Manufactured nanomaterials (MNMs) from the rapidly increasing number of consumer products that contain MNMs are being discharged into waste streams. Increasing evidence suggests that several classes of MNMs may accumulate in sludge derived from wastewater treatment and ultimately in soil following land application as biosolids. Little research has been conducted to evaluate the impact of MNMs on terrestrial ecosystems, despite the fact that land application of biosolids from wastewater treatment will be a major pathway for the introduction of MNMs to the environment. To begin addressing this knowledge gap, we have conducted a series of experiments designed to test how bioavailable MNMs are to terrestrial ecoreceptors when exposed through a variety of pathways. First, we used the model organisms Nicotiana tabacum L. cv Xanthi (tobacco) and Triticum aestivum (wheat) to investigate plant uptake of 10, 30 and 50 nm diameter gold (Au) MNMs coated with either tannate (T-MNMs) or citrate (C-MNMs). Both C-MNMs and T-MNMs of each size treatment bioaccumulated in tobacco, but no bioaccumulation of MNMs was observed for any treatment in wheat. In a second exposure, we investigated the potential for bioaccumulation of MNMs from contaminated plant surfaces by a terrestrial secondary consumer, tobacco hornworm (Manduca sexta). We found that hornworms bioaccumulate Au MNMs, but that the assimilation efficiency of bioaccumulation was low. Hornworms eliminate ingested Au MNMs rapidly from 0-24 h, but very slowly from 1 d to 7 d. Finally, we used the model organisms tobacco and tobacco hornworm to investigate the potential for trophic transfer of Au MNMs. Biomagnification of Au MNMs was observed in the hornworms. We have demonstrated that MNMs of a wide range of size and with different surface chemistries are bioavailable to plants, that MNMs resuspended by wind, rain, biota, and mechanical disturbance from soil onto plant surfaces are bioavailable to terrestrial consumers, and that trophic transfer and biomagnification of plant accumulated MNMs can occur. These results have important implications for risks associated with nanotechnology, including the potential for human exposure.

The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained through a combination of steady-state and time-resolved spectroscopy in conjunction with quantum chemical calculations aided in the elucidation of the dynamics and the mechanism of light harvesting in the multichromophoric phycobiliprotein phycocyanin PC645 in vitro. Investigation of the light-harvesting efficiency and optimization of energy transfer with respect to the structural organization of light-harvesting chromophores on the nanoscale, can provide us with fundamental information necessary for the development of synthetic light-harvesting devices capable of mimicking the efficiency of the natural system.

With size down to nanoscale, nanomaterials exhibit novel properties exceeding or differing significantly from their bulk counterparts. In particular, amongst a wide range of interesting new nanostructures, tungsten based nanomaterials have demonstrated super physical, chemical, electronical and mechanical properties in a diverse range of applications which has been comprehensively reviewed. However, challenges still remain high on the effective processes to scale up the manufacturing of such nanomaterials, with desired shape, size and quality. These tungsten based nanomaterials are thus become the research subject of this project, and the study on continuous manufacturing of specifically inorganic fullerene WS2 (IF-WS2) nanoparticles, and their potential exploration as fillers to polymer matrix to fabricate nanocomposites with improved mechanical properties are the main objectives of this research. After a thorough assessment of the extremely promising potentials of tungsten based nanostructures, and review of the current bottleneck for large quantity production of IF-WS2, a generic experimental methodology and techniques used for the investigations have been described in experimental methodology part. In the following chapters, this thesis demonstrates the following research works: A novel rotary furnace for continuous scaling up manufacturing of IF-WS2 nanoparticles has been designed, constructed, tested and refined in this work. The new furnace consists of several key components: a tube furnace, self-contained rotary system, dynamic seal system, modified new tube with baffle, and a continuous gas-blow feeding system. Test results show that the rotary reactor has improved the lab scale manufacturing of IF-WS2 from sub-gram to several tens of grams per batch without agglomeration, which makes this technique a promising alternative for the replacement of the existing tall fluidised tower processing in industrial level production. As an important precursor for IF-WS2 nanomaterials production, the synthesis of WOx nanoparticles by high temperature thermal decomposition of Ammonium Paratungstate (APT) has been investigated, and the parameters have been optimised (with Ar flow at 6 L/min at 1350°C ) for achieving desired sizes. Further studies on the creation of uniform and ultra-thin WOx nanowires were carried out using solvothermal technique. The solvent concentrations, reaction time and solvent types have been systematically investigated, and the resulting WOx nanowires from tungsten chloride precursor in mixed cyclohexanol and ethanol solvent exhibited a record high specific surface area of 275 m2/g. This is fundamentally significant for their applications in sensor and electro-chromic devices. Reverse patterned growth of WOx nanorods was realised for the first time on an Au-coated W foil by a simple W-water vapour reaction. The resulting nanorods of different diameters, lengths and patterns have been created by tuning the growth parameters. Further nitriding under NH3 atmosphere at elevated temperature, converted the WOx nanorods, as a template, to WOxNy nanorods. The WOxNy nanorods have been found to inherit the patterns on the substrate and kept the size and shape of WOx nanorods. An interesting morphology revolution for the conversion of WOx to WOxNy nanorods was observed, and a mechanism has been proposed accordingly to account for the growth. This result represents a simple, innovative and efficient process for the reverse-patterned growth of new nanomaterials. Further development of the rotary furnace has led to a unique new class of core-shell composite nanoparticles, carbon (C)-coated IF-WS2 hollow nanoparticles, by continuous chemical vapour deposition (CVD) production. The composite nanoparticles exhibited a uniform and adjustable C coating, with little or no agglomeration. Importantly, the thermal stability of the core-shell C-coated IF-WS2 against oxidation in air has been improved by about 70°C, compared to the pristine IF-WS2. This new material could find applications where thermal stability is critical. Exploration of 0-4 wt% IF-WS2 as reinforcement in nylon 12 matrix nanocomposites has been carried out for the first time, using a combination of ultrasonic dispersion and magnetic stirring technique to achieve excellent IF-WS2 dispersion in the matrix. Tensile and bending test results showed moderate improvements of 27% and 28% respectively, with a 2 wt% IF-WS2 addition, but a staggering 185% and 148% improvement in toughness for the addition of 0.25 and 0.5 wt% IF-WS2 samples, against pure nylon 12, suggesting that such composites are promising candidates for structural and ballistic fibre applications.

Research in carbon nanotubes (CNTs) has become a very active field in the past decades, with much interest in their electronic and mechanical properties. However, the thermal properties of CNTs are still not well understood, in particular the process of annealing; i.e. purification of samples by desorption of internal and external impurities. Understanding the response of carbon nanotubes to high temperatures is critical for proper characterization of CNTs and CNT-based materials; especially because purportedly non-destructive characterization techniques such as Raman spectroscopy can induce high temperatures through laser heating. This thesis delineates an experiment aimed at elucidating the annealing and destruction process of carbon nanotubes. The experiment consists of heat treatments of single-walled nanotubes (SWNTs), monitoring nanotube abundance and purity by Raman spectroscopy. The samples are HiPCO-produced SWNTs of very high purity, separated in open and closed (end-capped) tubes. They are wetted with H2O in order to fill the open tubes, but are otherwise kept in their raw (as-produced) form of flakes of bundled tubes. This means that they have a low thermal conductivity as compared to dispersed CNTs, making them sensitive to overheating. The samples are heated in both air and argon environments in order to study the effect of oxidation. It is found that all tubes exhibit some annealing after heat treatment at temperatures as low as 100 °C. Temperatures higher than that are sufficient to degrade the samples in the case of closed tubes, which are found to be more thermally sensitive than open tubes, especially in air environments as oxidation is found to be a major component of the destructive mechanisms of CNTs. With higher temperature heat treatments at 500 °C, some of the open tubes exhibit a further step of annealing. This correlates with tube diameter, thus indicating that this annealing step can be associated with the desorption water from the CNTs' interior. A transition is found after heat treatment at 600 °C, although the new phase is not conclusively established, with evidence pointing to either charge transfer (by way of intercalation of dopant atoms in CNTs) or graphitization.

Information processors that harness quantum mechanics may be able to outperform their classical counterparts at certain tasks. Quantum information processing (QIP) can utilize the quantum mechanical phenomenon of entanglement to implement quantum algorithms. Endohedral fullerenes, where atoms, ions or clusters are trapped in a carbon cage, are a class of nanomaterials that show great promise as the basis for a solid-state QIP architecture. Some endohedral fullerenes are spin–active, and offer the potential to encode information in their spin-states. This thesis addresses the challenges of how to engineer the components of a scalable QIP architecture based on endohedral fullerenes. It focuses on the synthesis and characterization of molecules which may, in the future, permit the demonstration of entanglement; the optical read-out of quantum states; and the creation of quasi-one-dimensional molecular arrays. Due to its long spin decoherence time, N@C₆₀ is the selected as the basic molecular unit for ‘coupled’ fullerene pairs, molecular systems for which it may be possible to demonstrate entanglement. To this end, isolated fullerene pairs, in the form of spin-bearing fullerene dimers, are created. This begins with the processing of N@C₆₀ at the macroscale and leads towards the synthesis of ¹⁵N@C₆₀-¹⁵N@C₆₀ dimers at the microscale. High throughput processing is introduced as the most efficient technique to obtain high purity N@C₆₀ on a reasonable timescale. A scheme to produce symmetric and asymmetric fullerene dimers is also demonstrated. EPR spectroscopy of the dimers in the solid-state confirms derivatization, whilst permitting the modelling of spin–spin interactions for 'coupled' fullerene pairs. This suggests that the optimum inter–spin separation for which to observe spin–spin coupling in powders is circa 3 nm. Motivated by the properties of the trivalent erbium ion for the optical detection of quantum states, optically–active erbium–doped fullerenes are also investigated. These erbium metallofullerenes are synthesized and isolated as individual isomers. They are characterized by low temperature photoluminescence spectroscopy, emitting in the infra- red at a wavelength of 1.5 μm. The luminescence is markedly different where a C₂ cluster is trapped alongside the erbium ions in the fullerene cage. Er₂C₂@C₈₂ (isomer I) exhibits emission linewidths that are comparable to those observed for Er³⁺ in crystals. Finally, the discovery of a novel praseodymium-doped fullerene is reported. The balance of evidence favours the structure being assigned as Pr₂@C₇₂. This novel endohedral fullerene forms quasi-one-dimensional arrays in carbon nanotubes, which is a useful proof-of-principle of how a scaled fullerene-based architecture may be achieved.

Nanoparticles produced with surfaces functionalised by highly specific molecular tags are able to target aberrant cells and detect or eliminate them without causing damage to surrounding healthy tissues. Single-stranded DNA (ssDNA) and RNA which fold to form secondary or tertiary structures, termed aptamers, represent a new class of such molecular tags. The nanoparticles, in turn, may carry therapeutic payload or luminescent entities which enable elimination or visualisation of targeted cells respectively. This project presents fabrication and isolation of a surface-functionalised nanoparticle construct, namely aptamer-tagged silica nanoparticles. DNA aptamers were chosen with the intention to make them useful for clinical or diagnostic applications of targeting neoplastic cells. Indeed, the ssDNA applied here is known to bind mucin-1 which in turn is a biomarker found on the surface of metastatic breast cancer cells. The separation of the construct was made possible by the inclusion of oligonucleotide-bound superparamagnetic particles in the construct; these enabled separation by magnetic capture. This project investigates two approaches to fabrication of the construct. In the first approach, aptamers, oligonucleotides and magnetic particles are mixed in solution. In the second, silica nanoparticles are functionalised with aptamers, oligonucleotides are bound to magnetic particles and the resulting two parts are hybridised together. The first approach gives higher yields. This may suggest that binding of silica nanoparticles to aptamers may hinder aptamer hybridisation to oligonucleotide fragments, thus resulting in lower construct synthesis yields. However, it is not known yet how the yield changes upon addition of silica nanoparticles into the solution. Therefore, the second experimental approach provides a starting point for fabrication and purification of an anti-cancer drug targeting platform in a simple bench-top setting. In addition, this thesis discusses the fabrication of silica nanoparticles which were intended to constitute an element of the construct. The work on nanoparticle fabrication aimed to develop a quick and repeatable synthesis method which would result in monodisperse entities. Despite trying various experimental approaches, suitable particles could not be reproducibly obtained. Agglomeration was identified as a major obstacle in the silica nanoparticle production process. Finally, this project assesses whether the chosen aptamers bind to the metastatic breast cancer cells, which would be necessary if they were to be used for diagnosis or therapy. FACS analysis indeed indicate that ssDNA aptamers attach to the MCF7 cell line, but the optimum conditions for that attachment remain to be determined.

Des nanoparticules d’or fonctionnelles ont été synthétisées avec pour objectifs l’élaboration de nanomatériaux pour applications biomédicales et propriétés physiques originales. L’étude de la fonctionnalisation a conduit à utiliser le chimie “click” entre des nanoparticules d’or portant des ligands thiolates azoturés et des alcynes terminaux en utilisant un catalyseur au cuivre (I) renforcé par un ligand polyazoté, ce qui a permis d’introduire des fonctions très variées. En particulier le récepteur folate a été greffé de cette façon pour la synthèse de nouveaux vecteurs du docétaxel, un puissant agent anti-cancéreux dont l’étude est menée en collaboration. Des nanoparticules d’or fonctionnelles ont aussi servi de support pour le greffage de complexes du fer (II) à transition de spin, ce qui a permis de réaliser l’étude en 2D par différentes techniques physiques en collaboration. Enfin un nouveau ligand azoté a été mis au point pour la synthèse de nanoparticules d’or originales. / The thesis concerns functionalizations and applications of gold nanoparticles (AuNPs). In the aspects of functionalization of AuNPs, we concentrated on efficiently functionalized AuNPs by “Click” chemistry. In the aspects of applications, the PEG capped AuNPs was prepared to encapsulate vitamins, which has a potential use in hydrophobic part of human body; the folate functionalized AuNPs was used for docetaxel delivery for cancer therapy; the novel synthesis of triazole stabilized AuNPs used for biosensors; and the citrate capped AuNPs introduced into the silica thin films to check the SERS effect and spin crossover of iron complexes.

Orientador: Alexandre Mesquita / Resumo: O titanato de cálcio CaTiO3 é um material com estrutura de tipo perovskita que tem sido aplicado como luminóforo. É bem estabelecido que a inserção de íons de terra rara no sítio ocupado pelo Ca2+ provoca mudanças significativas nas suas propriedades estruturais e produz efeitos luminescentes na faixa do visível. Entretanto não existem trabalhos reportando a inserção do La3+ no sítio do Ca2+ no que se refere às características estruturais e luminescentes desses materiais. Portanto, o presente trabalho estuda as propriedades fotoluminescentes apresentadas pela matriz à base de titanato de cálcio dopada com praseodímio, lantânio e alumínio. O material foi sintetizado a partir do método Pechini, que se mostrou um método eficaz na preparação de acordo com a caracterização estrutural realizada. A técnica de difração de raio X permitiu identificar que todas as amostras de CaTiO3 apresentam-se na fase cristalina com simetria ortorrômbica. Através da espectroscopia de absorção de raio X na borda K do Ti4+ constatamos a ocorrência de maior simetria do Ti4+ em relação aos átomos ao seu redor quando aumentamos a temperatura de calcinação e que a substituição de íons no sítio do Ca2+ não altera essa simetria. Em razão do aumento da concentração dos dopantes, tanto no sítio do Ca2+ quanto no sitio do Ti4+, foram observados alterações nos modos de vibração dos espectros Raman. Constatou-se o aumento da torção entre os octaedros de TiO6 em relação ao aumento da concentração dos dopantes. No... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The calcium titanate CaTiO3 is a perovskite structure material which has been used as phosphor. It is well established that the incorporation of rare earth ions in the place occupied by Ca2+ cause significant changes in their structural properties and produce luminescent effects in the visible range. However, there are no studies reporting the insertion of La3+ on the Ca2+ site with respect to structural and luminescent characteristics of these materials. So, this work studies the photoluminescent properties presented by the matrix based on calcium titanate doped with praseodymium, lanthanum and aluminum. The material was synthesized by the Pechini method, which proved an effective method of preparation according to the structural characterization performed. The technique of X-ray diffraction showed that all samples are organized and exhibit orthorhombic symmetry. Using X-ray absorption spectroscopy at the K edge of Ti4+, we found that the occurrence of major symmetry of Ti4+ with respect to the neighbor atoms when the calcination temperature was increased and that the substitution of ions Ca2+ by Pr3+ does not change this symmetry. With the concentration of dopants increasing at the Ca2+ and Ti4+ sites, changes of the vibration modes in the Raman spectra were observed. It was found an increased torque between the TiO6 octahedra as a function of the increase in concentration of dopants. In the luminescence spectra, increasing the structural defect density enhanced the light e... (Complete abstract click electronic access below) / Mestre

Cette thèse visait à développer des techniques d'ablation au laser et de fragmentation dans des liquides pour la synthèse de nouveaux NPs ayant des fonctionnalités utiles. L’approche de la thèse est axée sur l’élaboration de la technique ablative au laser pour la synthèse de matériaux conventionnels avec des paramètres pour des applications biomédicales sélectionnées, ainsi que sur le développement de cette technique pour la synthèse de nouveaux nanomatériaux destinés à des applications biomédicales. En particulier, il comprend:1. Nous avons élaboré un régime de fragmentation laser fs à partir de colloïdes de Si pour la synthèse de NPs de Si ayant une taille, une cristallinité et un état d'oxydation contrôlables.Nous avons testé un certain nombre d’applications biomédiales particulières de Si Si préparés de cette manière.2. Nous avons développé une technique d'ablation et de fragmentation au laser fs pour fabriquer des noyaux Au NPs et des carottes en Au-Si nus pour SERSapplications. Une approche est basée sur l'ablation au laser de la cible Au dans une solution colloïdale de NP Si.3. Pour la première fois, nous avons synthétisé de nouveaux NP plasmoniques à base de nitrure de titane. Nous avons également montré qu’une étape supplémentaire de fragmentation du laser fs entraînait une diminution de la taille des NP à 5 nm. En outre, nous avons constaté que ces NP ont un très large pic d'extinction dans le proche IR.4. Pour la première fois, nous avons démontré la synthèse de NPs organiques fluorescentes d'un luminophore à émission induite par agrégation spécialement conçu (AIE LP). La luminosité de ces NP a été jugée comparable à celle des points quantiques. / This thesis as aimed at the development of techniques of fs laser ablation and fragmentation in liquids for the synthesis of novel NPs having useful functionalities. The approach of the thesis is focused on the elaboration of the laser ablative technique for the synthesis of conventional materials with parameters for selected biomedical applications, as well as the development of this technique for the synthesis of novel nanomaterials for biomedical applications. In particular it includes:1. We elaborated a regime of fs laser fragmentation from Si colloids for the synthesis of Si NPs having controllable size, crystallinity and oxidation state. We tested so-prepared Si NPs a number of particular biomedial applications.2. We elaborated a technique of fs laser ablation and fragmentation to fabricate bare Au NPs and Au-Si core-shells for SERSapplications. One approache is based on laser ablation of Au target in colloidal solution of Si NPs. 3. For the first time we synthesized novel plasmonic NPs based on titanium nitride. We also showed that an additional fs laser fragmentation step leads to the decrease of NPs size to 5 nm. Besides, we found that such NPs have a very broad extinction peak in the near IR.4. For the first time we demonstrated the synthesis of fluorescent organic NPs of specially designed aggregation-induced emission luminophore (AIE LP). The brightness of such NPs was determined to be comparable to that of quantum dots.

<p>Many anti-cancer drugs are poorly water-soluble and show undesirable pharmacokinetics and low bioavailability. Nanoparticles (NP) are used as delivery vehicles to improve bioavailability and biodistribution of such drugs. For clinical translation of an NP product, it is critical that the NP carry a large amount of drug and maintain good stability during circulation. A typical drug loading capacity of current NP formulations is less than 20% of the total mass, which is concerning from the standpoint of safety and administration convenience. Current NP formulations are also limited in retaining a drug during circulation and release the drug prematurely before they reach target tissues. These challenges are responsible at least partly for recent failure of leading NP products in clinical trials. </p> Given these challenges, I have focused on developing a stable NP formulation with high drug loading capacity, drug-rich nanocores stabilized by interfacial assemblies of iron-tannic acid (pTA) and albumin. Tannic acid is a polyphenol of natural origin and can form coordination complexes with Fe³⁺ ions that stabilize the interface between drug rich core droplets and aqueous solution. The underlying hypotheses are that (i) NP core formed solely of drug will offer a high drug loading capacity and (ii) the strong interaction of TA with drug molecules will maintain the nanocore stability and avoid premature drug release. Carfilzomib (CFZ), an epoxyketone peptide and a second-generation proteasome inhibitor, the use of which is limited to multiple myeloma due to the low stability, was chosen as a model drug to encapsulate in the new NP formulation. The NP surface was further functionalized with albumin, quinic acid derivative and plasmid DNA based on their affinity for TA complex. With an additional albumin coating, CFZ nanocore (CFZ-pTA-alb) showed sustained drug release and metabolic stability. In murine syngeneic model of B16F10 melanoma, systemically administered CFZ-pTA-alb showed enhanced biodistribution and anti-tumor effect than commercial cyclodextrin-based CFZ (CFZ-CD). With localized intratumoral administration, CFZ-pTA-alb also outperformed CFZ-CD in antitumor efficacy, potentially by prolonged drug retention, reduced damage to tumor-infiltrating lymphocytes, and enhanced delivery of tumor antigens to DCs.