominent researchers in the scientific community. Special focus is given to optical, quantum optical, and spin properties of single quantum dots.

Download or read book Semiconductor Quantum Dots written by Ladislaus Alexander Banyai and published by World Scientific. This book was released on 1993-05-28 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconductor Quantum Dots presents an overview of the background and recent developments in the rapidly growing field of ultrasmall semiconductor microcrystallites, in which the carrier confinement is sufficiently strong to allow only quantized states of the electrons and holes. The main emphasis of this book is the theoretical analysis of the confinement induced modifications of the optical and electronic properties of quantum dots in comparison with extended materials. The book develops the theoretical background material for the analysis of carrier quantum-confinement effects, introduces the different confinement regimes for relative or center-of-mass motion quantization of the electron-hole-pairs, and gives an overview of the best approximation schemes for each regime. A detailed discussion of the carrier states in quantum dots is presented and surface polarization instabilities are analyzed, leading to the self-trapping of carriers near the surface of the dots. The influence of spin-orbit coupling on the quantum-confined carrier states is discussed. The linear and nonlinear optical properties of small and large quantum dots are studied in detail and the influence of the quantum-dot size distribution in many realistic samples is outlined. Phonons in quantum dots as well as the influence of external electric or magnetic fields are also discussed. Last but not least the recent developments dealing with regular systems of quantum dots are also reviewed. All things included, this is an important piece of work on semiconductor quantum dots not to be dismissed by serious researchers and physicists.

Download or read book Peptide coated Semiconductor Quantum Dots and Their Applications in Biological Imaging of Single Molecules in Live Cells and Organisms written by Fabien Floren Pinaud and published by . This book was released on 2007 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imaging from Cells to Animals In Vivo written by Margarida Barroso and published by CRC Press. This book was released on 2020-12-03 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers an overview of imaging techniques used to investigate cells and tissue in their native environment. It covers the range of imaging approaches used, as well as the application of those techniques to the study of biological processes in cells and whole tissues within living organisms.

Download or read book Correlations Between Single Cell Signaling Dynamics and Protein Expressions Profiles written by and published by . This book was released on 2005 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: A platform technology for monitoring signaling pathways in single T cells using optical nanoprobes has been developed to provide a stable and biocompatible environment for the cells, and allow acquisition of additional data on cellular metabolic and physiological activity using other assays. Platform components were developed and validated to study the signaling dynamics of multiple T cells. MALDI-TOF protein detection, OCIBD IL2 quantification, and the use of quantum dots in live cell imaging were optimized for single cell applications. MALDI data showed clear activation dependence, but there was insufficient MALDI data for statistical analysis; ongoing technical developments are addressing this. Future efforts will fully integrate the microfluidic nanophysiometer, OCIBD analyze detection system, MALDI-TOF protein traps, and cell loading with quantum dots to achieve a fully-integrated, self-contained and instrumented cellular microenvironment that supports precise and timely decisions regarding when best to probe the cell invasively for more detailed intracellular signaling information. This system will allow the identification of unique patterns of signaling pathways of stimuli that can be used to identify previously unknown or maliciously engineered toxins, pathogens, antidotes, and prophylactics.

Download or read book Cadmium Telluride Quantum Dots written by John Donegan and published by CRC Press. This book was released on 2013-12-03 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades, semiconductor quantum dots—small colloidal nanoparticles—have garnered a great deal of scientific interest because of their unique properties. Among nanomaterials, CdTe holds special technological importance as the only known II–VI material that can form conventional p–n junctions. This makes CdTe very important for the development of novel optoelectronic devices such as light-emitting diodes, solar cells, and lasers. Moreover, the demand for water-compatible light emitters and the most common biological buffers give CdTe quantum dots fields a veritable edge in biolabeling and bioimaging. Cadmium Telluride Quantum Dots: Advances and Applications focuses on CdTe quantum dots and addresses their synthesis, assembly, optical properties, and applications in biology and medicine. It makes for a very informative reading for anyone involved in nanotechnology and will also benefit those scientists who are looking for a comprehensive account on the current state of quantum dot–related research.