CMOS and MEMS Based Microsystems for Manipulation and Detection of Magnetic Beads for Biomedical Applications

RÉSUMÉ Les micro et nano billes magnétiques dédiées à l'étiquetage des bio-particules attirent de plus en plus d'intérêt dans de nombreuses applications environnementales et sanitaires, tels que l'analyse de gènes, le transport des médicaments, la purification et l'immunologie. Les dimensions réduites et la haute sensibilité des billes magnétiques rendent leurs manipulations à haute précision possibles. Leur simplicité de suivi dans le milieu biologique et leur biocompatibilité permettent d’effectuer des détections rapides et à haute sensibilité pour des applications in vivo et in vitro. L'utilisation traditionnelle des billes magnétiques prend place dans un laboratoire se servant du matériel encombrant et dispendieux. Avec le développement de la technologie de microfabrication, des billes magnétiques peuvent être traitées dans un microsystème, plus précisément, dans une structure laboratoire sur puce (LoC). La combinaison microfluidique et microélectronique offre des possibilités d’autoévaluation, ce qui peut augmenter l'efficacité du travail. Cette thèse est orientée vers de nouvelles approches pour la manipulation et la détection de bio-particules se servant de la technologie de microsystèmes basées sur des structures microelectroniques et microfluidiques et en utilisant des marqueurs de billes magnétiques. Basé sur un réseau de microbobines à la fois comme une source de champ magnétique et un capteur inductif, le microsystème proposé est réalisé grâce à l'efficacité de fabrication de structures CMOS-MEMS, ainsi que des circuits intégrés dédiés CMOS de haute performance afin d'obtenir un rendement élevé de manipulation et de détection de billes magnétiques. Plusieurs défis ont été analysés dans la mise en œuvre de ces microsystèmes et des solutions correspondantes fournies. Plus précisément, la conception et la mise en œuvre d'une plate-forme contrôlée en température en format portable sont d'abord présentées, dans un effort réalisé pour résoudre la question de la chaleur par effet Joule lors de l'application du réseau de microbobines comme une source de champ magnétique dédié à la manipulation de billes magnétiques. Une plateforme similaire à cette dernière a été améliorée pour effectuer une analyse magnétique immunologique, en ajoutant des circuits de détection par des billes magnétiques. De plus, des IgG et anti-IgG de souris ont été utilisés dans des expériences pour vérifier les performances de détection de la plateforme de microsystème proposé.----------ABSTRACT Magnetic micro/nano beads as labels of bio-particles have been attracting more and more interest in many environmental and health applications, such as gene and drug delivery, purification, and immunoassay. The miniature size and high sensitivity of magnetic bead allow accurate manipulation, whereas its high distinguishability from biological background and biocompatibility make fast and high sensitivity detection possible for in vitro and in vivo applications. Traditional employment of magnetic beads is done in laboratory environment with the assist of bulky and expensive equipment. Thanks to the development of microfabrication technology, magnetic beads therefore can be handled on a microsystem, more specifically, a Lab-on-Chip (LoC). The combination of microfluidics with microelectronics offers the possibility of automatic analyses, which can liberate the labor and increase the efficiency.This thesis focuses on new approaches for bio-particles manipulation and detection on microelectronic/microfluidic hybrid microsystems using magnetic beads as labels. Based on planar microcoil array as both magnetic field source and the front-end inductive sensor, the proposed microsystems can take advantage of the massive producible CMOS/MEMS fabrication process, as well as the customized high performance CMOS circuits, to achieve a high efficient magnetic beads manipulation and a quantitative detection. Several challenges in implementing such microsystems are analyzed and corresponding solutions are provided. Specifically, the design and implementation of a temperature controllable LoC platform in portable format is firstly presented, for the sake of resolving the Joule heat issue when applying microcoil array as magnetic field source in magnetic beads manipulation. The similar platform is then improved to be used for magnetic immunoassay, by adding magnetic beads sensing circuits. Mouse IgG and anti-mouse IgG are employed in experiments to verify the detection performance of the proposed microsystem platform. Additionally, a fully integrated silicon substrate MEMS chip which integrates both microfluidic channel and microcoil array on a single chip is designed and fabricated following the Finite Element Analysis (FEA) simulation results and tested using bio-particles attached magnetic beads. This monolithic chip has the potential to be applied for in vivo applications

Procédé de fabrication de dispositifs microfluidiques intégrant des microbobines – Piégeage de nanoparticules magnétiques pour des applications en biologie

In this study, a concept of microfluidic chip with embedded planar coils is designed and fabricated for the aim of trapping effectively functionalized magnetic nanobeads and immobilizing antibody (IgG type). The planar coils as a heart of microfluidic chip is designed with criterion parameters which are optimized from simulation parameters of the maximum magnetic field, low power consumption and high power efficiency by FE method. The characterization of microcoils such as effectively nanobeads (300 nm) at low temperature (<37oC) is performed and confirmed. The channel network in PDMS material is designed for matching with entire process (including mixing and trapping beads) in microfluidic chip. A process of PDMS’s surface modification is also carried out in the assemble step of chip in order to limit the non-specific adsorption of many bio substances on PDMS surface. The microfluidic chip assemble is performed by using some developed techniques of reversible packaging PDMS microfluidic chip (such as stamping technique, using non-adhesive layer, oxygen plasma combining with solvent treatment). These packaging methods are important to reused microchip (specially the bottom substrate) in many times. The immobilization of antibody IgG-type is performed inside microfluidic chip following the standard protocol of bead-based ELISA in micro test tube. The result showed that IgG antibodies are well grafted on the surface of carboxyl-beads (comparing to result of standard protocol); these grafted antibodies are confirmed by coupling them with labeled second antibody (Fab-FITC conjugation).Le but de cette étude est de concevoir, fabriquer et caractériser une puce microfluidique afin de mettre en oeuve la capture de nanoparticules magnétiques fonctionnalisées en vue de la reconnaissance d’anticorps spécifiques (couplage d’une très grande spécificité et sensibilité). Après avoir modélisé et simulé les performances de la microbobine intégrée dans le canal de la puce microfluidique en prenant soin de limiter la température du fluide à 37°C, la capture devant être effective, le microsystème est fabriqué en salle blanche en utilisant des procédés de fabrication collective. La fabrication du microdispositif en PDMS a aussi donné lieu à l’optimisation de procédés de modification de surface afin d’assurer la ré-utilisation du microdispositif (packaging réversible) et la limitation de l’adsorption non spécifique. L’immobilisation des anticorps su les billes (300 nm) a été menée à l’intérieur du canal en utilisant un protocole de type ELISA éprouvé. Le procédé a montré qu’il était également efficient pour cet environnement puisque nous avons pu mettre ne évidence la capture de nanoparticule

Development and application of microtechnologies in the design and fabrication of cell culture biomimetic systems

“Lab-On-a-chip” systems have proved to be a promising tool in the field of biology. Currently, cell culture is performed massively on Petri dishes, which have traditionally been used in cell culture laboratories and tissue engineering. However, having proved to be a widely used tool until now, the scientific community has largely described the lack of correlation between the results obtained in the laboratory and the clinical results. This lack of connection between what has been studied in the laboratories and what has been observed in the clinic has led to the search for more advanced alternative tools that allow results to be obtained closer to reality. Thus, the use of microtechnologies in the field of biomedical engineering, presents itself as the perfect tool as an alternative to obsolete traditional media. Thanks to the low volumes of liquid it presents for its use, it also makes it an essential technology for the testing of drugs, new compounds and materials. By being able to more accurately reproduce the biomimetic environment of cell cultures and tissues, they make this technique fundamental as an intermediate step between basic in vitro laboratory tests and preclinical animal tests, resulting from this way in the best alternative for the reduction of both the use of animal models, as in times and costs. For a biomimetic system to be as such, it also needs another series of complementary devices for its better functioning. Micro-valves, micro pumps, flow sensors, O2 sensors, pH, CO2 are fundamental for the correct functioning andsophistication of biomimetic systems. This complexity, on the other hand, is often not perceived by the user since the miniaturization of all these components makes “Lab-On-a-Chip” systems smaller every day, despite numerous control components that can be incorporated.This thesis presents some examples of different microfluidic devices designed and manufactured through the use of microtechnologies, with all applications, focused on their use in biomimetic systems.<br /

SQUIDs in biomagnetism : A roadmap towards improved healthcare

This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 686865.Peer reviewedPublisher PD

Towards Single Bacterium Detection: A Microelectronic/Microfluidic Hybrid System Based on a CMOS Technology

RÉSUMÉ Cette thèse porte sur le développement d'un biocapteur hybride CMOS microfluidique capable de détecter des bactéries pathogènes une à une en temps réel basé sur un principe de spectroscope impédimétrique. Le biocapteur proposé se compose d'une matrice de capteurs qui comportent une matrice de microélectrodes, desmultiplexeurs à commande numérique, et des circuits de détection intégrés sur une puce de silicium CMOS. Cette recherche propose une nouvelle structure de microélectrodes qui permet à une structure de microélectrodes face à face à haute densité intégrable par post-traitement d’une puce CMOS. Au lieu d’être créée par le dépôt et la gravure de couches métalliques supplémentaires, la structure de microélectrodes face à face est construite en exploitant un empilement de couches métalliques disponible avec la technologie CMOS adoptée. Les détecteurs sont obtenus en construisant des microcanaux qui traversent le substrat. Ces microcanaux passent entre les microélectrodes face à face. Lorsque les fluides où se trouvent les échantillons traversent le microcanal, le système détecte de façon continue les changements d'impédance entre les microélectrodes induits par le passage de chaque bactérie . Cette thèse étudie le processus de microfabrication qui permet de libérer la matrice de microélectrodes et de fabriquer les microcanaux traversant le substrat. Les techniques dites de FIB (pours Focused Ion Beam) et de DRIE (pour Deep Reactive Ion Etching) sont utilisées. Les forces et faiblesses de chaque technologie sont analysées et des recettes de processus optimisés sont étudiées. La matrice de microélectrodes a été réalisée avec succès par les deux technologies. Comme preuve de concept, plusieurs microcanaux traversant le substrat sont également formés en utilisant la technologie FIB. Cette thèse propose également un nouveau circuit de détection. Réalisé grâce à la micro-électronique, ce circuit est capable de détecter les changements d'impédance causés par le passage d’une seule bactérie dans un milieu conducteur. Sans conditionnement de signaux et de circuit de traitement complexes, tels que des amplificateurs de haute précision, des filtres ou des convertisseurs analogue à numérique ou numérique à analogique, les circuits de détection sont conçus pour offrir une bonne sensibilité et une configurabilité qui permet de l'adapter aux différentes conditions de détection. Une technique de mise en boîtier biocompatible est également mise en oeuvre pour encapsuler le capteur intégré tout en fournissant des interfaces fluidiques et électriques pour l'injection d'échantillons et de signaux électriques. Une nouvelle approche pour améliorer la sélectivité de détection basée sur l’utilisation de bactéries magnétotactiques est également proposée dans cette thèse. Sous le contrôle d’un champ magnétique extérieur, les bactéries magnétotactiques sont utilisées comme bio-transporteurs, qui peuvent chercher activement et capturer les bactéries pathogènes cibles afin de les amener à la zone de détection. Une puce microfluidique est fabriquée grâce à des techniques de prototypage rapide afin de valider les idées proposées et de fournir des guides de conception d'une puce plus avancés. Les résultats de microfabrication et les résultats des tests préliminaires montrent que l'intégration monolithique des technologies CMOS et microfluidique est possible et qu’elle permet la réalisation de microélectrodes face à face dans une plate-forme capable de détecter le passage d’une seule bactérie en isolation.----------ABSTRACT This thesis reports on the development of a CMOS Microfluidic hybrid biosensor technology that is proposed to detect single pathogenic bacterium in real time based on impedimetric spectroscopy. The proposed biosensor consists of a CMOS silicon die that incorporates a microelectrode array, digitally controlled multiplexers, and sensing circuits. This research proposes a novel microelectrode structure, which is obtained by first manufacturing high density face to face microelectrodes on a CMOS die, possible by a relatively simple CMOS post-processing. Instead of deposition and patterning of additional metal layers, the face to face microelectrode array is constructed by stacking metal and via layers of the adopted CMOS technology. By constructing through substrate microchannels in between pairs of face to face microelectrodes, when a fluid sample flows through the microchannel, the microelectrodes on the wall detect the impedance change induced by bacterium in the fluid in a continuous way. This thesis investigates the microfabrication process of releasing microelectrode arrays and constructing through substrate microchannels. FIB (Focused Ion Beam) and DRIE (Deep Reactive Ion Etching) technologies are utilized. The strength and weakness of each technology are analyzed and optimized process recipes are investigated. Microelectrode array were successfully released using both process technologies. As a proof of concept, several through substrate microchannels were also formed by using the FIB technology. This thesis also proposes a novel sensing microelectronic circuit, which is able to sense the impedance change caused by a single bacterium in a conductive medium. The system does not require complex signal conditioning and processing circuits, such as high precision amplifiers, filters or ADC/DAC. The proposed simple sensing structure offer high sensitivity, reliability and configurability. A dedicated biocompatible packaging is also implemented to encapsulate the CMOS die and provide a microchamber, fluidic and electrical interfaces for sample injection and signal interfaces. A new approach to achieve detection selectivity or specificity assisted by magnetotactic bacterium is also proposed in this thesis. Under the control of an external magnetic field, the viii magnetotactic bacteria are used as bio-carriers, which can actively search and capture some target pathogenic bacteria and bring them to the sensing area. A microfluidic chip is fabricated by rapid prototyping techniques to validate the proposed idea and to provide design guides for a more advanced and highly integrated CMOS chip. The achieved microfabrication results and preliminary testing results show that the monolithic integration of CMOS and microfluidic technology, especially the face to face microelectrode structure is a suitable platform for single bacterium detection and analysis

Microfluidics and Nanofluidics Handbook

The Microfluidics and Nanofluidics Handbook: Two-Volume Set comprehensively captures the cross-disciplinary breadth of the fields of micro- and nanofluidics, which encompass the biological sciences, chemistry, physics and engineering applications. To fill the knowledge gap between engineering and the basic sciences, the editors pulled together key individuals, well known in their respective areas, to author chapters that help graduate students, scientists, and practicing engineers understand the overall area of microfluidics and nanofluidics. Topics covered include Finite Volume Method for Numerical Simulation Lattice Boltzmann Method and Its Applications in Microfluidics Microparticle and Nanoparticle Manipulation Methane Solubility Enhancement in Water Confined to Nanoscale Pores Volume Two: Fabrication, Implementation, and Applications focuses on topics related to experimental and numerical methods. It also covers fabrication and applications in a variety of areas, from aerospace to biological systems. Reflecting the inherent nature of microfluidics and nanofluidics, the book includes as much interdisciplinary knowledge as possible. It provides the fundamental science background for newcomers and advanced techniques and concepts for experienced researchers and professionals

An Exploration of Paul Bowles\u27 Piano-Solo Pieces

This research paper provides a general overview of the piano-solo literature by the American composer Paul Frederic Bowles (1910-1999). Thanks to recent contributions, this repertoire is now available in recordings and musical scores as it has never been before.;This paper is divided into two sections. The first covers the biography of Paul Bowles and his musical achievements as a composer, along with his research into the folk music of Morocco and his literary writings as a music critic for the journal Modern Music and for The New Herald Tribune. The second part is about Bowles\u27 piano-solo output, divided thematically into pieces with similar forms and structures.;For Bowles\u27 solo piano music, theoretical analysis and a review of existing literature help to reveal style traits; these include his preference for short character pieces, in which Bowles employs neoclassical elements, such as melodies with classical harmonies that display bitonal and pandiatonal tendencies, along with ostinato patterns and Alberti-bass accompaniments. Bowles\u27 music often displays ternary or free structures, with motivic development techniques through which themes or passages are derived from previous motives. Jazz and folk idioms are also an important aspect of Bowles\u27 piano music, particularly in his dancelike pieces, many of which display a Latin-American flavor

Makmal-Atas-Cip dengan medan magnet berkecerunan tinggi bagi aplikasi pengasingan sel biologi

High gradient magnetic separation (HGMS) capable of producing high magnetic flux density magnitude and gradient in magnetic capturing force. Since its introductory, HGMS concept has been widely employed in the field of biotechnology, chemistry and medical. However, huge magnetic system, complicated fabrication process, inadjustable magnetic field and its gradient and Joule heating effect are some of the past research problems. In this research, a novel design of high magnetic gradient LOC magnetic separator has been simulated, fabricated and tested. This simple and easy fabricated LOC magnetic separator comprising of spiral-shaped magnet wire coil, V-shaped nickel ferrite (Ni80Fe20) magnetic core and a microfluidics channel. The V-shaped magnetic core is fabricated by KOH anisotropic wet etching of bulk micromachining and Ni80Fe20 electroplating processes. The current density of 10 - 15 mA/cm2 used in the electroplating process have successfully co-deposited Ni and Fe alloy in its stoichiometric composition of nickel 72.6 – 81.9 % and ferrite 28.4 – 18.1 %. Microfluidics channel has been successfully fabricated using replica molding technique using PDMS and PUMA polymer materials. A trapping chamber at the microchannel centre is designed to minimize the fluid velocity and thus lowering down the drag force on the magnetic microbeads. The integration of spiral-shaped magnet wire coil and Ni80Fe20 magnetic core is able to generate high magnetic fluxs magnitude of Br = 225 - 20 mT, Bz = 390 - 25 mT, and high gradient of dBr/dr = 300 x 103 - 150 x 103 T/m and dBz/dz = 160 x 103 - 80 T/m from the core hujung of size 1 – 14 516 ?m2. Moreover, tuning of the magnetic field and its gradient is enable with the electric current supplied to the magnetic system. Functional test demonstrated the 20 nm and 2.5 ?m diameter magnetic nano particles and microbeads capturing on the V-shaped magnetic core hujung. In addition, proportional relationship between the direct currect injection and the magnetic nano particles and microbeads capturing area is also observed. Joule heating effect is substantial in magnet wire coil system, however, the combination of spiral-shaped magnet wire coil of N = 20 and on-silicon chip V-shaped magnetic core has reduced the Joule heating effects of ~ 26 % at maximum direct current, IDC of 2.5 A. The reduced Joule heating effect is expected due to silicon of high thermal conductivity material enable fast heat dissipation. Magnetic beads trapping effectiveness of 100 % and 95 % has been determined using 4.5 ?m and 2.5 ?m diameter respectively at volume flow rate of 1 ?L/min using magnetic core hujung of ~ 14 516 ?m2, N = 20 and IDC = 1.0 A. The trapping efficiency is inversely proportional with the volume flow rate used in the microfluidics. In conclusion, an efficient LOC HGMS device for functional biological cells labelled with magnetic micro beads is accomplished in this study