Metal and semiconducting nanocrystals have received a great deal of attention from fundamental scientists and application-oriented researchers due to their physical and chemical properties, which differ from those of bulk materials. Nanocrystals are essential building blocks in the development of nanostructured devices for energy conversion. Colloidal metals and metal chalcogenides have been developed for use as nanocrystal inks to produce efficient solar cells with lower costs. All high-performing photovoltaic nanocrystals contain toxic elements, such as Pb, or scarce elements, such as In; thus, the production of solution-processable nanocrystals from earth-abundant materials using environmentally benign synthesis and processing methods has become a major challenge for the inorganic semiconductor-based solar field. This dissertation, divided into two parts, addresses several aspects of these emerging challenges. The first portion of the thesis describes the synthesis and characterization of nanocrystals of antimony sulfide, which is composed of non-scarce and non-toxic elements, and examines their performance in photovoltaic devices. The effect of various synthetic parameters on the final morphology is explored. The structural, optical and morphological properties of the nanocrystals were investigated, and Sb2S3 nanocrystal-based solid-state semiconductor-sensitized solar cells were fabricated using different deposition processes. We achieved promising power conversion efficiencies of 1.48%. The second part of the thesis demonstrates a novel method for the in situ synthesis and patterning of nanocrystals via reactive inkjet printing. The use of low-cost manufacturing approaches for the synthesis of nanocrystals is critical for many applications, including photonics and electronics. In this work, a simple, low-cost method for the synthesis of nanocrystals with minimum size variation and waste using reactive inkjet printing is introduced. As a proof of concept, the method was used for the in situ synthesis of gold nanoparticles as a model system. Relatively monodisperse gold nanoparticles were produced. The size and shape of gold nanoparticles can be controlled by the gold precursor and surfactant concentration in the ‘ink.’ This approach can be extended to the synthesis of other nanocrystals and is thus a truly impactful process for the low-cost synthesis of materials and devices incorporating nanocrystals.

One of the main subjects of this thesis is to design a novel synthetic route to covalently functionalize carbon nanotubes with various molecules in a non-toxic way on both surface and suspension. Functionalized carbon nanotubes are of great interest in the field of molecular electronics, materials science and nano-bio applications because of their remarkable structural, chemical and physical properties. First, the single-walled carbon nanotubes are functionalized with gold nanoparticles by the route, which involves silanization and copper-free click chemistry (SPAAC). We characterize the functionalized nanotubes through XPS, IR and Raman spectroscopic techniques to identify the surface attachment of molecules after each step. We observe a drastic change in homogeneity and functionalization density of single-walled carbon nanotubes with gold nanoparticles concerning solvent through TEM. Employing the same route, biomolecules such as fluorescent dyes and single-stranded DNA molecules are integrated with SWNTs. Fluorescence lifetime analysis of AF647 functionalized SWNTs is reduced compared to free dye due to the fluorescence quenching phenomenon of carbon nanotubes. Functionalized SWNTs are characterized with FLIM, SEM, and Raman for better correlation at the same area of interest. Furthermore, the nanotubes are resolved at the nanoscale level through STORM imaging technique with a limited photon budget. Single-stranded DNA molecules of different lengths are used to investigate the fluorescence quenching as they are distance-dependent. DNA-PAINT is engaged in imaging the functionalized SWNTs with an unlimited photon budget, overcoming STORM's challenge. Lastly, the route is transferred to surface-grown CNTs through the CVD technique, in which both the gold nanoparticles and fluorescent dyes are grafted with nanotubes selectively. CVD is carried out on different substrates Si/SiO2, quartz substrate and quartz coverslip for substrate functionalization. Catalyst deposition plays a significant role in not only the CVD growth but also in the lifetime analysis of the substrate functionalized nanotubes. We observe similar fluorescence quenching of nanotubes in the substrate compared with nanotubes functionalized in suspension. Surface-grown nanotubes in the optically transparent substrate can be resolved through STORM at the nanoscale level. In conclusion, we demonstrate a synthetic design to functionalize SWNTs which provides the possibility to be versatile and non-toxic. Moreover, we show that the nanotubes can be functionalized through this route homogeneously and selectively on both surface and suspension. This work lays the foundation for tailoring SWNTs with not only a wide range of molecules and to study their functional characteristics but also to carry out functionalization on different substrates for various applications.

Tato práce se zabývá syntézou sférických zlatých nanočástic pro biomedicínské aplikace. Zlaté nanočástice byly syntetizovány ekologicky nezávadnými metodami, kterým je věnována i značná část rešerše. Cílem bylo nasyntetizovat stabilní koloidní zlaté nanočástice vhodné pro různé biomedicínké aplikace zejména, pro in vivo a in vitro zobrazovací metody, kterých přehled je take obsažen v teoretické části práce. Také byl proveden test cytotoxicity, jelikož částice mají být použitelné pro in vivo aplikace. Částice byly dale charakterizovány metodami SEM, DLS a UV-VIS.

The diploma thesis deals with synthesis of gold nanoparticles and their surface functionalization suitable for in vitro imaging. In this view there are requirements for optical properties such as stability, monodispersity and no presence of cytotocxicity. In order to fulfill these demands the synthesis by Turkevich method with surface modification by glutathione and polytethylenglycol was performed. Analytical methods such as DLS, SEM and Zeta potential measurement were utilized to characterize the physical and chemical properties of synthesized gold nanoparticles. Finally, MTT assay was performed to evaluate toxicity of gold nanoparticles using HEK 293 cell line.

La manipulation de micro- et nano- particules en solution peut être réalisée grâce aux interactions de ces objets avec des champs électromagnétiques. La lumière ou bien encore les champs électriques continus (DC) ou alternatifs (AC) peuvent être utilisés. Dans le cas d’un champ électrique non uniforme appliqué entre deux électrodes séparées par quelques micromètres, des gradients de champs très intenses et localisés sont ainsi créés. Ces gradients de champ localisés au niveau des électrodes engendrent la création de mouvements de charges composant la solution (effets électro-hydrodynamique). Mais aussi des charges confinées au niveau des particules à l’interface liquide/solide. Les particules en suspension subissent alors une force attractive ou répulsive appelée diélectrophorèse. Cette force est décrite dans la littérature pour des particules isolantes de taille supérieure à 200 nm. Dans cette étude par détection optique (videomicroscopie par champ sombre ou spectroscopie en microfluidique) la gamme de taille de particules est élargie (40-150 nm) pour étudier leurs réponses diélectrophorètique. En effet la diélectrophorèse dépend de la taille des particules, de son environnement et des paramètres du champ appliqué (fréquence, amplitude, topologie) La diélectrophorèse est mise en compétition avec le mouvement Brownian pour des particules d’or d’aussi petites tailles. La réponse pour des nanoparticules d’or en solution alors connue, il est envisageable de faire varier les paramètres, comme l’environnement de la particule ou bien la complexité des systèmes étudiés. / The manipulation of micro- and nano- particles in solution can be achieved through the interactions of these objects with electromagnetic fields. Emitted light, continuous (DC) or alternating (AC) electric fields can be used. In the case of a non-uniform electric field applied between two electrodes separated by a few micrometers, very intense and localized field gradients are created. These field gradients localised close to the electrodes generates a motion of the mass solution (electro-hydrodynamic effects). The charges confined onto particles at the liquid/solid interface are also subjected to motion. Suspended particles undergo an attractive or repulsive force called dielectrophoresis.This force is described in the literature for insulating particles larger than 200 nm. In this study optical detection was used (dark field videomicroscopy or microfluidic spectroscopy) to expand the range of particle size (40-150 nm) and to study their dielectrophoretic responses. Indeed, the dielectrophoresis is dependent on the size of particles, their environment and the parameters of the applied electric field (frequency, amplitude, topology). The dielectrophoresis is in competition with the Brownian motion of these gold nanoparticles. By, knowing the dielectrophoretic response of these particles in solution, it is possible to vary parameters, such as the suspension composition of the particles or the complexity of the systems studied.

Correct diagnosis of disease is essential in the effort to save and improve lives. Point of care (POC) diagnostics are in-vitro tests that assist in patient diagnosis and can be used at the location of patient care. POC diagnostics are easy to use and provide near-instant readouts allowing medical providers and patients to make rapid decisions about treatment. Increased access to POC testing is especially beneficial to low-income and low resource areas that cannot afford expensive lab testing. The World Health Organization (WHO) has outlined at least 113 diseases for which POC diagnostics are needed. Because of this, developing effective, efficient, and economical methods for creating new POC tests is essential. Work in section one of this thesis describes strategies by which new POC bio-diagnostics can be created. The use of oxidized cellulose as a vector for antibody immobilization was explored in several cellulose-based materials to provide quick, economical tests while still obtaining effective limits of detection when used to detect the pregnancy hormone Human Chorionic Gonadotropin (HCG) in a proof of concept study. The majority of these tests could detect as low as 100 ng/mL of HCG well below the clinical level necessary for detection at 2400 ng/mL. The use of a hand-powered syringe-based POC named the fast flow immunoassay (FFI) was tested for its ability to increase observable signal in a sandwich immunoassay by passing the sample through the test filter multiple times. 10 passes through the filter resulted in a signal approximately 17x more intense than a 1-hour dot-blot sandwich immunoassay. Both oxidized cotton and FFI systems can be used to develop new POC assays quickly and economically. Future use of these POC systems could help expand the availability of diagnostic testing to disadvantaged areas. Gold-based drugs have been used and investigated as medications multiple times throughout history to treat various diseases such as Rheumatoid arthritis, parasitic infections, and cancer. In the last few decades, gold nanoparticles have been used as drug delivery agents and catalysts for various reactions. Recently catalytic gold nanocrystals have been characterized for their ability to treat neurodegenerative diseases. Although these results were promising, much is still unknown about their mechanism of action. Section two of this thesis investigates potential molecular pathways that gold nanocrystals could be affecting, specifically the IL-6/Jak/STAT3 inflammation pathway and the Nrf2 antioxidant pathway. The gold nanocrystals we tested did not affect these pathways at physiologically obtainable concentrations. Additional work was done to characterize protein interactome or protein corona of gold nanocrystals. Preliminary proteomic characterization of this protein corona in fetal bovine serum (FBS) identified 118 potential interactors and classified those based on function and structure. Future work will need to be done to follow up on these identifications and to determine what mechanistic implications they may have.

Metal nanoparticles have been a primary focus in areas of catalysis and electrocatalysis applications as a result of their large surface area-to-volume ratios. While there is an increased interest in understanding the properties and behaviors of metal nanoparticles, they can become expensive over time. Recent research has incorporated the idea of using heteroatom-doped materials as a cheaper catalytic alternative to metal nanoparticles. In this study nitrogen-doping and phosphorous-doping techniques were applied to chemical vapor-deposited carbon ultramicroelectrodes in order to study the electrocatalytic properties toward the oxygen reduction reaction and the enhanced affinity for the deposition of gold nanoparticles onto the electrodes.

Studies of single, isolated nanoparticles provide better understanding of the structure-function relationship of nanoparticles since they avoid complications like interparticle distance and nanoparticle loading that are typically associated with collections of nanoparticles distributed on electrode supports. However, interpretation of results obtained from single nanoparticle immobilization studies can be difficult to interpret since the underlying nanoelectrode platform can contribute to the measured current, or the immobilization technique can adversely affect electron transfer. Here, we immobilized ligand-free gold nanoparticles on relatively electrocatalytically inert nitrogen-doped carbon ultramicroelectrodes that were prepared via a soft nitriding method. Sizes of the particles were estimated by a recently reported electrochemical method and were found to vary linearly with deposition time. The particles also exhibited electrocatalytic activity toward methanol oxidation. This immobilization strategy shows promise and may be translated to smaller nanoelectrodes in order to study electrocatalytic properties of single nanoparticles.

La thérapie génique est probablement une des approches la plus ambitieuse de l'histoire de l'humanité pour éliminer des maladies résistantes à tout autre traitement. Cependant, c'est une approche qui doit encore être développée afin d'obtenir un meilleur contrôle du processus de délivrance des médicaments et aussi de réduire les coûts. À cette fin, ce projet de thèse est axé sur l’optimisation et le contrôle de la délivrance d’oligonucléotides basée sur l'utilisation de nanobâtonnets d'or (Gold NanoRods, GNRs). De telles nanoparticules (40 nm de long et 10 nm de diamètre) sont internalisées par les cellules et grâce à leurs propriétés physiques extraordinaires permettent de délivrer les médicaments dans le cytoplasme de manière contrôlée. En effet, leur absorption très élevée dans le proche infrarouge du spectre électromagnétique permet de convertir l’énergie lumineuse en chaleur à l’intérieur et autour des nanobâtonnets, sans affecter la cellule. L’avantage d’une absorption dans l’infrarouge est qu’à cette longueur d’onde la lumière pénètre profondément dans les tissus humains (3 cm). Le contrôle de la température autour des nanoparticules permet la libération d'oligonucléotides par simple dénaturation du duplex à un instant donné.L’obtention de nanoparticules pouvant être considérées comme un « cargo » implique de remplir les conditions suivantes : stabilité de la forme colloïdale en milieu complexe, conservation des propriétés physiques et chimiques une fois administrées et possibilité d’immobiliser et de libérer le médicament de manière contrôlée.La première étape de mon projet a consisté à établir un protocole de synthèse de nanobâtonnets d’or afin d’obtenir une solution colloïdale mono-disperse et dont la bande d’absorption de plasmon longitudinal soit dans le proche infrarouge. L'étape suivante était d’optimiser un protocole de fonctionnalisation de la surface des GNRs. Le défi ici est associé à l'agrégation des GNRs lorsque le surfactant (CTAB) nécessaire au maintien des GNRs en solution est remplacé par des biomolécules (oligonucléotides). Cependant, après une étude systématique et détaillée, la déstabilisation de la couche protectrice de surfactant sur la surface métallique et l’ajout d’oligonucléotides ayant une fonction thiol à une des deux extrémités dans un rapport approprié ont permis une bio-fonctionnalisation efficace des nanobâtonnets. En conséquence, les nanoparticules fonctionnalisées, après redispersion dans la solution, ont les propriétés physico-chimiques nécessaires. En outre, l’immobilisation des oligonucléotides sur la surface des nanoparticules est spécifique (via la liaison thiol-Au) et permet leur transfert dans des solutions tamponnées ou dans des milieux complexes sans affecter leur stabilité. Après hybridation entre le simple brin immobilisé sur la surface des nanobâtonnets et le brin complémentaire, j’ai démontré que les oligonucléotides étaient stables et que le nombre de doubles brins qui se forment par hybridation peut être contrôlé. L’analyse des propriétés des nanomatériaux a constitué la seconde étape clé de mon travail, car elle revêt une importance cruciale pour la délivrance contrôlée de médicaments. J'ai décidé d'appliquer des méthodes uniquement optiques couvrant l'absorption des nanobâtonnets et l'analyse de la fluorescence des oligonucléotides marqués et des images TEM.Au cours du projet, il a donc été possible d’établir une nouvelle approche de fonctionnalisation et de créer un protocole de caractérisation efficace, axé sur les oligonucléotides. / Gene therapy is probably one of the most ambitious approaches in human history that aims to eliminate diseases, often those completely resistant to other treatments. However, this approach requires further development in order to obtain better control over the process of drug delivery and reduce costs. For this purpose, this project has focused on delivery of oligonucleotides using gold nanorods (GNRs). Such nanoparticles, (40 mm in length and 10 nm in diameter) can be internalized by cells and their extraordinary physical properties allow the delivery of drugs to the cytoplasm of cells in a controlled manner. Indeed, their strong absorption in the near-infrared part of the electromagnetic spectrum allows conversion of the energy of light into heat around the nanorods without affecting the cells. The advantage of absorption in the infrared is that at this wavelength the light can penetrate human tissues (3 cm). Control of the temperature around the nanoparticles allows the release of oligonucleotides by simple denaturation of the duplex at a given time.Obtaining nanoparticles that can be considered as a "cargo ship" implies fulfilling the following conditions: stability of the colloidal form in a complex medium, preservation of the physical and chemical properties once administered and the ability to immobilize and release the drug in a controlled manner.The first step of my project was to establish a nanorods synthesis protocol in order to obtain a monodisperse colloidal solution whose longitudinal absorption band is in the near infrared. The next step was to optimize the functionalisation protocol of the surface of the GNRs. The challenge here is associated with the aggregation of GNRs when the surfactant (CTAB) needed to maintain the GNRs in solution is replaced by biomolecules (oligonucleotides). However, after a systematic and detailed study, the destabilisation of the surfactant protective layer on the metal surface and the addition of oligonucleotides having a thiol function at one of the two extremities in a suitable ratio allowed an efficient bio-functionalisation of the nanoparticles. As a consequence, the functionalised nanoparticles, after redispersion in solution, possess the necessary physicochemical properties. In addition, the immobilisation of oligonucleotides on the surface of the nanoparticles is specific (via the thiol-Au bond) and allows their transfer into buffered solutions or in complex media without affecting their stability. After hybridisation between the single strand immobilized on the surface of the nanorods and the complementary strand, I demonstrated that the oligonucleotides were stable and that the number of double strands that are formed by hybridization can be controlled. The analysis of the properties of nanomaterials was the next important part of the work, as it is of crucial importance for the controlled delivery of drugs. I decided to apply only optical methods covering nanorods absorption and fluorescence analysis of labeled oligonucleotides and TEM images.In summary, during the project it was possible to establish a new functionalization approach and create a protocol for efficient characterization, focused on oligonucleotides. We expect that these observations will aid further research in the field of gene delivery based on gold nanoparticles.

This dissertation thesis is focus on using toxicity tests with testing organism - terrestrial isopod Porcellio scaber. This organism is use for toxicity assessment of selected anorganic compunds which could contaminate terrestrial ecosystem. This organism was selected for several reasons - sophisticated test methodology; well known biology of these animals and their ecological relevance. Besides classical endpoints such as mortality, change in mass of test specimens and the effect of the presence and concentration of contaminants onto food consumption; we monitored changes in the morphometric characteristics at the level of tissues and cells, the cytotoxicity and possibly bioaccumulation in various parts of the body of the organism. Selected test substance in this thesis were nanoparticles and inorganic salts. Wherein for chosen gold nanoparticles was carried out a complete study presents several levels of organization of living matter (organism, tissue, cell). For selected salts compound, this study was carried out on the behavior of organisms and classical endpoints.