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Fabrication and application of polymer based microfluidic devices /Koesdjojo, Myra T. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references. Also available on the World Wide Web.
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Development of nanofluidic/microfluidic interfaces as analyte concentrators for proteomic samplesReschke, Kathleen C. January 2010 (has links)
Thesis (Ph. D.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains xii, 124 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Elastomeric microfluidic devices for biological studies /Hsu, Chia-Hsien. January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 66-80).
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Polymeric microfluidic devices : development of thermoset polyester microfluidic devices and use of poly(dimethylsiloxane) devices for droplet applications /Fiorini, Gina S., January 2007 (has links)
Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 140-155).
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From electrophoresis to dielectrophoresis : designing, fabricating, and evaluating an electroformed ratchet type microfluidic dielectrophoresis device /Gonzalez, Carlos F. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 133-137). Also available on the World Wide Web.
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Novel polymer-based microfluidic devices: fabrication and application for controllable reactionsHu, Chong 31 January 2018 (has links)
The present thesis includes a series of studies on microfluidic technology from novel microfabrication methods in polymers to diverse microfluidic applications. Specifically, this study focuses on some key issues in microfluidics, regarding the development of microfluidic fabrication strategy, material selection for microfabrication, and applications, in particularly controllable reactions of novel polymer-based microfluidic devices. We have developed novel methods, which hold completely different idea/ concept with conventional approaches', for fabrication of microfluidic chips with polymer materials. While for the microfluidic applications, the thesis exhibits cell perfusion experiments with freestanding 3D microchannels made of alginate hydrogel, convenient and sensitive lead(Ⅱ) ions detection on a plastic membrane microfluidic chip which was fabricated by the proposed novel one-step strategy, as well as and microfluidic controllable synthesis of enzyme-embedded metal-organic frameworks in a laminar flow;In the first part, we proposed an inside-out fabrication strategy using a copper scaffold as the sacrificial template to create freestanding 3D microvascular structures containing branched tubular networks with alginate hydrogel. The microvascular structures produced with this method are strong enough to allow handling, biocompatible for cell culture, appropriately porous to allow diffusion of small molecules, while sufficiently dense to prevent blocking of channels when embedded in various types of gels. In addition, other materials and biomolecules could be pre-loaded in our hydrogel tubular networks by mixing them with alginate solution, and the thickness of tubule wall is tunable. Compared to other potential strategies of fabricating free-standing gel channel networks, our method is parallel processing using an industrially mass-producible template, making our method rapid, low-cost and scalable. We demonstrated cell culture in a nutrition gradient based on a microfluidic diffusion device made of agar, a hydrogel traditionally hard to microfabricate, by embedding the synthesized tubules into the agar gel. In this way, the freestanding hydrogel vascular network we produced is a universal functional unit that can be integrated with other gel-based devices to build up the supporting matrix for 3D cell culture outside the hydrogel vascular structure; allowing great convenience and flexibility 3D culture. The method is readily implementable to have broad applications in biomedicine and biology, such as vascular tissue regeneration, drug discovery, and delivery system in 3D culture.;The second part, we developed a one-step method to mass produce microfluidic chip with thermal plastic membranes. We used a perfluoropolymer perfluoroalkoxy (often called Teflon PFA) negative mold, which is very nonsticky and has ultrahigh melting point, as solid stamp to thermal-bond two pieces of plastic membranes, low density polyethylene (LDPE) and polyethylene terephthalate (PET) coated with ethylene-vinyl acetate copolymer (EVA), which have different coefficients of thermal expansion. During the short period of contact with the heated Teflon stamp, the pressed area of the membranes permanently bonded, while the LDPE membrane spontaneously rose up at the area not pressed, forming microchannels automatically. These two regions were clearly distinguishable even at micrometer scale so that we were able to fabricate microchannels with width down to 50 microns. By using thermal-bonding, the pattern of Teflon mold will be transferred to the plastic membrane forming channels while two membranes will be bonded at the same time. The method enables generation of microchannels and bonding process to accomplish in a single step without sophisticated instruments. One Teflon mold can be used to mass replicate many plastic membrane chips in a short time because each round needs only a few seconds. Our method can fabricate a plastic microfluidic chip rapidly (within 12 seconds per piece) at an extremely low price (less than 0.02{dollar} per piece). We also showed some identical microfluidic manipulations with the flexible plastic membrane chips including droplet formation, microfluidic capillary electrophoresis and squeezing-pump for quantitative injection. In addition, we demonstrated convenient on-chip detection of lead ion by a peristaltic-pumping design, as an example of the applications of the plastic membrane chips in resource-limited environment. Due to the fast production method and low-cost of plastic materials, this one-step method will hopefully lead to new opportunities for the commercial implementations of microfluidic technologies.;Finally, on the basis of preliminary study of microfluidic laminar flow synthesis of MOFs in aqueous system in Chapter 4, we successfully synthesized and investigated formation of enzyme-embedded metal-organic frameworks (MOFs) in a continuous laminar flow on a microfluidic chip. Resultant enzyme-MOF composites displayed higher enzymatic activity than enzyme-MOF composites from bulk solution synthesis. A possible reason was that the precisely controlled and yet changeable reaction conditions such as reaction time and diffusive mixing of reagents allowed the fast reaction to be isolated into controllable processes and studied with predesigned yet changing conditions. This, in return, led to distinct morphological characteristics and activities of the enzyme-MOF composites compared to those from bulk synthesis. The results indicated that the highest activity of enzyme-MOF composites was obtained when metal ions and organic ligands were first gradually mixed within a few seconds before enzyme molecules joined the gradual mixing process. We found that the crystallinity degree of as-produced enzyme-MOF composites was reduced via the microfluidic flow synthesis, containing more structural defects compared to those with high degree of crystallinity from bulk synthesis. The reduced crystallinity allowed more effective approaching of substrates with enzyme embedded in composites and therefore an increased enzyme activity compared to enzyme-MOF composites from bulk synthesis. We further demonstrated that enzyme-MOF composites showed enhanced stability against elevated temperature and protease digestion compared with free enzymes, allowing their wider utility in biotechnology.
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Flow induced mixing in high aspect ratio microchannelsSiripoorikan, Bunchong 12 February 2003 (has links)
Micro-fluid mixing is an important aspect of many of the various micro-fluidic
systems used in biochemical production, biomedical industries, micro-energy
systems and some electronic devices. Typically, because of size
constraints and laminar flow conditions, different fluids may only have the
opportunity to mix by diffusion, which is extremely rate limited. Therefore, active
or highly effective passive mixing techniques are often required. In this study, two
pulsed injectors are used to actively enhance mixing in a high aspect ratio
microchannel (125 ��m deep and 1 mm wide). The main channel has two adjacent
flowing streams with 100% dye and 0% dye concentrations, respectively. Two
injectors (125 ��m deep and 250 ��m wide) are located on separate sides of the
channel, with one downstream 2 mm (equivalent to two main channel widths or
eight injector widths) from the other. This results in an asymmetric mixing as the
flow proceeds downstream. A dye solution is used to map local mixing
throughout the channel by measuring concentration variations as a function of both
space and time. The primary flow rates are varied from 0.01 to 0.20 ml/min
(Reynolds numbers of 0.3 to 26.6), the injector flow rate ratios are varied from
0.125 to 2, and the pulsing frequencies are varied from 5 to 15 Hz.
Images of the concentration variations within the channel are used to
quantify mixing by calibrating the intensity of the image with the concentration of
the dye solution. The degree of mixing (DoM) is used as a measure of quality and
is defined based on the integration across the channel of the difference between the
local concentration and the 50% concentration values. DoM is normalized by the
50% concentration value and subtracted from one to yield a parameter that varies
from 0 (no mixing) to 1 (perfect mixing). It is shown that there is a high degree of
repeatability of concentration distribution as a function of phase of the pulsing
cycle. A mixing map is constructed over the range of variables tested which
indicates an optimum set of flow and pulsing conditions needed to achieve
maximum mixing in the main channel flow. The flow rate ratio between the
injectors and main channel is found to be the most influential parameter on overall
mixing. The highest DoM in the main channel was found to be 0.89. It is also
noticed that improved mixing can occur at very low flow ratios under a unique set
of primary flow and low frequency pulsing conditions. In general, there is an
inverse relationship between primary flow rate and pulsing frequency to achieve
better overall mixing. / Graduation date: 2003
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Development of a microfluidic module for DNA purification via phenol extractionMorales, Mercedes C. January 2008 (has links)
Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Biomedical Engineering." Includes bibliographical references (p. 60-62).
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Microfluidic and microscale cell cultures for high-throughput cell-based assays and bioprocess developmentWen, Yuan, January 2009 (has links)
Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 119-224).
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Thermal digital microfluidic devices for rapid DNA analysisChen, Tian Lan January 2017 (has links)
University of Macau / Faculty of Science and Technology / Department of Electrical and Computer Engineering
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