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1
Dilanson, Nadea. "Halfsphere Derivatisation of Magnetic Micro Particles." Thesis, Mälardalen University, Mälardalen University, Department of Biology and Chemical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-1415.
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This exam project is an effort to derivatize one side of magnetic beads with one kind of molecule , and another one on the opposite side. First the surface of the sphere is loaded with a suitable linker with, e.g. amino or hydroxyl groups. In the second step, these groups are derivatized with a photosensitive protecting group such as Nitroveratryloxycarbonyl. In the third step, the particles are placed on a surface and then irradiated with UltraViolet light (320 nm) from above, which will cleave off the Nitroveratryloxycarbonyl on the upper half, while leaving in place the ones at the lower half. The linker groups of the upper half can now be derivatized by other reagents of choice. The remaining Nitroveratryloxycarbonyl groups can be removed by suspending the particles in a solvent and then exposing them to UltraViolet light. Finally the linker groups on this half of the particles can be derivatized by a second reagent.
Magnetic particles were marked with FITC, two different kinds of magnetic particles were selected, sikastar-NH2 function and sikastar-COOH function. Five different solvents were used to wash the magnetic particles and remove the bounded FITC, solvents are Acetone, 1-butanol, DMSO, 4-propanol, and Urea. Magnetic particles sikastar-NH2 and sikastar-COOH were washed with Tween 20 and SDS to remove non-specific binding of FITC. Sikastar particles were treated with IgG*FITC in constant presence of the following solvents: PBS*10, Pluronic-F127, Tween 20. Pegylation of sikastar particles got done to reduce non-specific binding. Derivatisation of Nitroveratryloxycarbonyl got done and specific bindning of IgG*FITC to micromer particles got done by protein thiolation.
When a different concentration of FITC was tested to control specific and non-specific binding to sikastar functions, we observed that we had a specific binding to sikastar-NH2 in the lowest concentration. In choice of magnetic particles we had specific binding with sikastar-NH2. Using a different solvents Acetone, 1-butanol, 4-propanol, and Urea to remove bounded FITC, sikastar-NH2 showed stronger fluoresence than sikastar-COOH after washing because of specific binding and it was difficult to remove FITC with Acetone, 1-butanol, 4-propanol,and Urea, on the other hand DMSO could remove bounded FITC from sikastar particles. When we washed magnetic particles sikastar-NH2 and sikastar-COOH with Tween 20 and SDS to remove non-specific binding of FITC, we could see that magnetic particles showed fluoresence in both functions due to non-specific binding. When sikastar particles got treated with IgG*FITC in constant presence of solvents PBS*10, Pluronic-F127, and Tween 20, we had a specific binding between sikastar particles and IgG*FITC in a presence of pluronic-F127. Pegylation of sikastar particles with a different kind of a PEG was possibl to reduce non-specific bindning. The derivatisation of Nitroveratryloxycarbonyl could be done in a N2 environment, and Nitroveratryloxycarbonyl-sikastar-NH2 could be radiated with UltraViolet light to remove Nitroveratryloxycarbonyl. Also thiolation method could be used to perform specific binding of IgG*FITC to micromer particles.
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Alexander, Lois Meryl. "Micro-particles as cellular delivery devices." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4012.
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Narrowly dispersed amino-functionalised polystyrene microspheres, with a range of diameters, were successfully synthesised via emulsion and dispersion polymerisation. Fluorescent labelling allowed cellular translocation to be assessed in a variety of cell lines and was found to be very high, but controllable, whilst exhibiting no detrimental effect on cellular viability. In order to fully determine the mode of microsphere uptake, “beadfected” melanoma (B16F10) cells were studied using both chemical and microscopic methods. Uptake was found to be wholly unreliant upon energetic processes, with microspheres located cytoplasmically and not encapsulated within endosomes, an important characteristic for delivery devices. In order to demonstrate the effective delivery of exogenous cargo mediated by microspheres, short interfering (si)-RNAs were conjugated to beads and investigated for the gene silencing of enhanced green fluorescent protein (EGFP) in cervical cancer (HeLa) and embryonic (E14) stem cells. EGFP knockdown was found to be highly efficient after 48 – 72 hours. Dual-functionalised microspheres displaying a fluorophore (Cy5) and siRNA allowed only those cells beadfected with the delivery vehicle (and thus containing siRNA) to be assessed for EGFP expression, yielding an accurate assessment of microsphere-mediated gene silencing. In addition, by manipulation of the microsphere preparation conditions, micro-doughnuts and paramagnetic microspheres were produced and their cellular uptake assessed. Paramagnetic microspheres were found to enter cells efficiently and were subsequently used to bias the movement of beadfected cells in response to an externally applied magnet, while micro-doughnuts were found to exhibit cell selective properties and were noted to traffic specifically to the liver in vivo.
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Xiang, Yanqiao. "Capillary Liquid Chromatography Using Micro Size Particles." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd531.pdf.
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Meehan, Timothy D. Superfine Richard. "Quantitative magnetophoresis of micro and nano particles." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,2272.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Jun. 26, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.
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Yang, Fengchang. "Dynamics of Micro-Particles in Complex Environment." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78398.
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Micro-particles are ubiquitous in microsystems. The effective manipulation of micro-particles is often crucial for achieving the desired functionality of microsystems and requires a fundamental understanding of the particle dynamics. In this dissertation, the dynamics of two types of micro-particles, Janus catalytic micromotors (JCMs) and magnetic clusters, in complex environment are studied using numerical simulations.
The self-diffusiophoresis of JCMs in a confined environment is studied first. Overall, the translocation of a JCM through a short pore is slowed down by pore walls, although the slowdown is far weaker than the transport of particles through similar pores driven by other mechanisms. A JCM entering a pore with its axis not aligned with the pore axis can execute a self-alignment process and similar phenomenon is found for JCMs already inside the pore. Both hydrodynamic effect and 'chemical effect', i.e., the modification of the concentration of chemical species around JCMs by walls and other JCMs, play a key role in the observed dynamics of JCMs in confined and crowded environment.
The dynamics of bubbles and JCMs in liquid films covering solid substrates are studied next. A simple criterion for the formation of bubbles on isolated JCMs is developed and validated. The anomalous bubble growth law (r~t^0.7) is rationalized by considering the relative motion of growing bubbles and their surrounding JCMs. The experimentally observed ultra-fast collapse of bubbles is attributed to the coalescence of the bubble with the liquid film-air interface. It is shown that the collective motion of JCMs toward a bubble growing on a solid substrate is caused by the evaporation-induced Marangoni flow near the bubble.
The actuation of magnetic clusters using non-uniform alternating magnetic fields is studied next. It is discovered that the clusters' clockwise, out-of-plane rotation is a synergistic effect of the magnetophoresis force, the externally imposed magnetic torque and the hydrodynamic interactions between the cluster and the substrate. Such a rotation enables the cluster to move as a surface walker and leads to unique dynamics, e.g., the cluster moves away from the magnetic source and its trajectory exhibits a periodic fluctuation with a frequency twice of the field frequency.Ph. D.
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Li, Xue. ""Cage" Nano and Micro-particles for Biomedical Applications." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS316/document.
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Les systèmes à délivrance de médicaments sont des technologies conçues pour administrer des molécules actives de façon optimisée afin d’améliorer leurs effets thérapeutiques tout en minimisant les effets secondaires. En effet, ces systèmes permettent une libération au niveau d’une cible thérapeutique. Les particules de type «cage» ont récemment attiré une attention particulière en raison de leur capacité accrue à (co)incorporer et à protéger des molécules actives vis-à-vis de dégradations in vivo. Les cyclodextrines (CDs) sont des exemples type de molécules "cage", possédant une cavité hydrophobe et une surface extérieure hydrophile. Nous avons élaboré tout d’abord des assemblages supramoléculaires à base de CDs d'environ 100 nm par une méthode douce consistant à mélanger deux solutions aqueuses de polymères neutres : 1) polymère de β-CD et 2) dextrane greffé avec la benzophénone, molécule invitée formant des complexes d’inclusion avec les CDs. La procédure de préparation « verte» en une seule étape rend la formulation attractive, malgré sa relativement faible capacité d’encapsulation (5%pds). Afin d'améliorer cete charge, nous avons élaboré des particules hybrides organiques-inorganiques (MOFs) à base de CDs. Avantageusement, les CD-MOF comportent non seulement des cavités de CD, mais aussi de larges pores engendrés lors l’auto-assemblage de CDs. Le lansoprazole a été incorporé avec succès (23%pds) dans les CD-MOFs et nous avons montré que chaque CDs était capable d’accueillir une molécule de principe actif. Cependant, l’inconvénient majeur des CD-MOFs est leur faible stabilité en milieu aqueux, limitant leur domaine d’application. Une modification de surface est apparue donc nécessaire pour améliorer leur stabilité. Notre stratégie a été d’incorporer les CD-MOFs dans des matrices d'acide polyacrylique (PAA). Des microsphères composites d’environ 650 nm ont été élaborées avec succès et ont permis une bonne stabilité et une libération prolongée sur plus de 48 h. Avantageusement, ces particules composites n’étaient pas toxiques in vitro même à des concentrations élevées. Ainsi, nous nous sommes orientés vers l’étude comparative de MOFs plus stables dans l’eau, à base de trimesate de fer. Les MIL-100 (Fe) (Material of Institute Lavoisier) figurent parmi les premiers MOF étudiés en tant que nanomédicaments (nanoMOFs). Ces particules, parfaitement stables dans l'eau, se dégradent dans des milieux contenant des phosphates en perdant rapidement leur caractère cristallin et leurs ligands constitutifs. De façon étonnante, nous avons constaté que malgré leur dégradation, ces MOFs conservent leur taille intacte. Une analyse approfondie basée sur la microscopie de Raman a permis d’obtenir des informations pertinentes sur la morphologie et la composition chimique de particules individuelles. Ainsi, il a été montré qu’un front d'érosion délimitait nettement un cœur intact et une coquillé inorganique érodée. Cependant, ni l’encapsulation ni la modification de surface des MOFs n’altérait leur intégrité. Enfin, nous avons étudié la co-encapsulation de deux molécules actives utilisées en combinaison (amoxicilline et clavulanate de potassium) dans les nanoMOFs stables à base de MIL-100 (Fe). Les antibiotiques ont été incorporées par imprégnation et chaque molécule s’est localisée préférentiellement dans un compartiment (large ou petite cage) corroborant parfaitement les simulations par modélisation moléculaire. De plus, il a été découvert, de manière surprenante, qu’un grand nombre de nanoMOFs se localisait au voisinage des bactéries (S.aureus) dans des cellules infectées. En se dégradant dans ces cellules, les nanoMOFs contenant les antibiotiques ont réduit de manière importante la charge bactérienne intracellulaire. Ces études révèlent le potentiel des particules de type «cage» pour une incorporation efficace de molécules actives et leur libération contrôlée et ouvrent de nombreuses possibilités d’applicationDrug delivery systems are engineered technologies to administer pharmaceutical ingredients to improve their therapeutic effects, aiming at minimizing their side effects by means of targeted delivery and/or controlled release. “Cage” particles recently drew special attention since they could act as “drug containers” which potentially load large amount of drugs, improve their stability and offer the possibilities to co-encapsulate synergetic drugs. Cyclodextrins (CDs) are typical “cage” molecules with a hydrophobic cavity and a hydrophilic outer surface. Taking advantage of the host-guest interactions between β-CD and benzophenone (Bz), CD based nanoparticles (CD-NPs) were the first formulation investigated. CD-NPs of around 100 nm were instantaneously produced by mixing two aqueous solutions of neutral polymers: 1) poly-CD containing β-CDs, and 2) Bz grafted Dex (Dex-Bz). The “green” and facile preparation procedure makes it attractive formulation, whereas its limitation lies on the low drug payloads (~ 5 wt%). In order to improve the drug loading capacity of CDs, porous CD based metal organic frameworks (CD-MOFs) were synthesized, which contain not only CD cavities, but also large pores built up by CDs self-assembly. Lansoprazole (LPZ) was incorporated in CD-MOF microcrystals (~ 6 µm) reaching payloads as high as 23.2 ± 2.1% (wt). Remarkably, each CD cavity was able to host a drug molecule, offering new opportunities for the use of CD-MOFs for drug delivery purposes. However, these particles disassembled in aqueous media, which limits their application for oral and intravenous administration. Surface modification is therefore necessary to improve their stability in water. The drug loaded CD-MOF nanocrystals (~ 650 nm) were successfully embedded in polyacrylic acid (PAA) polymer matrices. The composite microspheres exhibited spherical shapes and sustained drug release over a prolonged period of time (over 48 h). Drug loaded MOF/PAA composite microspheres were not toxic in vitro (cell viability ~ 90%) even at very high concentrations up to 17.5 mg/mL. MOF/PAA composite microspheres constitute an efficient and pharmaceutically acceptable MOF-based carrier for sustained drug release. However, the process of surface modification was complicated and lead to larger particles and reduced drug payloads. Water-stable MOFs are a novel type of hybrid particles, showing a high potential as drug carriers. Iron trimesate MOFs, namely, MIL-100 (Fe) (MIL stands for Material of Institute Lavoisier) was among the first nano-scaled MOFs used for drug delivery. These particles were stable in water but degraded in phosphate buffer saline (PBS) losing their crystallinity and constitutive trimesate linkers. However, it was discovered that they kept their morphology intact. A thorough analysis based on Raman microscopy was carried on to gain insights on both the morphology and chemical composition of individual particles. It was evidenced the formation of a sharp erosion front during particle degradation. Noteworthy, the MOFs did not degrade during drug loading nor surface modification. Co-encapsulation of two synergic antibiotics (amoxicillin and potassium clavulanate) in MIL-100 (Fe) nanoMOFs was achieved following a “green” procedure by soaking nanoMOFs in aqueous solutions of both drugs. Molecular modelling showed that each drug preferentially located in a separate nanoMOF compartment. Surprisingly, nanoMOFs were prone to co-localize with bacteria once internalized in infected macrophages. NanoMOFs acted synergistically with the entrapped drugs to kill intracellular S. aureus, in vitro. These results pave the way towards the design of engineered nanocarriers in which each component synergistically plays a role in fighting the disease. These studies unravel the potential of “cage” particles for efficient drug entrapment and controlled release and open numerous possibilities for applications
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Mitchell, Thomas James. "The ballistics of micro-particles into mucosa and skin." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275252.
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Deng, Mao [Verfasser]. "Micro-Structure of Functional Particles and Particle Systems / Mao Deng." Kiel : Universitätsbibliothek Kiel, 2015. http://d-nb.info/1073868400/34.
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Ooe, Katsutoshi, and Toshio Fukuda. "Development of micro particles separation device with piezo-ceramic vibrator." IEEE, 2009. http://hdl.handle.net/2237/13949.
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Sergides, M. "Optical manipulation of micro- and nano-particles using evanescent fields." Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1410938/.
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We present a study of the manipulation of micro-particles and the formation of optically bound structures of particles in evanescent wave traps. Two trapping geometries are considered: the first is a surface trap where the evanescent field above a glass prism is formed by the interference of a number of laser beams incident on the prism-water interface; the second uses the evanescent field surrounding a bi-conical tapered optical fibre that has been stretched to produce a waist of sub-micron diameter. In the surface trap we have observed the formation of optically bound one- and two-dimensional structures of particles and measured the binding spring constant by tracking particle motion and the extent of the particle’s Brownian fluctuations. Additionally, we have measured the inter-particle separations in the one-dimensional chain structures and characterised the geometry of the two-dimensional arrays. In the tapered optical fibre trap we demonstrated both particle transport for long distances along the fibre, and the formation of stable arrays of particles. We present the fabrication of tapered optical fibres using the 'heat-and-pull` technique, and evanescent wave optical binding of micro-particles to the taper. Calculations of the distribution of the evanescent field surrounding a tapered fibre are also presented. We show that the combination of modes can give control over the locations of the trapping sites. Additionally, we show how the plasmon resonance of metallic nano-particles can be exploited to enhance the optical trapping force, and suggest how a bi-chromatic nano-fibre trap for plasmonic particles may be implemented. In both experiments we implement video microscopy to track the particle locations and make quantitative measures of the particle dynamics. The experimental studies are complemented by light scattering calculations based on Mie theory to infer how the geometries of the particle structures are controlled by the underlying incident and scattered optical fields.
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Hardy, Matthew Philips. "Numerical investigation of gas-powered delivery of micro particles to tissue." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289337.
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Cockcroft, Stephanie. "VUV 157nm F₂ laser irradiation of micro- and nano-scale particles." Thesis, University of Hull, 2012. http://hydra.hull.ac.uk/resources/hull:7106.
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Micro- and nanoscale particles have recently become the focus of a great deal of research interest due to their wide-ranging potential in a number of applications. This thesis concerns the interaction of small particles with the 157nm wavelength vacuum ultraviolet, VUV, emission from a molecular fluorine gas, F₂, laser. The laser system is introduced and an overview of laser ablation of polymers is presented. Small particles of different materials and sizes, supported on polymeric substrates, are irradiated at a wavelength of 157nm. The silica particles are transparent to the 157nm radiation, which leads to a lens effect. The polystyrene, silicon carbide and silver particles are opaque to the 157nm radiation, leading to a substrate-shielding effect. The lens effect results in the focussing of the incident laser beam into a hotspot at the interface between the particle and the substrate. The enhancement leads to the removal of substrate material underneath the particle to form a dimple on the surface of the substrate. The substrate-shielding effect leads to the removal of the substrate material around the opaque particle while the underlying material is left behind. This forms a polymeric support structure, with the seeding particle attached to the top. The shape of the seeding particle dictates the shape of the support structure, for example spherical particles seed composite conical structures and cylindrical particles seed linear prismatic structures. The polystyrene and silver particles are seen to undergo shape and size transformations as a result of laser irradiation. This is discussed in terms of mass loss through heating. Finite Element Method modelling is used to investigate and support the experimental results. Fluorescent polystyrene particles are also irradiated at a wavelength of 157nm. They retain their fluorescence after irradiation and exhibit Whispering Gallery Mode resonances, ideal for high-sensitivity sensing applications and Lab-on-a-Chip microreactors.
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Spinella-Mamo, Vincent Paul. "Control of micro- and nano- particles with electric and magnetic fields." Connect to Electronic Thesis (CONTENTdm), 2008. http://worldcat.org/oclc/458547540/viewonline.
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Moakes, Richard John Asa. "Whey protein micro-particles as multifunctional materials for structure and delivery." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8160/.
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This thesis seeks to augment the understanding of gelled micro-particulate suspensions known as sheared/fluid gels, by investigating the use of dairy proteins (whey, WPI) as the gelling material. The research used a microstructural approach to probe the underlying design principles governing the formation, and subsequent material properties of WPI microgel systems. The work initially focused on preparing suspensions through both thermal and cold-set approaches. By controlling two key processing parameters: shear and gelling rate, it was shown that a range of suspension properties could be produced. In both cases, it was demonstrated that structural characteristics could be controlled, for tailored rheologies. The shear technology was then applied to a more complex system of oil and whey protein, resulting in the formation of microcapsules; as the WPI gelled around the oil droplets in a core-shell model. Again, controllable structural properties were obtained, however, the lipophilic core provided a reservoir for potential delivery. This multi-functional formulation was then investigated under gastro-intestinal conditions, highlighting controllable release as a function of the type of oil used in production. Therefore, the potential use of WPI/WPI-oil micro-particles have been presented as a multi-functional composite for both structure and delivery within food ingredients.
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Soliman, Salah M. "Micro-Particles and Gas Dynamics in an Axi-Symmetric Supersonic Nozzle." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1313772443.
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Othman, Rahimah. "Production of functional pharmaceutical nano/micro-particles by solvent displacement method using advanced micro-engineered dispersion devices." Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/22905.
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The rapid advancement of drug delivery systems (DDS) has raised the possibility of using functional engineered nano/micro-particles as drug carriers for the administration of active pharmaceutical ingredients (APIs) to the affected area. The major goals in designing these functional particles are to control the particle size, the surface properties and the pharmacologically active agents release in order to achieve the site-specification of the drug at the therapeutically optimal rate and dose regimen. Two different equipment (i.e. glass capillary microfluidic device and micro-engineered membrane dispersion cell) were utilised in this study for the formation of functional nano/micro-particles by antisolvent precipitation method. This method is based on micromixing/direct precipitation of two miscible liquids, which appear as a straightforward method, rapid and easy to perform, does not require high stirring rates, sonication, elevated temperatures, surfactants and Class 1 solvents can be avoided. Theoretical selection of a good solvent and physicochemical interaction between solvent-water-polymer with the aid of Bagley s two-dimensional graph were successfully elucidated the nature of anti-solvent precipitation method for the formation of desired properties of functional pharmaceutical nano/micro-engineered particles. For the glass capillary microfluidic experiment, the organic phase (a mixture of polymer and tetrahydrofuran/acetone) was injected through the inner glass capillary with a tapered cross section culminated in a narrow orifice. The size of nanoparticles was precisely controlled by controlling phase flow rates, orifice size and flow configuration (two- phase co-flow or counter-current flow focusing). The locations at which the nanoparticles would form were determined by using the solubility criteria of the polymer and the concentration profiles found by numerical modelling. This valuable results appeared as the first computational and experimental study dealing with the formation of polylactide (PLA) and poly(ε-caprolactone) (PCL) nanoparticles by nanoprecipitation in a co-flow glass capillary device. The optimum formulations and parameters interactions involved in the preparation of paracetamol encapsulated nanoparticles (PCM-PCL NPs) using a co-flow microfluidic device was successfully simulated using a 25-full factorial design for five different parameters (i.e. PCL concentration, orifice size, flow rate ratios, surfactant concentration and paracetamol amount) with encapsulation efficiency and drug loading percentage as the responses. PCM-loaded composite NPs composed of a biodegradable poly(D,L-lactide) (PLA) polymer matrix filled with organically modified montmorillonite (MMT) nanoparticles were also successfully formulated by antisolvent nanoprecipitation in a microfluidic co-flow glass capillary device. The incorporation of MMT in the polymer matrix improved the drug encapsulation efficiency and drug loading, and extended the rate of drug release in simulated intestinal fluid (pH 7.4). The encapsulation of MMT and PCM in the NPs were well verified using transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). PCL drug-carrier nanoparticles were also produced by rapid membrane micromixing combined with nanoprecipitation in a stirred cell employing novel membrane dispersion. The size of the NPs was precisely controlled by changing the aqueous-to-organic volumetric ratio, stirring rate, transmembrane flux, the polymer content in the organic phase, membrane type and pore morphologies. The particle size decreased by increasing the stirring rate and the aqueous-to-organic volumetric ratio, and by decreasing the polymer concentration in the aqueous phase and the transmembrane flux. The existence of the shear stress peak within a transitional radius and a rapid decline of the shear stress away from the membrane surface were revealed by numerical modelling. Further investigation on the PCL nanoparticles loaded immunosuppressive rapamycin (RAPA) drug were successfully synthesised by anti-solvent nanoprecipitation method using stainless steel (SS) ringed micro-engineered membrane. Less than 10 μm size of monohydrate piroxicam (PRX) micro-crystals also was successfully formed with the application of anti-solvent precipitation method combined with membrane dispersion cell that has been utilised in the formation of functional engineered nanoparticles. This study is believed to be a new insight into the development of integrated membrane crystallisation system.
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Anene, Chinedu A. "Platelet micro-particles induce angiogenesis through the delivery of the micro-RNA Let-7a into endothelial cells." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/16041.
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Cardiovascular disease is a major cause of morbidity and mortality around the globe, which is linked to athero-thrombosis. The risk factors for atherothrombosis, thus cardiovascular disease is impaired anti-thrombotic and antiinflammatory functions of the endothelium. Thrombosis is a hallmark of cardiovascular disease/complications characterised by increased platelet activation and increased secretion of platelet micro-particles that induce angiogenesis. This study determined the role of platelet micro-particles derived microRNA in the regulation of angiogenesis and migration, with a focus on the regulation of thrombospondin-1 release by platelet micro-particles delivered Let- 7a. The role of thrombospondin-1 receptors (integrin beta-1 and integrin associated protein) and downstream caspase-3 activation were explored by Let-7a inhibition prior to PMP treatment. MicroRNA dependent modulation of proangiogenic proteins including monocyte chemoattractant protein-1 and placental growth factor, and recruitment of activating transcription factor-4 protein to their promoter regions were explored. Main findings are: 1. Platelet micro-particles induce angiogenesis, migration, and release of novel cytokine subsets specific to platelet micro-particle’s RNA content. 2. The targeting of thrombospondin-1 mRNA by platelet micro-particles’ transferred Let-7a chiefly modulate the angiogenic effect on endothelial cells. 3. The inhibition of thrombospondin-1 translation enable platelet micro-particles to increase angiogenesis and migration in the presence of functional integrin beta-1 and integrin associated protein, and reduced cleaving of caspase-3. 4. Platelet micro-particle modulate the transcription of monocyte chemoattractant protein-1 and placental growth factor in a Let-7a dependent manner. 5. Let-7a induce angiogenesis ii independent of other platelet micro-particle’s microRNAs. Platelet micro-particle derived Let-7a is a master regulator of endothelial cell function in this model, which presents an opportunity for the development of new biomarkers and therapeutic approaches in the management of cardiovascular disease. Future studies should aim to confirm these findings in-vivo.
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Zhang, Ning. "Motion and distribution of micro-sized solid particles in turbulent gas flow /." Search for this dissertation online, 2005. http://wwwlib.umi.com/cr/ksu/main.
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Ozcan, Sinan. "Simulation of field controllable fluids with suspended ferrous particles in micro tubes." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1433348.
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Zhang, Dongwei. "Application of microneedles to enhance delivery of micro-particles from gene guns." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/13744.
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Gene gun assisted micro-particle delivery system is an excellent method for the delivery of DNA into target tissue so as to carry out gene transfection in the target cells. The gene gun is primarily a particle accelerator which accelerates DNA-coated micro-particles to sufficient velocities to breach the target layer enabling the micro-particles to penetrate to a desired depth and target the cells of interest to achieve gene transfer. However, an inevitable problem in this process is the tissue/cell damage due to the impaction of the pressurized gas and micro-particles on the target. The purpose of this research is developing a new conceptual system which improves the penetration depth of micro-particles at less imposed pressure and particle injection velocity. This is achieved by applying a microneedle array and ground slide in the gene gun system, thus a study involving microneedle assisted micro-particle delivery is conducted in this work. Microneedle array is used to create holes in the target which allows a number of micro-particles to penetrate through the skin which enhances the penetration depth inside target. The ground slide is used to load a pellet of the micro-particles and prevent the pressurized gas to avoid the impaction on the target. The operation principle is that the pellet is attached to ground slide which is accelerated to a sufficient velocity by the pressurized gas. The pellet is released from the ground slide which separates into individual micro-particles by a mesh and penetrates to a desired depth inside the target. An experimental rig to study various aspects of microneedle assisted micro-particle delivery is designed in this PhD research. The passage percentage of the micro-particles and size of the separated micro-particles are analysed in relation to the operating pressure, mesh pore size and Polyvinylpyrrolidone (PVP) concentration to verify the applicability of this system for the micro-particle delivery. The results have shown that the passage percentage increases from an increase in the mesh pore size and operating pressure and a decrease in PVP concentration. A mesh pore size of 178 μm and pellet PVP concentration of 40 mg/ml were used for the bulk of the experiments in this study as these seem to provide higher passage percentage and the narrow size distribution of the separated micro-particles. In addition, the velocity of the ground slide is detected by the photoelectric sensor and shown that it increases from an increase in operating pressure and reaches 148 m/s at 6 bar pressure, A further analysis in the penetration depths of the micro-particles to determine whether they achieve enhanced penetration depths inside the target after using microneedles is carried out. A skin mimicked agarose gel is obtained from comparing the viscoelastic properties of various concentration of agarose gel in comparison with the porcine skin, which is assumed to mimic the human skin. These experiments are used to relate the micro-particle penetration depth with the operating pressure, microneedle length and particle size. In addition, a theoretical model is developed based on the experimental data to simulate the microneedle assisted micro-particle delivery which provide further understanding of the microneedle assisted micro-particle delivery. The developed model was used to analyse the penetration depth of micro-particles in relation to the operation pressure, target properties, microneedle length and particle size and density. The modelling results were compared with the experimental results to verify the feasibility of the microneedle assisted micro-particle delivery for micro-particles delivery. As expected, both experimental and theoretical results show that the micro-particles achieve an enhanced penetration depth inside target. The maximum penetration depth of micro-particles is increased from an increase in operating pressure, microneedle length, particle size and density.
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Marcetich, Adam Michael. "Ultrasound spectral parameters of micro- and nano- particles: measurement software and modeling." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1413384380.
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Yusop, Siti Nurul'Ain. "Characterisation of the morphological and surface properties of organic micro-crystalline particles." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/8920/.
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The surface properties of single and agglomerated micro-crystals are characterised using the micro-focus X-ray beams available at a third generation synchrotron light source together with other laboratory facilities. The influence of the crystallisation environment, on the resultant product crystals is studied by both varying the cooling rates during crystallisation and through the addition of impurities and cross-correlated with the morphology and size changes. Unmodified urea crystallised in 99% ethanol produce needle-like crystals whilst addition of 4% of biuret in crystallisation of urea produce a more prismatic crystal shape. At faster cooling rates smaller sized crystals are produced and vice versa. Dispersive surface energy analysis using inverse gas chromatography (IGC) shows that unmodified urea has lower dispersive surface energy than urea modified by biuret. The dispersive surface energy also increases as the cooling rates increased. Both the morphology changes and surface energy measurements are validated using molecular modelling. The morphological prediction intermolecular force calculations of unmodified urea and urea modified by biuret are used to calculate a weighted value for the whole crystals’ dispersive surface energies. The results are in good agreement with experimental results from IGC. The sorption of urea crystals on water moisture showed that unmodified urea samples adsorbed water higher than urea modified by biuret by the observation of the percentage of mass change with respect to the relative humidity. The study of variability within powdered samples was found that no significant different in the unit cell parameters values of each single crystals. The orientation relationship between agglomerated micro-crystalline particles of aspirin showed the agglomerates tend to interact at the faces that have ability to form bonding. In urea samples, most of the agglomerates are mostly aligned due to epitaxy growth of the crystals. The XMT experiment also was carried out on agglomerated α-LGA and the 3-dimensional (3D) shape the samples were obtained.
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Johansson, LarsErik. "Controlled manipulation of microparticles utilizing magnetic and dielectrophoretic forces." Licentiate thesis, Mälardalens högskola, Akademin för hållbar samhälls- och teknikutveckling, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-10544.
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This thesis presents some experimental work in the area of manipulation of microparticles. Manipulation of both magnetic and non magnetic beads as well as microorganisms are addressed. The work on magnetic bead manipulation is focused on controlled transport and release, on a micrometer level, of proteins bound to the bead surface. Experimental results for protein transport and release using a method based on magnetization/demagnetization of micron-sized magnetic elements patterned on a modified chip-surface are presented. Special attention has been placed on minimizing bead-surface interactions since sticking problems have shown to be of major importance when protein-coated beads are used. The work with non-magnetic microparticles is focused on the dielectrophoretic manipulation of microorganisms. Preliminary experimental results for trapping and spatial separation of bacteria, yeast and non-magnetic beads are presented. The overall goal was to investigate the use of dielectrophoresis for the separation of sub-populations of bacteria differing in, for example, protein content. This was, however, not possible to demonstrate using our methods.Within the non-magnetic microparticle work, a method for determining the conductivity of bacteria in bulk was also developed. The method is based on the continuous lowering of medium conductivity of a bacterialsuspension while monitoring the medium and suspension conductivities.
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Simpson, Brian Keith Jr. "Strain engineering as a method for manufacturing micro- and; nano- scale responsive particles." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34728.
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Strain engineering is used as a means of manufacturing micro- and nano- scale particles with the ability to reversibly alter their geometry from three dimensional tubes to two dimensional flat layers. These particles are formed from a bi-layer of two dissimilar materials, one of which is the elastomeric material polydimethylsiloxane (PDMS), deposited under stress on a sacrificial substrate. Upon the release of the bi-layer structure from the substrate, interfacial residual stress is released resulting in the formation of tubes or coils. These particles possess the ability to dramatically alter their geometry and, consequently, change some properties that are reversible and can be triggered by a stimulus. This work focuses on the material selection and manufacturing of the bi-layer structures used to create the responsive particles and methods for characterizing and controlling the responsive nature of the particles. Furthermore, the potential of using these particles for a capture/release application is explored, and a systematic approach to scale up the manufacturing process for such particles is provided. This includes addressing many of the problems associated with fabricating ultra-thin layers, tuning the size of the particles, understanding how the stress accumulated at the interface of a bi-layer structure can be used as a tool for triggering a response as well as developing methods (i.e. experiments and applications) that allow the demonstration of this response.
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Luo, Ye. "Some optical techniques for characterizing micro-scale particles and on-chip plasmonic nanofocusing." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52335.
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The content in the dissertation is divided into two main categories: (1) micro-particle characterization techniques based on elastic light scattering, and (2) ultra-compact on-chip plasmonic light concentration and its applications. For category (1), I developed two techniques, one is in vitro and the other is in the scenario of flow cytometry. I investigated theoretically and experimentally the spectra of scattered light from spherical dielectric particles at certain fixed angles, and demonstrate the linearity between the peak positions in the Fourier domain and the diameter of the particle. Based on this discovery, I demonstrate an efficient and accurate technique for in-vitro micro-particle sizing. Moreover, I theoretically analyzed the far-field elastic scattering signals from micro-particles passing through a flow cytometer with tightly focused incident beams, and established an algorithm to extract size information from the detected signals with higher accuracy than that in conventional flow cytometry systems. For category (2), I proposed an on-chip plasmonic nanofocusing technique whose unit device is a plasmonic triangle-shaped nanotaper mounted upon a dielectric optical waveguide. This structure provides highly efficient and robust light concentration into the tip of the nanotaper. Near-field measurements were performed to thoroughly investigate a fabricated sample and prove the concept. I also proposed theoretically a novel concept named phase-induced local-field configuration with logic behaviors, whose actuators are composite devices built on units of single on-chip plasmonic light concentrators mentioned above.
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Qin, Zhenpeng. "Modeling of Ion Transport for Micro/Nano Size Particles in Coulter Counter Application." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1240858653.
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Gun, S. "Electrohydrodynamic atomization forming of micro and nano-scale magnetic particles for biomedical applications." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1468713/.
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Production of polymeric magnetic micro and nano-particles is a rapidly emerging area in pharmaceutical and biomedical science. In this thesis, the capability of the electrohydrodynamic atomization (EHDA) process for preparing biodegradable polymeric magnetic particles with different sizes was explored. The EHDA processing method offers several advantages over conventional coprecipitation and emulsification techniques for the preparation of magnetic particles. Most significant are the process efficiency and preservation of the iron oxide nanoparticles and/or therapeutic agents functionality, as complex multistep processing involving harsh solvents, additives and elevated temperatures or pressure are avoided. The first part of the thesis describes a detailed investigation of how the size, morphology and shape of the particles generated can be controlled through the operating parameters; specifically the flow rate and applied voltage. The particle diameter was greatly influenced by flow rate and applied voltage. The mean size of the particles changed from1.6µ m to 17.8µm as the flow rate increased from 100µl/min-1 to 400µl/min-1. The research also focuses on the effects of these parameters on the jetting modes of the E H DA process, in particular the con-jet mode operation. Magnetic nanospheres were also produced using single needle processing with mean size of 56nm with a corresponding polydispersivity index of 16%. Nanospheres exhibited a high saturation magnetization at room temperature (67emu/g). Chlorotoxin, a scorpion venom was chosen as the therapeutic agent model because it is non-toxic, non-immunogenic along with other favourable characteristics such as small size high stability and most importantly only binds to tumour cells and not healthy cells. Scorpion venom loaded magnetic microspheres were produced using single needle processing, with a particle size of 2µm. This work demonstrates a powerful method of generating micro and nano magnetic polymeric particles, with control over the size of particles prepared.
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Leong, Hon Sing. "The PAI-1-vitronectin-vimentin ternary complex : mechanism of extracellular assembly and role in transplant vasculopathy." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2509.
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The active state of plasminogen activator inhibitor type-1 (PAI-1) is prolonged when it forms a complex with vitronectin (VN), a major serum protein. Active PAI-1 in the PAI-1:VN complex serves many functions related to fibrinolysis and cell migration but key to these effects is its extracellular distribution. PAI-1:VN complexes can bind to exposed vimentin (VIM) on activated platelet and platelet microparticles, resulting in the assembly of PAI-1:VN:VIM ternary complexes. However, the manner in which the vimentin cytoskeleton is presented extracellularlyi s not well understood.
I hypothesized that PAI-1:VN:VIM ternary complex assembly occurs on cell surfaces when microparticle release leads to exposure of vimentin cytoskeleton which can lead to either assembly of the ternary complex or become involved in an autoimmune response specific for vimentin.
To follow the intracellular and extracellular fate of PAI-1, I constructed an expression vector encoding PAI-1-dsRed, a fluorescent form of PAI-1, which would permit live cell tracking of PAI-1 in megakaryocytes and endothelial cells. Secondly, to study how vimentin is expressed on platelets and platelet microparticles, flow cytometry was used to isolate vimentin positive platelets or PMP's and atomic force microscopy was performed to image platelets or PMP's at nanoscale resolution. From these studies, I propose a model of vimentin expression in which the junction of microparticle release results in the exposure of cytoskeletal vimentin on both the cell and the microparticle. This exposed vimentin could potentially induce VN multimerization on the same cell surface leading to incorporation of multiple PAI-1:VN complexes.
Finally, I investigated how anti-vimentin antibodies can induce platelet:leukocyte conjugate formation. To achieve this, in vitro tests were performed to determine the binding site of anti-vimentin antibodies (AVA's) and how they induce blood cell activation. Overall, my results suggest that vimentin exposure in our model of microparticle release can lead to ternary complex assembly if suitable quantities of PAI-1 are released during platelet activation. In the setting of transplant vasculopathy with high titres of AVA's, vimentin-positive granulocytes can bind these autoantibodies, which then leads to platelet activation and the formation of platelet:leukocyte conjugates.
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Enayati, M. "Electric jet assisted production of micro and nano-scale particles as drug delivery carriers." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1334119/.
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In this thesis, the capability of the electrohydrodynamic atomization (EHDA) process for preparing drug delivery carriers consisting of biodegradable polymeric particles with different sizes and shapes was explored. The first part of the thesis describes a detailed investigation of how the size, morphology and shape of the particles generated can be controlled through the operating parameters; specifically the flow rate, applied voltage and the properties of the solutions. Diameter and shape of the particles were greatly influenced by viscosity and applied voltage. The mean size of the particles changed from 340 nm to 4.4 μm as the viscosity increased from 2.5 mPa s to 11 mPa s. Also, using more concentrated polymer solution (30 wt%) and higher applied voltage (above 14 kV) were found to be ideal for promoting chain entanglement and shape transition from spherical to oblong to a more needle-like shape. Estradiol-loaded micro and nanoparticles were produced with mean sizes ranging from 100 nm to 4.5 μm with an encapsulation efficiency ranging between 65% to 75%. The in vitro drug release profiles of the particles started with an initial short burst phase and followed by a longer period characterised by a lower release rate. Two strategies were developed to tailor these profiles. First, ultrasound was explored as a non-invasive method to stimulate “on demand” drug release from carrier particles. Systematic investigations were carried out to determine the effect of various ultrasound exposure parameters on the release rate in particular output power, duty cycle and exposure time. These three exposure parameters were seen to have a significant enhancing effect upon the drug release rate (up to 14%). The second strategy explored was coating the surface of the particles with chitosan and gelatin. This enabled control and reduction of the prominence ‘burst release’ phase without affecting other parts of the release profile. Coating the particle surface with 1 wt% chitosan solution considerably reduces the initial release by 62%, 60% and 42% for PLGA 2 wt%, 5 wt% and 10 wt%, respectivly in the first 72 hours This work demonstrates a powerful method of generating micro and nano drug-loaded polymeric particles, with modified release behaviour and with control over the initial release.
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Milliez, Anne. "UP-CONVERSION IN RARE-EARTH DOPED MICRO-PARTICLES APPLIED TO NEW EMISSIVE 2D DISLAYS." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3966.
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Up-conversion (UC) in rare-earth co-doped fluorides to convert diode laser light in the near infrared to red, green and blue visible light is applied to make possible high performance emissive displays. The infrared-to-visible UC in the materials we study is a sequential form of non-linear two photon absorption in which a strong absorbing constituent absorbs two low energy photons and transfers this energy to another constituent which emits visible light. Some of the UC emitters' most appealing characteristics for displays are: a wide color gamut with very saturated colors, very high brightness operation without damage to the emitters, long lifetimes and efficiencies comparable to those of existing technologies. Other advantages include simplicity of fabrication, versatility of operating modes, and the potential for greatly reduced display weight and depth. Thanks to recent advances in material science and diode laser technology at the excitation wavelength, UC selected materials can be very efficient visible emitters. However, optimal UC efficiencies strongly depend on chosing proper operating conditions. In this thesis, we studied the conditions required for optimization. We demonstrated that high efficiency UC depends on high pump irradiance, low temperature and low scattering. With this understanding we can predict how to optimally use UC emitters in a wide range of applications. In particular, we showed how our very efficient UC emitters can be applied to make full color displays and very efficient white light sources.Ph.D.
Other
Optics and Photonics
Optics
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Horie, Rie. "Treatment of inner ear disorders using nano/micro particles based on drug delivery system." Kyoto University, 2011. http://hdl.handle.net/2433/142087.
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Grant, Neil Cameron. "Emulsion templating as a route to the release of organic micro- and nano- particles." Thesis, University of Liverpool, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569572.
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Many useful organic molecules such as drugs are poorly soluble in water. Novel ways of the deployment of these molecules are as stable nanodispersions. In our research we aim to produce a method for the creation of nanoparticles via a technique called emulsion-evaporation. These techniques include the creation of emulsions, ~olymerisation and A.,. .•••• ,. • freeze-drying. The production of these nanoparticles in-situ with templated porous polymers by these techniques was used. This avoids the problem of nanoparticle aggregation. These nanoparticles can be released into an aqueous medium by diffusing out of the porous scaffold or by a stimuli-sensitive trigger. We describe here the preparation of porous poly N-isopropylacrylamide. The swelling of the polymer and contraction above a solution temperature were explored for the uptake and release of polymeric colloids. The thesis discusses the application of readily soluble aqueous nanodispersions prepared by using a polyvinyl alcohol/sodium dodecyl sulphate (PVA/SDS) monolith prepared by emulsion templating. The monoliths can be prepared with the in-situ formation of drug nanoparticles which, readily solubilises the drug as nanodispersions. The thesis continues to explore stimuli as a method for the release of the organic nanoparticles: a chitosan based emulsion templated monolith was prepared which can release the formed nanoparticles from the scaffolds via control of pH. Finally, the use of a disulphide crosslinked polymer was explored for the release of organic nanoparticles. The particles could be released from the polymer by using a disulphide bond "cleaver" which degrades the polymer and thus releasing the internal organic nanoparticles. ii
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Ferrante, Francesco. "Antisolvent Precipitation of L-Asparagine in a Commercial Micromixer." Thesis, KTH, Skolan för kemivetenskap (CHE), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-146310.
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A commercial valve-assisted micromixer, manufactured by Ehrfeld (Germany), was tested for its use to precipitate L-asparagine from an aqueous solution using isopropanol as antisolvent. In a first part the mixing quality provided by the micromixer was studied by means of a competitive/parallel set of reactions following the approach of Baldyga, Bourne and Walker, Canadian J. Chem. Eng. 76 (1998) 641-649. Different experiments have been implemented and interpreted considering the average of Reynolds number of the inlet streams. Results show a good mixing quality that is comparable, in terms of absolute values of conversion, with other works present in literature. The precipitation experiments that followed revealed the limitation of the micromixer. The system was instable and particles adhesion occurred inside the mixing chamber. Improvements have been realized by changing the spring tension of the valve and introducing a commercial surfactant TRITON X-100.
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Muppalla, Harish. "Highly hydrophilic electrospun fibers for the filtration of micro and nanosize particles treated with coagulants." Thesis, Wichita State University, 2011. http://hdl.handle.net/10057/5191.
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Electrospinning has been widely used in the last decade for research in the field of nanotechnology because of its ability to create sub-micron to nanoscale fibers. In this research work, hydrophilic nanofiber membranes were produced by using the electrospinning process at three different spinneret distances (20 cm, 25 cm, and 30 cm) utilizing a polymeric solution of polyvinyl chloride (PVC) incorporated with polyvinylpyrrolidone (PVP) at different weight proportions ranging from 2% to 5%. Water contact angle values were measured for all of the membranes, and it is observed that membranes produced by maintaining a spinneret distance of 30 cm resulted in a lower contact angle in comparison with other spinneret distances. At the spinneret distance of 30 cm, the 2% and 3% PVP membranes exhibited hydrophobic properties. At 5%, PVP membranes exhibited that of a super hydrophilic nature. The membranes produced at 4% PVP showed the desired hydrophilic nature, which were utilized for the filtration process. Three water samples were selected for the filtration experiments including: lake water, abrasive particles from a water jet cutter, and magnetite nanoparticles. The main concentration of the current research work was to create highly hydrophilic nanofiber membranes and utilize them to filter water at an optimal level of purification (i.e., drinking water). In order to overcome the fouling property of the membrane, coagulation, which enhances the efficiency of the membrane in the removal of colloidal particles, was used as a pre-treatment process. Two coagulants, Tanfloc and Alum, were used during the coagulation process. The removal efficiency of the suspended particles in liquid was measured in terms of turbidity, pH, and total dissolved solids (TDS). It was observed that the coagulation/filtration experiments have shown higher efficiency in the removal of turbidity in comparison with the direct filtration process.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
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Penon, Esteva Oriol. "Synthesis and functionalization of nano- and micro-particles for sensing and therapy in living cells." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/132676.
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In the present thesis Supramolecular chemistry is exploited to approach applications in the area of Nanomedicine, and it is, focused on the design and preparation of different micro and nanotools for sensing and therapy, in living cells. Initially, the combination of silicon surface chemistry with the incorporation of bioactive molecules has been investigated in order to obtain a potentially microtool suitable for cell tagging. Furthermore, the design and synthesis of organic compounds as intracellular chemosensors was also explored. On the other hand, this report also includes the synthesis and characterization of dissymmetrical porphyrin derivatives and their subsequent incorporation to metal nanoparticles (gold and iron oxide) for their use in photodynamic therapy (PDT), due to their capacity to produce reactive oxygen species after irradiation, inducing the cell death. The preparation of novel metallo-porphyrins as components of molecular machines was also achieved.
First, the formation of self-assembled monolayers (SAM) on polysilicon surfaces was investigated, using different silanes to obtain a functionalization protocol which can be easily repetitive and effective. Thus, three silanes with different functional groups, an aldehyde, an epoxide and an activated ester, have been tested to prepare a SAM and subsequently, prompting us to immobilize a bioactive molecule. Different parameters of the functionalization methodology have been examined, such as the silanization time, deposition method, the type of solvent and silane concentration. Once the SAM formation was optimized, the immobilization of the protein what germ agglutinin (WGA) was achieved, because its ability of cell membrane recognition. The WGA used, included a fluorescent dye (Texas red) to be able to characterize the immobilization of the protein on a silicon surface by fluorescence microscopy, and similar successful results were obtained in the three different silanes used. The same methodology (SAM formation and WGA immobilization) was subsequent applied in silicon encoded microparticles designed for tagging cells. Experiments using mouse embryos have been performed to determine the extracellular adhesion level of the encoded microparticles, resulting above 90 % in all cases. Proper immobilization of WGA protein was the key factor in cell labeling, because WGA recognizes specifically certain carbohydrates expressed in the external membrane (zona pellucida) of the embryo.
Synthesis and immobilization of an aminoanthracene derivative as pH sensor was carried out, and its subsequent immobilization on silicon microparticles was achieved. Fluorescence spectroscopy measurements demonstrated that the aminoanthracene derivative immobilized on silicon microparticles could be a potential microtool for sense intracellular pH. Fluorescence spectroscopy experiments showed an important increase at acid pH, whereas from pH 7 to pH 12 the fluorescence emission was very low. On the other hand, aminoanthracene incorporating an aza-crown ether was also prepared as a possible candidate for calcium sensing. Preliminary studies using fluorescence spectroscopy, demonstrated a good selectivity for calcium in comparison with other cations such as magnesium, sodium and potassium.
Dissymmetrical porphyrin derivatives have been synthesized and then immobilized on gold and iron oxide nanoparticles, obtaining water soluble metallic nanoparticles incorporating the photosensitizer. The capacity to produce singlet oxygen to induce the cell death following irradiation was investigated, resulting porphyrin immobilized gold or iron oxide nanoparticles. Thus, the prepared porphyrin derivatives and their corresponding nanotools exhibited a high formation of singlet oxygen, resulting nanotools potentially suitable for PDT. Otherwise, anti-erbB2 antibody, a specific antibody for a membrane receptor overexpressed in breast cancer cells, was immobilized onto water soluble porphyrin-gold nanoparticles. Preliminary experiments in a breast cancer cell line, demonstrated the capacity of the porphyrin-antibody-gold nanoparticle to produce the cell death following irradiation. Finally a metallo-porphyrins derivative was synthesized and characterize as a promising component for molecular rotors.El diseño y la preparación, mediante la utilización de procesos de biofuncionalización de micro / nanosistemas que puedan tener aplicación en células vivas es un tema de actualidad en campos como la Nanobiotecnología y la Nanomedicina. De este modo, en la presente tesis se ha estudiado el proceso de biofuncionalización de micropartículas de polisilicio, para actuar como etiquetas celulares, debido al interés que genera la posibilidad de poder etiquetar células vivas y así conocer el comportamiento de las células de manera individual. Sucesivamente, también se ha estudiado la preparación de quimiosensores de dos parámetros intracelulares (pH y calcio) basados en compuestos con capacidad de variar la intensidad de su fluorescencia, según cambios del medio. Concretamente, se ha trabajado en la síntesis e inmovilización de derivados del aminoantraceno en micropartículas de silicio como posibles candidatos para obtener microherramientas capaces de detectar cambios en el pH o en la concentración de calcio intracelulares. Por otro lado, la tesis también describe la preparación de nanosistemas para su aplicación en terapia fotodinámica. La terapia fotodinámica (PDT) se basa en el uso de moléculas específicas (fotosensibilizadores), que en presencia de luz (generalmente un láser), activan el proceso de la muerte celular debido a la formación de radicales libres de oxígeno. La combinación de la utilización de nanopartículas modificadas con un fotosensibilizador resulta un reto interesante que podría mejorar la terapia antitumoral, disminuyendo sus efectos secundarios. Concretamente, en la tesis se describe la preparación de nuevos fotosensibilizadores derivados de porfirinas, con el fin ser incorporados a nanopartículas de óxido de hierro y de oro. También se detalla el estudio de la capacidad de los nuevos nanosistemas obtenidos de producir oxígeno singlete como elemento inductor de la apoptosis celular, y resultados preliminares in vivo indican su potencial aplicación en PDT. Estos estudios, demuestran la posibilidad de dichos nanosistemas para ser usados en terapia fotodinámica. Por último, también se han sintetizado derivados de metalo-porfirinas como componentes de rotores moleculares.
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Bodnár, Eszter. "Electrospraying of polymer solutions for the generation of micro-particles, nano-structures, and granular films." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/379820.
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S'ha realitzat un estudi sobre els mecanismes de formació de micropartícules polimèriques i les seves pel•lícules granulars, a partir de l'assecat de microgotes de electrosprays. L'estudi se centra en diferents solucions de tres polímers insolubles en aigua: polimetil(metacrilat), poliestirè, i etil cel•lulosa. L'assecat d'aquests electrosprays dóna lloc a diverses morfologies de partícula, que han estat determinades mitjançant microscòpia d'escombrat electrònic, i han estat caracteritzades en funció del solvent, concentració del polímer, el seu pes molecular, i la humitat relativa ambient. Les morfologies obtingudes inclouen una varietat d'estructures de partícula globulars i filamentoses, que, a humitat relativa elevada, poden desenvolupar porositat. Aquestes característiques morfològiques han estat explicades mitjançant models qualitatius que involucren fenòmens fluid dinàmics i sobre separació de fases, presents en sistemes relacionats amb els estudiats. Un dels fenòmens fluid dinàmics involucrats clau són les inestabilitats coulòmbiques de gotes elèctricament carregades. A més, la interacció de no solvent de l'aigua en la precipitació del polímer pot donar lloc a textures poroses sobre la superfície de les partícules. Les diferents formes de textura han estat explicades en referència als fenòmens de breath figure formation (BFF), i a la inversió de fases induïda per vapor (vapor induced phase separation, o VIPS). També hem estudiat el creixement de les pel•lícules granulars formades a partir de les partícules polimèriques. Demostrem que la càrrega elèctrica transportada per les partícules cap a la pel•lícula influeix fortament en la dinàmica de creixement d’aquesta. Un millor coneixement dels mecanismes estudiats en aquesta tesi hauria de permetre dissenyar nous processos de manufactura de partícules i recobriments basats en electrospray.
Se ha realizado un estudio sobre los mecanismos de formación de micropartículas poliméricas y sus películas granulares, a partir del secado de microgotas de electropras. El estudio se centra en diferentes soluciones de tres polímeros insolubles en agua: polimetil(metacrilato), poliestireno, y etil celulosa. El secado de estos electrosprays da lugar a diversas morfologías de partícula, que han sido determinadas mediante microscopía de barrido electrónico, y han sido carSe ha realizado un estudio sobre los mecanismos de formación de micropartículas poliméricas y sus películas granulares, a partir del secado de microgotas de electropras. El estudio se centra en diferentes soluciones de tres polímeros insolubles en agua: polimetil(metacrilato), poliestireno, y etil celulosa. El secado de estos electrosprays da lugar a diversas morfologías de partícula, que han sido determinadas mediante microscopía de barrido electrónico, y han sido caracterizadas en función del solvente, concentración del polímero, su peso molecular, y la humedad relativa ambiente. Las morfologías obtenidas incluyen una variedad de estructuras de partícula globulares y filamentosas, que, a humedad relativa elevada, pueden desarrollar porosidad. Estas características morfológicas han sido explicadas mediante modelos cualitativos que involucran fenómenos fluido dinámicos y sobre separación de fases, presentes en sistemas relacionados con los estudiados. Uno de los fenómenos fluido dinámicos involucrados clave son las inestabilidades coulómbicas de gotas eléctricamente cargadas. Además, la interacción de no solvente del agua en la precipitación del polímero puede dar lugar a texturas porosas sobre la superficie de las partículas. Los diferentes tipos de texturas han sido explicadas en referencia a los fenómenos de breath figure formation (BFF), y a inversión de fases inducida por vapor (vapor induced phase separation, o VIPS). También hemos estudiado el crecimiento de las películas granulares formadas a partir de las partículas poliméricas. Demostramos que la carga eléctrica transportada por las partículas hacia la película influye fuertemente en la dinámica de crecimiento de ésta. Un mejor conocimiento de los mecanismos estudiados en esta tesis debería permitir diseñar nuevos procesos de manufactura de partículas y recubrimientos basados en electrospray.
A study has been made of the mechanisms underlying the formation of polymeric microparticles and of their granular films, by drying of electrospray microdroplets. The study is focused on different solutions of three water-insoluble polymers: polymethyl(methacrylate), polystyrene, and ethyl cellulose. The drying of such electrosprays result in diverse particle morphologies, which have been determined by scanning electron microscopy, and have been characterized as a function of the solvent, polymer concentration, polymer molecular weight, and ambient relative humidity. The morphologies obtained include a variety of globular and filamented particle structures, which, at elevated relative humidity, can develop porosity. These morphological features have been explained using qualitative models involving fluid dynamic and phase separation phenomena which are known to occur in closely related systems. One of the key fluid dynamic phenomena involved is the coulombic instability of electrically charged droplets. In addition, the non-solvent interaction of water on the precipitation of the polymer can lead to porous textures on the particles surfaces. The different kinds of textures have been explained by reference to breath-figure formation (BFF) and vapor induced phase separation (VIPS) phenomena. We have also studied the growth of the granular films of such polymer particles. We show that the electrical charge transported by the particles to the film have a strong influence on the film growth dynamics. The better understanding of the mechanisms studied in this thesis, should help design new manufacturing processes of particles and coatings based on electrospray.
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Campbell, Andrew Lee. "Fabrication of novel functional anisotropic micro-particles for foam stabilisation and structuring in food formulations." Thesis, University of Hull, 2009. http://hydra.hull.ac.uk/resources/hull:2488.
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This thesis is concerned with the fabrication of novel food-grade anisotropic solid particles for foam stabilisation and applications in food formulations. Two main techniques were employed for the fabrication of these particles. Acidic hydrolysis of Nata de Coco bacterial cellulose was used to form cellulose nano-rods which were applied as a foam scaffolding material. Characterisation and modification of Nata de Coco nano-rods was also carried out. It was found that cellulose nano-rods modified with a surface layer of ethyl cellulose exhibited good foamability.Secondly, a combination of in-shear-flow dispersion and solvent attrition techniques were employed to form micro-rods from the edible polymeric materials shellac, ethyl cellulose and zein. Characterisation of the properties of shellac, ethyl cellulose and zein micro-rods was carried out, together with assessments of their foam stabilisation ability. Stable aqueous foams were produced using shellac, ethyl cellulose and zein micro-rods as stabilisers, and ethyl cellulose micro-rods were also used to form water-in-oil emulsions.An extension of this technique was used in the fabrication of novel functional anisotropic food-grade micro-rods with micro-particle inclusions giving altered morphology. Enhanced foamability and drainage retardation was achieved using lumpy yeast-shellac micro-rods to stabilise aqueous foams. The method was extended to the production of aqueous dispersions of ballooned micro-rods, formed by two different protocols.This procedure also allowed the formation of novel, dual-function micro-rod capsules or ‘micro-ampules’ for stabilisation and encapsulation by inclusion of oils into the dispersed phase prior to micro-rod fabrication. The oils became trapped within the micro-rods resulting in micro-ampules with a range of morphologies which were characterised by fluorescence doping and microscopy.
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Pai, Jay-Min, and 白杰民. "Manipulation of Micro-magnetic Particles Numerical Study." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/24346781063133760137.
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Sheu, Shih-Tsung, and 許世璁. "Manipulation of Micro-magnetic Particles Experimental Study." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/21197829867640380863.
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Yin-CheChien and 簡胤哲. "Stochastic Resonance in Visual Manipulation of Micro Particles." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19224986901685795685.
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碩士國立成功大學
機械工程學系碩博士班
101
Stochastic resonance is a phenomenon of enhancing the signal response by adding noise. Stochastic Resonance is widely used in 1-D signal processing. After researchers' dedicating to their study, they found that the phenomenon also can be applied to 2-D image processing. In this thesis, DSR-DWT (Dynamic stochastic resonator with discrete wavelet transform) method is used to enhance the contrast of the low contrast image such that the focus plane can be obtained by calculating conventional focus function. Results of present research revel that the focus quality by utilizing DSR-DWT method is better than not used. Then, SSR (Suprathreshold stochastic resonator) method is used to improve the gradient image by Sobel operator for edge detection. This approach can improve the performance of edge detection. The edge detection algorithm together with circular Hough transformation is employed for tracking moving micro-particle. The present research finally achieves the goal of auto-focusing, tracking and pushing the 30 to 50 μm micro-particle.
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Pan, Jia-Cheng, and 潘家成. "Study of Micro Particles Manipulation on Electrodeless Dielectrophoresis Chip." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/93177437931092406593.
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碩士義守大學
機械與自動化工程學系碩士班
98
Several kinds of physical forces have been successfully employed for particle trapping and manipulation in the last decades. Among these methods, dielectrophoretic approach has become a promising technology to apply onto the micro-total-analysis-system (μTAS). Some disadvantages of traditional DEP applications using microelectrodes include fouling and destruction of the microelectrodes due to large current densities. Hence, EDEP has been used to trap different species of bacteria or single- or double-stranded DNA and to separate particles according to their size. Currently, these AC electro-kinetic phenomena are interested because they can be used for the characterization and manipulation of bacterial and cells. Among these applications, trapping and characterization of biological particles is one of the fundamental procedures in clinical fields. In this study, we are going to present the development of a continuous-flow based on electrodeless dielectrophoresis (EDEP) techniques to trap the micropartilces for high throughput and sensibility. The sample trapping of EDEP devices is composed of two triangular insulated structures and a microchannel onto the micro-chip. This work also examines the driving frequency effects of operating conditions on the behaviors of micro polystyrene microparticles under EOF and DEP circumstance. The results of the experiment investigated the characteristic factors of the driving potential and frequency can be defined that capture the effects of constrictions in the channel and that modulating the domination of the resulting local EOF and DEP force. Furthermore, EOF transported mechanism can be used to pump the bidiection flow to enhance bio sample concentration region by adjusting the driving frequency. Similarly, DEP can be used to trap and preconcentrate bio-sample near the constriction by using the optimum frequency. Finally, the EDEP chip will be successfully demonstrated to enhance the performance of trapping bio-sample. These findings will allow improving the performance of EDEP microdevices achieving the highest trapping effect.
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Huang, Cheng-Hsuan, and 黃政瑄. "Electrophoretic Motion of Colloidal Particles in a Micro/Nanochannel." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/92685206748285429722.
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博士國立臺灣大學
化學工程學研究所
100
General microfluidic and nanofluidic electrokinetics in a cylindrical channel is investigated in this project, which emphases the electrophoresis and electroosmosis of a spherical non-rigid colloidal particle, including soft composited particles, porous particles, and droplets. Both spherical and cylindrical coordinates are adopted to describe the physical systems. General electrokinetic equations are employed and solved with a pseudo-spectral method based on Chebyshev polynomials and Newton-Raphson schemes. Traditional studies of electrophoresis have been focused on characteristics of the particle, such as the surface potential of particles, the fixed charge density and homogeneous frictional force on polymer layers, and the viscosity ratio of microemulsions, and so on. Thanks to the advances of the micro-/nanofabrication technology, microdevices with even smaller features can be produced now and the electrokinetic technique can be further downscaled to tens or hundreds of nanometers, allowing manipulation of even smaller colloidal particles. Therefore, it is essential to consider aforementioned electrokinetic phenomena to develop a comprehensive transport model of molecules in micro-/nanofluidic channels. We found, among other things, that the higher the particle surface potential or the fixed charge density of the polymer layer, the more serious distortion of the ion clouds, which generates an induced electric field opposite to the particle motion, thus reducing the electrophoretic velocity. This phenomenon can be enhanced by the presence of a nearby channel. The particle mobility is found to decrease as the permeability of the porous layer decreases and exhibit an extreme value in the profile with varying double-layer thickness. Furthermore, the confinement effect of the fluidic channel can be so drastic when double-layer thickness is thick, however vanishing when the thickness is thin. In particular, an intriguing phenomenon is observed for the highly permeable particle: The narrower the channel is, the faster the particle moves! The reason behind it is thoroughly explained here. Moreover, as the fluidic channel is quite narrow, that the lowly charged droplet may move faster than the highly one! Finally, charged channels can exert electroosmosis flow so dominant that sometimes it may even reverse the direction of the particle motion. This has direct impact in practical applications of nanofluidics when a weak electric field is applied. Conducting operations near these critical double-layer thicknesses should be avoided in practice
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Hsu, Li-Chung, and 許力中. "Optical Manipulation of Micro-particles on Integrated Photonic Devices." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/23420788958533798101.
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碩士國立清華大學
光電工程研究所
101
In this thesis, we present the design and fabrication of directional couplers and multi-mode interferometers (MMI) for realizing micro-particle transport and switch through optical force. The evanescent field of the integrated photonic devices is able to propel a micro-particle to flow and control the trajectory of particle movement, according to the optical field distributed within the devices. By launching the TM polarized laser at the power of 50mW, the micro-particles can be transported to different output ports by selecting wavelengths between 1540nm and 1550nm. Optical force acting on the micro-particle is calculated by MATLAB, and the field of force is used for optical manipulation. Coupling lengths of directional coupler and MMI as a function of optical wavelengths are also analyzed by MATLAB and confirmed by experiments. It shows that the calculated coupling length agrees well with the results of experiments, where the trajectory of the micro-particle follows the optical interference pattern in the photonic device.
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Yi-WeiChen and 陳奕維. "Trapping of micro-sized particles by vortex laser beams." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/9uq6nx.
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碩士國立成功大學
物理學系
102
The thesis is divided into three parts. Firstly, a q-plate is produced based on dye-doped liquid crystal (DDLC) cell using the photoalignment technique. Then the q-plate is used to produce a vortex beam verified using a Michelson’s interferometer. In the second part, we construct an optical tweezers system. Finally, the trapping of the micron-sized particles with different refractive index is investigated using the vortex-beam optical tweezers system. The results show that the manipulation of particles of the vortex-beam optical tweezers is significantly affected by the q-value of a q-plate. The smaller the q-value is, the longer distance of the particle can be moved and trapped by the tweezers. Also, regardless of the refractive index, the particle is trapped in a similar location by the vortex beam.
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Wu, Kuan-I., and 吳冠毅. "Motion of the micro-particles in the optoelectronic tweezers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/96f472.
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碩士國立交通大學
光電系統研究所
103
Many techniques have been developed to manipulate micrometer-scale particles and biological cells in recent years, such as magnetic tweezers, optical tweezers, dielectrophoresis (DEP) and optoelectronic tweezers (OET). Among them, the OET system has emerged as a powerful technique for dynamic and massively parallel manipulation of particles. The operational principle of the OET device is to produce an optically controlled DEP force generated by the high-resolution patterning of electric fields on a photoconductive surface for manipulating single particles. In this work, we demonstrated the manipulation of 20 μm polystyrene beads in the de-ionized water solution by using OET. The optically controlled DEP force was adjusted by changing the driving frequency and the permittivity and the conductivity of the de-ionized water. The DEP force can be calculated in advance as long as the permittivity and the conductivity of the polystyrene beads and the de-ionized water are known. We also found that the polystyrene beads travel in the Z-axis direction of the cell from the observation of their motion. The manipulation of particles in three dimensional spaces can improve the performances and widen the applications of the OET.
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Barbosa, Ana Sofia Oliveira Queiroz Ferreira. "Improved toughness of adhesives filled with cork micro particles." Tese, 2017. https://repositorio-aberto.up.pt/handle/10216/103840.
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Hsieh, Hui-Ling, and 謝蕙蔆. "Synthesis and Characterization of Nanoparticles-Embedded Polystyrene Micro Particles." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46913419413289346116.
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碩士國立臺灣科技大學
化學工程系
103
This work points to a relatively easy and convenient two-step process for the sequential synthesis of iron-coating carbon nanoparticles (Fe0@C) and of polystyrene (PS) microparticles with samarium(Ⅲ) oxide (Sm) and Fe0@C. Fe0@C was synthesized by the chemical reduction method and hydrothermal carbonization method at different ratios of FeCl3‧6H2O and citric acid. The result showed that the ratio of [FeCl3‧6H2O]: [Citric acid] = 1: 5 was better than the others, since iron nanoparticles were homogeneously dispersed in carbon matrix and can be attracted by magnet. PS microspheres were synthesized by suspension polymerization in water system. The morphology of polystyrene microspheres was observed using optical microscopic and scanning electron microscopic (SEM) studies. When 2,2-azobis-isobutyronitrile (AIBN) of 10 mg was chosen, the PS particles were large in number and were observed as a sphere with a narrow size distribution. Materials of Sm, PS and Fe0@C were mixed to synthesize PS/Sm and PS/Sm/Fe0@C by polymerization. In thermal gravimetric analysis (TGA), the weight loss curve of PS/Sm showed that after 450 °C, the PS was burned off and PS/Sm weight remained 6.1 %, attributed to the Sm. The morphology of PS/Sm/Fe0@C was similar between optical microscopic images and SEM images. The PS/Sm/Fe0@C particles had a diameter between 20~50 μm, but the smaller particles with amorphous shape coexisted. According to the research results, PS/Sm/Fe0@C particles should be suitable for using cancer therapy and deliver it to the tumors via its blood supply.
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Huang, Chih-Yu, and 黃智祐. "Design and Fabrication of Dielectrophoresis Micro-Particles Sorting Chip." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/15764596639830886935.
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碩士國立屏東科技大學
生物機電工程系所
100
The purpose of the study is expected to design and fabrication a dielectrophoresis micro-particles sorting chip. We change the particle routes by dielectrophoresis (DEP) force to shifting, sorting, focus or taking in the mixed particles buffer. In the experiment, we design the tilting interdigitated electrodes to sort the target particle, the double curved electrodes to focus the target particle, and the catellated electrodes to take the target particle that using software CFD-RC to simulate the electric field strength and density of the electrodes edges. Using MEMS process we fabricate the electrodes of dielectrophoresis chip, and using SU-8 and PMMA we fabricate protruding channel model to reproduction by PDMS. In the particle experiment, the chip using the castellated electrodes arranged in staggered is inputted voltage AC 20V to find out the conditions of 3μm size Latex under different DEP force by AC frequency scanning techniques. The n-DEP force is effected on the particles in the different electrodes area fit crossover flow rate be Good working efficiency when we input the voltage AC 20V and AC frequency 1M Hz. Through using particles separate testing parameter, we can filter out the separate parameter of 1μm and 3μm Latex mixed particles. Hopefully dielectrophoresis micro particles sorting chip can be applied for technique which are used in the field of cell and microbiology for the examining and technology skills in the future.
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Yu-ChengChien and 簡佑丞. "Visual Servo for Tracking Micro Particles in Liquid Environment." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/34216186256371404986.
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Barbosa, Ana Sofia Oliveira Queiroz Ferreira. "Improved toughness of adhesives filled with cork micro particles." Doctoral thesis, 2017. https://repositorio-aberto.up.pt/handle/10216/103840.
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