[PDF] Evaluation Of Dna Labeled Silica Nanoparticles For Use As Hydrogeologic Tracers Field Study And Column Experiments eBook

Author : Juan Vivero-Escoto
Publisher :
Page : 0 pages
File Size : 29,27 MB
Release : 2012
Category : Biotechnology
ISBN : 9781613244524

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In this book, the authors present topical research in the study of the preparation, properties and use of silica nanoparticles. Topics discussed include the reactivity of inorganic radicals and excited triplet states in colloidal silica suspensions; multifunctional mesoporous silica nanoparticles for controlled drug delivery, multimodal imaging and simultaneous imaging and drug delivery; monodisperse luminescent silica nanoparticles and their application to DNA microarray technology.

Author : Asha Narayan Sharma
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Page : 0 pages
File Size : 10,71 MB
Release : 2010
Category :
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In order to answer questions that involve multiple and potentially interacting hydrological flowpaths, multiple tracers with identical transport properties that can nonetheless be distinguished from each other are required. This thesis describes the development and proof of concept of a new kind of engineered tracer system that allows a large number of individual tracers to be simultaneously distinguished from one another. This new tracer is composed of polylactic acid (PLA) microspheres into which short strands of synthetic DNA and paramagnetic iron oxide nanoparticles are incorporated. The synthetic DNA serves as the "label" or "tag" in our tracers that allow us to distinguish one tracer from another and paramagnetic iron oxide nanoparticles are included in the tracer to facilitate magnetic concentration of the tracers in water samples. The potential advantages of this strategy compared to conventional tracers are the elimination of background interferences, the ability to segregate superimposed flowpaths through the design of strictly unique DNA tags and the biodegradability of the tracers.

Author : Ying Sun
Publisher :
Page : pages
File Size : 46,70 MB
Release : 2019
Category :
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As nanomaterials continue to garner interest in a wide range of industries and scientific fields, commercial suppliers have met growing consumer demand by readily offering custom particles with size, shape and surface functionality made-to-order. By circumventing the challenging and complex synthesis of functionalized nanoparticles, these businesses seek to provide greater access for the experimentation and application of these nanoscale platforms. In many cases, amine functional groups are covalently attached as a surface coating on a nanoparticle to provide a starting point for chemical derivatization and commonly, conjugation of biomolecules in medical science applications. Successful conjugation can improve the compatibility, interfacing and activity of therapeutic and diagnostic nanomedicines. Amines are amongst the most popular reactive groups used in bioconjugation pathways owing to the many high-yield alkylation and acylation reaction are involved in. For the design of functionalized nanomaterials with precisely tuned surface chemical properties, it is important to develop techniques and methods which can accurately and reproducibly characterize these materials. Quantification of surface functional groups is crucial, as these groups not only allow for conjugation of chemical species, but they also influence the surface charge and therefore aggregation behavior of nanomaterials. The loss of colloidal stability of functionalized nanomaterials can often correspond to a significant if not complete loss of functionality. Thus, we sought to develop multiple characterization approaches for the quantification of surface amine groups. Silica nanoparticles were selected as a model nanomaterial as they are widely used, commercially available, and their surface chemistry has been investigated and studied for decades. Various commercial batches of silica nanoparticles were procured with sizes ranging from 20 - 120 nm. Two colorimetric assays were developed and adapted for their ease-of-use, sensitivity, and convenience. In addition, a fluorine labelling technique was developed which enabled analysis by quantitative solid-state 19F NMR and X-ray photoelectron spectroscopy (XPS). XPS provided data on surface chemical composition at a depth of ≈ 10 nm, which allowed us to determine coupling efficiencies of the fluorine labelling technique and evaluate the reactivity of the two assays. The ensemble of surface-specific quantification techniques was used to evaluate multiple commercial batches of aminated silica and investigate batch-to-batch variability and the influence of particle size with degree of functionalization. In addition, resulting measurements of surface amine content were compared and validated by an independent method based on quantitative solution 1H NMR, which was developed for total functional group content determination. This allowed for us to assess the role of accessibility and reactivity of the amine groups present in our silica particles. Overall, the objective of this study was to develop a multi-method approach for the quantification of amine functional groups on silica nanoparticles. At the same time, we hoped to set a precedent for the development and application of multiple characterization techniques with an emphasis of comparing them on the basis of reproducibility, sensitivity, and mutual validation.

Author : Teresa Yi Kao
Publisher :
Page : 338 pages
File Size : 18,80 MB
Release : 2017
Category :
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Silica chemistry provides a uniquely tunable platform for nanoparticle synthesis, where particle size, nanoscale morphology, and surface properties can be precisely controlled. Recent advances demonstrate that conveniently accessible parameters, including silica precursor chemistry, solvent, and reaction pH, can be used to tune particle size down to below 10 nm. By cooperative assembly of inorganic silica species and organic molecular structure directing agents, a diverse range of mesoporous silica nanoparticles with hexagonal, cubic, and multicompartment structures can be produced. This versatile chemistry provides pathways for answering fundamental questions about structure formation and developing novel functional nanomaterials for applications including separation, catalysis, and drug delivery. In this dissertation, two examples of such silica nanoparticle systems are discussed. As a first example, the development of an intensity-based fluorescent silica nanoparticle barcode is discussed. This work is motivated by a need for fluorescent tags that increase the number of molecular species that can be simultaneously labeled and reliably distinguished using commercially available fluorescence microscopes. In this study, the synthetic parameters that govern the incorporation of precisely controlled numbers of fluorescent dyes into silica nanoparticles in batch reactions are identified. Heterogeneities within particle batches are mapped using single particle fluorescence microscopy. Proof-of-concept experiments demonstrate that fluorescent silica nanoparticles with well-separated high and low fluorescence intensity distribution levels can be synthesized in batch reactions and used as an intensity barcode in fluorescence microscopy. In the second example, a mesoporous silica nanoparticle system, structure directed by surfactant-micelle self-assembly, is investigated. As a function of an added pore expander molecule or reaction stirring rate, a series of four distinct mesoporous silica nanoparticle structures is observed: hexagonal, cubic/hexagonal multicompartment, cubic, and dodecagonal quasicrystalline. The mechanism driving the structural transition between cubic crystalline and dodecagonal quasicrystalline mesoporous silica nanoparticles is investigated. Control of nanoparticle size down to a single tiling unit (

Author : Yupeng Shi
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Page : 0 pages
File Size : 34,87 MB
Release : 2018
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Silica nanoparticles, thanks to the great easy and adaptability of particle synthesis and limited biotoxicity, is very widely studied for biomedical applications. This thesis conducted a large diversity of investigations involving silica nanomaterials. Firstly, the physicochemical properties and biodegradation properties of three types of structured silica nanoparticles were studied in a buffer, a culture medium and in contact with human dermal fibroblasts that suggest that, under these conditions, the silica nanoparticles must be mainly considered as degraded by hydrolysis and not biodegraded. Then, multifunctional silica nanoparticles which are consist of hollow silica nanoparticles and MnO2 nanosheets were synthesized. And the control drug release and imaging performance of this nanoplatforms were studied from 2D to 3D models. This approach could be used for a rapid assessment of the biofunctionality of nanoparticles before setting up in vivo experiments. Furthermore, a new 3D collagen-based nanocomposites using silica rods were studied and the relationships between the composite composition, structure and mechanical properties, emphasizing the key role of collagen-silica interactions. The influence of these parameters on the adhesion and proliferation of fibroblast cells was also investigated. In addition, we prepared and used magnetic silica nanorods to control particle orientation within the collagen network thanks to an external magnetic field. All the results bring new insights on the preparation and properties of bionanocomposites and open the route to multifunctional hydrogels.