Lab-on-a-chip systems for point-of-care testing demonstrate a promising development towards more accurate diagnostic tests that are of extreme importance for the future global health. This work presents an agglutination assay performed in micrometer sized well using Janus PS/Ag/AgCl micromotors to enhance the interactions between goat anti-human IgM functionalized particles and Human IgM. The fabricated microwell chips are a suitable platform to analyze the interaction between different particles and to perform the agglutination assays. The interaction between active Janus particles and passive and functionalized particles is studied, as well as the influence of ions on the motion of the Janus particles. Agglutination assays are performed with and without the presence of Janus particles, and in different PBS concentrations. Once illuminated with blue light, passive SiO2 particles were effectively excluded from Janus particles, while SiO2 NH2 particles revealed attraction. In contrast, functionalized SiO2 NH2 Ab particles suspended in PBS did not show any interaction. It was found that the optimal working conditions for antibodies and Janus particles differed and, as a result, the Janus particles did not reveal a desirable interaction between the functionalized particles and IgM. Further experiments should be performed to find the proper conditions in which the antibodies and the Janus particles maintain their activities. It is believed that an effective interaction between the functionalized and Janus particles could be achieved by modifying the parameters that affect their interaction such as the zeta potential and the medium in which the assay is being performed. This preliminary work provides the first steps towards the development of a fully integrated lab on a chip system for point of care testing.:Abstract ........................................................................................................................ iii Acknowledgments.......................................................................................................... v Table of Contents .......................................................................................................... vi List of Tables ............................................................................................................. viii List of Figures ............................................................................................................... ix Abbreviations ................................................................................................................. x 1. Introduction ............................................................................................................ 1 1.1 In vitro diagnostic tests ........................................................................................ 1 1.1.1 Point-of-care tests ......................................................................................... 2 1.2 Agglutination assay .............................................................................................. 2 1.3 Lab-on-a-chip ....................................................................................................... 5 1.4 Self-propelled particles ........................................................................................ 6 1.4.1 Light-driven Ag/AgCl micromotors ............................................................. 6 1.5 Aim ...................................................................................................................... 9 2. Materials and Methods ......................................................................................... 11 2.1 Microwell fabrication .................................................................................... 11 2.2 Microswimmers fabrication .......................................................................... 12 2.3 Functionalization of particles ........................................................................ 12 2.4.1 Scanning electron microscope ............................................................... 14 2.4.2 UV-vis spectroscopy .............................................................................. 14 2.4.3 Zeta potential ......................................................................................... 14 2.4.4 Optical microscopy ................................................................................ 15 2.5 Motion Experiments ...................................................................................... 15 2.6 Agglutination assay ....................................................................................... 16 2.7 Effect of PBS ................................................................................................. 16 2.7.1 Janus particles ........................................................................................ 16 2.7.2 Agglutination assay ................................................................................ 17 2.7.3 Exclusion of functionalized particles ..................................................... 17 3. Results and Discussion ........................................................................................ 18 3.1 Microwell chip with integrated Janus particles ................................................. 18 3.2 Characterization of particles .............................................................................. 19 3.2.1 UV-vis spectroscopy ................................................................................... 19 3.2.2 Zeta potential .............................................................................................. 21 3.2.3 Agglutination assay in PEG-covered glass slides ....................................... 22 3.3 Motion experiments ........................................................................................... 23 3.3.1 Exclusion time ............................................................................................ 23 3.3.2 On/off light cycles....................................................................................... 26 3.4 Agglutination assay ............................................................................................ 28 3.4.1 Assay performed in wells............................................................................ 28 3.4.2 Assay performed in wells with Janus particles ........................................... 29 3.5 Effect of PBS concentration............................................................................... 30 3.5.1 Janus particles ............................................................................................. 30 3.5.2 Agglutination assay ..................................................................................... 32 3.5.3 Exclusion of functionalized particles .......................................................... 33 4. Conclusions .......................................................................................................... 35 References .................................................................................................................... 37 Declaration of Research Integrity and Good Scientific Practice ................................. 42

Des colloïdes à base de silice et de polystyrène ont été synthétisés. Les particules d’oxyde ont d’abord été élaborées et modifiées en surface, puis ont servi de germes au cours d’une étape de polymérisation du styrène. Deux procédés de polymérisation en phase hétérogène ont été utilisés (émulsion ou dispersion) menant à des colloïdes aux morphologies originales et contrôlées. Une étude morphologique par tomographie électronique a permis de mieux comprendre les mécanismes de croissance et d’organisation des particules de latex autour des germes de silice. La synthèse de particules Janus pour l’imagerie biomédicale est aussi décrite. Ces particules de silice ont été modifiées en surface par un chromophore biphotonique et un agent de reconnaissance de certaines cellules tumorales. Des études spectroscopiques et des tests de cytotoxicité ont été entrepris. / Hybrid colloids based on silica and polystyrene have been synthesized. Oxide particles were first elaborated, surface modified, and then used as seed in a styrene polymerization step. Two heterogeneous polymerisation proceeds were employed (emulsion or dispersion) leading to colloids with original and controlled morphologies. A morphological study by electronic tomography enabled to better understand growth and organisation mechanisms of latexes around silica seeds. Janus particles synthesis for biomedical imaging is also described. Silica particles were surface modified with a biphotonic chromophore and a tumor cells targeting agent. Spectroscopic studies and cytotoxicity tests were investigated.

L’électrochimie bipolaire est possible quand un substrat conducteur qui n’est pas directement connecté à un générateur est exposé à un champ électrique. Il s’agit donc d’une technique « sans fil ». La polarisation du substrat par rapport à la solution génère une différence de potentiel entre les extrémités du substrat qui peuvent devenir le siège de réactions rédox et briser ainsi la symétrie à la surface du substrat. Dans cette thèse, cette méthode a été appliquée à l’élaboration de matériaux ainsi qu’à l’étude de systèmes biologiques. L’électrochimie bipolaire a été adaptée pour la préparation « bulk » de particules asymétriques également appelées particules « Janus ».Des substrats conducteurs de différentes natures, tailles et formes ont été modifiées avec des dépôts métalliques, ioniques ou inorganiques. De plus, un contrôle de la morphologie du dépôt a été possible sur des substrats d’échelle variée. L’électrodéposition bipolaire permet d’étudier la génération de différentes morphologies métalliques, ainsi que la micro-structuration sur des objets conducteurs grâce au développement de nouveaux setups expérimentaux. Le concept s’est également montré très utile dans le domaine de la mise en mouvement de particules. D’une part, les objets asymétriques qui ont été préparés par électrodéposition bipolaire peuvent agir comme des micro-nageurs capables de mouvement de translation ou de rotation. D’autre part, l’application d’un champ électrique peut directement induire le déplacement d’objets isotropes par génération localisée de bulles. Un mouvement de lévitation combinée à l’émission de lumière est également possible. Finalement, l’électrochimie bipolaire a été utilisée pour étudier la conductivité de biomolécules (ADN), ce qui est d’une grande importance dans le domaine de la nanotechnologie. / Bipolar electrochemistry deals with the exposure of an isolated conducting substrate that has no direct connection with a power supply except via an electric field. Therefore it can be considered as a “wireless technique”. The polarization of the substrate with respect to the surrounding medium generates a potential difference between its opposite ends which can support localized electrochemical oxidation reduction reactions and break the surface symmetry of the substrate. The method was applied in the present thesis to materials science and biological systems. In the frame of designing asymmetric particles, also called “Janus” particles, bipolar electrochemistry was adapted for the bulk preparation of these objects. Conductive substrates with different nature, sizes and shapes have been modified with various materials such as metals, ionic and inorganic compounds using this approach. Moreover, a control over the deposit topology could be achieved for substrates at different length scales. Bipolar electrodeposition is also a good tool for investigating the generation of different metal morphologies. Further developments in the bipolar setup allowed us to use the technology for microstructuration of conductive objects. Furthermore the concept has shown to be very useful in the field of the induced motion of particles. The asymmetric objects that have been prepared by bipolar electrodeposition were employed as microswimmers which could show both translational and rotational motion. The application of electric fields in the bipolar setup can be used for the direct generation of motion of isotropic objects through bubble generation. A levitation motion of objects combined with light emission was possible using this concept. Finally, bipolar electrochemistry was also used for studying the intrinsic conductivity of biological molecules (DNA), which is of great importance in the nanotechnology.

This thesis described the development of new strategies for the preparation of micro- and nano-structured polymer materials. In particular, this thesis focused on: i) the synthesis of polymer particles in microreactors, and ii) the self-assembly of inorganic nanorods. First, this thesis presented the synthesis of polymer particles and capsules with pre-determined sizes and narrow size distributions (CV<2%) in continuous microfluidic reactors. The method includes (i) the emulsification of monomers in a microfluidic flow-focusing device and (ii) in-situ solidification of droplets via photopolymerization. This microfluidic synthesis provides a novel strategy for the control over the shapes, compositions, and morphologies of polymer particles. In particular, we demonstrated the control over particle shapes by producing polymer ellipsoids, disks, rods, hemispheres, plates, and bowls. We produced polymer particles loaded with dyes, liquid crystals, quantum dots, and magnetic nanoparticles. We generated core-shell particles, microcapsules, Janus and three-phasic polymer particles. Control over the number of cores per droplet was achieved by manipulating the flow rates of liquids in the microchannels. We further investigated the hydrodynamic mechanism underlying the emulsification of droplets, which helps in guiding scientists and engineers to utilize this technique. Second, we described the self-assembly of inorganic nanorods by using a striking analogy between amphiphilic ABA triblock copolymers and the hydrophilic nanorods tethered with hydrophobic polystyrene chains at both ends. We organized metal nanorods in structures with various geometries such as nanorings, nanochains, bundles, bundled nanochains, and nanospheres by tuning solely the quality of solvents. The self-assembly was tunable and reversible. This approach paved the way for the organization of anisotropic nanoparticles by using the strategies that are well-established for the self-assembly of block copolymers. We further described a systematic study of the self-assembly of polymer-tethered gold nanorods as a function of solvent composition in the system and the molecular weight of the polystyrene blocks. We found that the structure of the polymer pom-poms played an important role on the organization of polymer-tethered gold NRs. The 'supramolecular' assembly was governed by the competition between the end-to-end and side-by-side association of NRs and resulted in the controlled variation of the plasmonic properties of NRs, reflected in a 3-D plasmonic graph.

This thesis described the development of new strategies for the preparation of micro- and nano-structured polymer materials. In particular, this thesis focused on: i) the synthesis of polymer particles in microreactors, and ii) the self-assembly of inorganic nanorods. First, this thesis presented the synthesis of polymer particles and capsules with pre-determined sizes and narrow size distributions (CV<2%) in continuous microfluidic reactors. The method includes (i) the emulsification of monomers in a microfluidic flow-focusing device and (ii) in-situ solidification of droplets via photopolymerization. This microfluidic synthesis provides a novel strategy for the control over the shapes, compositions, and morphologies of polymer particles. In particular, we demonstrated the control over particle shapes by producing polymer ellipsoids, disks, rods, hemispheres, plates, and bowls. We produced polymer particles loaded with dyes, liquid crystals, quantum dots, and magnetic nanoparticles. We generated core-shell particles, microcapsules, Janus and three-phasic polymer particles. Control over the number of cores per droplet was achieved by manipulating the flow rates of liquids in the microchannels. We further investigated the hydrodynamic mechanism underlying the emulsification of droplets, which helps in guiding scientists and engineers to utilize this technique. Second, we described the self-assembly of inorganic nanorods by using a striking analogy between amphiphilic ABA triblock copolymers and the hydrophilic nanorods tethered with hydrophobic polystyrene chains at both ends. We organized metal nanorods in structures with various geometries such as nanorings, nanochains, bundles, bundled nanochains, and nanospheres by tuning solely the quality of solvents. The self-assembly was tunable and reversible. This approach paved the way for the organization of anisotropic nanoparticles by using the strategies that are well-established for the self-assembly of block copolymers. We further described a systematic study of the self-assembly of polymer-tethered gold nanorods as a function of solvent composition in the system and the molecular weight of the polystyrene blocks. We found that the structure of the polymer pom-poms played an important role on the organization of polymer-tethered gold NRs. The 'supramolecular' assembly was governed by the competition between the end-to-end and side-by-side association of NRs and resulted in the controlled variation of the plasmonic properties of NRs, reflected in a 3-D plasmonic graph.

Dans cette thèse nous avons étudié la mise en forme de matériaux carbonés par des méthodes électrochimiques pour des applications dans les domaines des capteurs et de l’énergie. Dans la première partie, l’électrochimie bipolaire, qui permet de réaliser des réactions électrochimiques sur un objet conducteur présent dans une solution et soumise à un champ électrique, a été utilisée pour générer des objets de type Janus. Ces objets asymétriques ont été modifiés à une extrémité par du poly(N-isopropylacrylamide (pNIPAM), un hydrogel sensible à la température, et par une peinture électrophorétique à l’autre extrémité. En contrôlant l’intensité du champ électrique ainsi que son temps d’application il a été possible de varier la longueur ainsi que l’épaisseur de l’hydrogel. Ces objets sensibles à la température, émettant de la lumière, ont des applications potentielles dans le domaine des capteurs ou dans le milieu médical.Dans la seconde partie, la mise en forme de carbone poreux pour des applications électrochimiques a été étudiée. La carbonisation de polymères contenant du zinc a été utilisé pour synthétiser du carbone micro/mésoporeux possédant ainsi une grande surface spécifique. Les polymères contenant du zinc ont été préparés à partir de différents types de ligands d’acide dicarboxylique par une méthode solvothermique. Ils ont ensuite été carbonisés pour obtenir des matériaux poreux avec des caractéristiques et des propriétés particulières. Ils ont été utilisés comme matériaux d’électrode pour des supercondensateurs, montrant des capacités élevées. De plus ils possèdent également une activité électrocatalytique à la réaction de réduction de l’oxygène. / In this thesis, the design of advanced carbon materials via electrochemical techniques and for electrochemical applications have been studied. In the first part, the concept of bipolar electrochemistry, which allows carrying out electrochemical reactions on a free-standing conductive object in an electric field, was employed to generate Janus-type objects. These objects are modified with a thermoresponsive hydrogel of poly(N-isopropylacrylamide) (pNIPAM) on one side and an electrophoretic deposition paint (EDP) on the other side. The results show that the length and the thickness of the hydrogel can be controlled by varying the electric field and the time of the experiment. The concept can be further generalized to other micro- and nanometer-sized objects, thus opening up perspectives for various applications.In the second part, the design of porous carbon structures for electrochemical applications was studied. The direct carbonization of non-porous zinc containing polymers was used to synthesize micro/mesoporous carbons with high surface area, pore volume. Non-porous zinc containing polymers with various types of dicarboxylic acid ligands prepared by solvothermal method were used as templates and starting materials. After carbonization porous carbons with various characteristics and properties were obtained. The synthesized porous carbon samples showed good electrochemical performance with high capacitance values. In addition, the derived materials exhibit excellent electrocatalytic activity with respect to the oxygen reduction reaction (ORR).

The exploitation of colloidal building blocks with morphological and functional anisotropy facilitates the generation of complex structures with unique properties, which are not exhibited by isotropic particle assemblies. Herein, we demonstrate an easy and scalable bottom-up approach for the programmed assembly of hairy oppositely charged homogeneously decorated and Janus particles based on electrostatic interactions mediated by polyelectrolytes grafted onto their surface. Two different assembly routes are proposed depending on the target structures: raspberry-like/half-raspberry-like or dumbbell-like micro-clusters. Ultimately, stable symmetric and asymmetric microstructures could be obtained in a well-controlled manner for the homogeneous–homogeneous and homogeneous–Janus particle assemblies, respectively. The spatially separated functionalities of the asymmetric Janus particle-based micro-clusters allow their further assembly into complex hierarchical constructs, which may potentially lead to the design of materials with tailored plasmonics and optical properties.

The main subject of this thesis is to examine thermo-osmotic flows, which occur on interfaces of non-uniform temperature. Such thermo-osmotic flows are purely non-thermal equilibrium phenomena. Along the non-isothermal interface, specific interaction of a liquid and its solutes with a boundary vary in strength across the interface, according to the local temperature. This boundary can be a solid, a membrane or a phase boundary. The flow is thereby continuously pumping fluid across the interface in direction of the local temperature gradient, resulting in an extended flow pattern in the bulk due to mass conservation. In a system containing particles and heat sources in a liquid under spatial confinement, the thermo-osmotic flow may drive particles in a directed manner, or can lead to collective phenomena. To approach this broad topic of (self-)thermophoresis and collective motion of active particles and quantify the role of the thermo-osmotic flow upon the latter effects, different experiments have been performed: The first experiments aim to quantify the thermo-osmotic flow at a non-isothermal liquid/solid interface for two fundamentally different substrate properties. Further, the bulk flow was investigated for two different systems. The form and spatial extension of this bulk flow pattern depends sensitively on the form of the container and the interface, as well as on the thermo-osmotic flow. The first system is a liquid film confined between two planar glass cover slips. The second case is a Janus particle immobilized on one of the glass slips. In the first case, the non-uniform temperature profile is generated by optical heating of a nanometer sized gold colloid, and in the second case, the heat source is the Janus particle. The bulk flow pattern consists, for the second case, of the flow pattern created by the glass cover slips and the one created by the Janus particle. The following experiments are focusing on the dynamics of mobile self-thermophoretic Janus particles. In particular, their dynamics and the contributions of the thermo-osmotic flow to the interaction of multiple active particles are investigated. To investigate those particles under controlled conditions and examine their interactions at low concentrations for an effectively unlimited amount of time, a real-time feedback algorithm was co-developed to gain control of the motion of multiple active particles simultaneously, called ”photon nudging”. With the help of this method, first experiments have been performed to quantify the dynamics of a Janus particle located close to a heat source.

No description available.

Tesis por compendio / [ES] La presente tesis doctoral titulada "Nanodispositivos mesoporosos híbridos funcionalizados con enzimas para detección, liberación controlada y comunicación molecular" se centra en el diseño, preparación, caracterización y evaluación de distintos nanodispositivos híbridos orgánico-inorgánicos utilizando como soporte nanopartículas tipo Janus de oro y sílice mesoporosa, que se equipan con enzimas, especies fluorescentes y puertas moleculares. Como conclusión general, los estudios realizados muestran que la incorporación de enzimas sobre nanopartículas permite introducir funciones de reconocimiento con alta especificidad y diseñar nanodispositivos avanzados para distintas finalidades. La combinación de nanopartículas híbridas con grupos orgánicos como puertas moleculares, efectores enzimáticos y especies cromo- fluorogénicas o fármacos puede resultar muy versátil; y se espera que los resultados obtenidos puedan inspirar el desarrollo de nuevos materiales inteligentes con aplicación en distintas áreas como la nanomedicina y la detección de moléculas de interés. / [CA] La present tesi doctoral titulada "Nanodispositius mesoporosos híbrids funcionalitzats amb enzims per a detecció, alliberació controlada i comunicació molecular" es centra en el disseny, preparació, caracterització i avaluació de distints nanodispositius híbrids orgànic-inorgànics utilitzant com a suport nanopartícules tipus Janus d'or i sílice mesoporosa, que s'equipen amb enzims, espècies fluorescents i portes moleculars. Com a conclusió general, els estudis realitzats mostren que la incorporació d'enzims sobre nanopartícules permeten introduir funcions de reconeixement amb alta especificitat i dissenyar nanodispositius avançats per a distintes finalitats. La combinació de nanopartícules híbrides amb grups orgànics com portes moleculars, efectors enzimàtics i espècies cromo-fluorogèniques o fàrmacs pot resultar molt versàtil; i s'espera que els resultats obsessos inspiren el desenvolupament de nous materials intel·ligents amb aplicació en distintes àrees com la nanomedicina i la detecció de molècules d'interés. / [EN] This PhD thesis entitled "Enzyme-functionalized hybrid mesoporous nanodevices for sensing, controlled release and molecular communication" is focused on the design, synthesis, characterization and evaluation of several hybrid organic-inorganic nanodevices using Janus gold-mesoporous silica nanoparticles as scaffolds, equipped with enzymes, fluorescent species and molecular gates. In conclusion, these studies show that the incorporation of enzymes on nanoparticles allows to introduce recognition capabilities with high specificity and to design advanced nanodevices for different purposes. The combination of hybrid nanoparticles with organic groups such as molecular gates, enzymatic effectors and chromo-fluorogenic species or drugs can be very versatile; and we hope that the obtained results inspire the development of new smart materials with application in different areas such as nanomedice and sensing. / Llopis Lorente, A. (2019). Enzyme-functionalized hybrid mesoporous nanodevices for sensing, controlled release and molecular communication [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/117612 / Compendio