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Air-core microcavities and metal-dielectric filters - building blocks for optofluidic microsystemsAllen, Trevor W. Unknown Date
No description available.
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SAW-basierte, modulare Mikrofluidiksysteme hoher FlexibilitätWinkler, Andreas 13 March 2012 (has links) (PDF)
Diese Dissertation beschäftigt sich mit der Entwicklung eines neuartigen Konzepts für Herstellung und Handhabung von Mikrofluidiksystemen auf der Basis akustischer Oberflächenwellen (SAW) sowie der Nutzung dieses Konzepts zur Fertigung anwendungsrelevanter Teststrukturen. Schwerpunkte sind dabei unter anderem eine hohe Leistungsbeständigkeit und Lebensdauer der Chipbauelemente und eine hohe technologische Flexibilität bezüglich Herstellung und Einsatz. Ausgehend von einer modularen Betrachtungsweise der Bauelemente wurden vielseitig einsetzbare, elektrisch-optimierte Interdigitalwandler entworfen, verschiedene Herstellungsvarianten für vergrabene Interdigitalwandler hoher Leistungsbeständigkeit auf piezoelektrischen Lithiumniobat-Substraten entwickelt und experimentell verifiziert, ein Sputterverfahren für amorphe SiO2-Dünnschichten hoher Qualität optimiert und eine Federstiftkontakt-Halterung entworfen. Durch Kombination dieser Technologien wurden SAW-Bauelemente für die mikrofluidische Aktorik mit hoher Performance und Reproduzierbarkeit entworfen, charakterisiert und beispielhaft für das elektroakustische Zerstäuben von Fluiden und das Mischen in Mikrokanälen eingesetzt.
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Label-Free Measurements of Amyloid Formation by Suspended Microchannel ResonatorsWang, Yu 15 January 2014 (has links)
No description available.
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Particle interactions in a magnetophoretic systemOduwole, Olayinka January 2016 (has links)
The continuous flow separation of magnetic particles from a mixture of particles could improve the performance of magnetic bead based assays but the formation of agglomerates limit the separation efficiency. Bead agglomerates are formed as a result of magnetic binding forces while the hydrodynamic fluid environment strongly influences their movement. The ability to predict the interaction between nearby beads will help to determine a threshold separation distance which will be recommended for use when obtaining measurement within a magnetic bead assay for a specified time interval. The introductory part of this thesis explored the development of a two dimensional numerical model in Matlab which predicts the trajectory pattern as well as magnetic induced velocities between a pair of super-paramagnetic beads suspended in water within a uniform field. The movement of a bead pair interacting due to both magnetic and hydrodynamic forces within a magnetophoretic system was recorded using an optical system; the beads' movements were compared with the simulated trajectories and gave a good agreement. The model was used to predict the shortest agglomeration time for a given separation distance which is of practical benefit to users of bead based assays. The concluding part of this thesis expanded the simulation into a three dimensional model to predict the interactions among three super-paramagnetic beads within a magnetophoretic system. In order to determine the height of the magnetic beads, a Huygens-Fresnel model was implemented in Matlab which was compared with off-focused diffracted images of the beads viewed under an optical system. A good comparison was obtained by comparing the simulated three-dimensional trajectories with experimental data.
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Strain-engineering of thin polymer films : a novel route for the development of functional materials and microfluidic devices / Ingénierie des contraintes de films minces de polymères : une nouvelle voie pour le développement de matériaux fonctionnels et d'outils microfluidiquesEgunov, Aleksandr 23 November 2015 (has links)
Les deux systèmes de création d’une contrainte dans les films polymériques ont été développés, chacun répondant à un gradient de gonflement du polymère dans la direction normale au film. Ce gonflement peut être provoqué soit par la présence d’un gradient de densité de réticulation dans la direction normale à la surface (films de poly(4-vinylpyridine) réticulés par UV ou dans les films de chitosan réticulés thermiquement et ioniquement ; ou soit par une pénétration asymétrique de vapeur de solvant dans le film (ici le polydiméthylsiloxane oxydé en surface). Un troisième système polymérique auto-enroulant a également été réalisé par la création d’une contrainte permanente au sein du film de polydiméthylsiloxane, grâce à l’extraction sélective d’un additif non-réticulé, l’huile de silicone. Un modèle théorique du processus d’auto-enroulement, basé sur la théorie linéaire d’élasticité a ainsi pu être proposé. / Two systems of stress creation in the polymer films were developed, each based on the swelling gradient in the direction normal to the film. This swelling may be caused either by the presence of a crosslinking density gradient in the direction normal to the surface (poly (4-vinylpyridine film) crosslinked by UV or in the thermally or ionically crosslinked chitosan films; or by asymmetric penetration of solvent vapor in the film (here polydimethylsiloxane surface-oxidized). A third self-rolling polymeric system has also been realized by the creation of a permanent strain in the polydimethylsiloxane film by selective extraction of a non-cross-linked additive, silicone oil. A theoretical model of self-rolling process based on the linear theory of elasticity has been proposed.
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Modelagem de microbomba peristaltica de elastomero usando a tecnica de analogias eletro-mecanicas / Modeling peristaltic micropump with electro-mechanical analogiesEspindola, Alexey Marques 24 February 2006 (has links)
Orientador: Luiz Otavio Saraiva Ferreira / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-06T16:27:32Z (GMT). No. of bitstreams: 1
Espindola_AlexeyMarques_M.pdf: 1293939 bytes, checksum: 66ab2d16dc552294762d6c3708cda71b (MD5)
Previous issue date: 2006 / Resumo: Os sistemas microfluidicos estão evoluindo rapidamente, encontrando vastas aplicações na mais diversas áreas do conhecimento. Os Lab-on-Chips, LOCs, são dispositivos capazes de realizar análises químicas e bioquímicas em um único chip. Este dispositivo pode causar grande impacto no mercado de análises laboratoriais, por este motivo vem ganhando grande atenção Para realizar estas análises os LOCs necessitam de microbombas capazes de transportar quantidades ínfimas de fluidos em seus canais de maneira acurada e uniforme. Desta forma, o interesse em modelar e fabricar microbombas tomou-se uma área fértil para a pesquisa. Neste trabalho foi desenvolvida a modelagem de uma microbomba peristáltica de elastõmero, tipo de bomba mais conveniente para Lab-on-Chips, utilizando a técnica de analogias eletro-mecânicas que consiste em representar um dispositivo por um circuito elétrico equivalente. As análises das simulações podem ser realizadas usando programas de análise de circuitos elétricos. Dois modelos foram apresentados neste trabalho. O primeiro é a reprodução do modelo de bomba criado por Jacques Goulpeau, em que o modelo de uma válvula é extrapolando para toda a microbomba. O segundo contém o circuito elétrico equivalente da bomba completa mostrando a interações entre suas partes. Os resultados mostram que o comportamento da microbomba não pode ser completamente descrito pelo modelo extrapolado a partir de uma válvula, devido às interações entre três válvulas. As simulações do circuito equivalente da bomba completa mostraram que os efeitos das interações entre as válvulas explicam claramente a diferença entre a vazão prevista pelo modelo de Goulpeau e os dados experimentais por ele obtidos, sendo possível ajustar o modelo aos dados experimentais / Abstract: Microfluidies systems are growing rapidly, finding a large nwnber of applications in many fields. Lab-on-ehips, LOC, are deviees that ean perform ehemical and biochemical analyses in a ehip. This device ean cause high impact on laboratorial analyses market, and then it is gaining large attention. In order to execute these analyses on LOC, mieropumps are necessary to transport a tiny quantity of fluid between the channeIs with accuracy and uniformity. Thus, the interests of modeling and fabrication mieropwnps are increasing and become a fertile research field. The goal of this work were a modeling of elastomer peristaltic micropwnp, the most suitable pwnp for LOCs, using the electro- mechanical analogy technique that consist in represent the device in a electrical equivalent networks. Then the simulation analyses can be done on electrical simulation tools. Two models were presented in this work. The first is reproduction of the pwnp model made by Jacques Goulpeau et aI., where the valve model is extrapolated to the whole mieropwnp. The second contains the electrical equivalent circuit that represents the whole device showing the interactions between its eomponents. The results showed that micropump behavior eouldn't completely deseribe by the extrapolated model ftom a valve, because the interactions between the three valves. The simulations of electrical equivalent eircuit of the whole pwnp showed that the interaction between the valves explain the difference between of flow rate foreseen by Goulpeau model and his experimental data, being possible to adjust the model to the experimental data / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica
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SAW-basierte, modulare Mikrofluidiksysteme hoher FlexibilitätWinkler, Andreas 24 November 2011 (has links)
Diese Dissertation beschäftigt sich mit der Entwicklung eines neuartigen Konzepts für Herstellung und Handhabung von Mikrofluidiksystemen auf der Basis akustischer Oberflächenwellen (SAW) sowie der Nutzung dieses Konzepts zur Fertigung anwendungsrelevanter Teststrukturen. Schwerpunkte sind dabei unter anderem eine hohe Leistungsbeständigkeit und Lebensdauer der Chipbauelemente und eine hohe technologische Flexibilität bezüglich Herstellung und Einsatz. Ausgehend von einer modularen Betrachtungsweise der Bauelemente wurden vielseitig einsetzbare, elektrisch-optimierte Interdigitalwandler entworfen, verschiedene Herstellungsvarianten für vergrabene Interdigitalwandler hoher Leistungsbeständigkeit auf piezoelektrischen Lithiumniobat-Substraten entwickelt und experimentell verifiziert, ein Sputterverfahren für amorphe SiO2-Dünnschichten hoher Qualität optimiert und eine Federstiftkontakt-Halterung entworfen. Durch Kombination dieser Technologien wurden SAW-Bauelemente für die mikrofluidische Aktorik mit hoher Performance und Reproduzierbarkeit entworfen, charakterisiert und beispielhaft für das elektroakustische Zerstäuben von Fluiden und das Mischen in Mikrokanälen eingesetzt.:i Kurzzusammenfassung . 5
ii Abstract. 5
iii Inhaltsverzeichnis . 7
iv Abkürzungen und Symbole . 9
1 Überblick . 11
2 Grundlagen und Stand der Technik . 13
2.1 Mikrofluidik . 13
2.1.1 Vom Labor zum Chiplabor . 13
2.1.2 Besonderheiten in miniaturisierten Fluidvolumina . 16
2.2 SAW-basierte Mikrofluidiksysteme . 18
2.2.1 Akustische Oberflächenwellen (SAW) . 18
2.2.2 SAW-Mikrofluidik . 19
2.2.3 SAW-induzierte Strömung ("Acoustic Streaming") . 22
2.2.4 Anforderungen an SAW-basierte Mikrofluidiksysteme . 24
2.2.5 Schädigung SAW-basierter Mikrofluidiksysteme . 26
2.3 Dünnschichten für SAW-basierte Mikrofluidiksysteme . 28
2.3.1 Überblick . 28
2.3.2 Metallisierungssysteme für Interdigitalwandler . 28
2.3.3 Amorphe SiO2-Schichten . 30
2.3.4 Deck- und Funktionsschichten . 32
3 Analysemethoden . 35
4 Technologiekonzept für SAW-basierte Mikrofluidiksysteme . 47
4.1 Modulare Systembeschreibung . 47
4.2 Substratmodul . 50
4.3 Transducermodul . 52
4.3.1 Layout der PSAW-Chipbauelemente . 52
4.3.2 Reinigungsverfahren . 53
4.3.3 Übersicht der untersuchten Herstellungsverfahren . 54
4.3.4 Nasschemisches Ätzverfahren für Al/Ti . 56
4.3.5 Lift-Off Verfahren für Al/Ti . 62
4.3.6 Damaszentechnik für Al2O3/Cu/Ta-Si-N . 65
4.3.7 Vergleich der Herstellungsverfahren . 72
4.4 Funktionsmodul . 75
4.4.1 Hochqualitative SiO2-Schichten . 75
4.4.2 Mikrokanäle . 88
4.4.3 Silanisierung. 88
4.5 Handlingmodul . 90
5 Realisierung und Charakterisierung SAW-basierter Fluidaktoren . 93
5.1 Flexibles Layout für Aktorik-Chipbauelemente . 93
5.2 Chiplayouts für spezielle Anwendungen . 95
5.2.1 Chiplayouts zur IDT-Charakterisierung . 95
5.2.2 Chiplayouts für stehende Wellenfelder . 96
5.2.3 Chiplayouts für "SAW-Stabmixer" . 98
5.2.4 Chiplayouts für tropfenbasierte Fluidik auf Oberflächen . 99
5.3 Wärmeeintrag in Fluide durch "acoustic streaming" . 101
5.4 SAW-basierte Fluidzerstäubung . 104
6 Zusammenfassung & Ausblick . 111
v Literaturverzeichnis . 115
vi Abbildungsverzeichnis . 123
vii Tabellenverzeichnis . 128
viii Selbstständigkeitserklärung . 129
ix Anhang . 131
A1 Bestimmung der Abtragsrate beim Cu-CMP . 131
A2 Ellipsometrie-Modell . 133
A3 "Thin plate spline" Methode für räumlich verteilte Messwerte . 134
A4 Modell des Kammerdrucks . 134
A5 Verzeichnis weiterer Formeln . 136
A6 Visual Basic Programm zur Aerosolcharakterisierung . 138
A7 Visual Basic Programm zur Steppplan-Generierung . 144
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Lateral porous silicon membranes for planar microfluidic applications / Intégration de membranes de silicium poreux à pores latéraux dans des systèmes microfluidiques planairesHe, Yingning 22 November 2016 (has links)
Les laboratoires sur puce visent à miniaturiser et à intégrer les fonctions couramment utilisées dans les laboratoires d'analyse afin de cibler des applications en santé avec un impact prometteur sur le diagnostic médical au lit du patient. Les membranes poreuses sont d'un grand intérêt pour la préparation et l'analyse d'échantillon sur puce car elles permettent la séparation par taille/charge de molécules, mais également leur pré-concentration. Parmi les matériaux disponibles pour constituer des membranes poreuses, le silicium poreux présente de nombreux avantages tels que le contrôle précis de la taille des pores et de la porosité, une chimie de surface pratique et des propriétés optiques uniques. Les membranes de silicium poreux sont généralement intégrées dans des puces fluidiques en les montant entre deux couches comportant des micro-canaux, formant ainsi des réseaux fluidiques à trois dimensions, peu pratiques et peu adaptés à l'observation directe par microscopie. Dans ces travaux de thèse, nous avons développé deux méthodes de fabrication de membranes de silicium à pores latéraux qui permettent leur intégration monolithique dans des systèmes microfluidiques planaires. Le premier procédé est fondé sur l'utilisation d'électrodes localement structurées afin de guider la formation de pores de manière horizontale, en combinaison avec des substrats type silicium sur isolant (SOI) pour localiser spatialement la formation de silicium poreux dans la profondeur du canal. La deuxième méthode repose sur le fait que la formation de silicium poreux par anodisation est fortement dépendante du type de dopant et de sa concentration. Bien que nous utilisons encore le même type d'électrodes structurées sur les parois latérales de la membrane pour injecter le courant lors de l'anodisation, le dopage par implantation permet de confiner la membrane, de façon analogue mais à la place de l'oxyde enterré du SOI. Des membranes à pores latéraux ont été fabriquées par ces deux méthodes et leur fonctionnalité a été démontrée en réalisant des expériences de filtrage. En plus de la filtration d'échantillon, les membranes ont été utilisées pour étudier la possibilité d'effectuer de la pré-concentration électrocinétique et de la détection interférométrique. La sélectivité ionique des membranes microporeuse permet la pré-concentration moléculaire avec des facteurs de concentration pouvant atteindre jusqu'à 103 en 10 min en appliquant moins de 9 V. Ces résultats sont comparables à ceux rapportés dans la littérature à l'aide par exemple de nanocanaux avec une consommation d'énergie beaucoup plus faible. Enfin, nous avons pu détecter une variation de l'indice de réfraction du silicium poreux par le décalage du spectre d'interférence lors du chargement de différents liquides injectés dans les membranes. Le travail présenté dans cette thèse constitue la première étape dans la démonstration de l'intérêt du silicium poreux pour la préparation d'échantillon et la biodétection dans des laboratoires sur puce planaires. / Lab on a chip devices aim at integrating functions routinely used in medical laboratories into miniaturized chips to target health care applications with a promising impact foreseen in point-of-care testing. Porous membranes are of great interest for on-chip sample preparation and analysis since they enable size- and charge-based molecule separation, but also molecule pre-concentration by ion concentration polarization. Out of the various materials available to constitute porous membranes, porous silicon offers many advantages, such as tunable pore properties, large porosity, convenient surface chemistry and unique optical properties. Porous silicon membranes are usually integrated into fluidic chips by sandwiching fabricated membranes between two layers bearing inlet and outlet microchannels, resulting in three-dimensional fluidic networks that lack the simplicity of operation and direct observation accessibility of planar microfluidic devices. To tackle this constraint, we have developed two methods for the fabrication of lateral porous silicon membranes and their monolithic integration into planar microfluidics. The first method is based on the use of locally patterned electrodes to guide pore formation horizontally within the membrane in combination with silicon-on-insulator (SOI) substrates to spatially localize the porous silicon within the channel depth. The second method relies on the fact that the formation of porous silicon by anodization is highly dependent on the dopant type and concentration. While we still use electrodes patterned on the membrane sidewalls to inject current for anodization, the doping via implantation enables to confine the membrane analogously to but instead of the SOI buried oxide box. Membranes with lateral pores were successfully fabricated by these two methods and their functionality was demonstrated by conducting filtering experiments. In addition to sample filtration, we have achieved electrokinetic pre-concentration and interferometric sensing using the fabricated membranes. The ion selectivity of the microporous membrane enables to carry out sample pre-concentration by ion concentration polarization with concentration factors that can reach more than 103 in 10 min by applying less than 9 V across the membrane[TL1]. These results are comparable to what has already been reported in the literature using e.g. nanochannels with much lower power consumption. Finally, we were able to detect a change of the porous silicon refractive index through the shift of interference spectrum upon loading different liquids into the membrane. The work presented in this dissertation constitutes the first step in demonstrating the interest of porous silicon for all-in-one sample preparation and biosensing into planar lab on a chip.
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Quantifying the roles of stimulated osteocytes and inflammation in bone remodelingGeorge, Estee L. 21 June 2019 (has links)
No description available.
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Thin Film Microfluidic and Nanofluidic DevicesHamblin, Mark Noble 09 August 2010 (has links) (PDF)
Lab-on-a-chip devices, also known as micro total analysis systems (μTAS), are implementations of chemical analysis systems on microchips. These systems can be fabricated using standard thin film processing techniques. Microfluidic and nanofluidic channels are fabricated in this work through sacrificial etching. Microchannels are fabricated utilizing cores made from AZ3330 and SU8 photoresist. Multi-channel electroosmotic (EO) pumps are evaluated and the accompanying channel zeta potentials are calculated. Capillary flow is studied as an effective filling mechanism for nanochannels. Experimental departure from the Washburn model is considered, where capillary flow rates lie within 10% to 70% of theoretical values. Nanochannels are fabricated utilizing cores made from aluminum, germanium, and chromium. Nanochannels are made with 5 μm thick top layers of oxide to prevent dynamic channel deformation. Nanochannel separation schemes are considered, including Ogston sieving, entropic trapping, reptation, electrostatic sieving, and immutable trapping. Immutable trapping is studied through dual-segment nanochannels that capture analytes that are too large to pass from one channel into a second, smaller channel. Polymer nanoparticles, Herpes simplex virus type 1 capsids, and hepatitis B virus capsids are trapped and detected. The signal-to-noise ratio of the fluorescently-detected signal is shown to be greater than 3 for all analyte concentrations considered.
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