Investigating the Interaction of Semiconductor Quantum Dots with in Vivo and Cellular Environments to Determine Disposition and Risk PDF Download

Author: Hans Christian Fischer
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Maoquan Chu
Publisher: #N/A
ISBN: 9813142901
Category : Technology & Engineering
Languages : en
Pages : 191

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Book Description
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.

Author: Robson Ferreira
Publisher: Morgan & Claypool Publishers
ISBN: 1681741539
Category : Technology & Engineering
Languages : en
Pages : 148

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Book Description
This is an overview of different models and mechanisms developed to describe the capture and relaxation of carriers in quantum-dot systems. Despite their undisputed importance, the mechanisms leading to population and energy exchanges between a quantum dot and its environment are not yet fully understood. The authors develop a first-order approach to such effects, using elementary quantum mechanics and an introduction to the physics of semiconductors. The book results from a series of lectures given by the authors at the Master’s level.

Author: Y. Masumoto
Publisher: Springer Science & Business Media
ISBN: 3662050013
Category : Technology & Engineering
Languages : en
Pages : 500

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Book Description
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.

Author: Luke Jonathan Mortensen
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
"Exposure to engineered nanoparticles (NPs) is becoming near-inescapable as their unique size dependent properties have ensured integration into a wide range of consumer products and research tools. One of the most biologically impactful of these applications is in consumer products such as sunscreens and other cosmetics, where consumer use commonly consists of topical application to UVB damaged skin. A number of studies have investigated the ability of NPs to penetrate the skin barrier, but very few are available on NP permeation differences that result from clinically relevant skin barrier disruptions such as UVB. This thesis uses semiconductor quantum dots (QDs) as a model nanoparticle to investigate the impact of UVB on skin permeability. QDs are NPs with advantageous fluorescence properties including high quantum yield, broad excitability, and narrow emission bandwidth. This doctoral dissertation evaluates the impact of UVB on QD skin penetration, investigates the effects of UVB primary keratinocyte QD cellular interaction, and expands the technical palette with whole tissue confocal imaging development. UVB radiation causes a host of biological changes in the skin, one of which is epidermal barrier disruption. In the first portion of this thesis, the skin penetration of carboxylated QD through the skin of SKH-1 mice with and without UVB exposure was evaluated immediately after irradiation. Skin samples collected at 8 and 24 hours after QD application demonstrated low levels of penetration in non-UVB exposed mice and qualitatively higher but still low levels of QD penetration in the UVB exposed mice. To approach a quantitative evaluation of both UVB-induced defect and QD skin penetration, this dissertation next used a designed experiment approach to evaluate the effects of UVB on skin barrier function as measured by transepidermal water loss and the impact of UVB on skin penetration of QDs with atomic absorption spectroscopy. UVB induced a strong defect that peaked 4-6 days after exposure. Carboxylic acid coated QDs were applied to SKH-1 mice over the peak barrier disruption 24 hours, and both a qualitative increase in skin penetration after UVB exposure using microscopy and a low-level quantitative increase in Cd levels in the liver were found, suggesting increased systemic access. Interestingly, experiments found statistically significant but still low levels of QD collection in the lymph nodes without UVB exposure whose magnitude decreased with UVB. Increased QD skin penetration with UVB exposure suggests that topically applied QDs will be able to interact with local cells in the epidermis. To investigate this possibility, differences in acute QD cytotoxicity and uptake of carboxylated QDs between proliferative and differentiated primary keratinocytes with and without UVB exposure have been evaluated. Despite similarities between proliferative and differentiated keratinocytes in UVB and QD cytotoxicity, the proliferative cells have a much greater ability to endocytose QDs than differentiated cells. These results suggest the greater potential for QD interaction with proliferative basal and suprabasal cells in the epidermis which could potentiate a higher risk of possible long-term effects from NP contact with UVB exposed skin. A challenge in the evaluation of NP skin penetration is sampling error and other problems associated with histological processing. Current literature suggests the usefulness of confocal or multiphoton microscopies to address these issues. The final portion of this thesis introduces the design, implementation, and validation of a fluorescence and reflectance confocal microscopy system that utilizes far-red excitation to detect near- IR lead sulfide QDs through ex vivo human stratum corneum and in the epidermis. The tested system achieves QD sensitivity measures on par with those reported in the literature for other techniques, and is demonstrated to detect QDs permeating skin. This dissertation presents the first published results to evaluate the impact of UVB on skin penetration of QDs and keratinocyte interaction with QDs, and has advanced technology for whole-tissue confocal microscopic evaluation of QD skin penetration. Important advancements have been made, suggesting that UVB may increase risk of systemic exposure to NPs, and that the lymphatic system may play an important role in the translocation of topically applied NPs."--Leaves vii-ix

Author: Lucjan Jacak
Publisher: Springer Science & Business Media
ISBN: 3642720021
Category : Technology & Engineering
Languages : en
Pages : 176

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Book Description
We present an overview of the theoretical background and experimental re sults in the rapidly developing field of semiconductor quantum dots - systems 8 6 of dimensions as small as 10- -10- m (quasi-zero-dimensional) that contain a small and controllable number (1-1000) of electrons. The electronic structure of quantum dots, including the energy quan tization of the single-particle states (due to spatial confinement) and the evolution of these (Fock-Darwin) states in an increasing external magnetic field, is described. The properties of many-electron systems confined in a dot are also studied. This includes the separation of the center-of-mass mo tion for the parabolic confining potential (and hence the insensitivity of the transitions under far infrared radiation to the Coulomb interactions and the number of particles - the generalized Kohn theorem) and the effects due to Coulomb interactions (formation of the incompressible magic states at high magnetic fields and their relation to composite jermions), and finally the spin-orbit interactions. In addition, the excitonic properties of quantum dots are discussed, including the energy levels and the spectral function of a single exciton, the relaxation of confined carriers, the metastable states and their effect on the photoluminescence spectrum, the interaction of an exciton with carriers, and exciton condensation. The theoretical part of this work, which is based largely on original re sults obtained by the authors, has been supplemented with descriptions of various methods of creating quantum-dot structures.

Author: Ladislaus Alexander Banyai
Publisher: World Scientific
ISBN: 9814504238
Category : Science
Languages : en
Pages : 264

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Book Description
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.

Author: Luke Jonathan Mortensen
Publisher:
ISBN:
Category :
Languages : en
Pages : 438

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Book Description
"Exposure to engineered nanoparticles (NPs) is becoming near-inescapable as their unique size dependent properties have ensured integration into a wide range of consumer products and research tools. One of the most biologically impactful of these applications is in consumer products such as sunscreens and other cosmetics, where consumer use commonly consists of topical application to UVB damaged skin. A number of studies have investigated the ability of NPs to penetrate the skin barrier, but very few are available on NP permeation differences that result from clinically relevant skin barrier disruptions such as UVB. This thesis uses semiconductor quantum dots (QDs) as a model nanoparticle to investigate the impact of UVB on skin permeability. QDs are NPs with advantageous fluorescence properties including high quantum yield, broad excitability, and narrow emission bandwidth. This doctoral dissertation evaluates the impact of UVB on QD skin penetration, investigates the effects of UVB primary keratinocyte QD cellular interaction, and expands the technical palette with whole tissue confocal imaging development. UVB radiation causes a host of biological changes in the skin, one of which is epidermal barrier disruption. In the first portion of this thesis, the skin penetration of carboxylated QD through the skin of SKH-1 mice with and without UVB exposure was evaluated immediately after irradiation. Skin samples collected at 8 and 24 hours after QD application demonstrated low levels of penetration in non-UVB exposed mice and qualitatively higher but still low levels of QD penetration in the UVB exposed mice. To approach a quantitative evaluation of both UVB-induced defect and QD skin penetration, this dissertation next used a designed experiment approach to evaluate the effects of UVB on skin barrier function as measured by transepidermal water loss and the impact of UVB on skin penetration of QDs with atomic absorption spectroscopy. UVB induced a strong defect that peaked 4-6 days after exposure. Carboxylic acid coated QDs were applied to SKH-1 mice over the peak barrier disruption 24 hours, and both a qualitative increase in skin penetration after UVB exposure using microscopy and a low-level quantitative increase in Cd levels in the liver were found, suggesting increased systemic access. Interestingly, experiments found statistically significant but still low levels of QD collection in the lymph nodes without UVB exposure whose magnitude decreased with UVB. Increased QD skin penetration with UVB exposure suggests that topically applied QDs will be able to interact with local cells in the epidermis. To investigate this possibility, differences in acute QD cytotoxicity and uptake of carboxylated QDs between proliferative and differentiated primary keratinocytes with and without UVB exposure have been evaluated. Despite similarities between proliferative and differentiated keratinocytes in UVB and QD cytotoxicity, the proliferative cells have a much greater ability to endocytose QDs than differentiated cells. These results suggest the greater potential for QD interaction with proliferative basal and suprabasal cells in the epidermis which could potentiate a higher risk of possible long-term effects from NP contact with UVB exposed skin. A challenge in the evaluation of NP skin penetration is sampling error and other problems associated with histological processing. Current literature suggests the usefulness of confocal or multiphoton microscopies to address these issues. The final portion of this thesis introduces the design, implementation, and validation of a fluorescence and reflectance confocal microscopy system that utilizes far-red excitation to detect near- IR lead sulfide QDs through ex vivo human stratum corneum and in the epidermis. The tested system achieves QD sensitivity measures on par with those reported in the literature for other techniques, and is demonstrated to detect QDs permeating skin. This dissertation presents the first published results to evaluate the impact of UVB on skin penetration of QDs and keratinocyte interaction with QDs, and has advanced technology for whole-tissue confocal microscopic evaluation of QD skin penetration. Important advancements have been made, suggesting that UVB may increase risk of systemic exposure to NPs, and that the lymphatic system may play an important role in the translocation of topically applied NPs."--Leaves vii-ix.

Author: Peter A. Ling
Publisher: Nova Publishers
ISBN: 9781594544064
Category : Science
Languages : en
Pages : 278

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Book Description
A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atoms are quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology, they are called quantum bits or qubits. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10-9 meter or a millionth of a millimetre. The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. Other applications of quantum dots include nanomachines, neural networks, and high-density memory or storage media. Research is being carried out on nano-crystals, self-assembled dots, and gated structures. This book presents leading-edge research from around the world.

Author: Mark Green
Publisher: Royal Society of Chemistry
ISBN: 1782628355
Category : Science
Languages : en
Pages : 295

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Book Description
Quantum dots are nano-sized particles of semiconducting material, typically chalcogenides or phosphides of metals found across groups II to VI of the periodic table. Their small size causes them to exhibit unique optical and electrical properties which are now finding applications in electronics, optics and in the biological sciences. Synthesis of these materials began in the late 1980’s and this book gives a thorough background to the topic, referencing these early discoveries. Any rapidly-expanding field will contain vast amounts of publications, and this book presents a complete overview of the field, bringing together the most relevant and seminal aspects literature in an informed and succinct manner. The author has been an active participant in the field since its infancy in the mid 1990’s, and presents a unique handbook to the synthesis and application of this unique class of materials. Drawing on both his own experience and referencing the primary literature, Mark Green has prepared. Postgraduates and experienced researchers will benefit from the comprehensive nature of the book, as will manufacturers of quantum dots and those wishing to apply them.