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Full-Text Articles in Engineering
Extensional Flows Of Polymer Solutions In Planar Microchannels, Mahmud Kamal Raihan
Extensional Flows Of Polymer Solutions In Planar Microchannels, Mahmud Kamal Raihan
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Non-Newtonian fluids such as polymer solutions often flow under microscale extensional conditions in many natural and engineering flow fields such as in microfluidic chips, porous rocks, biological membranes and filters, printheads in additive manufacturing, etc. The changing cross sectional areas of the internal flow passages therein exert additional extension on the flow along with the shearing. Numerous studies have been dedicated to understanding the extensional flows of polymer solutions over the years. However, most of these studies only focused on flexible polymers exhibiting elasticity in their macroscopic rheology, whereas rigid polymers that portray shear-thinning but often elude elasticity in the …
Inertial Focusing Of Particles In Curved Microchannels, Ketaki Joshi
Inertial Focusing Of Particles In Curved Microchannels, Ketaki Joshi
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Since the beginning of microfluidics, the ability to control motion of particles in microchannels has always been fascinating. Microfluidic techniques such as dielectrophoresis, magnetophoresis rely on externally applied fields to separate particles while others like hydrophoresis and deterministic lateral displacement depend on low Reynolds number operation for particle manipulation. One of these techniques is inertial focusing of particles in microchannels. The particles and channel interact to cause lateral migration of particles to equilibrium positions within channel cross-section in flow regime where inertia and viscosity of fluid are finite. Inertial focusing has wide range of applications in fields of chemical synthesis, …
Electrokinetic Particle Manipulations In Spiral Microchannels, John Dubose
Electrokinetic Particle Manipulations In Spiral Microchannels, John Dubose
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Recent developments in the field of microfluidics have created a multitude of new useful techniques for practical particle and cellular assays. Among them is the use of dielectrophoretic forces in 'lab-on-a-chip' devices. This sub-domain of electrokinetic flow is particularly popular due to its advantages in simplicity and versatility. This thesis makes use of dielectrophoretic particle manipulations in three distinct spiral microchannels. In the first of these experiments, we demonstrate the utility of a novel single-spiral curved microchannel with a single inlet reservoir and a single outlet reservoir for the continuous focusing and filtration of particles. The insulator-based negative-dielectrophoretic (repulsive) force …
Magnetic Manipulation Of Particles And Cells In Ferrofluid Flow Through Straight Microchannels Using Two Magnets, Jian Zeng
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Microfluidic devices have been increasingly used in the past two decades for particle and cell manipulations in many chemical and biomedical applications. A variety of force fields have been demonstrated to control particle and cell transport in these devices including electric, magnetic, acoustic, and optical forces etc. Among these particle handling techniques, the magnetic approach provides clear advantages over others such as low cost, noninvasive, and free of fluid heating issues. However, the current knowledge of magnetic control of particle transport is still very limited, especially lacking is the handling of diamagnetic particle. This thesis is focused on the magnetic …
Engineering Single-Molecule, Nanoscale, And Microscale Bio-Functional Materials Via Click Chemistry, Michael Daniele
Engineering Single-Molecule, Nanoscale, And Microscale Bio-Functional Materials Via Click Chemistry, Michael Daniele
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To expand the design envelope and supplement the materials library available to biomaterials scientists, the copper(I)-catalyzed azide-alkyne cycloaddition (CuCAAC) was explored as a route to design, synthesize and characterize bio-functional small-molecules, nanoparticles, and microfibers. In each engineered system, the use of click chemistry provided facile, bio-orthogonal control for materials synthesis; moreover, the results provided a methodology and more complete, fundamental understanding of the use of click chemistry as a tool for the synergy of biotechnology, polymer and materials science. Fluorophores with well-defined photophysical characteristics (ranging from UV to NIR fluorescence) were used as building blocks for small-molecule, fluorescent biosensors. Fluorophores …
Nanopillar Based Electrochemical Biosensor For Monitoring Microfluidic Based Cell Culture, Rajan Gangadharan
Nanopillar Based Electrochemical Biosensor For Monitoring Microfluidic Based Cell Culture, Rajan Gangadharan
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In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events.
With this motivation we developed a highly sensitive, selective and stable microfluidic …