An understanding of the motion of soft capsules in microchannels is useful for a number applications. This knowledge can be used to develop devices to sort biological cells based on their size and stiffness. For example, cancer cells have a different stiffness from healthy cells and thus can be readily identified. Additionally, devices can be developed to detect flaws in synthetic particles. Using a 3D hybrid lattice Boltzmann and lattice spring method, the motion of rigid and soft capsules in a pressure-driven microfluidic flow was probed. The effect of inertial drift is evaluated in channels different Reynolds numbers. Other system parameters such as capsule elasticity and channel size are also varied to determine their effect. The equilibrium position of capsules in the channel is also obtained. The equilibrium position of rigid and soft capsules depends on the relative particle size. If the capsule is small, the equilibrium position is found to be closer to the channel wall. Conversely, for larger capsules, the equilibrium position is closer to the channel centerline. The capsule stiffness affects the magnitude of the cross-stream drift velocity. For a given Reynolds number, the equilibrium position of softer capsules is closer to the channel centerline. However, It is found that the equilibrium position of soft capsules is insensitive to the magnitude of the Reynolds number.

Quantifying the velocity field near the wall in microfluidic devices is important because surface effects become significant at micro- to nanometer scales. Recent studies have suggested that the "no-slip" boundary condition breaks down in microscale flows of Newtonian liquids, where the amount of slip is usually extrapolated from velocity components measured far from the wall. This doctoral thesis presents a new technique, multilayer nano-particle image velocimetry (MnPIV), for measuring the tangential velocity components at different distances from and within about 500 nm of the wall and its application to measuring slip. The feasibility of MnPIV was demonstrated using synthetic images of plane Couette flow incorporating Brownian diffusion and imaging noise. The errors in MnPIV data were then quantified with Brownian dynamics simulations. Calibration experiments were used to correlate the image intensity of the tracer to its distance from the wall z. Multilayer nPIV was then used to determine the z-positions and distribution of the particles for z < 500 nm in experimental studies of microscale Poiseuille flow. The tracers were divided into three distinct layers based on their image intensities, and the average velocity of each layer was placed at the average z-position sampled by the particles in that layer. The resultant velocity gradients were within 6% on average of analytical predictions for 2D Poiseuille flow. Finally, the results of MnPIV studies of aqueous solutions flowing through microchannels with hydrophilic and hydrophobically-coated fused silica surfaces suggest that if the slip lengths are nonzero for both of these surfaces, they are less than the uncertainty in these results, or 27 nm and 31 nm for the hydrophilic and hydrophobic channels, respectively.

No description available.

“Lab on a Chip” technologies have revolutionized the field of bio-chemical analytics. The crucial role of optical techniques in this revolution resulted in the emergence of a field by itself, which is popularly termed as “optofluidics”. The miniaturization and integration of the optical parts in the majority of optofluidic devices however still remains a technical challenge. The works described in this thesis focuses on developing integration methods to combine various optical techniques with microfluidics in an alignment-free geometry, which could lead to the development of portable analytical devices, suitable for field applications. The integration approach was applied to implement an alignment-free optofluidic chip for optical chromatography; a passive optical fractionation technique fractionation for cells or colloids. This system was realized by embedding large mode area photonic crystal fiber into a microfluidic chip to achieve on-chip laser beam delivery. Another study on passive sorting envisages an optofluidic device for passive sorting of cells using an optical potential energy landscape, generated using an acousto-optic deflector based optical trapping system. On the analytical side, an optofluidic chip with fiber based microfluidic Raman spectroscopy was realized for bio-chemical analysis. A completely alignment-free optofluidic device was realized for rapid bio-chemical analysis in the first generation by embedding a novel split Raman probe into a microfluidic chip. The second generation development of this approach enabled further miniaturization into true microfluidic dimensions through a technique, termed Waveguide Confined Raman Spectroscopy (WCRS). The abilities of WCRS for online process monitoring in a microreactor and for probing microdroplets were explored. Further enhanced detection sensitivity of WCRS with the implementation of wavelength modulation based fluorescent suppression technique was demonstrated. WCRS based microfluidic devices can be an optofluidic analogue to fiber Raman probes when it comes to bio-chemical analysis. This allows faster chemical analysis with reduced required sample volume, without any special sample preparation stage which was demonstrated by analyzing and classifying various brands of Scotch whiskies using this device. The results from this study also show that, along with Raman spectroscopic information, WCRS picks up the fluorescence information as well, which might enhance the classification efficiency. A novel microfabrication method for fabricating polymer microlensed fibers is also discussed. The microlensed fiber, fabricated with this technique, was combined with a microfluidic gene delivery system to achieve an integrated system for optical transfection with localized gene delivery.

This thesis was about finding a recovery method for TiO2, using a TiO2 recovery technology, which was high enough to be economical ($10 - $15 per 1,000 gallons) to be adopted by wastewater treatment plants. When comparing recovery technologies, the top three which were investigated further through experimentation were a centrifuge, sedimentation tank, and microfilter membrane. Upon experimentation and research, the TiO2 recovery efficiencies of these technologies were 99.5%, 92.5%, and 96.3%, respectively. When doing economic analysis on these technologies comparing TiO2 efficiencies and capital and operational costs, the centrifuge was the most preferred economic option. Also, its cost did were in the economical range ($10 - $15/1,000 gallons) which makes even this technology economical. Besides that, important and valuable information about TiO2: settling behavior, particle size and zeta potential, interactions with COD, and filter operations (particle characterization) were discovered for future research and future testing on this issue. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

O uso da microfluídica na área de análises genéticas possibilita não apenas a diminuição de custos, mas também menor manipulação de amostras e reagentes e ainda maior portabilidade das análises. Com isso aumenta a possibilidade da sua utilização em locais remotos, sem a infraestrutura de um laboratório bem equipado. Dispositivos capazes de usar apenas a força centrifuga para movimentação de fluidos juntamente com a utilização de válvulas passivas para controle dos fluidos pode potencializar a sua utilização nos diagnósticos Point-of-Care. Este trabalho teve como objetivo o desenvolvimento de um microdispositivo descartável de poliéster para análises genéticas, visando a extração e amplificação do DNA alvo, de forma rápida, barata, integrada e automatizada. Os resultados confirmam a viabilidade dos dispositivos poliéster-toner (PeT) e poliéster-fita dupla face (PeDF) automatizados de extração, obtendo por meio da extração dinâmica em fase sólida de amostras complexas, DNA com qualidade compatível à técnica da reação em cadeia de polimerase (PCR). Esses resultados foram confirmados por meio da amplificação por PCR dos genes &beta;-globina nas amostras de sangue e urina, e o gene malB nas amostras de Escherichia coli. Também foi confirmado a compatibilidade dos dispositivos de PeT para amplificação por PCR mediado por infravermelho (IV-PCR) do gene malB presente no DNA genômico de bactéria E. coli. Por fim, os dispositivos de extração e amplificação foram interligados para obtenção de um dispositivo integrado e automatizado formado pela combinação de dispositivos fabricados com diferentes filmes e métodos, PeT e PeDF. O controle de todas as soluções no interior dos dispositivos foi realizado por meio da força centrífuga combinada a válvulas passivas, sem qualquer necessidade de equipamento adicional. Portanto, podemos concluir que o dispositivo integrado PeDF - PeT possui grande potencial para aplicações em análises genéticas de forma mais barata, portátil e com menor manipulação das amostras pelo analista. / The development of microfluidics for genetic analysis allows not only cost reduction but also reduces sample and reagents handling, and increases the chances of a portable analysis. With this, increasing the possibility to use the techniques on remote places without the infrastructure of an equipped laboratory. Microdevices capable of using the centrifugal force in combination with passive valves to fluidic control can promote Point-of-Care analysis. The primary goal of this thesis was to associate these tools for the development of a disposable microdevice for genetic analysis, aiming faster, inexpensive, integrated and automated DNA extraction and amplification. The results confirmed the viability of PeT and PeDF automated microdevices, for DNA dynamic solid phase extraction, in providing high-quality DNA compatible to PCR analysis using complex samples. These results were confirmed by the &beta;-globin PCR amplification using blood and urine samples, and the malB gene amplification in Escherichia coli samples. We have also verified the compatibility of the PeT microdevices with IV-PCR for malB gene amplification in genomic E. coli DNA. The extraction and amplification modules were interconnected to obtain an integrated and automated microdevice by the combination of devices made with different films and microfabrication methods, PeT and PeDF. The fluidic control in the devices was made using the centrifugal force combined to passive valves, with no requirement of any extra equipment. Therefore, we can conclude that the integrated PeDF - PeT microdevice has a great potential for cheaper and portable genetic analysis application, with less operator manipulation.

O uso da microfluídica na área de análises genéticas possibilita não apenas a diminuição de custos, mas também menor manipulação de amostras e reagentes e ainda maior portabilidade das análises. Com isso aumenta a possibilidade da sua utilização em locais remotos, sem a infraestrutura de um laboratório bem equipado. Dispositivos capazes de usar apenas a força centrifuga para movimentação de fluidos juntamente com a utilização de válvulas passivas para controle dos fluidos pode potencializar a sua utilização nos diagnósticos Point-of-Care. Este trabalho teve como objetivo o desenvolvimento de um microdispositivo descartável de poliéster para análises genéticas, visando a extração e amplificação do DNA alvo, de forma rápida, barata, integrada e automatizada. Os resultados confirmam a viabilidade dos dispositivos poliéster-toner (PeT) e poliéster-fita dupla face (PeDF) automatizados de extração, obtendo por meio da extração dinâmica em fase sólida de amostras complexas, DNA com qualidade compatível à técnica da reação em cadeia de polimerase (PCR). Esses resultados foram confirmados por meio da amplificação por PCR dos genes &beta;-globina nas amostras de sangue e urina, e o gene malB nas amostras de Escherichia coli. Também foi confirmado a compatibilidade dos dispositivos de PeT para amplificação por PCR mediado por infravermelho (IV-PCR) do gene malB presente no DNA genômico de bactéria E. coli. Por fim, os dispositivos de extração e amplificação foram interligados para obtenção de um dispositivo integrado e automatizado formado pela combinação de dispositivos fabricados com diferentes filmes e métodos, PeT e PeDF. O controle de todas as soluções no interior dos dispositivos foi realizado por meio da força centrífuga combinada a válvulas passivas, sem qualquer necessidade de equipamento adicional. Portanto, podemos concluir que o dispositivo integrado PeDF - PeT possui grande potencial para aplicações em análises genéticas de forma mais barata, portátil e com menor manipulação das amostras pelo analista. / The development of microfluidics for genetic analysis allows not only cost reduction but also reduces sample and reagents handling, and increases the chances of a portable analysis. With this, increasing the possibility to use the techniques on remote places without the infrastructure of an equipped laboratory. Microdevices capable of using the centrifugal force in combination with passive valves to fluidic control can promote Point-of-Care analysis. The primary goal of this thesis was to associate these tools for the development of a disposable microdevice for genetic analysis, aiming faster, inexpensive, integrated and automated DNA extraction and amplification. The results confirmed the viability of PeT and PeDF automated microdevices, for DNA dynamic solid phase extraction, in providing high-quality DNA compatible to PCR analysis using complex samples. These results were confirmed by the &beta;-globin PCR amplification using blood and urine samples, and the malB gene amplification in Escherichia coli samples. We have also verified the compatibility of the PeT microdevices with IV-PCR for malB gene amplification in genomic E. coli DNA. The extraction and amplification modules were interconnected to obtain an integrated and automated microdevice by the combination of devices made with different films and microfabrication methods, PeT and PeDF. The fluidic control in the devices was made using the centrifugal force combined to passive valves, with no requirement of any extra equipment. Therefore, we can conclude that the integrated PeDF - PeT microdevice has a great potential for cheaper and portable genetic analysis application, with less operator manipulation.

The consumption of omega-3 fatty acids and phytosterol promotes the reduction of cholesterol and triacylglycerol levels. However, such compounds are susceptible to oxidation, which hampers their application. First, the aim of this work was to encapsulate echium oil (Echium plantagineum L.), source of omega-3 fatty acids, with hydrophilic phenolic compounds (sinapic acid and rutin) by double emulsion followed by complex coacervation in order to evaluate the best hydrophilic phenolic compound. In this case, sinapic acid showed better performance as antioxidant. Then, the second objective of this work was to study the microencapsulation of echium oil by complex coacervation using gelatin-arabic gum and gelatin-cashew gum as wall materials and sinapic acid and transglutaminase as crosslinkers. In this step, it was possible to observe that sinapic acid, besides to be an antioxidant, could also act as crosslinker. So, the third objective was to study the effect of sinapic acid in echium microparticles obtained by emulsion followed by spray or freeze drying using arabic gum as carrier agent in order to compare different encapsulation techniques. In addition to these methods, the fourth objective was to compare these techniques already mentioned to the combination of microfluidic devices and ionic gelation in order to encapsulate echium oil. In this case, sinapic acid and quercetin were also incoporated in the microcapsules. All the microcapsules/ microparticles obtained in the mentioned different techniques presented characteristics feasible for application and also promoted the protection of the oil. However, the encapsulation by complex coacervation and the addition of sinapic acid as crosslinkers was the method choosen for the coencapsulation of echium oil and phytosterols since presented the better results. Moreover, the treatment GA075 (microcapsule with gelatin-arabic gum as wall materials and 0.075g sinapic acid/ g gelatin) promoted the better protection to the encapsulated compounds. In this way, this treatment was applied into yogurt and compared to the one with the compounds nonencapsulated and the yogurt control. The yogurt containing microcapsules, presented a pH range from 3.89-4.17 and titratable acidity range from 0.798-0.826%, with good sensorial acceptance. It was possible to apply the microcapsules in yogurt, without compromising the rheological properties and physicochemical stability of the product, obtaining a functional product rich in omega-3 fatty acids, phytosterols and phenolic compound. / O consumo de ácidos graxos ômega-3 e fitosterol promove a redução dos níveis de colesterol e triacilglicerol. No entanto, esses compostos são susceptíveis à oxidação, o que dificulta sua aplicação. Primeiramente, o objetivo deste trabalho foi encapsular o óleo de echium (Echium plantagineum L.), fonte de ácidos graxos ômega-3, com compostos fenólicos hidrofílicos (ácido sinápico e rutina) por emulsão dupla seguida de coacervação complexa com intuito de avaliar o melhor composto fenólico hidrofílico. Neste caso, o ácido sinápico apresentou melhor desempenho como antioxidante. Em seguida, o segundo objetivo deste trabalho foi estudar a microencapsulação do óleo de echium por coacervação complexa utilizando as combinações gelatina-goma arábica e gelatina-goma de caju como materiais de parede e ácido sinápico e transglutaminase como agentes de reticulação. Nesta etapa, foi possível observar que o ácido sinápico, além de ser um antioxidante, também pode atuar como agente de reticulação. Assim, o terceiro objetivo foi estudar o efeito do ácido sinápico em micropartículas de óleo de echium obtidas por emulsão seguida de atomização ou liofilização utilizando goma arábica como agente carreador, com a finalidade de comparar diferentes técnicas de encapsulação. Além desses métodos, o quarto objetivo foi comparar essas técnicas já mencionadas com a combinação de dispositivos microfluídicos e gelificação iônica utilizando o óleo de echium como composto bioativo. Neste caso, o ácido sinápico e a quercetina também foram incorporados nas microcápsulas. Todas as microcápsulas/ micropartículas obtidas pelas diferentes técnicas mencionadas apresentaram características viáveis para aplicação e também promoveram a proteção do óleo. No entanto, a encapsulação por coacervação complexa e a adição de ácido sinápico como reticulante foi o método escolhido para a coencapsulação de óleo de echium e fitosteróis, uma vez que apresentou melhor resultado. Além disso, o tratamento GA075 (microcápsula com gelatina-goma arábica como materiais de parede e 0,075g de ácido sinápico/ g gelatina) promoveu a melhor proteção aos compostos encapsulados. Desta forma, este tratamento foi aplicado em iogurte e comparado com o mesmo adicionado dos compostos não encapsulados e o iogurte controle. O iogurte contendo microcápsulas apresentou faixa de pH de 3,89-4,17 e acidez titulável de 0,798-0,826 %, com boa aceitação sensorial. Foi possível a aplicação das microcápsulas no iogurte, sem comprometer as propriedades reológicas e a estabilidade físico-química do produto, obtendo um produto funcional rico em ácidos graxos ômega-3, fitosteróis e compostos fenólicos.

Le procédé d’estampage à chaud est considéré comme l'un des procédés les plus prometteurs de micro-Réplication pour l'élaboration des micro-Composants ou nano-Composants avec des matériaux polymériques dans différents domaines d'application . La mémoire consiste à caractériser les propriétés physiques des polymères thermoplastiques amorphes (PS, PMMA et PC) sur une large plage de température, ainsi que la modélisation physique, la simulation numérique et vérification expérimentale du procédé d’estampage à chaud.[...]Les propriétés visco élastiques des polymères retenus ont été caractérisées avec les essais décompression dynamiques. Le module de conservation, le module de perte et le facteur d'amortissement de polymère PMMA à partir de la température ambiante jusqu'à légèrement au-Dessus de Tg ont été obtenues. Le comportement visco élastique des polymères a été décrit par un modèle de Maxwell Généralisé et un bon accord a été observé. La simulation numérique des étapes du remplissage de procédé d’estampage à chaud a été réalisée enprenant compte des propriétés visco élastiques de polymère. Les effets de la température et dela pression de compression sur l'exactitude de réplication dans le procédé d’estampage à chaud ont été étudiés.[...]Un nouveau moule de compression complet, y compris le système de chauffage, le système de refroidissement et le système de vide a été développé dans notre groupe de recherche. Les dispositifs micro fluidiques avec la dimension de la cavité : environ 200 μm, 100 μm et 50 μmen PS, PMMA et PC plaque (épaisseur de 2 mm) ont été élaborés par le procédé d’estampage à chaud. Les effets des paramètres du procédé, tels que l’entrefer imposé, la température décompression, la matière compressée et la dimension de micro cavité, sur l’exactitude de réplication du procédé d’estampage à chaud ont été étudiés. / Hot embossing process is considered as one of the most promising micro replication processes for the elaboration of micro or nano components with polymeric materials invarious application fields. The thesis consists to characterize the physical properties of widelyused amorphous thermoplastic polymers (PS, PMMA and PC) over a large temperature range,along with the physical modelling, numerical simulation and experimental verification of thehot embossing process.[...] The polymers’ viscoelastic properties have been characterized with the dynamical compression tests. The storage modulus, loss modulus and damping factor of PMMA polymerfrom ambient temperature to lightly above Tg have been obtained. The viscoelastic behaviourof polymer has been described by a proposed Generalized Maxwell model and a good agreement has been observed. The numerical simulation of filling stage of hot embossing process has been achieved by taking into account of polymer’s viscoelastic properties. Theeffect of compression temperature and pressure on the replication accuracy in hot embossing process has been investigated in the simulation.[...] A new complete micro compression mould tools, including heating system, cooling system and vacuum system have been developed in our research group. The microfluidic devices with the cavity dimension eq. to about 200 μm, 100 μm and 50 μm in PS, PMMA and PC plate(thickness eq. to 2 mm) have been elaborated by the hot embossing process. The effects of the processing parameters, such as the compressive gap imposed, compression temperature, embossed material and die cavity dimensions, on the replication accuracy of hot embossing process have been investigated.

The consumption of omega-3 fatty acids and phytosterol promotes the reduction of cholesterol and triacylglycerol levels. However, such compounds are susceptible to oxidation, which hampers their application. First, the aim of this work was to encapsulate echium oil (Echium plantagineum L.), source of omega-3 fatty acids, with hydrophilic phenolic compounds (sinapic acid and rutin) by double emulsion followed by complex coacervation in order to evaluate the best hydrophilic phenolic compound. In this case, sinapic acid showed better performance as antioxidant. Then, the second objective of this work was to study the microencapsulation of echium oil by complex coacervation using gelatin-arabic gum and gelatin-cashew gum as wall materials and sinapic acid and transglutaminase as crosslinkers. In this step, it was possible to observe that sinapic acid, besides to be an antioxidant, could also act as crosslinker. So, the third objective was to study the effect of sinapic acid in echium microparticles obtained by emulsion followed by spray or freeze drying using arabic gum as carrier agent in order to compare different encapsulation techniques. In addition to these methods, the fourth objective was to compare these techniques already mentioned to the combination of microfluidic devices and ionic gelation in order to encapsulate echium oil. In this case, sinapic acid and quercetin were also incoporated in the microcapsules. All the microcapsules/ microparticles obtained in the mentioned different techniques presented characteristics feasible for application and also promoted the protection of the oil. However, the encapsulation by complex coacervation and the addition of sinapic acid as crosslinkers was the method choosen for the coencapsulation of echium oil and phytosterols since presented the better results. Moreover, the treatment GA075 (microcapsule with gelatin-arabic gum as wall materials and 0.075g sinapic acid/ g gelatin) promoted the better protection to the encapsulated compounds. In this way, this treatment was applied into yogurt and compared to the one with the compounds nonencapsulated and the yogurt control. The yogurt containing microcapsules, presented a pH range from 3.89-4.17 and titratable acidity range from 0.798-0.826%, with good sensorial acceptance. It was possible to apply the microcapsules in yogurt, without compromising the rheological properties and physicochemical stability of the product, obtaining a functional product rich in omega-3 fatty acids, phytosterols and phenolic compound. / O consumo de ácidos graxos ômega-3 e fitosterol promove a redução dos níveis de colesterol e triacilglicerol. No entanto, esses compostos são susceptíveis à oxidação, o que dificulta sua aplicação. Primeiramente, o objetivo deste trabalho foi encapsular o óleo de echium (Echium plantagineum L.), fonte de ácidos graxos ômega-3, com compostos fenólicos hidrofílicos (ácido sinápico e rutina) por emulsão dupla seguida de coacervação complexa com intuito de avaliar o melhor composto fenólico hidrofílico. Neste caso, o ácido sinápico apresentou melhor desempenho como antioxidante. Em seguida, o segundo objetivo deste trabalho foi estudar a microencapsulação do óleo de echium por coacervação complexa utilizando as combinações gelatina-goma arábica e gelatina-goma de caju como materiais de parede e ácido sinápico e transglutaminase como agentes de reticulação. Nesta etapa, foi possível observar que o ácido sinápico, além de ser um antioxidante, também pode atuar como agente de reticulação. Assim, o terceiro objetivo foi estudar o efeito do ácido sinápico em micropartículas de óleo de echium obtidas por emulsão seguida de atomização ou liofilização utilizando goma arábica como agente carreador, com a finalidade de comparar diferentes técnicas de encapsulação. Além desses métodos, o quarto objetivo foi comparar essas técnicas já mencionadas com a combinação de dispositivos microfluídicos e gelificação iônica utilizando o óleo de echium como composto bioativo. Neste caso, o ácido sinápico e a quercetina também foram incorporados nas microcápsulas. Todas as microcápsulas/ micropartículas obtidas pelas diferentes técnicas mencionadas apresentaram características viáveis para aplicação e também promoveram a proteção do óleo. No entanto, a encapsulação por coacervação complexa e a adição de ácido sinápico como reticulante foi o método escolhido para a coencapsulação de óleo de echium e fitosteróis, uma vez que apresentou melhor resultado. Além disso, o tratamento GA075 (microcápsula com gelatina-goma arábica como materiais de parede e 0,075g de ácido sinápico/ g gelatina) promoveu a melhor proteção aos compostos encapsulados. Desta forma, este tratamento foi aplicado em iogurte e comparado com o mesmo adicionado dos compostos não encapsulados e o iogurte controle. O iogurte contendo microcápsulas apresentou faixa de pH de 3,89-4,17 e acidez titulável de 0,798-0,826 %, com boa aceitação sensorial. Foi possível a aplicação das microcápsulas no iogurte, sem comprometer as propriedades reológicas e a estabilidade físico-química do produto, obtendo um produto funcional rico em ácidos graxos ômega-3, fitosteróis e compostos fenólicos.