Le contrôle des propriétés physicochimiques et de l’état de surface des solides constituent un enjeu majeur pour le développement des biotechnologies, et notamment des bio-capteurs. Pour des applications en analyse et diagnostic biologique, la fonctionnalisation des surfaces à base de silicium peut être réalisée grâce à la formation d’un nano-film organique appelé SAM (Self-Assembled Monolayer). L'objectif de ce travail de thèse est ainsi de synthétiser des monocouches sur des substrats de silice afin de les rendre biofonctionnels en vue de développer une plateforme de biodétection polyvalente.Pour ce faire, deux types d'agents de couplages ont été envisagés : l'un possédant un motif azoture et l'autre une biotine. L’obtention de ces deux types de molécules a fait l’objet d’un travail de synthèse permettant d’aboutir à de nouveaux organosilanes fonctionnels directement greffables sur des surfaces de SiO2. La biofonctionnalité est introduite sur le substrat par la biotine, soit directement lors de la formation de la SAM, soit par chimie click sur les monocouches fonctionnalisées par des azotures.Les différentes surfaces obtenues ont ensuite été caractérisées par Spectroscopie Infrarouge de Réflexion–Absorption par Modulation de Polarisation (PM-IRRAS) et par Microscopie de Force Atomique (AFM). La bioactivité des SAMs biotinylées a enfin été évaluée par un protocole mettant en jeu une streptavidine modifiée par une enzyme (la HRP) capable de catalyser des réactions d’oxydoréduction de molécules chromogènes. / Control of surface physicochemical properties is a key aspect for the development of many biotechnological tools, such as biosensors. For analysis and diagnostic, the functionalization of silica-based surfaces may be carried out through the creation of an organic nano-film named a Self-Assembled Monolayer (SAM). The main goal of this PhD work is thus to synthesize monolayer on SiO2 substrates in order give them biofunctionality, aiming at developing a versatile biodetection platform.In order to do so, we focused on the synthesis of two types of coupling agents, either bearing an azide moiety or a biotin. This organic synthesis work led to two new sorts of functional organosilanes which can be directly grafted onto silica surfaces. Biofunctionality itself is introduced by the biotin, either through the formation of the monolayer or through click chemistry on azide-functionalized SAMs.Said surfaces were then fully characterized using Polarization Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS) an Atomic Force Microscopy (AFM). Bioactivity of biotinylated surfaces was then monitored using streptavidin conjugated with HRP in order to catalyze the redox reaction of chromogenic substrates.

Philosophiae Doctor - PhD / In this work, DNA aptamer biosensor systems were developed for the detection of l7p-estradiol - an estrogeneous endocrine disrupting chemical (EDC). Endocrine disrupting chemicals are group of compounds that impact negatively on the endocrine system of humans and wildlife. High concentrations of l7p-estradiol in water or food chain disrupts the physiology of the endocrine system of various animal species, leading to feminisation in fish and stimulates the proliferation of cancer cells in humans. Aptasensor systems for the determination of l7pestradiol were prepared with three immobilization platforms: (i) poly(3,4- ethylenedioxythiophene) {PEDOT} doped with gold nanoparticles (AuNPs) to form PEDOTIAuNPs polymeric nanocomposite, (ii) generation 1 poly(propylene thiophenoimine)-copoly( 3 ,4-ethy lenedioxythiophene) dendritic star copolymer (G 1PPT -co-PEDOT), and (iii) generation 2 poly (propylene thiophenoimine)-co-poly(3,4-ethylenedioxythiophene) dendritic star copolymer (G2PPT-co-PEDOT). The morphological properties of the sensor platforms were interrogated by scanning emission microscopy (SEM) and atomic force microscopy (AFM), while their spectroscopic characteristics were studied by Fourier transform infra red spectroscopy (FTIR) and fluorescence spectroscopy. The electrochemical behaviour of the platforms and the aptasensors were studied by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and square wave voltammetry (SWV). The DNA aptamer developed for detecting 17~-estradiol and which was used in the fabrication of all aptamer biosensors in this study is a 76-mer biotinylated aptamer (5'-BiotinGCTTCCAGCTTATTGAATTACACGCAGAGG TAGCGGCTCTGCGCATTCAATGCTGCGCGCTGAAGCGCGGAAGC-3'). AulPEDOTIAuNPslAptamer (platform 1) was obtained by covalently attaching streptavidin to the polymeric nanocomposite platform using carbodiimide chemistry and the aptamer immobilized via streptavidin-biotin interaction. The electrochemical signal generated from the aptamer-target molecule interaction was monitored electrochemically using cyclic voltammetry and square wave voltammetry in the presence of [Fe(CN)6J 3-/4- as a redox probe. The signal current observed was inversely proportional to the concentration of 17Bestradiol. The aptasensor demonstrated specificity toward 17~-estradiol. The detectable concentration range of the 17B estradiol was 0.01 nM-O .09 nM with a detection limit of 3.2 pM. The 76-mer biotinylated aptamer for 17~-estradiol was incorporated into a generation 1 poly(propylenethiophenoimine )-co-poly(3 ,4-ethylenedioxythiophene) dendritic star copolymer modified Au electrode via biotin-avidin interaction (platform 2). The Bode plot shows that the charge transfer dynamics of the nanoelectrode can be frequency modulated while the AulG 1PPTco- PEDOT nanoelectrode exhibited greater semi-conductor behavior (higher phase angle value) than AulG 1PPT due to the incorporation of charged functionalized dendrimer at low frequencies (100 mHz). The biosensor response to 17~-estradiol was based on the decrease in the SWV current as the EDC binds to the ssDNA aptamer on the biosensor. The dynamic linear range of the sensor was 0.01-0.07 nM with a detection limit of7.27 pM. Synthesis of electro synthetic generation G2PPT-co-PEDOT (platform 3) was performed by copolymerization of PEDOT with G2PPT dendrimer modified electrode immersed in a solution of 0.1 M LiCI04 containing 0.1 M EDOT monomer and 0.1 M sodium dodecyl sulphate (SDS) for ten (10) cycles. The electrochemical behaviour of the dendritic star copolymer was investigated with CV and EIS in LiCI04 and phosphate buffer solutions. The results show that the electrochemical deposition of G2PPT-co-PEDOT on gold electrode decreased the electrochemical charge transfer resistance when compared to AuiPEDOTILiCI04 and AuiLiCI04 interfaces. Bode impedimetric analysis indicates that G2PPT-co-PEDOT is a semiconductor. The fabrication of two novel aptasensors (based on platforms 2 and 3) simultaneously on a screen printed micro array electrode of 96-well multichannel electrochemical robotic sensor testing system for the detection of endocrine disrupting l7~-estradiol, was also carried out. The aptasensors responses to l7~-estradiol, based on the decrease in the SWV current, were evaluated.

This thesis deals with bolted steel tanks, especially modification one of them. This modification is realized in cooperation with Kohimex spol. s r.o., which is assembling theese tanks for many years. The thesis continues on the bachelor one called "ASSEMBLED STEEL TANKS", which has already dealt with this issue. At the beginning of the thesis the issue of tanks is explained. Furthermore, there is made description of the tank modification details. At the next stage, the work presents stress-strain states of the tank, first for the current tank and then for the modified option. On the basis of completed analysis is made economic evaluation of design modified tank option due to the current tank. The results of this study allow better issue understanding of bolted tanks designing or they give impuls to improve the current way of designing.

Die Oberflächeneigenschaften eines Festkörpers können mit Hilfe dünner, durch Selbstorganisation gebildeter Molekülschichten aus Alkoxysilan-Molekülen gezielt verändert werden. Mikrostrukturierte selbstangeordnete Monolagen (SAM) können für die Anwendung in Bauelementen aus organischen Halbleitern von großem Interesse sein. Mikrokontaktdruck und Photolithographie sind zwei etablierte Verfahren, die jedoch Vorlagen und Masken zur Strukturierung benötigen. Dadurch entstehen bei häufig wechselnden Strukturen nicht zu vernachlässigende Rüstzeiten und Kosten. In der vorliegenden Arbeit wird die Erzeugung lateral strukturierter Schichten von Octadecyltrichlorsilan (OTS) auf Siliziumoxidoberflächen am konkreten Beispiel zweier alternativer, sowohl maskenloser als auch kontaktloser Methoden demonstriert: (i) Tintenstrahlverfahren als rein additive Strukturierung, und (ii) laserinduzierte, photothermische Desorption als subtraktive Strukturierung einer OTS-SAM . Für das Tintenstrahldruckverfahren wird an einem Kontaktwinkelmessgerät eine Methode zur Beobachtung und Auswertung der Tropfenverdampfung implementiert und ein Modell für kleine Tropfen entwickelt. Für die subtraktive Strukturierung werden an einem selbst entwickelten Versuchsaufbau die leistungs- und geschwindigkeitsabhängige Strukturbreite untersucht. Die Ergebnisse der beiden Technologieansätze werden verglichen. / With help of thin layers of alkoxysilane molecules formed by self-assembly, the surface properties of solids can be controlled. Microstructured self-assembled monolayers (SAMs) are interesting for applications in components based on organic semiconductors. Two established technologies for the structuring of molecular monolayers are microcontact printing and photolithography, for which templates and masks need to be structured. In this way, setting times and costs are high if variable patterns have to be structured. In this work, the fabrication of laterally structured monolayers from octadecyltrichlorosilane (OTS) is demonstrated for two examples of alternative, both template-free and maskless technologies: (i) inkjet as a purely additive method, and (ii) photothermal laser desorption as a subtractive structuring of an OTS-SAM. For the inkjet technology, a method for the observation and analysis of the evaporation of a droplet is implemented at a goniometer and a mathematical model for small inkjet droplets is extrapolated, For the subtractive laser structuring, the achievable patterning resolution is investigated as a function of laser intensity and scanning speed. The results of both technological approaches are compared.

This work is aimed at the preparation and morphological and spectroscopic characterization of the interphase nanocomposite (NC) two-dimensional (2D) self-assembled systems of Ag and Au nanoparticles (NPs). The NPs were functionalized with the following ligands with terpyridine end-groups: 2,2′:6′,2′′-terpyridine (tpy), 4'-(2-thienyl)-2,2':6',2''- terpyridine (T-tpy), α,ω-bis(terpyridyl)-2,2'-bithiophene (tpy-2T-tpy) and α,ω-bis(terpyridyl)- 2,2':5',2''-terthiophene (tpy-3T-tpy). The morphological analysis of transmission electron micrographs proves the preservation of the average interparticle distance in closely spaced NP pairs, independent of the ligand. The value of the total average interparticle distance increases in the order: tpy < T-tpy < tpy- 2T-tpy < tpy-3T-tpy, while the average occupied area fraction in the same order decreases. The morphological descriptors (i.e. interparticle distance and occupied area fraction) were found to correlate with the shift of the SPE (surface plasmon extinction) maxima of NCs (tpy > T-tpy > tpy-2T-tpy > tpy-3T-tpy). The results show that the shift of SPE band maximum depends on the degree of surface plasmon delocalisation rather than on the value of the average interparticle distance in closely spaced NP pairs. The smaller are the islands formed by closely...

RésuméLes monocouches auto-assemblées d'ADN immobilisées sur électrodes d'or sont à la base de nombreux biocapteurs électrochimiques. Le contrôle du comportement interfacial de l'ADN par le biais d'un champ électrique est intéressant pour la détection de polymorphisme nucléotidique simple (PNS). La caractérisation in situ de monocouches d'ADN à l'échelle moléculaire est importante pour la fabrication de biocapteurs robustes, fiables et sensibles.La thèse porte sur la détection du PNS dans l'ADN par le biais d'hybridation/dénaturation induite par le champ électrique. La microscopie de fluorescence sous conditions électrochimiques est utilisée comme méthodologie de détection et outil de caractérisation de l'interface d'ADN. À cette fin, des séquences d'ADN marquées par des sondes fluorescentes sont immobilisées sur des électrodes d'or sous forme de monocouches auto-assemblées (SAM) thiolées.Premièrement, les SAMs sont composées de séquences cibles présentant ou non une mutation ponctuelle. La relation entre le potentiel appliqué et la dénaturation du double brin est étudiée. La dénaturation électrochimique est observée à -0,25 V vs Ag / Deoxyribonucleic acid (DNA) self-assembled monolayers (SAMs) immobilized on gold electrodes are the basis of many electrochemical biosensors. Control of the interfacial behavior of DNA by means of an electric field is of interest for sensing applications such as the detection of single nucleotide polymorphisms (SNPs). Moreover, the in situ characterization of immobilized DNA monolayers at a molecular level is important for the fabrication of robust, reliable and sensitive sensors.The thesis aims at studying the discrimination between DNA strands containing SNPs on the basis of electric-field assisted hybridization/denaturation of DNA. In situ electrochemical fluorescence microscopy is used as a detection methodology and characterization tool for DNA interfaces. For this purpose, fluorescently labeled DNA sequences are immobilized at gold electrodes as thiol SAMs.First, the SAMs under investigation were composed of perfect match or SNP-containing target sequences. The relationship between the applied potential and the denaturation of DNA duplexes was investigated. Electrochemical melting was observed at -0.25 V vs. Ag / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

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Diese Arbeit beinhaltet unsere Studien an selbstorganisierenden Monoschichten (engl. SAM = self- assembled monolayer) einiger aromatischer Thiole auf Gold- und Kupferoberflächen. Die Bildung von Monoschichten von Thiophenol, 4-Mercaptophenol, 4-Nitrothiophenol, 4-Aminothiophenol, 1,4-Dithiobenzol, 4-Mercaptopyridin und 2-Mercaptopyridin auf Au und Cu wurde untersucht und charakterisiert. Das abschirmende Verhalten und die strukturelle Anordnung dieser Monoschichten wurden mit Hilfe elektrochemischer und spektroskopischer Methoden geprüft und bestimmt. Zyklische Voltammetrie und oberflächenverstärkte Raman Spektroskopie wurden intensiv zur Aufklärung von Elektronentransferreaktionen an diesen mit SAMs modifizierten Oberflächen genutzt. Elektrochemische Studien von Monoschichten aus Thiophenol, 4-Mercaptophenol, 4-Nitrothiophenol, 4-Aminothiophenol, 1,4-Dithiobenzol, 4-Mercaptopyridin und 2-Mercaptopyridin in 0,1 M wässriger KClO4-Lösung lassen schlussfolgern, dass diese Moleküle schwefelseitig an die Substratoberfläche gebunden sind. In 0,1 M wässriger KClO4-Lösung aufgenommene zyklische Voltammogramme an Gold- und Kupferoberflächen, welche mit oben genannten, aromatischen Thiolen beschichtet wurden, legen nahe, dass Adsorptionsschichten von Thiophenol und 1,4-Dithiobenzol eine stärkere Tendenz zum Abschirmen besitzen als andere. Durch das Einbringen von Kupferproben, welche mit genannten aromatischen Thiolen behandelt wurden, in 0,1 M Silbernitrat-Lösung können sehr leicht Silber-Nanodendritstrukturen erhalten werden. Abscheidezeit und Konzentration der Silbernitrat-Lösung haben einen großen Einfluss auf das Wachstum der Silber-Nanodendritstrukturen auf den modifizierten Kupferproben. Diese Silber-Nanodendritstrukturen besitzen eine hohe katalytische Aktivität hinsichtlich der Oxidation von Hydroquinon. Untersuchungen zur Korrosion an polykristallinem Kupfer, welches mit obigen aromatischen Thiolen modifiziert wurde, in 0,1 M Silbernitrate-Lösung ließen vermuten, dass dieses Kupfersubstrat mehr anodisches Verhalten zeigte als reines Kupfer bei ähnlichen Bedingungen. Zyklische Voltammetrie an wie oben behandeltem Kupfer in 0,1M wässriger KClO4-Lösung zeigte, dass die Geschwindigkeit der Kupferauflösung bei diesen Messungen erhöht war gegenüber anderen, in welchen reines Kupfer bei identischen Bedingungen eingesetzt wurde. / It deals with our studies on self-assembled monolayers of aromatic thiols on gold and copper surfaces. Monolayer formation of thiophenol, 4-mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 1,4-dithiobenzene, 4-mer¬cap¬to¬pyridine and 2-mercaptopyridine on Au and Cu surfaces was studied and characterized. The blocking behaviour and structural arrange¬ments of these monolayers were evaluated and characterized using electrochemical and spec¬troscopic techniques. Cyclic voltammetry and surface enhanced Raman spectroscopy were extensively used for the study of electron transfer reactions on these SAM modified surfaces. Electrochemical and spectroelectrochemical studies of thiophenol, 4-mercaptophenol, 4-nitrothiophenol, 4-aminothiophenol, 1,4-dithiobenzene, 4-mercaptopyridine and 2-mercaptopyridine monolayers in aqueous solution of 0.1 M KClO4 suggest that these molecules adsorbed to substrate. Cyclic voltammetry of gold and copper covered with these aromatic thiolates recorded in aqueous solution of 0.1 M KClO4 suggests that adlayers of thio¬phenol and 1,4-dithiobenzene exhibit more blocking behavior than the other ones. Silver nanodendritic structures are easily produced by placing copper samples modified with these aromatic thiolates into 0.1 M silver nitrate solution. Deposition time and concentration of silver nitrate solution have great influence on growing up silver nanodendritic structures on the surface of modified copper samples. These silver nanodendritic structures exhibit electrocatalytic activity towards the oxidation of hydroquinone. Corrosion investigation of polycrystalline copper modified with these aromatic thiolates in 0.1 M silver nitrate solution suggest that copper substrate might be more anodic compared to bare copper under identical condition. Cyclic voltammetry of copper modified with these aromatic thiolates suggests that the rate of dissolution copper in aqueous solution of 0.1 M KClO4 is higher than bare copper in the same condition.

Im Vortrag wird die Vorgehensweise zur Modellierung des Ventiltriebs eines Einzylinder-Motorradmotors beschrieben. Dieser setzt sich aus zwei gebauten, wälzgelagerten Nockenwellen zusammen. Die Ventile werden über Schlepphebel betätigt. Das Hauptaugenmerk liegt dabei auf den Pressverbindungen zwischen Nocken und Welle sowie auf den Wälzlagerungen. Um die Belastungszustände zu ermitteln ist eine detaillierte Simulation nötig. Diese Mehrkörpersimulation wird in Mathcad mit Hilfe eines eigenen Lösers durchgeführt.

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