In this dissertation, guided surface acoustic wave sensors were investigated theoretically and experimentally in detail for immunosensing applications. Shear horizontal polarized guided surface acoustic wave propagation for mass loading sensing applications was modeled using analytical modeling and characterized by perturbation analysis. The model verification was performed experimentally and a surface acoustic wave immunosensor case study was presented. The results of the immunosensing were also investigated using the perturbation analysis. Guided surface acoustic wave propagation problem was investigated in detail for gravimetric (or mass loading) guided wave sensors, more specifically for immunosensors. The analytical model was developed for multilayer systems taking viscoelasticity into account. The closed form algebraic solutions were obtained by applying appropriate boundary conditions. A numerical approach was used to solve dispersion equation. Detailed parametric investigation of dispersion curves was conducted using typical substrate materials and guiding layers. Substrate types of ST-cut quartz, 41° YX lithium Niobate and 36° YX lithium tantalate with guiding layers of silicon dioxide, metals (chromium and gold), and polymers (Parylene-C and SU-8) were investigated. The effects of frequency and degree of viscoelasticity were also studied. The results showed that frequency only has effect on thickness with same shaped dispersion curves. Dispersion curves were found to be unaffected by the degree of viscoelasticity. It was also observed that when there was a large shear velocity difference between substrate and guiding layer, a transition region with a gradual decrease in phase velocity was obtained. However, when shear velocities were close, a smooth transition was observed. Furthermore, it was observed that, large density differences between substrate and guiding layer resulted in sharp and with nearly constant slope transition. Smooth transition was observed for the cases of minimal density differences. Experimental verification of the model was done using multi-layer photoresists. It was shown that with modifications, the model was able to represent the cases studied. Perturbation equations were developed with first order approximations by relating the slope of the dispersion curves with sensitivity. The equations were used to investigate the sensitivity for material selection (substrate, guiding layer, and mass perturbing layer) and degree of viscoelasticity. The investigations showed that the sensitivity was increased by using guiding layers with lower shear velocities and densities. Among the guiding layers investigated, Parylene C showed the highest sensitivity followed by gold and chrome. The perturbation investigations were also extended to viscoelasticity and to protein layers for immunosensing applications. It was observed that, viscous behavior resulted in slightly higher sensitivity; and sensitivity to protein layers was very close to sensitivity for polymers. The optimum case is found to be ST-cut quartz with Parylene-C guiding layer for protein layer sensing. Finally, an immunosensing case study was presented for selective capture of protein B-cell lymphoma 2 (Bcl-2), which is elevated in many cancer types including ovarian cancer. The immunosensor was designed, fabricated, and experimentally characterized. An application-specific surface functionalization scheme with monoclonal antibodies, ODMS, Protein A/G and Pluronic F127 was developed and applied. Characterization was done using the oscillation frequency shift of with sensor used as the feedback element of an oscillator circuit. Detection of Bcl-2 with target sensitivity of 0.5 ng/ml from buffer solutions was presented. A linear relation between frequency shift and Bcl-2 concentration was observed. The selectivity was shown with experiments by introducing another protein, in addition to Bcl-2, to the buffer. It was seen that similar detection performance of Bcl-2 was obtained even with presence of control protein in very high concentrations. The results were also analyzed with perturbation equations.

Yes / A new approach is described herein, where neutron reflectivity measurements that probe changes in the density profile of thin films as they absorb material from the gas phase have been combined with a Love wave based gravimetric assay that measures the mass of absorbed material. This combination of techniques not only determines the spatial distribution of absorbed molecules, but also reveals the amount of void space within the thin film (a quantity that can be difficult to assess using neutron reflectivity measurements alone). The uptake of organic solvent vapours into spun cast films of polystyrene has been used as a model system with a view to this method having the potential for extension to the study of other systems. These could include, for example, humidity sensors, hydrogel swelling, biomolecule adsorption or transformations of electroactive and chemically reactive thin films. This is the first ever demonstration of combined neutron reflectivity and Love wave-based gravimetry and the experimental caveats, limitations and scope of the method are explored and discussed in detail.

Surface acoustic wave sensors have been a focus of active research for many years. Its ability to respond for surface perturbation is a basic principle for its sensing capability. Sensitivity to surface perturbation changes with every inter-digital transducer (IDT) design parameters, substrate selection, metallization choice and technique, delay line length and working environment. In this thesis, surface acoustic wave (SAW) sensors are designed and characterized to improve sensitivity and reduce loss. To quantify the improvements with a specific design configuration, the sensors are employed to measure temperature. Four SAW sensors design configurations, namely bi-directional, split electrode, single phase unidirectional transducer (SPUDT) and metal grating on delay line (shear transvers wave sensors) are designed and then fabricated in Nanotechnology Research and Education Center (NREC) facility using traditional MEMS fabrication processes Additionally, sensors are then coated with guiding layer SU8-2035 of 40 m using spin coating and SiO2 of 6 m using plasma enhanced chemical vapor deposition (PECVD) process. Sensors are later diced and tested for every 5oC increment using network analyzer for temperature ranging from 30oC–0.5oC to 80oC–0.5oC. Data acquired from network analyzer is analyzed using plot of logarithmic magnitude, phase and frequency shift. Furthermore, to investigate the effect of metallization technique on the sensor performance, sensors are also fabricated on substrates that were metallized at a commercial MEMS foundry. All in-house and outside sputtered sensor configurations are compared to investigate quality of sputtered metal on wafer. One with better quality sputtered metal is chosen for further study. Later sensors coated with SU8 and SiO2 as guiding layer are compared to investigate effect of each waveguide on sensors and determine which waveguide offers better performance. The results showed that company sputtered sensors have higher sensitivity compared to in-house sputtered wafers. Furthermore after comparing SU8 and SiO2 coated sensors in the same instrumental and environmental condition, it was observed that SU8 coated di-directional and single phase unidirectional transducer (SPUDT) sensors showed best response.

Ces travaux de thèse, financés par la Région Aquitaine et partie intégrante des projets ASCOBAR et OSQUAR (2007-2009 et 2009-2011), ont été effectués au sein du laboratoire IMS-Bordeaux (Université Bordeaux 1, CNRS, UMR 5218) et sont le fruit de la collaboration de trois laboratoires. Ils ont visé l'étude d'une plateforme à ondes acoustiques transverses horizontales guidées, ou ondes de Love, dédiée à la détection de phycotoxines responsables d'empoisonnement par consommation de chair de coquillage.Cette plateforme intègre une partie microfluidique destinée à assurer un contrôle du flux de l'échantillon d'analyse au voisinage de l'interface sensible, tout en réduisant les volumes utilisés. Des tests de détections ont été réalisés, en collaboration avec le Laboratoire d'Immunologie-Parasitologie de l’Université Bordeaux 2, en équipant le capteur d'un biorécepteur spécifique de type anticorps, commercial pour la détection d'acide okadaïque, ou, pour l'acide domoïque, fabriqué à partir d'un haptène formé avec un mimotope d'une famille de toxines du type amnésiante (ASP) synthétisé par l'Institut des Sciences Moléculaires (Université Bordeaux 1, CNRS UMR 5255).Grâce aux efforts synergiques de ce consortium et à l'élaboration de protocoles de détections spécifiques, les premiers résultats permettent de discriminer un échantillon empoisonné au seuil sanitaire, soit 0,2 ppm pour l'acide okadaïque, 20 ppm pour l'acide domoïque (200 ng d'acide domoïque dans seulement 10 mg de chair de coquillage). / These works have been funded by "la Région Aquitaine" as part of the projects ASCOBAR (2007-2009) and OSQUAR (2009-2011). They have been done in the IMS-Bordeaux (Université Bordeaux 1, CNRS, UMR 5218) with the collaboration of two others laboratories.The main goal was to create a guided transverse horizontal acoustic wave (Love wave) platform for specific detection of phycotoxins, responsible of shellfish poisoning. The microfluidic chip integrated into this platform allows control of the sample flow above the sensitive surface while saving biological liquid consumption.Detection tests have been done with the collaboration of the "Laboratoire d'Immunologie-Parasitologie" (Université Bordeaux 2). The sensitive surface was made of antibodies, created from a hapten made with a mimotope synthesized by "l'Institut des Sciences Moléculaires" (Université Bordeaux 1, CNRS UMR 5255). This mimotope is a molecule part which is common to a family of amnesic phycotoxin (ASP).Thanks to the synergistic efforts of this consortium and development of specific detection protocols, results can discriminate poisonous samples at sanitary threshold, that is, containing 0.2 ppm of okadaic acid, 20 ppm of domoic acid (200 ng of domoic acid into only 10 mg of shellfish flesh).

Ces travaux de recherches concernent l'association de la technologie des polymères à empreintes moléculaires aux dispositifs acoustiques à onde de Love afin de réaliser un biocapteur dans le cadre d'un projet ANR Tecsan. La première partie de ces travaux de thèse a dressé plus spécifiquement la mise au point d'un protocole de dépôt localisé de polymères imprimés (MIP) et non imprimés (NIP) en films minces compatibles avec la propagation de l'onde élastique. La seconde aprtie des travaux a visé une caractérisation des films et des capteurs ainsi réalisés, par microscopie à balayage et apr mesures de détection sous gaz. Des éléments relatifs aux propriétés mécaniques (porosité, surfaces spécifiques) des MIPs et NIPs, avant extraction de la molécule cible, puis après extraction et après recapture, ont permis de valider le principe du capteur, ouvrant la voie à l'application en milieu liquide. / This work deals with the association of molecularly imprinted polymers technology and Love wave devices in order to develop a biosensor in the frame of ANR project, Tecsan. The first part of this work concerned the development and the validation of a protocol for localized deposition of imprinted (MIP) and non-imprinted (NIP) polymeric thin film compatible with the propagation of acoustic wave. The second part exhibited the cahracterization of the coated sensors, by scanning microscopy and deep gas characterization. The proposed characterization technique gives information on surface morphology and porosity of thin MIP films before extraction of the target molecule, then after extraction and after rebinding. It allowed hence, the validation of the sensor principle. These results constitute a god background for future application in medium liquid.

Ces travaux de thèse présentent le développement de capteurs à ondes acoustiques, plus particulièrement de capteurs à ondes de Love, à l’aide de matériaux mésoporeux. La première partie de ces travaux a porté sur la mise au point d’une méthode de caractérisation du module de rigidité d’un film mésoporeux déposé sur un capteur et soumis à un flux d’humidité. Le banc de mesure développé permet d’effectuer simultanément des mesures acoustiques et ellipsométriques. Les variations du module de rigidité d’un film mésoporeux d’oxyde de titane en fonction du taux d’humidité ont ensuite été calculées à l’aide d’une procédure d’ajustement de courbe entre les résultats expérimentaux et un modèle numérique dédié modélisant la propagation des ondes de Love dans la structure multicouche. Nous avons ainsi montré que l’influence de la sorption sur le comportement mécanique d’un film mésoporeux est un facteur important à prendre en compte, notamment lors de la conception de micro-capteurs. Par la suite, des dispositifs recouverts de SiO2 et de TiO2 mésoporeux ont été développés pour différentes applications: la détection de composés organiques volatils, la détection d’espèces biologiques et le suivi d’une réaction de photocatalyse. Enfin, nous avons réalisé des capteurs recouverts d’une unique couche mésoporeuse de TiO2 assurant simultanément les fonctions de guide d’onde et de couche sensible, permettant d’augmenter de manière significative la sensibilité du capteur. / This research thesis presents the development of acoustic wave sensors, particularly Love wave sensors, using mesoporous materials. The first part of this work has focused on the development of a method to characterize the stiffness modulus of a mesoporous film, deposited on a sensor, and under humidity exposure. The experimental setup allows simultaneous acoustic and ellipsometric measurements. Changes in the stiffness modulus of a mesoporous titania film as a function of humidity were calculated using a curve-fitting procedure between experimental results and a numerical model dedicated to modeling the Love waves propagation in the structure. We have shown that the influence of sorption on the mechanical behavior of a mesoporous film is an important factor to consider, especially in the design of micro-sensors. Subsequently, devices coated with SiO2 and TiO2 mesoporous were developed for different applications: the detection of volatile organic compounds, the detection of biological species and the monitoring of a photocatalysis reaction. Finally, we realized sensors coated with a single layer of mesoporous TiO2 that performs the functions of waveguide and sensitive layer, which enable to increase significantly the sensor sensitivity.

En las últimas dos décadas, han surgido diferentes tecnologías acústicas para aplicaciones biosensoras como alternativas a tecnologías de detección bien establecidas ¿acústicas o ópticas¿ como son la Microbalanza de Cuarzo (QCM, por sus siglas en inglés) y la Resonancia de Plasmón de Superficie (SPR, de sus siglas en inglés). En la primera parte de este documento se revisan dichas tecnologías alternativas para aplicaciones en medio líquido. Como resultado de esta revisión, se determina que los dispositivos de onda acústica superficial Love (LW, de sus siglas en inglés) son los más prometedores y viables para conseguir el principal objetivo de esta Tesis, que es establecer una comparativa en las mismas condiciones entre inmnosensores desarrollados con la tecnología seleccionada en esta tesis y los inmunosensores desarrollados con QCMs de Alta Frecuencia Fundamental (HFF-QCM, por sus siglas en inglés). Después de esta revisión se presenta el estado del arte de los dispositivos LW en su aplicación como biosensores, así como una discusión de las tendencias y retos actuales de este tipo de sensores. Posteriormente se reúne la información más actualizada sobre aspectos de diseño, principios de operación y modelado de estos sensores. Algunos aspectos de diseño son estudiados y probados para establecer el diseño final de los dispositivos LW. Previamente a su fabricación, también se realizan simulaciones para modelar el comportamiento del dispositivo elegido previamente a su fabricación. Posteriormente, se describe la fabricación del dispositivo así como la celda de flujo diseñada para trabajar con el dispositivo en medios líquidos. Adicionalmente, un sistema electrónico de caracterización, previamente validado para sensores QCM, se adapta para sensores LW. Como resultados, se valida el sistema electrónico para caracterizar los sensores LW fabricados y montados en la celda de flujo y, finalmente, se desarrolla un inmunosensor para la detección del pesticida carbaril que se compara con otras tecnologías inmunosensoras. / In the last two decades, different acoustic technologies for biosensors applications have emerged as promising alternatives to other better established detection technologies ¿ acoustic or optic ones- such as traditional Quartz Crystal Microbalance (QCM) and Surface Plasmon Resonance (SPR). The alternative acoustic technologies for in liquid measurements are reviewed in this manuscript. Surface Acoustic Wave (SAW) Love Mode or Love Wave (LW) sensors are determined to be the most promising and viable option to work with for achieving the main aim of this Thesis. Such aim is the development of a LW immunosensor for its comparison with the same application based on High Fundamental Frequency-QCM (HFF-QCM) sensors and under the same conditions. Consequently, the state-of-the-art of LW devices for biosensing is provided and a discussion about the current trends and future challenges of these sensors is presented. In order to start working with suitable LW devices, upto- date information regarding the design aspects, operation principles and modeling of such devices is gathered. Some design aspects are explored and tested to establish the design of the final LW device. Different simulations for modeling the chosen device behavior are carried out before its fabrication. Later, the device fabrication is described. Next, to start working with the fabricated device in liquid media, a flow cell is designed and implemented. In addition, an electronic characterization system, previously validated for QCM sensors, is adapted and tested for the fabricated LW device. As results, the adapted electronic characterization system is validated for LW devices mounted in the fabricated flow cell and, finally, a LW-based immunosensor for the determination of carbaryl pesticide was developed and compared with other immunosensor technologies. / Rocha Gaso, MI. (2013). Analysis, implementation and validation of a Love mode surface acoustic wave device for its application as sensor of biological processes in liquid media [Tesis doctoral]. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/32492

Ce travail a pour objectif de développer de nouveaux microcapteurs à onde acoustique de surface (SAW) capables de détecter le dioxyde de souffre (SO₂) à l’échelle de traces par l’intermédiaire d’une couche sensible à base d’un polymère fonctionnel. Une famille originale de cinq polyuréthaneimides (PUIs) à blocs contenant un nombre contrôlé de sites amines tertiaires de structures différentes a été synthétisée et caractérisée. Ces matériaux présentent des propriétés originales, en solution et à l’état solide, qui sont dues essentiellement à la présence des sites basiques et à la structure à blocs associant des blocs souples polyéthers et des blocs rigides en partie fluorés. Leur excellent caractère filmogène a permis leur application en tant que couche sensible au SO₂ sur des microcapteurs SAW. Deux structures de microcapteurs à onde de Love, bicouche et tri-couche, ont été développées en respectant les conditions de génération de l’onde. La structure bicouche comporte le Quartz-ST 90° comme substrat et l’un des PUIs joue le double rôle de couche guidante et sensible. Cette structure génère bien l’onde de Love mais elle présente une forte sensibilité à la température, inconvénient majeur pour les capteurs de gaz. L’ajout d’une couche guidante à base de ZnO, dans une structure tri-couche, a permis de rendre le dispositif peu sensible à la température et donc compatible avec l’application visée. Les résultats des tests de détection du SO₂ montrent que tous les PUIs étudiés contribuent à une amélioration de la sensibilité comparativement au dispositif sans couche polymère. La présence des sites amines tertiaires conduit à une amélioration importante de la sensibilité qui n’est pas seulement gouvernée par leur basicité mais également par leur encombrement stérique dont le rôle apparaît déterminant / This work aimed at developing new surface acoustic wave (SAW) microsensors capable of detecting traces of sulfur dioxide (SO₂) through a sensitive layer based on a functional polymer. An original family of five polyurethaneimide (PUI) block copolymers containing a controlled number of tertiary amine sites with different chemical structures was synthesized and characterized. These materials exhibited original properties in solution and solid state, which were mainly due to the presence of the basic sites and the block structure combining polyether soft blocks and partially fluorinated hard blocks. Their excellent film-forming character allowed their application as SO₂ sensitive layers on SAW microsensors. Two bi-layer and three-layer structures of Love wave microsensors were developed by respecting the conditions of the Love wave generation. The bi-layer structure included the Quartz ST-90° as the piezoelectric substrate and one of the PUIs acting as both guiding and sensitive layer. This structure generated the Love wave but its high sensitivity to temperature was a major drawback for gas sensors. The addition of a ZnO guiding layer in a three-layer structure led to a microsensor almost insensitive to temperature and thus compatible with the targeted application. The experimental results for SO₂ detection showed that all the PUIs contributed to improve the sensitivity compared to the device without polymer layer. The presence of tertiary amine sites led to a significant improvement in gas sensitivity which was not only governed by their basicity but also by their steric hindrance which played a determining role

Notre thèse vise la conception d'un biocapteur ultra-sensible à base d'Arthrospira platensis pour la détection des substances toxiques (métaux lourds et pesticides) pour un contrôle environnemental. Cette étude concerne, dans un premier lieu, le développement de systèmes impédimétriques et à ondes acoustiques de Love, associés à des puces en Polydimethylsiloxane (PDMS) et fonctionnalisés par des cellules d'Arthrospira platensis immobilisées sur une multicouche de polyélectrolytes déposés par la méthode « Layer by Layer ». L'étude fondamentale des interactions physiques-chimiques-biologiques mises en jeu lors des étapes de fonctionnalisation du capteur, et son application à la détection de cadmium et de mercure, est également abordée, à travers une étude acoustique (suivi en temps réel), électrochimique et microscopique (microscopie à force atomique (AFM) en milieu sec ou liquide et microscopique électronique à balayage (MEB)). Dans un deuxième lieu, cette étude présente les systèmes conductimétriques basés sur l'inhibition des activités enzymatiques de la cyanobactérie par les polluants. Différents modes d'immobilisation sur des microcapteurs interdigités (IDF) en or, ont été étudiés : immobilisation via les monocouches auto-assemblées « Self Assembled Monolayers », immobilisation via les nanoparticules d'or revêtues par du PAH et co-réticulées à l'albumine à l'albumine de sérum bovin sous vapeur saturée de glutaraldéhyde. Ce principe de détection consiste à inhiber l'Activité Phophatase Alcaline (APA) par les métaux lourds et l'Activité Estérase (AChE) par les pesticides. Des limites de détection excellente (10-20 M) ont été obtenues. Un biocapteur bi-enzymatique a été élaboré avec le même biorécepteur (Arthrospira platensis) pour une multi-détection des polluants. Ce capteur a été testé sur des échantillons d'eaux prélevés sur des effluents hospitaliers et urbains (eaux brutes et traitées) / This thesis focuses on the design of an ultra-sensitive biosensor based on Arthrospira platensis for the detection of toxic substances (heavy metals and pesticides) for environmental monitoring. This study deals with, first, the development of impedimetric and Love acoustic wave systems, associated with Polydimethylsiloxane (PDMS) chips and functionalized with Arthrospira platensis cells immobilized on polyelectrolyte multilayers deposited by the “Layer and Layer” method. Electrochemical, acoustic and microscopic interactions with cadmium and mercury (atomic force microscopy (AFM) in dry or liquid medium and studies of scanning electron microscopy (SEM)) have been performed. This work focuses also on conductometric system based on the inhibition of enzymatic activities of cyanobacteria by pollutants. Different modes of immobilization on gold interdigitated microsensors (IDTs) were studied: immobilization via self-assembled monolayers, immobilization with gold nanoparticles coated with PAH and co-reticulated with bovine serum albumin under saturated vapor of glutaraldehyde. They were based on the inhibition of Alkaline Phosphatase activity (APA) by heavy metals Esterase Activity (AChE) by pesticides. Excellent detection limits (10-20 M) were obtained. A bi-enzymatic biosensor was developed with the same bioreceptor (Arthrospira platensis) for polluants multi-detection. This sensor has been tested on water samples of urban and hospitals effluents (before and after treatment)

Les chiffres des statistiques du cancer colorectal en France et dans le mondemontrent la nécessité de développement de plateformes technologiques plus rapides,sensibles et spécifiques pour assurer le diagnostic du cancer. Un diagnostic rapide va ainsiaider à améliorer l’état de santé et réduire le temps d’attente des résultats qui peut être ungrand facteur de stress pour les patients. L’analyse des biomarqueurs dans le sang, lesurines et autres fluides corporels est l’une des méthodes appliquées pour la détectionprécoce de la maladie. Dans le cadre de ce projet des nucléosides urinaires ont été identifiéscomme biomarqueurs pour le cancer colorectal. Financée par l’Agence Nationale de laRecherche (ANR), à travers le projet CancerSensor (programme TECSAN), cette thèse s’estdéroulée au sein de l’équipe MDA (Microsystèmes de Détection Acoustique) du laboratoireIMS. Dans le cadre de ce projet, nous avons proposé une solution technologique dedétection et de suivi de biomarqueurs du cancer colorectal. Notre choix de la stratégie dedétection s’est porté sur les polymères à empreintes moléculaires comme élément dereconnaissance des biomarqueurs. Celui-ci sera associé à un transducteur acoustique àondes de Love mis au point lors de travaux précédents au sein de l’équipe MDA. Lebiocapteur ainsi développé va cibler les nucléosides mis en évidence pour le cancercolorectal. / Colorectal cancer statistics in France and all over the world demonstrate theneed for fast, sensitive and specific technological platforms development for cancerdiagnosis. A rapid diagnosis will improve the patients’ health status and reduce the resultswaiting time which could be a great stress factor. Biomarkers analysis in blood, urine andother body fluids is recognized as one of the applied methods for early cancer detection. Inframe of this project, urinary nucleosides have been identified as colorectal cancerbiomarkers. Funded by the National Research Agency (ANR), through the cancer sensorproject (TECSAN program), this thesis was carried out in IMS laboratory. Hence, a colorectalcancer biomarkers detection and monitoring technological solution has been proposed. Inour detection strategy, Molecularly Imprinted Polymers (MIP) has been identified asbiomarker recognition element. The MIP layer has been associated to Love Wave acoustictransducer. This biosensor will sense the identified colorectal cancer nucleosides.