1 / Xiaoye Su

A general expression for quantum transmission of non-interacting spinless electrons through models of a fully connected network of sites that can be regarded as a nanoparticle is obtained using matrix algebra. This matrix algebra method leads to the same results given by the Green’s function method without requiring the mathematical sophistication as required by the later. The model of the nanoparticle in this study comprises a single linear array of atoms that profile the input and output leads connected to a fully connected blob of atoms. A simple tight-binding Hamiltonian motivates the quantum transmission in the discrete lattice system. If there are n atoms in the nanoparticle, the methodology requires the inverse of a n × n matrix. The solution is obtained analytically for different cases: a single atom in the nanoparticle, a single dangle atom, n fully connected atoms in a meanield type cluster with symmetric input and output connections, and the most general case where the n fully connected atoms can be connected arbitrarily to the input and output leads. A numerical solution is also provided for the case where the intra-bonds among the atoms in the nanoparticle are varied (a case with notully connected atoms). The expression for the transmission coefficient thus obtained using the matrix method is compared with the transmission coefficients derived using the real space Renormalization Group method and the Green’s function method.

L'objectif de ce travail concerne le transport à travers des membranes lipidiques de l'eau et d' ions par des canaux artificiels auto-assembles, et le design des nano-contacts organiques auto-assembles pour des applications macro échelle : biocathodes. La première partie est concentre sur le transport de l'eau et d'ions à travers des membranes bicouches. L'objectif est la réplication de la fonction des protéines naturelles, utilisant des composées ureido-heterocycle. L'influence de la composition des espèces est évaluée par rapport à leur structure supramoléculaire et la liaison entre elle et son activité. Le premier chapitre traite le transport des ions travers les bicouches lipidiques générées en grandes vésicules unilamellaires (LUVs), en termes d'activité et sélectivité dépendants de la structure de composées. Le deuxième chapitre présente le transport de l'eau à travers des systèmes LUV. Une approche combinée a été utilisée pour évaluer l'activité des canaux, par les placer a l'extérieur des liposomes comme même directement dans le couche lipidique. Finalement le transport de protons a été évalué pour ces structures, relevant des canaux de protons très efficients. Le troisième chapitre aborde une approche interdisciplinaire. Certaines triarylamines (TAAs) ont la propriété à former des nano fibrilles sur l'irradiation par la formation des radicaux-cations. Ceci représente une voie de conduction directionnelle pour électrons avec une conductivité similaire aux métaux. Les fibrilles, quelles déchire en absence de lumière, offrent des possibilités intéressants au rapport de nano-échelle contacts électriques. Une matrice de silice mésoporeuse a été utilisée pour confiner les TAAs . La nouveauté de cette approche c'est que le système présent des conductivités à travers les nano fils de TAA, alors que la matrice de silice est isolante. Ce dispositif a été caractérisé et utilisé comme un bio cathode contenant l'enzyme laccase et ont été testes pour prouver le role des nano contacts TAAs comme les seuls fournisseurs d'électrons pour l'enzyme. / The objective of this work is the study of the transport through lipid membranes of water and ions using self-assembled artificial channel structures and the design of nano sized self-assembled organic contacts for macroscale applications: biocathodes.The first part focuses on the transport through membrane bilayers. The objective is to replicate the function of naturally occurring proteins using ureido-hetreocycle compounds. The influence of species composition is assessed versus the supramolecular structure it generates and the link between it and activity. The first chapter treats the transport of ions through the lipid bilayers of large unilamellar vesicles (LUVs), in terms of total activity and selectivity vs. the structure of compounds. The second chapter refers to the transport of water on LUV systems. Here, a combined approach was used in evaluating the channels' activity, by placing them both on the outside of the liposomes but also directly in the lipid layer. Finally the protons transport of these structures was assessed reveling very efficient proton channels. The third chapter has an interdisciplinary approach combining several topics. The triaryl amines (TAAs) have to propriety of forming self-assembled nano sized fibrils when irradiated by the generation of cation-radicals. These present a directional electronic conduction pathway and are reported to display metal-like conductivity. These fibrils, which unravel in the absence of light, provide interesting possibilities as organic nano scale electrical contacts. A matrix of mesoporous silica was created via electrodeposition in order to enclose the TAAs in a confined medium. The novelty of the approach is that the system only has electron conductivity trough the TAAs nano wires while the silica mass is insulating. The resulting device's proprieties were characterized and further it was used as a bio cathode. The biocathodes containing the enzyme Laccase were then tested to prove the functioning of the matrix of nano contacts as the only providers of electrons to the enzyme.

Pancreatic cancer remains a major unsolved health problem, with conventional cancer treatments having little impact on disease course. The objective of this thesis is to create innovative tools to better understand and improve chemotherapeutic treatment of pancreatic cancer. Towards this end, nanosystems were designed with a dual purpose: to carry chemotherapeutic drugs and act as photoacoustic imaging contrast agents. The overarching hypothesis is that these nanosystems can provide enhanced therapy for pancreatic cancer and enable visualization of drug delivery. Demonstrated in this dissertation is the design, synthesis, and characterization of two such nanosystems built to carry the chemotherapeutic agent gemcitabine while acting as a photoacoustic imaging contrast agent. The nanosystems were also shown to be multifunctional with possible application as photothermal therapy agents and cellular functional sensors. Although future research is required to fully investigate the clinical potential of these systems for pancreatic cancer, the work presented in this dissertation is a step towards creation of multifunctional nanosystems that will enable non-invasive, in vivo photoacoustic imaging of drug delivery. / text

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Nanotechnology has received great prominence in recent years due to the versatility of new materials and its applications at the various sectors of society. The functionalized magnetic nanoparticles have been the focus of intense research because of the ability to use on different systems, with emphasis on the catalytic processes of environmental decontamination. In particular, we have seen a growing demand for hybrid catalysts capable of utilizing sunlight, constructed from TiO2 particles by photosensitised dyes. Thus, this study aimed to develop a new magnetic nanosystem, based on use of meso-porphyrins derived from Cashew Nut Shell Liquid (CNSL), coated with TiO2, with potential application in heterogeneous photocatalysis. Moreover, produce a new ferrofluid derived biomass from the anacardic acid (AA MAG). To this end, were synthesized Fe3O4 nanoparticles with an average size of 11nm, coated with a 1st layer of oleic acid and a 2nd layer of meso-porphyrin (3-n-PDPP). This nanosystem also was covered with a layer of TiO2. This procedure produced a new magnetic nanosystem of porphyrin (NMP). The new ferrofluid AA-MAG and magnetic nanosystems were characterized by Transmission Electron Microscopy (TEM), infrared spectroscopy, Thermal analysis (TG) and magnetization curves. The results showed that NMP showed good thermal stability, superparamagnetic behavior and dimension nanometric (≈ 14nm). The fluorescent properties were little affected, which enables its application in photocatalytic systems. / A nanotecnologia vem recebendo grande destaque nos Ãltimos anos graÃas à versatilidade dos novos materiais gerados e suas aplicaÃÃes nos diversos setores da sociedade. As nanopartÃculas magnÃticas funcionalizadas tÃm sido foco de intensas pesquisas devido à capacidade de utilizaÃÃo em diferentes sistemas, com destaque para os processos catalÃticos de descontaminaÃÃo ambiental. Em especial, tem-se observado uma crescente demanda por catalisadores hÃbridos capazes de utilizar a luz solar, construÃdos a partir de partÃculas de TiO2 fotossensibilizadas por corantes. Assim, o presente trabalho teve por objetivo desenvolver um novo nanosistema magnÃtico, baseado no emprego de meso-porfirinas derivadas do LÃquido da Casca da Castanha de Caju (LCC), recobertas com TiO2, com potencial aplicaÃÃo em fotocatÃlise heterogÃnea. AlÃm disso, produzir um novo ferrofluido derivado da biomassa, a partir do Ãcido anacÃrdico (AA-MAG). Para isso, foram sintetizadas nanopartÃculas de Fe3O4 com tamanho mÃdio de 11nm, revestidas por uma 1 camada de Ãcido oleico e uma 2 camada da meso-porfirina (3-n-PDPP). Esse nanosistema tambÃm foi recoberto por uma camada de TiO2. Este procedimento produziu um segundo novo nanosistema magnÃtico de porfirina (NMP). O novo ferrofluido AA-MAG e os nanosistemas magnÃticos foram caracterizados por Microscopia eletrÃnica de trasmissÃo (MET), Espectroscopia no Infravermelho, AnÃlise tÃrmica (TG) e curvas de magnetizaÃÃo. Os resultados mostraram que o NMP apresentou uma boa estabilidade tÃrmica, comportamento superparamagnÃtico e dimensÃes nanomÃtricas (≈ 14nm). As propriedades fluorescentes foram pouco afetadas, o que possibilita sua aplicaÃÃo em sistemas fotocatalÃticos.

This thesis proposes algorithms to construct various nanosystems such as nanotori, nanogear and nanojunctions based on graphite type structures, exploiting the observed pentagonal and heptagonal defects. These produced systems are then simulated to test for their thermal stability and for their electronic properties. A brief review of the methods used is also included.

La riboflavine (RF) est une vitamine essentielle pour la croissance et le développement cellulaire. Elle possède des propriétés physico-chimiques intéressantes et est internalisée dans les cellules par des transporteurs spécifiques. Le premier objectif de ce projet était de synthétiser des dérivés amphiphiles de la RF (RFA) et d'étudier leurs capacités d'auto-assemblages. Le second objectif était d'insérer les RFA dans des liposomes et d'évaluer leur efficacité de ciblage tumoral in vitro et in vivo. La préparation des différents RFA repose sur l'ajout d'un lipide en différentes positions de la RF. L’un d'eux, de type phospholipide (RfdiC14) a été capable de former des objets tridimensionnels de taille μm constitués de lamelles multicouches dont l’architecture et la dynamique sont très différentes de celles des phospholipides classiques. L’insertion de RfdiC14 dans des liposomes est efficace et n’influence pas leurs propriétés physico-chimiques. Les liposomes fonctionnalisés ont montré une internalisation cellulaire spécifique dans les lignées A431, PC3 et HUVECs. Afin de tester l’efficacité du ciblage tumoral in vivo, un analogue de RfdiC14 portant un espaceur PEG a été préparé puis inséré dans des liposomes péguylés. Grâce à un marquage adéquat (ICG et DiR), leur accumulation tumorale a été suivie par imagerie photoacoustique dans un modèle A431 et leur biodistribution évaluée par imagerie μCT/FMT dans un modèle PC3. Les résultats montrent une légère amélioration de l’accumulation tumorale dans les xénogreffes A431 et une augmentation du ciblage vasculaire dans le modèle tumoral PC3. La biodistribution globale des liposomes marqués est comparable à celle des contrôles. / Riboflavin (RF) is an essential vitamin for cell growth and development. It possesses interesting physicochemical properties and is internalized by the cells through specific transporters. The first aim of this study was to prepare amphiphile derivatives of RF (RFA) and study their auto-assembly. The second aim was to insert RFA into established drug delivery systems and test their tumour-targeting potential in vitro and in vivo. RFA were prepared by the molecule functionalization with lipid moieties in different positions. One of them, a phospholipid-like derivative (RfdiC14) was able to self-assembly in aqueous solutions into μm-sized 3D objects constituted from slightly curved multilayer lamellas. The bilayer architecture and dynamics were very different from ordinary phospholipids. In contrast, the insertion of small amount of RfdiC14 in a liposome did not influence membrane dynamics and physicochemical characteristics. RfdiC14-functionalised liposomes displayed high and specific uptake in vitro in A431, PC3 cells and HUVECs. The efficiency of RF targeting was also tested in vivo. For that purpose, liposome composition was optimized and a new RF amphiphile with a PEG spacer between RF and lipid was prepared. The tumour accumulation of the liposomes labelled with ICG was studied by photoacoustic imaging in A431 tumour model. The biodistribution of DiR labelled liposomes was accessed by combined μCT/FMT imaging in PC3 tumour model. The results show slight improvement of the tumour accumulation in A431 xenographts and the enhancement of vascular targeting in PC3 tumour model. The overall biodistribution of the RF-targeted liposomes was comparable to control.

Materials based on novel Off-Stoichiometry Thiol-Ene polymers, abbreviated OSTE, show promising properties as materials forlow cost and scalable manufacturing of micro- and nanosystems such as lab-on-chip devices. The OSTE materials have tunablemechanical properties, offer possibility for low temperature bonding to many surfaces via tunable surface chemistry, and can beused in soft lithography. Unlike the commonly used elastomer poly(dimethylsiloxane), PDMS, the OSTE materials have lowpermeability for gasses, are resistant to common solvents and can be more permanently surface modified.In this master’s thesis project, the OSTE materials have been evaluated with focus on compatibility with cells, possibility fornanostructuring using soft lithography and the use of OSTE as a flexible support for conducting polymers.Results from cell seeding studies with HEP G2 cells suggest that cells can proliferate on a low thiol off-stoichiometry OSTEmaterial for at least five days. The biocompatibility for this type of OSTE material may be similar to poly(styrene). However, highlevels of free thiol monomers in the material decrease cell viability considerably.By using soft lithography techniques it is possible to fabricate OSTE nanochannels with at least the dimensions of 400 nm x 15nm. Combined with the advantages of using the OSTE materials, such as low temperature bonding and possibility for stablesurface modifications, a candidate construction material for future development of systems for DNA analysis is at hand.OSTE can serve as a flexible support for an adsorbed film of a conducting polymer with the possibility for future applicationssuch as electronic interfaces in microsystems. In this project, a film of PEDOT:PSS with the electrical resistance of ~5 kΩ wascreated by adsorption to an flexible OSTE material. Furthermore, results suggest that it is possible to further optimize theconductivity and water resistance of PEDOT:PSS films on OSTE.

Modification of the properties of solid state structures, used for gas sensing is important task in making detection and measurement systems of volatile chemical compounds. These properties depend on material, inner structure and interaction with gas atmosphere. In hybrid materials (solid-biomolecular) biochemical recognition plays important role in gas sensing mechanism. In this work the methodologies of the SPM was applied for characterization of the local point and local area properties in the gas sensitive MO films with the nanoscaled thickness that can be used for nanosystems and hybrid materials in novel types of chemical detectors. In this dissertation morphology and physical properties of metal oxide films with thickness from a few to about 50 nm was investigated and described a relationship between the gas response and film thickness. It was experimentally shown that effects of external influence on the properties of the surface nanostructures can be described by the specific characteristics of the scanning probe spectroscopy displaying the dependences of the probe contact electric current on both the probe potential and the probe pressing force. An original method based on the SPM probe controlled electrical current was proposed for the formation of nanosystems with various electrical properties on the surfaces of thin MO films. / Kryptingas kietojo kūno darinių, naudojamų išorinio dujų poveikio detekcijai, savybių keitimas yra vienas iš aktualiausių uždavinių, sprendžiamų kuriant lakiųjų cheminių junginių poveikio atpažinimo ir matavimo sistemas. Šias savybes lemia darinių medžiaga, jų struktūra bei sąveikos su dujine aplinka ypatumai, kurie hibridiniuose dariniuose iš kietojo kūno ir biomolekulių gali būti lemiami dar ir biocheminiu atpažinimu. Šiame darbe tiriami dujoms jautrūs hibridiniai dariniai ir nanosistemos, integruotos metalo oksido plėvelėse, Skenuojančio zondo mikroskopijos (SZM) metodais. Disertacijoje susieti itin plonų (<30-50 nm) SnOx sluoksnių varžos atsako į dujas bei elektrinių savybių ypatumai su sluoksnių morfologija, priklausančia nuo auginimo sąlygų ir trukmės. Eksperimentiškai įrodyta, jog SZM lokalinių srovių tyrimai, priklausomai nuo matavimo parametrų, leidžia atskirai aprašyti technologiškai keičiamas dujoms jautrių darinių charakteristikas ir tik nanosistemose vykstančius procesus, kurie, kai kuriais atvejais, gali būti stebimi ir tipiškuose dujoms jautrių darinių taikymuose. Sukurtas originalus metodas, tinkantis nanostruktūroms metalo oksidų paviršiuje formuoti bei tų struktūrų elektrinėms savybėms keisti. Skirtingai nuo literatūroje žinomo paviršiaus nanooksidinimo, pritaikyto formuoti cheminiam poveikiui atsparias dangas, mūsų metodas leidžia formuoti įvairaus elektrinio laidumo nanostruktūras metalo oksidų paviršiuje.

Kryptingas kietojo kūno darinių, naudojamų išorinio dujų poveikio detekcijai, savybių keitimas yra vienas iš aktualiausių uždavinių, sprendžiamų kuriant lakiųjų cheminių junginių poveikio atpažinimo ir matavimo sistemas. Šias savybes lemia darinių medžiaga, jų struktūra bei sąveikos su dujine aplinka ypatumai, kurie hibridiniuose dariniuose iš kietojo kūno ir biomolekulių gali būti lemiami dar ir biocheminiu atpažinimu. Šiame darbe tiriami dujoms jautrūs hibridiniai dariniai ir nanosistemos, integruotos metalo oksido plėvelėse, Skenuojančio zondo mikroskopijos (SZM) metodais. Disertacijoje susieti itin plonų (< 30-50 nm) SnOx sluoksnių varžos atsako į dujas bei elektrinių savybių ypatumai su sluoksnių morfologija, priklausančia nuo auginimo sąlygų ir trukmės. Eksperimentiškai įrodyta, jog SZM lokalinių srovių tyrimai, priklausomai nuo matavimo parametrų, leidžia atskirai aprašyti technologiškai keičiamas dujoms jautrių darinių charakteristikas ir tik nanosistemose vykstančius procesus, kurie, kai kuriais atvejais, gali būti stebimi ir tipiškuose dujoms jautrių darinių taikymuose. Sukurtas originalus metodas, tinkantis nanostruktūroms metalo oksidų paviršiuje formuoti bei tų struktūrų elektrinėms savybėms keisti. Skirtingai nuo literatūroje žinomo paviršiaus nanooksidinimo, pritaikyto formuoti cheminiam poveikiui atsparias dangas, mūsų metodas leidžia formuoti įvairaus elektrinio laidumo nanostruktūras metalo oksidų paviršiuje. / Modification of the properties of solid state structures, used for gas sensing is important task in making detection and measurement systems of volatile chemical compounds. These properties depend on material, inner structure and interaction with gas atmosphere. In hybrid materials (solid-biomolecular) biochemical recognition plays important role in gas sensing mechanism. In this work the methodologies of the SPM was applied for characterization of the local point and local area properties in the gas sensitive MO films with the nanoscaled thickness that can be used for nanosystems and hybrid materials in novel types of chemical detectors. In this dissertation morphology and physical properties of metal oxide films with thickness from a few to about 50 nm was investigated and described a relationship between the gas response and film thickness. It was experimentally shown that effects of external influence on the properties of the surface nanostructures can be described by the specific characteristics of the scanning probe spectroscopy displaying the dependences of the probe contact electric current on both the probe potential and the probe pressing force. An original method based on the SPM probe controlled electrical current was proposed for the formation of nanosystems with various electrical properties on the surfaces of thin MO films.