Dissertations / Theses on the topic 'Microcontact printing'
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1
Rożkiewicz, Dorota Idalia. "Covalent microcontact printing of biomolecules." Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/58030.
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Zhou, Ye. "Microcontact printing for protein microarray applications /." Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/tek886s.pdf.
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Kendale, Amar Maruti 1978. "Automation of soft lithographic microcontact printing." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/89877.
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Bageant, Maia R. (Maia Reynolds). "Precision control of continuous microcontact printing." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115721.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis. Due to the condition of the original material, there are unavoidable flaws in this reproduction. Pages 257 to 263 in the original document contain text that runs off the edge of the page.
Includes bibliographical references (pages 265-271).
This work focuses on the development of experimental equipment enabling the scale-up of microcontact printing for industrial use. An examination of existing experimental microcontact printing hardware and identification of its deficiencies are given, and the design and implementation of improvements are detailed. In particular, these improvements focus on the enabling of closed-loop force control of the printing process by the establishment of a deterministic computational platform and additional sensing. An understanding and rationale for the overall control design of the microcontact printing process is developed. Though the goal is to control the compression of each individual microscale feature on the microcontact printing stamp, force control is shown to offer significant advantages over displacement control. Analytical dynamic models of the system are developed, iterated, and verified experimentally. Initially, a simple model consisting of two separable single-input, single-output (SISO) systems was developed, but this model was shown to fail to capture relevant dynamics. A twelfth-order multi-input, multi-output (MIMO) model describing the system was then developed and verified experimentally using specially constructed frequency response measurement tools. Controller design was then undertaken for both the simple and complex model. The simple model was accommodated with proportional-integral and pure integral designs. The complex model required an augmented full-state feedback controller with a Kalman state estimator, which was designed and implemented in discrete time. Nonideal properties inherent to the printhead system, including uncontrollability and unobservability, were quickly identified. Maximum potential control performance under these constraints was explored and demonstrated experimentally, and it was shown that the inherent limitations made satisfactory closed-loop performance impossible. A conceptual printhead design for control is also presented. Mechanical design principles based on the lessons indicated by the system model and control design are laid out. A conceptual design is developed based on these principles, and basic geometry, packaging, and component selection is completed, allowing for a dynamic system model to be evaluated. The new printhead design is found to offer a significantly improved dynamic response, making the force control problem very tractable, and additionally solves a number of other design flaws inherent to the original printhead. An example control design and resulting performance is presented.
by Maia R. Bageant.
Ph. D.
5
von, Post Fredrik. "Microcontact printing of antibodies in complex with conjugated polyelectrolytes." Thesis, Linköping University, The Department of Physics, Chemistry and Biology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10123.
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Microcontact printing using elastomeric stamps is a technique used in finding new and efficient ways to produce biodetection chips. Microcontact printed, with poly(dimetylslioxane) (PDMS) stamps, patterns of antibodies have been evaluated using fluorescence microscopy, imaging ellipsometry and atomic force microscopy. Fluorescent conjugated polyelectrolytes form non-covalent molecular complexes with Immunoglobulin-γ type antibodies, antigen binding to the tagged antibody result in spectroscopic shifts. Four different conjugated polyelectrolytes (POWT, POMT, PTT, PTAA) in complex with human serum albumin antibodies (aHSA) have been tested with fluorescence spectroscopy. Complexes of POWT and aHSA gave rise to thelargest wavelength shift when exposed to human serum albumin.
Several types of commercially available fluorescent antibodies and antigens were used to test the specificity of microcontact printed antibodies to different antigen solutions. Using fluorescence microscopy it could not be shown that printed antibody patterns promote specific adsorption of corresponding antigen. It is proposed however that changed surface characteristics of the substrate due to PDMS residues transferred during printing is the main driving force behind antigen adsorption.
POMT - poly (3-[(s)-5-amino-5-methoxylcarboxyl-3-oxapentyl]-2,5-thiophenylenehydrochloride)
POWT - poly (3-(s)-5-amino-5-carboxyl-3-oxapentyl]-2,5-thiophenylenehydrochloride)
PTAA - polytiophene acetic acid
PTT - poly (3-[2,5,8-trioxanonyl] thiophene)
6
Olofsson, Karl, and Gustav Stenbom. "Directed Migration of Natural Killer Cells by Microcontact Printing." Thesis, KTH, Tillämpad fysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145736.
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NK cells are large granular lymphocytes that patrol the body for defect or virally infected cells. The migration of natural killer (NK) cells is critical for the detection and elimination of aberrant cells such as tumor- and virally infected cells. If a NK cell stumbles upon a target, i.e. an aberrant or stressed cell, the NK cell has the ability to kill the target cell. Limitations in the efficiency of NK cells, such as limited migration speed, and the finite number of target cells that can be killed by one NK cell, leaves the immune system vulnerable to diseases. However it has been shown that NK cell populations are heterogeneous, and from one host to another the overall efficiency of NK cells may vary. If the most efficient NK cells could be isolated from a cell population and cultivated, great numbers of high performing NK cells could then possibly be reintroduced to a body and be used to fight maladies such as cancer and HIV. In an attempt to bring us closer to these possibilities, and further examine the characteristics of NK cells, a high quality master was manufactured and used for microcontact printing. This project has focused on how NK cell migration is affected by cell structure and whether NK cells can be directed along a pattern to provide a situation where NK cell migration speed can be measured rigorously. This was done by using microcontact printing to create micro patterns of proteins that mimics the geometry of the NK cells migrating phenotype. This report will give a description of the master fabrication process and it will be shown that NK cells can be influenced to move straighter by interacting with a microcontact printed pattern of proteins. Furthermore our results will conclude that NK cell migration speed is not affected significantly by the microcontact printed proteins.
7
Khanna, Kanika. "Analysis of the capabilities of continuous high-speed microcontact printing." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46150.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 86-87).
Microcontact printing uses elastomeric stamps to transfer ink onto a substrate by the process of self-assembly. It has the capability to print features as small as 200nm over large areas. Because of this it has many potential industrial applications in areas such as the manufacture of flexible displays and electronics. Roll to roll is the best model for the commercialization of microcontact printing since it offers advantages such as high throughput, convenient material handling and conformal contact propagation. We have designed and built a tool to study the behavior of microcontact printing in a roll to roll paradigm, with the three fold objective of printing at high speeds, over large areas and obtaining good quality. This thesis emphasizes the experimental part of our project. We have obtained results as low as 28 microns over areas of 5.8"x5" and tight dimensional distributions within 1 micron. According to our results, there is no evidence that the printing load and printing speed have any effect on the printing quality. We have been able to print at speeds as high as 400 fpm with contact times of 7 ms, over 8"x 8", albeit with defects such as air trapping at very high speeds. We have also built a prototype to demonstrate continuous etching as an accompanying process.
by Kanika Khanna.
M.Eng.
8
Chen, Tao, Rainer Jordan, and Stefan Zauscher. "Polymer brush patterning using self-assembled microsphere monolayers as microcontact printing stamps." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138826.
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Self-assembled microsphere monolayers (SMMs) hold significant promise for micro- and nanopatterning. Here we exploit, for the first time, SMMs as stamps for microcontact printing (μCP) and demonstrate this to fabricate patterned initiator templates that can subsequently be amplified into polymer brushes by surface initiated atom transfer radical polymerization (SI-ATRP). SMM stamps avoid the need for expensive and sophisticated instrumentation in pattern generation, and provide a broad range of accessible surface chemistries and pitch size control.
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Kim, LeeAnn. "Deposition of colloidal quantum dots by microcontact printing for LED display technology." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37207.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 81-84).
This thesis demonstrates a new deposition method of colloidal quantum dots within a quantum dot organic light-emitting diode (QD-LED). A monolayer of quantum dots is microcontact printed as small as 20 ,Lm lines as well as millimeter scale planes, and the resulting devices show quantum efficiencies as high as 1.2% and color saturation superior to previous QD-LEDs'. Through a modification of the polydimethylsiloxane (PDMS) stamp with a parylene-C coating, quantum dots solvated in chloroform were successfully inked and stamped onto various substrates, including different molecular organic layers. The ability to control the placement and the pattern of the quantum dots independently from underlying organic layers provides a new level of performance in QD-LEDs, increasing the possibility of QD-LED displays.
by LeeAnn Kim.
M.Eng.
10
Hale, Melinda (Melinda Rae). "Manufacturing conductive patterns on polymeric substrates : development of a microcontact printing process." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81752.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 215-233).
The focus of this research was to develop a process suitable for creating very high resolution conductive patterns on polymer substrates, in a way that can be scaled to high volume manufacturing. The original motivation for this work came from the problem of manufacturing electrodes on microfluidic devices (which in volume production are commonly formed from polymers), but the findings of this work also have applications in flexible electronics, optics, surface patterning, organic micromanufacturing, and photovoltaics. After an initial exploration of various micromanufacturing processes, microcontact printing (μCP) was chosen as the most promising technique for further study. By using μCP to directly pattern conductive inks, this work has demonstrated previously unachievable printing: feature sizes down to 5μm, using liquid inks on polymer substrates, with a process that can be scaled to high-volume production. An understanding of the mechanisms of direct liquid ink transfer was used to identify relevant process input and output factors, and then the process sensitivities of those factors were investigated with a careful design of experiments. From the empirical data, a process model was built with generalized variables. This model was then used to successfully predict behavior of other inks and other substrates, thus validating the model and showing that it is extendable for future work. By developing an empirically verified model of ink transfer at the micron scale, this work has enabled a process for low cost, high volume microfeature patterning over large areas on polymer substrates.
by Melinda Hale.
Ph.D.
11
Chen, Tao, Rainer Jordan, and Stefan Zauscher. "Polymer brush patterning using self-assembled microsphere monolayers as microcontact printing stamps." Royal Society of Chemistry, 2011. https://tud.qucosa.de/id/qucosa%3A27784.
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Self-assembled microsphere monolayers (SMMs) hold significant promise for micro- and nanopatterning. Here we exploit, for the first time, SMMs as stamps for microcontact printing (μCP) and demonstrate this to fabricate patterned initiator templates that can subsequently be amplified into polymer brushes by surface initiated atom transfer radical polymerization (SI-ATRP). SMM stamps avoid the need for expensive and sophisticated instrumentation in pattern generation, and provide a broad range of accessible surface chemistries and pitch size control.
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Ottesen, Vegar. "Bacterial Microarrays by Microcontact Printing : Development of a Method for Immobilizing Live Bacteria on Microarrays." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26120.
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Traditional microbiological experimental methods generally reveal population-wide statistics and are not capable of revealing variations between individual cells. In an effort to address this, a cheap, quick and easy means of producing micro-arrays with live bacteria immobilized on the array's coordinates has been developed. To achieve this, microcontact printing (µCP) was used to print circular PD ``islands'' onto a surface coated with either PEG or PVA. The bacteria, <i>Pseudomonas putida</i> KT2440 were successfully immobilized on approximately 97% of the printed islands, depending on island diameter. A LIVE/DEAD® <i>Bac</i>Light™ assay revealed that over 99% of the immobilized bacteria survive the immobilization on the array. Qualitative analysis suggests the bacteria survive for hours after immobilization, provided nutrients are available. The developed method may, by revising the stamp design and/or choice of elastomer, likely be optimized to immobilize only one bacterium per array coordinate.
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Libert, Adam M. (Adam Marcus). "Precision control of cylindrical stamp contact in a continuous roll-to-roll microcontact printing machine." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92218.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 140-142).
Microcontact printing is a form of soft lithography that uses a molded elastomeric stamp to print patterns with micron and sub-micron scale features. This is an effective low-cost technique for replicating master patterns onto substrates. However, the traditional embodiment of using a planar stamp with a planar substrate is limited in both scale and speed. In order to achieve higher production rates, the lab scale plate-to-plate microcontact printing method must be developed into a roll-based manufacturing process. The marriage of the precision of microcontact printing with the speed of traditional press printing will fill a niche in manufacturing capabilities. Large area, high rate patterning of micron and sub-micron scale features will help to enable the economic manufacturing of a wide range of emerging technologies. Specifically, this continuous microcontact printing process could be used to make flexible displays, thin film photovoltaic cells, transparent conductors, desalination membranes, and other large-scale surface modifications. This thesis details the development of a precision roll-to-roll microcontact printing machine. This pilot-scale web-handling machine serves as the platform for research on the continuous microcontact printing process. Specific consideration is given to the design of a precision print head that is capable of maintaining consistent contact pressure even while printing at high speeds. As well, a novel camera system is developed to achieve in-situ real-time inspection of the contact region between the stamp and the substrate. The visual data from this sensor is used as feedback for the controller, enabling the print head to maintain the desired evenly distributed pressure along the entire stamp width. Results show that the closed-loop control of print contact is able to compensate for eccentricities and disturbances in the system, significantly decreasing variation in print pressure. These tests show promise for the usefulness of this novel process control technique, rather than traditional downstream sensing. As well, this pilot-scale machine succeeds in serving as a platform for continuous roll-to-roll microcontact printing research that will help to guide the scale-up of the process into a high rate manufacturing technique.
by Adam M. Libert.
S.M.
14
Stagnaro, Adam. "Design and development of a roll-to-roll machine for continuous high-speed microcontact printing." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46479.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (leaves 120-121).
Microcontact printing ([mu]CP) is an emerging technique for patterning micro-scale features for electronics, optics, surface modifications, and a variety of other applications. Its many advantages over traditional techniques like photolithography include lower cost, ability to pattern on non-planar surfaces, and compatibility with a variety of materials. Low production rates are one of the major limitations, as the process remains primarily a lab-scale technique at this point. Commercialization of the process depends on the development of innovative ways of applying the techniques to fast and flexible process paradigms. This thesis proposes the use of roll-to-roll techniques to increase the throughput, flexibility, and printable area for [mu]CP, while maintaining high quality outputs. A three-part literature review is presented comprising microcontact printing, traditional printing techniques, and roll-to-roll web handling best practices. The development of a printing machine and continuous etching machine used to explore the application of [mu]CP in a high-speed roll-to-roll paradigm is then detailed. Finally, the results of the experimentation carried out are documented including effects on quality and limitations for high throughputs. It is concluded that roll-to-roll microcontact printing can produce high quality results over large areas at rates up to 400 feet per minute and possibly beyond.
by Adam Stagnaro.
M.Eng.
15
Ascoli, Peter A. "Fabrication and qualification of arbitrarily patterned seamless tooling for continuous roll-to-roll microcontact printing." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111771.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 315-318).
Microcontact printing is form of soft lithography utilizing an elastomeric stamp with a molded relief pattern to print features on substrates through ink transfer at micron and nanometer scales. This is a low-cost technique when compared with other printing and patterning processes. Traditional microcontact printing using flat stamps and planar, rigid substrates, which limit production output, manufacturing scale, and capital efficiency. However, a precise, scalable, roll-to-roll process could lower production costs, increase output, and enable the creation new technologies. Specifically, flexible displays, photovoltaic systems and accessories, and other large area electronics could be fabricated using a continuous roll-to-roll microcontact printing process. This work builds on existing research in fabricating seamless cylindrical PDMS stamps (tools) for microcontact printing using laser direct-write lithography for micro-patterning. Specifically, the scale-up requirement for microcontact printing to have arbitrarily patterned tools with diverse feature sets was addressed. The manufacturing process window of AZ 9260 photoresist was examined through numerical simulation and experimentation to determine an input set for the most robust performance and ideal tool feature geometry. A rasterscan protocol was developed to arbitrarily pattern the photoresist in a cylindrical setting. Additionally, non-destructive metrology equipment for analyzing the patterned photoresist and tool contact region were developed. Tools with multiple feature patterns were fabricated, and the evolution of critical feature dimensions were measured from simulation, to the photoresist mold, to the PDMS stamp, to the stamp in contact, and finally to the printed features. Manufacturing tools with diverse patterns was demonstrated, and the contribution of tool fabrication steps to ultimate print geometries was studied. The presented findings further the development of a scaled-up microcontact printing process in a continuous roll-to-roll setup.
by Peter A. Ascoli.
S.M.
16
Andersson, Helene. "Microfluidic devices for biotechnology and organic chemical applications." Doctoral thesis, Stockholm, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3248.
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Baldesi, Paolo. "Design and development of high precision five-axis positioning system for roll-to-roll multi-layer microcontact printing." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55211.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Includes bibliographical references (p. 102-104).
Microcontact printing is based on the use of elastomeric stamps to transfer ink onto a substrate taking advantage of the self-assembly process. Features as small as 300nm can be easily printed over an extended area. The accuracy and the speed of the process make it suitable for many industrial applications in areas such as the manufacture of flexible displays and electronics. In 2008, a group of MIT mechanical engineering students built a prototype machine that demonstrated the advantages of the roll-to-roll paradigm in terms of high throughput, convenient material handling and conformal contact propagation. The prototype machine, although characterized by defects such as air trapping at very high speed, was able to print at speeds as high as 400 fpm with contact times of 7 ms, over an 8"x 8" substrate area. This year, an improved quality printing output and multilayer printing process were set as goals. To achieve the objectives, a device that could cast a flat stamp with little variance was designed and machined.
(cont.) A high precision wrapping system was designed and fabricated. Finally, a high-precision positioning system was introduced to compensate for misalignment in the multi-layer printing process. This thesis describes the design of a five-axis high-precision positioning system to control the print roller along five degrees of freedom. Using flexures and micrometer heads as principal position control devices, the print roller can be positioned and oriented with high repeatability, 2.5lim accuracy, 2.5pm resolution, and the calibration showed that, in the worst case, the coupling among axes is limited to the 8%. Moreover, experimental results demonstrate that the new stamp casting method can accomplish ±16p.m flatness with thickness of 1194pm and that the innovative wrapping process ensures alignment of the backing plate with respect to the print roller with less than ±75V1m absolute misalignment. Consequently, using the upgraded roll-to-roll machine and the newly developed wrapping and stamp fabrication processes, deformation of the printed output is limited to an average of 3.8%. Finally, the multi-layer printing process was tested and a ±75V1m misalignment was achieved between two layers.
by Paolo Baldesi.
M.Eng.
18
Nill, Scott T. (Scott Thomas). "Integrated hardware, software, and sensor design for control of a scalable, continuous roll-to-roll microcontact printing process." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92152.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 146-150).
Soft lithography has been a long-time candidate for altering the landscape in micromanufacturing. Such processes promise lower cost in equipment and processed products while showing substantial gains in throughput and maximum dimensions. These distinct advantages allow for new advances in production ranging from inexpensive, fully flexible electronics to higher efficiency batteries and improved water purification systems. Microcontact printing ([mu]CP), a particular form of soft lithography, scales the rubber stamp concept down to the micron range. Past work has demonstrated sub-nanometer resolutions attainable with [mu]CP. Currently, microcontact printing is usually performed with a flat stamp and substrate thus limiting the process to batch processing. Recent advancements have enabled conversion of the plate process to a roll-to-plate configuration through in-depth understanding and control of the stamp contact. The transition to full roll-to-roll manufacturing, on increasingly larger scales, presents new challenges for sensing and control of this contact. In the past, the roll-to-roll printing process the control loop has not been closed around the actual contact and transfer process. This thesis presents a new method for sensing, in real-time, this contact process that can be used in roll-to-roll, high-throughput production. Second, the design and implementation of an integrated control and automation system, integrating the novel sensing, is presented. Finally, an overview of the design and production of a precision machine incorporating the sensing, control and automation is given.
by Scott T. Nill.
S.M.
19
Datar, Charudatta Achyut. "Design and development of high precision elastomeric-stamp wrapping system for roll-to-roll multi-layer microcontact printing." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55212.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 94-96).
Microcontact printing is an emerging printing technique that could potentially find application in the electronics industry. High-speed roll-to-roll equipment was built at Nano Terra, Inc in 2008, for microcontact printing. However, the equipment was a proof-of-concept, capable of single-layer printing, while the industry requires a multi-layer printing capability. In addition, the quality of printing it delivered was not industry competitive. The existing equipment has thus been upgraded with a view to achieve high-precision multi-layer microcontact printing; including a new method to manufacture a flat stamp, design of a high-precision wrapping system, design of a five-axis positioning system, and modification of the impression roller. This thesis describes in detail the design of an innovative high-precision system to wrap the elastomeric stamp on the print roller. This is followed by results of multilayer printing experiments, using the improved equipment. The potential for microcontact printing as a forthcoming technology for the electronics industry was confirmed. Further improvements are also suggested that would help deliver this promise.
by Charudatta Achyut Datar.
M.Eng.
20
Paulik, Matthew George. "The Modification of Gold Surfaces via the Reduction of Aryldiazonium Salts." Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/3105.
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This thesis presents the study of films derived from the reduction of aryldiazonium salts at gold surfaces. The properties of bare polycrystalline surfaces were investigated via the observation of the electrochemical oxidation and reduction of the gold. Films derived from diazonium salts were electrochemically grafted to the gold surface. The structure and stability of these interfaces was examined through the use of redox probes, gold oxide electrochemistry and water contact angle measurements. The spontaneous reduction of aryldiazonium salts at gold surfaces was investigated and the possible applications it presented towards printing and patterning of the gold surface with films were explained. Polycrystalline gold surfaces were prepared and subjected to various treatments, to observe the behaviour of gold oxide formation and reduction at the surface. Various effects on the surface structure were observed after treatment in solvents and electrolyte solutions. The surface structure of the gold atoms frequently changed due to the high mobilities of the gold atoms, and it is difficult to achieve a reproducibly stable surface. The electrochemical modification of gold surfaces via the reduction of aryldiazonium salts was investigated. Surfaces were modified with methylphenyl and carboxyphenyl films and exposed to various treatments. Monitoring the gold oxide reduction changes enabled the surface coverage of modifier directly attached to the surface to be calculated. The films appear to be stable, loosely packed and porous. The films are flexible in nature; redox probe responses showed reversible changes after repeated sonication in solvents of differing polarities and hydrophilicities. Contact angle measurements further support the notion of films that can reorganise in response to their environment. The spontaneous reduction of aryldiazonium salts at gold surfaces was observed. Film coverage was significantly lower at the spontaneously grafted surface than for films grafted electrochemically. Gold surfaces were successfully modified via microcontact printing, and surface coverages similar to the spontaneously grafted film were achieved. Microcontact printing was also used to pattern surfaces with films derived from diazonium salts. Feature sizes down to 100 µm were successfully achieved.
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Widyaya, Vania Tanda [Verfasser], and Karen [Akademischer Betreuer] Lienkamp. "Three-dimensional, bioactive microstructured surface-attached polymer network by microcontact printing - simultaneous antimicrobial activity, protein repellency, and cell compatibility." Freiburg : Universität, 2019. http://d-nb.info/1205663304/34.
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Merian, Christopher A. "Development of an inking system for continuous roll-to-roll microcontact printing of hexadecanethiol (HDT) on gold-coated PET." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104135.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 111-114).
Microcontact printing is a form of soft lithography that employs a molded polymer stamp to print substrates with pattern features as small as the sub-micron range. This is traditionally a plate-to-plate printing process, employing both flat stamps and flat, rigid substrates. However, to utilize this patterning technique in a truly low cost manner, it must evolve to a scalable roll-to-roll process. This combination of high precision patterning with high throughput manufacturing techniques could both reduce cost of current products, as well as enable a range of new technologies. Large area, high rate, continuous microcontact printing could be used to make flexible displays, photovoltaic dust sensors, and large area sensors among other products. This works describes the development of an inking system to enable continuous, roll-to-roll microcontact printing on a lab-scale machine. The molecular ink hexadecanethiol (HDT) is used to print self-assembling monolayers (SAMs) on flexible, gold-coated PET substrate. An ink tank and dryer system are designed and built to enable this material combination to be printed in a continuous manner. Measurement of print quality and pattern replication is executed to confirm that the system per- forms suitably at high throughput. The employment of the inking system facilitates a continuous, roll-to-roll microcontact printing process which can be used to further develop this manufacturing strategy.
by Christopher A. Merian.
S.M.
23
Nietner, Larissa F. "A direct-write thick-film lithography process for multi-parameter control of tooling in continuous roll-to-roll microcontact printing." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/92162.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 167-173).
Roll-to-roll (R2R) microcontact printing ([mu]CP) aims to transform micron-precision soft lithography in a continuous, large-scale, high-throughput process for large-area surface patterning, flexible electronics and engineered meta-surfaces. Efforts to implement this hybrid process have been limited by the inability to monitor and control the process and the lack of a continuous large-area polymer tool that embodies micron- to nano-scale patterns currently created with wafer-based lithography. Discontinuities arising from a wrapped image carrier, size limitations from silicon wafer sizes, difficulty in achieving uniform stamp thickness, and inability to monitor the contact region, pose challenges in scaling up [mu]CP to R2R processing. This work examines a new technique to produce seamless cylindrical tools for soft lithography using laser-based maskless lithography for micro-patterning. The process is parameterized and modeled to fabricate novel tooling structurally optimized for microcontact patterning. Positive-tone photoresists SPR 220 and AZ 9260 are examined in their process sensitivity and in their ability to provide tools for scalable [mu]CP. A fluorescent contact imaging technique is presented on the basis of fluorescent, layered composite PDMS image carriers. By adding fluorescent microparticles to PDMS, the stamp is shown to re-emit UV upon contact with the substrate. To scale the process for use in large-area applications, a machine design is suggested for a scalable implementation of the examined technique, which has the potential to provide large-scale microstructured tools and thereby facilitate process control and enable scale-up of microcontact printing.
by Larissa F. Nietner.
S.M.
24
Filipponi, Luisa, and n/a. "New micropatterning techniques for the spatial addressable immobilization of proteins." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20060905.113858.
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Bio-microdevices are miniaturised devices based on biologically derived components
(e.g., DNA, proteins, and cells) combined or integrated with microfabricated substrates.
These devices are of interest for numerous applications, ranging from drug discovery, to
environmental monitoring, to tissue engineering. Before a bio-microdevice can be fully
developed, specific fabrication issues need to be addressed. One of the most important
is the spatial immobilization of selected biomolecules in specific micro-areas of the
device. Among the biomolecules of interest, the controlled immobilization of proteins to
surfaces is particularly challenging due to the complexity of these macromolecules and
their tendency to lose bioactivity during the immobilization step. The present Thesis
reports on three novel micropatterning techniques for the spatial immobilization of
proteins with bioactivity retention and improved read-out of the resulting micropatterns.
The technologies developed are based on three different micropatterning approaches,
namely 1) direct-writing UV laser microablation (proLAB), 2) a novel microcontact
printing method (�CPTA) and 3) a replica molding method combined with bead selfassembly
(BeadMicroArray). The first two technologies, proLAB and �CPTA, are an
implementation of existing techniques (laser ablation and �CP, respectively), whereas
the third, i.e., the BeadMicroArray, is a totally new technique and type of patterning
platform.
'ProLAB' is a technology that uses a micro-dissection tool equipped with a UV laser
(the LaserScissors�) for ablating a substrate made of a layer of ablatable material, gold,
deposited over a thin polymer layer. The latter layer is transparent to the laser but
favours protein adsorption. In the present work microchannels were chosen as the
structure of interest with the aim of arranging them in 'bar-codes', so to create an
'information-addressable' microarray. This platform was fabricated and its application
to specific antigen binding demonstrated.
The second technique that was developed is a microstamping method which exploits the
instability of a high-aspect ratio rubber stamp fabricated via soft-lithography. The
technique is denominated microcontact printing trapping air (�CPTA) since the collapsing of a rubber stamp made of an array of micro-pillars over a plane glass surface
resulted in the formation of a large air gap around the entire array. The method can be
successfully employed for printing micro-arrays of proteins, maintaining biological
activity. The technique was compared with robotic spotting and found that microarrays
obtained with the �CPTA method were more homogeneous and had a higher signal-tonoise
ratio.
The third technique developed, the BeadMicroArray, introduces a totally new platform
for the spatial addressable immobilization of proteins. It combines replica molding with
microbead self-assembling, resulting in a platform where diagnostic beads are entrapped
at the tip of micropillars arranged in a microarray format. The fabrication of the
BeadMicroArray involves depositing functional microbeads in an array of V-shaped
wells using spin coating. The deposition is totally random, and conditions were
optimised to fill about half the array during spin coating. After replica molding, the
resulting polymer mold contains pyramid-shaped posts with beads entrapped at the very
tip of the post. Thanks to the fabrication mode involved, every BeadMicroArray
fabricated contains a unique geometric code, therefore assigning a specific code to each
microarray. In the present work it was demonstrated that the functionality of the beads
after replica molding remains intact, and that proteins can be selectively immobilized on
the beads, for instance via biorecognition. The platform showed a remarkable level of
selectively which, together with an efficient blocking towards protein non-specific
adsorption, lead to a read-out characterized by a very good signal-to-noise. Also, after
recognition, a code was clearly visible, therefore showing the encoding capacity of this
unique microarray.
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Zimmermann, Marc [Verfasser], Alexander [Akademischer Betreuer] Böker, Alexander [Gutachter] Böker, Bart Jan [Gutachter] Ravoo, and Klitzing Regine [Gutachter] von. "Multifunctional patchy silica particles via microcontact printing / Marc Zimmermann ; Gutachter: Alexander Böker, Bart Jan Ravoo, Regine von Klitzing ; Betreuer: Alexander Böker." Potsdam : Universität Potsdam, 2018. http://d-nb.info/1219514810/34.
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Zimmermann, Marc [Verfasser], Alexander [Akademischer Betreuer] Böker, Alexander Gutachter] Böker, Bart Jan [Gutachter] [Ravoo, and Klitzing Regine [Gutachter] von. "Multifunctional patchy silica particles via microcontact printing / Marc Zimmermann ; Gutachter: Alexander Böker, Bart Jan Ravoo, Regine von Klitzing ; Betreuer: Alexander Böker." Potsdam : Universität Potsdam, 2018. http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427731.
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Garcia, Cruz Alvaro. "Micro et Nano structuration du Poly(pyrrole) sur substrat polymérique : développement d’immunocapteur pour la détection des biomarqueurs du cancer." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10105.
Full textAbstract:
Les techniques non-conventionnelles de lithographie ont fait depuis deux décennies une entrée remarquée dans les sciences de l'ingénierie. Elles sont considérées aujourd'hui comme un enjeu majeur pour le développement des dispositifs. L'objectif principal de cette thèse est d'explorer de nouvelles voies pour la conception des micro&nanabiocapteurs en procédant à des impressions de poly(pyrrole) (PPy) à haute résolution par microtamponnage assisté par polymérisation catalytique (nanoCP-CCP) sur des substrats polymériques (poly(téréphtalate) d'éthylène (PETE), Copolymère d'oléfine cyclique (COC), polyétheréthercétone (PEEK), poly(éthylène 2,6-naphtalate (PEN) et le polyamide (PI)). Dans un premier temps, nous avons mis au point différentes techniques d'impression (greffage par impression, impression adressée et impression directe) et des conditions de polymérisation pour moduler les caractéristiques de PPy micro et nano-structurés, afin de contrôler la taille, la forme et les propriétés électriques désirées. Nous avons constaté que les paramètres les plus importants qui influent sur le processus d'impression surtout à l'échelle nanométrique sont: a) Le rapport des concentrations des réactifs pour le procédé de polymérisation qui comprend le Py-silane, nitrate d'argent (AgNO3), le chlorure du fer (III)/ le chlorure de Lithium (FeCl3/LiCl). b) Les paramètres physiques de la machine GeSIM; la pression d'impression, le niveau de contact, le temps d'encrage du tampon polydiméthylesiloxane (PDMS), et le temps d'impression. Finalement, on est arrivé à fabriquer des nanofils de PPy (PPy-NF) de 747±12,2 nm de largeur, 114±8 nm de hauteur et avec une séparation de 573±13,4 nm entre deux PPy-NF consécutifs. Ces films micro et nano-structurés ont été caractérisées par microscopie électronique à balayage (SEM), microscopie à force atomique (AFM) et spectrométrie de photon-électrons induits par rayons X (XPS). Dans une deuxième partie, on a développé des immunocapteurs à base de PPy-NF sensible aux biomarqueurs interleukine 8 et 6. Pour cela, différentes stratégies ont été adoptées pour immobiliser les anticorps spécifiques à ces deux biomarqueurs. Ces immunocapteurs ont été caractérisés par la méthode de spectroscopie d'impédance électrochimique (EIS). Les résultats obtenus par rapport à la sensibilité et la sélectivité sont très satisfaisants avec des limites de détection de l'ordre de quelques pg/L pour les deux immunocapteurs développésNon-conventional lithography techniques have made for the two last decades a huge impact in the engineering sciences. They are now regarded as a main challenge for the development of the devices. The objective of this thesis is to explore new alternative possibilities for designing micro & nano biosensors based on poly(pyrrole) (PPy) high resolution microprinting attended by catalytic polymerization (nanoCP-CCP) on substrates Polymer (poly (terephthalate) ethylene (PETE), cyclic olefin copolymer (COC), polyetheretherketone (PEEK), poly (ethylene 2,6-naphthalate (PEN), and polyamide (PI)). In a first step We have developed various printing techniques (grafting printing, addressed printing and direct printing) and polymerization conditions to modulate the characteristics of PPy micro and nano-structured in order to control the size, shape and Electrical desired properties. We found that the most important parameters that affect the printing process especially at the nanoscale are: a.) The ratio of the concentrations of reagents for the polymerization process which includes the Py-silane, nitrate silver (AgNO3), iron chloride (III) / lithium chloride (FeCl3 / LiCl). b) The physical parameters of the GeSIM machine; the printing pressure, contact level, the inking time stamp of polydimethylsiloxane (PDMS), and printing time. Finally, we got to manufacture PPy nanowires (PPy-NW) 747 ± 12.2 nm wide, 114 ± 8 nm in height and with a separation of 573 ± 13.4 nm between two consecutive PPy-NW. These micro and nano-structured films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and electron-photon spectroscopy induced by X-rays (XPS). In the second part, we have developed a PPy-NW-based immunosensors sensitive to interleukin 8 and 6 biomarkers. For this, different strategies have been adopted to immobilize antibodies specific to these two biomarkers. These immunosensors were characterized by electrochemical impedance spectroscopy method (EIS). The results obtained in relation to the sensitivity and selectivity are very satisfactory with the security detection limits of a few pg / L for both developed immunosensors
28
Wu, Cheng-Tse. "Drawing Functional Micropatterns on Flexible Polymer Substrates via VUV-lithography." Kyoto University, 2020. http://hdl.handle.net/2433/259044.
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Falk, Daniel. "Patterning of Highly Conductive Conjugated Polymers for Actuator Fabrication." Thesis, Linköpings universitet, Biosensorer och bioelektronik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-130465.
Full textAbstract:
Trilayer polypyrrole microactuators that can operate in air have previously been developed. They consist of two outer layers ofthe electroactive polymer polypyrrole (PPy) and one inner layer of a porous poly(vinylidene flouride) (PVDF) membranecontaining a liquid electrolyte. The two outer layers of PPy are each connected with gold electrodes and separated by the porousPVDF membrane. This microtool is fabricated by bottom-up microfabrication However, porous PVDF layer is not compatible with bottom upmicrofabrication and highly swollen SPE suffers from gold electrode delamination. Hence, in this MSc project/thesis a novelmethod of flexible electrode fabrication with conducting polymers was developed by soft lithography and drop-on-demandprinting. The gold electrodes were replaced by patterned vapor phase polymerized (VPP) poly(3,4-ethylenedioxythiophene) (PEDOT)electrodes due to its high electrical conductivity and versatile process ability. The replacement of the stiff gold electrodes byflexible and stretchable PEDOT allowed high volume change of the material and motions. The PEDOT electrodes werefabricated by patterning the oxidant iron tosylate using microcontact printing and drop-on-demand printing. Moreover, thePVDF membrane has been replaced by a nitrile butadiene rubber/poly(ethylene oxide) semi-interpenetrating polymer network(IPN) to increase ion conductivity and strechability and hence actuator performance.
30
Chirra, Dinakar Hariharasudhan. "NANOSCALE FUNCTIONALIZATION AND CHARACTERIZATION OF SURFACES WITH HYDROGEL PATTERNS AND BIOMOLECULES." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/60.
Full textAbstract:
The advent of numerous tools, ease of techniques, and concepts related to nanotechnology, in combination with functionalization via simple chemistry has made gold important for various biomedical applications. In this dissertation, the development and characterization of planar gold surfaces with responsive hydrogel patterns for rapid point of care sensing and the functionalization of gold nanoparticles for drug delivery are highlighted.
Biomedical micro- and nanoscale devices that are spatially functionalized with intelligent hydrogels are typically fabricated using conventional UV-lithography. Herein, precise 3-D hydrogel patterns made up of temperature responsive crosslinked poly(N-isopropylacrylamide) over gold were synthesized. The XY control of the hydrogel was achieved using microcontact printing, while thickness control was achieved using atom transfer radical polymerization (ATRP). Atomic force microscopy analysis showed that to the ATRP reaction time governed the pattern growth. The temperature dependent swelling ratio was tailored by tuning the mesh size of the hydrogel. While nanopatterns exhibited a broad lower critical solution temperature (LCST) transition, surface roughness showed a sharp LCST transition. Quartz crystal microbalance with dissipation showed rapid response behavior of the thin films, which makes them applicable as functional components in biomedical devices.
The easy synthesis, relative biocompatibility, inertness, and easy functionalization of gold nanoparticles (GNPs) have made them useful for various biomedical applications. Although ATRP can be successfully carried out over GNPs, the yield of stable solution based GNPs for biomedical applications prove to be low. As an alternative approach, a novel method of ISOlating, FUnctionalizing, and REleasing nanoparticles (ISOFURE) was proposed. Biodegradable poly(β-amino ester) hydrogels were used to synthesize ISOFURE-GNP composites. ATRP was performed inside the composite, and the final hydrogel coated GNPs were released via matrix degradation. Response analysis confirmed that the ISOFURE method led to the increased stability and yield of the hydrogel coated ISOFURE-GNPs. The ISOFURE protocol was also utilized in functionalizing GNPs with enzyme catalase in the absence of a stabilizing reagent. Biotin-streptavidin affinity was used as the bioconjugation method. Activity analysis of the conjugated enzyme showed that the ISOFURE-GNPs showed enhanced biomolecular loading relative to solution based stabilizing reagent passivated GNPs.
31
Mun, Kyu-Shik. "Monitoring Cell Behaviors on Variety of Micropatterns Created with Biodegradable Polymer." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1457426363.
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Thibault, Christophe. "Impression de biomolécules par lithographie douce, applications pour les biopuces, de l'échelle micrométrique." Phd thesis, INSA de Toulouse, 2007. http://tel.archives-ouvertes.fr/tel-00200042.
Full textAbstract:
L'objectif des travaux est de démontrer que la lithographie douce, quelquefois baptisée " Micro-Contcat Printing (µCP)", constitue une méthode de dépôt de biomolécules présentant de nombreux avantages pour des applications de type Biopuces. Pour la fabrication de puces à ADN, nous démontrons que le µCP est une technique compétitive par rapport au dépôt robotisé de gouttes traditionnellement utilisé. Le coût est inférieur, la densité des puces est augmentée et la qualité et la définition des motifs biomoléculaires sont supérieures. Une étude complète des mécanismes d'encrage des timbres élastomères d'impression ainsi que des mécanismes de transfert par contact des molécules vers le substrat est présentée. Le rôle prépondérant des fragments de polymère non réticulés présents à la surface des timbres est mis en évidence. Dans un second volet nous étudions la possibilité de générer par la même méthode des puces à biomolécules uniques. Nous montrons comment le µCP peut être poussé jusqu'à une résolution sub-micrométrique proche de 50 nm. Deux voies technologiques originales impliquant la lithographie douce sont proposées : l'une pour peigner individuellement en des sites organisés précisément sur la surface des longs brins d'ADN pour des études de génétique, l'autre pour fixer des molécules individuelles d'ADN par une extrémité rendant possible l'étude dynamique de molécules uniques (ADN) sur de larges populations.
33
Sefat, Farshid. "Cell engineering of human bone monolayers and the effect of growth factors and microcontact printed ECM proteins on wound healing. The role of ECM proteins, TGF¿-1, 2 and 3 and HCl/BSA in cellular adhesion, wound healing and imaging of the cell surface interface with the widefield surface plasmon microscope." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/5758.
Full textAbstract:
Bone repair is modulated by different stimuli. There is evidence that the Transforming Growth Factor-beta (TGF-¿) super-family of cytokines have significant effects on bone structure by regulating the replication and differentiation of chondrocytes, osteoblasts and osteoclasts. There is also significant evidence that interactions with extracellular matrix molecules also influence cell behaviour.
This study aimed at determining the role of the TGF-¿s, Collagen type I, Fibronectin and Laminin in bone cell behaviour. To do this MG63 bone cells were used to examine cell adhesion and alignment to different micro-contact printed ECM protein patterns of different widths. The study also aimed at examining how TGF-¿1, 2 and 3 and their solvent and carrier (HCl and BSA, respectively) effected cell surface interactions, cell morphology, cell proliferation and integrin expression. Finally, this study also aimed at examining how the TGF-¿s and their solvent and carrier influenced wound closure in an in vitro wound closure model and how TGF-¿s influence ECM secretion and integrin expression.
5, 10, 25, 50 and 100¿m wide repeat gratings of Collagen type I, Fibronectin and Laminin patterns were stamp patterned onto glass slides and plated with MG63 cells at 50,000 cells per coverslip. Cells on the fibronectin pattern attached and elongated soon after seeding, but did not adhere readily to collagen and laminin and appeared more rounded until 18hrs after seeding. Cells aligned significantly well on the 50¿m and 100¿m wide fibronectin patterned coverslips with mean angles of alignment ~7.87¿ ¿ 3.06SD and 6.45¿ ¿ 5.08SD, respectively, compared to those with smaller width (p<0.001). In comparison, cells aligned less readily to the other two ECM proteins, showing optimal alignments of 9.66¿ ¿ 4.18SD and 14.36¿ ¿ 1.57SD to the 50¿m wide collagen and laminin patterns, respectively. Differences in cell length mirrored those of alignment, with cells acquiring the greatest length when showing the greatest degree of alignment. The results indicate that MG63 cells responded significantly better to 50 and 100¿m wide fibronectin patterns compared to those with smaller width (p<0.001) indicating that the cells may attach mostly via fibronectin specific integrins.
Cell surface attachment was examined via a trypsinisation assay in which the time taken to trypsinise cells from the surface provided a means of assessing the strength of attachment. The results indicated that treatment with the solvent (HCl), TGF-¿1, 2 and 3 all decreased cell attachment, but this effect was significantly greater in the case of HCl and TGF-¿3 (p<0.001). However, there were significant differences in trypsinisation rates between HCl and TGF-¿3 (p<0.001). The wound healing response to the TGF-¿s and their solvent/carrier was also investigated in 300¿m ± 10-30¿m SD wide model wounds induced in fully confluent monolayers of MG63 bone cells. The results indicated that TGF-¿3 and HCl significantly enhance wound closure when compared against negative controls, TGF-¿1 and TGF-¿2 treatment (p<0.001). It was also found that TGF-¿1 and TGF-¿2 treatment significantly improved wound closure rate in comparison to the controls (p<0.001).
Experiments were performed to determine if the HCl effects on wound closure were dose dependent. Cells were incubated with 20¿M, 40¿M, 80¿M and 160¿M concentrations of HCl prior to wounding and wound closure rates were recorded. Wound closure was dependent on HCl dose with the 80¿M and 160¿M concentrations inducing increases in wound closure rates that were both significantly greater than those induced by 20¿M, 40¿M and control treatments (p<0.001). However, there were significant differences in wound closure between the 80¿M and 160¿M treatment groups after 30hrs of treatment (p<0.001).
The effect of different TGF-¿ isomers and their combinations on proliferation rate and cell length of human bone cells were also assessed. The results suggest that cell morphology changes were observed significantly more in cells treated with TGF-¿(2+3) and TGF-¿(1+3) (p<0.001). Any cell treated with TGF-¿1, TGF-¿(1+2) and TGF-¿(1+2+3) showed significantly less elongation compared to the control and other TGF-¿ isomers. In terms of proliferation rate, TGF-¿3 and TGF-¿(2+3) increased cell numbers more than TGF-¿1, TGF-¿2 and other combinations. TGF-¿1 and its combinations did not show significant proliferation and attachment compared to the control due to perhaps its inhibitory effect in contact with human bone cells.
Immunostaining indicated that treatment with TGF-¿3 significantly promoted the secretion of collagen type I and anti-human fibronectin in addition to integrin (¿3 and ¿1) expression. Statistically TGF-¿3 and their combinations showed significant differences in number of cells stained for collagen type I, anti-human fibronectin, ¿3 and ¿1integrin. Any cell treated with TGF-¿1 or any combination with TGF-¿1 showed significantly lower cell number stained with the same proteins and integrins (p<0.001). Imaging with WSPR allowed observation of the focal contacts without the need for immunostaining. WSPR images revealed guided cells with high contrast band like structures at the border of cells distal to the edge of guidance cue to which they aligned and with less concentrically formed band like features across the cell body. It is believed that the high contrast features are associated with the formation of focal contacts on the edge of the cells distal to the edge of fibronectin patterns, which suggests that cell guidance is aided by a decrease in cell attachment along a guidance feature. The WSPR experiments also indicated that TGF-¿s influenced the distribution of focal contacts. In the case of TGF-¿1 treated cells the bright high contrast regions were intense but only arranged around the periphery of the cell. In TGF-¿2 and TGF-¿3 cells the bright contrast regions were weaker but again mostly localised around the periphery. These findings supported the earlier trypsinisation results.
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Cheval, Kevin. "Étude et réalisation de circuits imprimés sur substrats polymères 3D (MID 3D) par microtamponnage." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10060/document.
Full textAbstract:
L'enjeu de ce travail est la réalisation de circuits électroniques sur des pièces polymères injectées à forme 3D, appelées MIDs, par microtamponnage (μTP). Le μTP, est une technique de localisation de substances (chimiques ou biologiques) par contact mécanique d'un tampon structuré sur un substrat. Il permet de localiser les pistes conductrices des MIDs en utilisant deux protocoles : le μTP passif et le μTP actif. La première méthode consiste à déposer de manière localisée un thiol par μTP sur la surface de la pièce préalablement métallisée. Le thiol permet de protéger les pistes métalliques qui doivent être conservées après gravure humide. Dans la seconde, un catalyseur (du palladium) est déposé par μTP, suivi de la métallisation electroless des pistes. La problématique du μTP 3D a été étudiée à l'aide d'un tampon épousant la forme de la pièce. Nos résultats expérimentaux couplés à des simulations par éléments finis de la déformation du tampon lors de sa compression au moment du contact avec la pièce, nous ont permis de déterminer les paramètres clefs du procédé : l'alignement du tampon par rapport à la pièce, la gestion du contact et la fabrication du tampon. Il a été mis en évidence que la tolérance de l'alignement est de l'ordre de 100μm pour des motifs structurés de 250μm de hauteur. Un tampon composé d'un support rigide surmonté d'une couche mince structurée permet de limiter ses déformations lors de sa compression. Les enseignements tirés nous ont permis de réaliser nos premiers circuits par μTP à l'aide d'une machine originale développée au laboratoire. La problématique de l'épaississement des couches de cuivre adhérentes sur des pièces en LCP est également abordée, un protocole d'épaississement ayant été validéThe main challenge of this work was the production of electronic circuits on injected 3Dshaped polymer components, called MIDs, by microcontact printing (μCP). μCP is a substance (chemical or biological) localisation technique through mechanical contact between a patterned stamp and a substrate. It enables the MIDs’ conductor tracks to be located using two techniques: passive μCP and active μCP. The first method involves locally depositing a thiol by μCP on the substrate’s surface, which has previously been coated with a thin metallic film. The thiol protects the metallic tracks, which must be preserved after wet chemical etching. Regarding the second method, a catalyst (palladium) is deposited by μCP, followed by the electroless metallization of the tracks. The 3D μCP issue was studied using a stamp, which matched the shape of the substrate. Our experimental results combined with finite element simulations of stamp deformation during compression and whilst in contact with the substrate, revealed the key parameters of the process: stamp/substrate alignment, contact control and stamp manufacturing. We found that the alignment tolerance was around 100μm for a 250μm thickness structured design. A stamp with a rigid support covered in a structured thin film minimises deformation during compression. Thanks to the lessons learned, we carried out our first circuits using μCP with a new machine, which was developed in the laboratory. We also addressed the problem of thickening adhesive copper layers on LCP components, as a thickening procedure had already been validated
35
Palleau, Etienne. "Assemblage électrostatique dirigé de nanoparticules colloïdales sur des surfaces par nanoxérographie par microscopie à force atomique." Thesis, Toulouse, INSA, 2011. http://www.theses.fr/2011ISAT0013/document.
Full textAbstract:
L’étude des propriétés singulières de nanoparticules colloïdales synthétisées par voie chimique et leur intégration dans des nano-composants requiert leur assemblage dirigé sur des zones parfaitement définies et localisées de surfaces solides. L’objet de cette thèse est le développement d’une méthode d’assemblage dirigé originale: la nanoxérographie par microscope à force atomique (AFM). Cette technique consiste à injecter localement, sur des zones spécifiques, des charges électrostatiques dans un matériau électret par l’intermédiaire d’une pointe d’AFM. Ces charges servent ensuite de pièges électrostatiques sur la surface pour les nanoparticules en solution. Dans le cadre de ce travail, l’injection, la rétention de charges dans de fines couches électrets de PolyMéthylMéthAcrylate (PMMA) et la quantification des densités de charges surfaciques des motifs chargés, ont été étudiées grâce au mode électrique dérivé de l’AFM, le microscope à force Kelvin (KFM). L’étude de l’assemblage de nanoparticules de différentes natures (métal, polymère (organique ou inorganique)), de taille moyenne variable dans un large domaine (2 nm - 1µm) et de potentiel zêta contrôlé a permis d’analyser les mécanismes de dépôt et de montrer les performances de la méthode et son aspect générique. Enfin deux techniques d’injection de charges parallèles ont été mises en place afin d’offrir des perspectives industrielles: le microcontact printing électrique et la nanoimpression électriqueThe study of original properties of colloidal nanoparticles and their integration into nanodevices requires their assembly onto specific areas of solid surfaces. The aim of this thesis work is to develop an innovative method for the directed assembly of colloidal nanoparticles: the nanoxerography process by atomic force microscope (AFM). This technique consists in injecting charges into electrets using an AFM tip. The injected charges are then used to electrostatically trap nanoparticles from suspensions onto the surface. In this context, the charge writing and charge decay in PolyMethyMethAcrylate (PMMA) thin films were studied and the charge density of the charged patterns were quantified using Kelvin force microscope (KFM), an electrical mode of AFM. Assemblies of nanoparticles of different nature (metallic, polymeric (organic and inorganic)), with average sizes extending over a large range (2 nm to 1 µm) and controlled zeta potential were obtained on PMMA thin films. This allowed the analysis of assembly mechanisms and demonstration of the excellent performance of the method. Finally, two techniques of parallel charge writing, viz., the electrical microcontact printing and the electrical nanoimprinting were explored with the prospect of extending the nanoxerography process to industrial scale
36
Sefat, Farshid. "Cell engineering of human bone monolayers and the effect of growth factors and microcontact printed ECM proteins on wound healing : the role of ECM proteins, TGFβ-1, 2 and 3 and HCl/BSA in cellular adhesion, wound healing and imaging of the cell surface interface with the widefield surface plasmon microscope." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/5758.
Full textAbstract:
Bone repair is modulated by different stimuli. There is evidence that the Transforming Growth Factor-beta (TGF-β) super-family of cytokines have significant effects on bone structure by regulating the replication and differentiation of chondrocytes, osteoblasts and osteoclasts. There is also significant evidence that interactions with extracellular matrix molecules also influence cell behaviour. This study aimed at determining the role of the TGF-βs, Collagen type I, Fibronectin and Laminin in bone cell behaviour. To do this MG63 bone cells were used to examine cell adhesion and alignment to different micro-contact printed ECM protein patterns of different widths. The study also aimed at examining how TGF-β1, 2 and 3 and their solvent and carrier (HCl and BSA, respectively) effected cell surface interactions, cell morphology, cell proliferation and integrin expression. Finally, this study also aimed at examining how the TGF-βs and their solvent and carrier influenced wound closure in an in vitro wound closure model and how TGF-βs influence ECM secretion and integrin expression. 5, 10, 25, 50 and 100μm wide repeat gratings of Collagen type I, Fibronectin and Laminin patterns were stamp patterned onto glass slides and plated with MG63 cells at 50,000 cells per coverslip. Cells on the fibronectin pattern attached and elongated soon after seeding, but did not adhere readily to collagen and laminin and appeared more rounded until 18hrs after seeding. Cells aligned significantly well on the 50μm and 100μm wide fibronectin patterned coverslips with mean angles of alignment ~7.87° ± 3.06SD and 6.45° ± 5.08SD, respectively, compared to those with smaller width (p<0.001). In comparison, cells aligned less readily to the other two ECM proteins, showing optimal alignments of 9.66° ± 4.18SD and 14.36° ± 1.57SD to the 50μm wide collagen and laminin patterns, respectively. Differences in cell length mirrored those of alignment, with cells acquiring the greatest length when showing the greatest degree of alignment. The results indicate that MG63 cells responded significantly better to 50 and 100μm wide fibronectin patterns compared to those with smaller width (p<0.001) indicating that the cells may attach mostly via fibronectin specific integrins. Cell surface attachment was examined via a trypsinisation assay in which the time taken to trypsinise cells from the surface provided a means of assessing the strength of attachment. The results indicated that treatment with the solvent (HCl), TGF-β1, 2 and 3 all decreased cell attachment, but this effect was significantly greater in the case of HCl and TGF-β3 (p<0.001). However, there were significant differences in trypsinisation rates between HCl and TGF-β3 (p<0.001). The wound healing response to the TGF-βs and their solvent/carrier was also investigated in 300μm ± 10-30μm SD wide model wounds induced in fully confluent monolayers of MG63 bone cells. The results indicated that TGF-β3 and HCl significantly enhance wound closure when compared against negative controls, TGF-β1 and TGF-β2 treatment (p<0.001). It was also found that TGF-β1 and TGF-β2 treatment significantly improved wound closure rate in comparison to the controls (p<0.001). Experiments were performed to determine if the HCl effects on wound closure were dose dependent. Cells were incubated with 20μM, 40μM, 80μM and 160μM concentrations of HCl prior to wounding and wound closure rates were recorded. Wound closure was dependent on HCl dose with the 80μM and 160μM concentrations inducing increases in wound closure rates that were both significantly greater than those induced by 20μM, 40μM and control treatments (p<0.001). However, there were significant differences in wound closure between the 80μM and 160μM treatment groups after 30hrs of treatment (p<0.001). The effect of different TGF-β isomers and their combinations on proliferation rate and cell length of human bone cells were also assessed. The results suggest that cell morphology changes were observed significantly more in cells treated with TGF-β(2+3) and TGF-β(1+3) (p<0.001). Any cell treated with TGF-β1, TGF-β(1+2) and TGF-β(1+2+3) showed significantly less elongation compared to the control and other TGF-β isomers. In terms of proliferation rate, TGF-β3 and TGF-β(2+3) increased cell numbers more than TGF-β1, TGF-β2 and other combinations. TGF-β1 and its combinations did not show significant proliferation and attachment compared to the control due to perhaps its inhibitory effect in contact with human bone cells. Immunostaining indicated that treatment with TGF-β3 significantly promoted the secretion of collagen type I and anti-human fibronectin in addition to integrin (α3 and β1) expression. Statistically TGF-β3 and their combinations showed significant differences in number of cells stained for collagen type I, anti-human fibronectin, α3 and β1 integrin. Any cell treated with TGF-β1 or any combination with TGF-β1 showed significantly lower cell number stained with the same proteins and integrins (p<0.001). Imaging with WSPR allowed observation of the focal contacts without the need for immunostaining. WSPR images revealed guided cells with high contrast band like structures at the border of cells distal to the edge of guidance cue to which they aligned and with less concentrically formed band like features across the cell body. It is believed that the high contrast features are associated with the formation of focal contacts on the edge of the cells distal to the edge of fibronectin patterns, which suggests that cell guidance is aided by a decrease in cell attachment along a guidance feature. The WSPR experiments also indicated that TGF-βs influenced the distribution of focal contacts. In the case of TGF-β1 treated cells the bright high contrast regions were intense but only arranged around the periphery of the cell. In TGF-β2 and TGF-β3 cells the bright contrast regions were weaker but again mostly localised around the periphery. These findings supported the earlier trypsinisation results.
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Ait-Ali, Imene Feriel. "Développement et intégration de microcapteurs de pH et de température dans des dispositifs microfluidiques polymères." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10003/document.
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Afin de réaliser des dispositifs en polymère à forte valeur ajoutée, l'industrie de la plasturgie s'intéresse depuis quelques années à la convergence possible entre les microtechnologies et les méthodes industrielles de mise en oeuvre des polymères (le thermoformage et la thermo-injection). Dans ce contexte, l'objectif de cette thèse est de démontrer l'intérêt d'une approche à base de microtamponnage pour l'intégration de capteurs à base métallique dans des circuits microfluidiques en thermoplastique réalisés par thermoformage. Pour ces matériaux, cette approche apparait plus pertinente en terme de production de masse qu'une approche de photolithographie classique. Nous avons choisi de démontrer ce concept en étudiant l'intégration d'un capteur de pH et d'un capteur de température dans un système microfluidique en copolymère d'oléfine cyclique (COC) réalisé par thermoformage. En effet, la mesure de ces paramètres physico-chimiques est extrêmement répandue dans différents domaines d'application allant de la chimie à la biologie et à la médecine. Pour le capteur de pH, nous avons développé une couche sensible au pH à base d'oxyde d'iridium (IrOx) électrodéposé sur or. L'influence de différents paramètres (solution d'électrodépôt, méthode d'électrodéposition, nature du substrat métallique et son mode de préparation) sur la réponse au pH de ces couches a été étudiée. Nous avons ainsi pu démonter qu'une approche par microtamponnage passive est adaptée à la préparation de capteurs de pH sur un substrat en COC/Au ayant une sensibilité de -72 mV/pH et une durée de vie de 1 an. Pour le capteur de température, la solution retenue est basée sur le principe d'une thermorésistance. Les capteurs ont été élaborés en utilisant une approche par microtamponnage actif avec croissance d'une couche de nickel (dont l'épaisseur varie entre 0,2 et 5 μm) par métallisation autocatalytique sur polyimide. La dérive des capteurs est actuellement trop importante pour une application pratique. Finalement, des résultats préliminaires d'intégration de ces capteurs dans un microsystème fluidique thermoformé sont présentés avec notamment une configuration originale de mesure différentielle du pHThe plastics industry has been interested for some years in the possible convergence between microtechnologies and conventional polymer manufacturing (hot embossing and injection molding). In this context, this thesis aims at demonstrating the potential of a process based on microcontact printing in order to integrate metal based sensors in thermoplastic microfluidic devices shaped by hot embossing. For the mass production of thermoplastic devices, this approach appears more relevant than conventional photolithography. We chose to demonstrate this concept by investigating the integration of both a pH sensor and a temperature sensor in a thermoformed Cyclo Olefin Copolymer (COC) microfluidic system. Indeed, the measurement of these physicochemical parameters are extremely widespread in different applicative areas ranging from chemistry tobiology and medicine. For the pH sensor, we developed a pH-sensitive layer based on electrodeposited iridium oxide (IrOx) on Au. The influence of various parameters (plating solution and method , nature of the metal substrate and its method of preparation) on the pH response of these layers was studied. We were able to demonstrate that microcontact printing based on a passive approach is suitable for the preparation of pH sensors on a COC substrate with a sensitivity of -72 mV/pH and a 1 year lifetime. As regards the temperature sensor, the solution was to design a thermistor. Sensors were implemented with an approach based on active microcontact printing followed by electroless deposition of nickel (thickness varies between 0,2 and 5 μm) on polyimide. The drift of these sensors is too large for practical application. Finally, preliminary results presenting the integrating of these sensors in a fluidic microsystem are reported using an original configuration based on differential measurement of pH
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Dezest, Denis. "Nanosystèmes électromécaniques pour la biodétection : intégration d'un moyen de transduction et stratégies de biofonctionnalisation." Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0034/document.
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Avec une limite de détection ultime pouvant atteindre le yoctogramme (1 yg = 10-24 g), les nanosystèmes électromécaniques (NEMS) employés comme capteurs gravimétriques présentent un fort potentiel pour la détection ultra-sensible et sans marquage de molécules biologiques. A l’heure actuelle, plusieurs défis restent cependant à relever avant de pouvoir envisager de manière réaliste leur utilisation comme outils de biodétection. Ces travaux de thèse adressent en particulier l’intégration du moyen de transduction et le développement de stratégies de biofonctionnalisation. En vue de répondre à la première problématique, l’intégration d’une couche piézoélectrique à base de Titano-Zirconate de Plomb (PZT) selon une approche de fabrication collective de réseaux de NEMS par voie descendante a été développée et caractérisée.Deux approches de biofonctionnalisation adaptées à une organisation de NEMS en réseaux,respectivement basées sur le dépôt localisé de matériel biologique par impression moléculaire et sur la structuration par photolithographie d’une couche bioréceptrice à base de polymères à empreintes moléculaires (MIP), ont ensuite été mises en oeuvre et ont permis de démontrer une première preuve de concept. Ces différentes contributions constituent un premier pas dans le développement des NEMS pour des applications de biodétectionWith an ultimate limit of detection down to the yoctogram regime (1 yg = 10-24 g),nanoelectromechanical systems (NEMS) resonators used as ultra-sensitive and label-free gravimetric sensors have a high potential for biodetection applications. To date, several challenges currently limit their wide spread use as viable biosensing tools. This PhD thesis addresses the issues related to the transducer integration and the biofunctionnalization. A Lead Zirconate Titatane (PZT)-based piezoelectric transducer has been implemented according to a top-down approach compatible with collective fabrication of NEMS arrays. Two biofunctionnalization strategies, suitable for a NEMS array organization and based on the localized deposition of biological material assisted by microcontact printing and the patterning of molecularly imprinted polymers (MIP) by photolithography, have also been investigated and first proof-of-concept biosensors were demonstrated. These various contributions have the potential to drive future advancements in the realm of NEMS as effective biosensing tools
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She, Zhe. "Generation of micro/nano metallic nanostructures using self-assembled monolayers as template and electrochemistry." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3089.
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This thesis studies a scheme to fabricate small-scaled metal structures by electrochemical metal deposition and lift off. The key point is the use of self-assembled monolayers (SAMs) to control both interfacial charge transfer in electrodeposition and adhesion of the deposit to the substrate. Patterned SAMs exhibiting blocking and non-blocking areas are applied as templates in electrochemical deposition of Cu or Au. Thiol SAMs on Au substrates are used, namely alkane thiols and thiols combining an aliphatic chain with a biphenyl or biphenyl analogous pyridine-phenyl moieties. The patterning of SAMs is realised with microcontact printing (μCP) and electron beam lithography. Electrochemical deposition based on defects in the SAMs is optimised towards generating small nanostructures and depending on the system single or stepped potential procedures are applied. Generated metal structures are transferred to an insulator by lift off. Au microstructures (~10 μm) have been made with microcontact printing and transferred onto epoxy glue, which can potentially be used as microelectrodes in electroanalytical chemistry. Sub-100 nm Cu features and sub-40 nm Au features have been created with electron beam lithography respectively. Lift off process has successfully transferred Cu nanostructures onto epoxy glue with high precision. In contrast to the deposition mediated by defects, Cu deposition mediated by discharging Pd²⁺ coordinated to a pyridine terminated SAM directly through the SAM molecules has been explored as a new approach. This new approach has potential to decrease the size of the metal structure further and the preliminary results show possibility of sub-10 nm features. SAMs prepared with a newly synthesised molecule, 3-(4'-(methylthio)-[1,1'-biphenyl]-4-yl)propane-1-thiol, are characterised by STM, XPS and NEXAFS. The metal structures are investigated by SEM, AFM and STM.
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Teulon, Lauryanne. "Nouvelles approches pour l'assemblage électrostatique de particules colloïdales par nanoxérographie : du procédé aux applications." Thesis, Toulouse, INSA, 2018. http://www.theses.fr/2018ISAT0044.
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Grâce à leurs propriétés physiques/chimiques uniques, les nanoparticules colloïdales sont au cœur de nombreuses applications innovantes. Afin de faciliter leur caractérisation ou de les intégrer dans des dispositifs fonctionnels, il est nécessaire de les assembler de manière dirigée sur des surfaces solides. Dans ce contexte, l’objectif de cette thèse est de mieux comprendre et d’optimiser la technique de nanoxérographie, méthode d’assemblage dirigé où des nanoparticules sont piégées sur des motifs de charges électrostatiques. Après un premier travail consistant à améliorer le procédé de nanoxérographie, trois problématiques spécifiques ont été adressées : (i) l’assemblage de particules micrométriques. Le couplage de simulations numériques et de manipulations expérimentales a permis d’identifier les paramètres clés de l’assemblage de telles particules colloïdales et d’élargir (facteur 100) la gamme de tailles de particules assemblables par nanoxérographie. (ii) l’analyse de l’assemblage multicouche. Par le biais de nanoparticules modèles luminescentes et par la mise en place d’un nouveau protocole d’assemblage, les critères clés génériques pour l’assemblage 3D de colloïdes par nanoxérographie ont été dégagés. (ii) l’assemblage dirigé de nanogels sensibles à un stimulus environnemental extérieur. L’utilisation d’un protocole d’assemblage optimisé a permis d’élaborer des assemblages de nanogels interactifs avec leur environnement et du faire du tri sélectif de ces nanoparticules sur une même surfaceOwing to their unique physico-chemical properties, colloidal nanoparticles are building blocks for the creation of plentiful innovative devices. In order to make easier their characterization and to incorporate them into functional nano-devices, it is necessary to perfectly control their directed assemblies onto solid surfaces. In this context, this thesis’ purpose is to simultaneously better understand and optimize the nanoxerography method, which allows electrostatic and selective directing assemblies of nanoparticles onto charged patterns. After an optimization of the nanoxerography process, three specific problematics have been addressed: (1) micron-sized particles assembly. The combined use of numerical simulations and experiments enabled to unveil the key parameters involved in micron-sized particles assembly and to expend the particle size range foreseeable for an assembly by nanoxerography (factor 100). (2) the 3D assembly analysis. The influence of diverse parameters on the 3D assembly of luminescent model nanoparticles was quantified by using a new assembly protocol. The results gave the generic key criterions for the 3D assembly of colloids by nanoxerography. (3) directed assembly of nanogels sensitive to an external environmental stimulus. The use of an optimized protocol allowed elaborating nanogels assemblies interactive with their environment and to sort these nanoparticles onto the same surface
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Russom, Aman. "Microfluidic bead-based methods for DNA analysis." Doctoral thesis, KTH, Skolan för elektro- och systemteknik (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-155.
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With the completion of the human genome sequencing project, attention is currently shifting toward understanding how genetic variation, such as single nucleotide polymorphism (SNP), leads to disease. To identify, understand, and control biological mechanisms of living organisms, the enormous amounts of accumulated sequence information must be coupled to faster, cheaper, and more powerful technologies for DNA, RNA, and protein analysis. One approach is the miniaturization of analytical methods through the application of microfluidics, which involves the manipulation of fluids in micrometer-sized channels. Advances in microfluidic chip technology are expected to play a major role in the development of cost-effective and rapid DNA analysis methods. This thesis presents microfluidic approaches for different DNA genotyping assays. The overall goal is to combine the potential of the microfluidic lab-on-a-chip concept with biochemistry to develop and improve current methods for SNP genotyping. Three genotyping assays using miniaturized microfluidic approaches are addressed. The first two assays are based on primer extension by DNA polymerase. A microfluidic device consisting of a flow-through filter chamber for handling beads with nanoliter liquid volumes was used in these studies. The first assay involved an allelespecific extension strategy. The microfluidic approach took advantage of the different reaction kinetics of matched and mismatched configurations at the 3’-ends of a primer/template complex. The second assay consisted of adapting pyrosequencing technology, a bioluminometric DNA sequencing assay based on sequencing-bysynthesis, to a microfluidic flow-through platform. Base-by-base sequencing was performed in a microfluidic device to obtain accurate SNP scoring data on nanoliter volumes. This thesis also presents the applications of monolayer of beads immobilized by microcontact printing for chip-based DNA analysis. Single-base incorporation could be detected with pyrosequencing chemistry on these monolayers. The third assay developed is based on a hybridization technology termed Dynamic Allele-Specific Hybridization (DASH). In this approach, monolayered beads containing DNA duplexes were randomly immobilized on the surface of a microheater chip. DNA melting-curve analysis was performed by dynamically heating the chip while simultaneously monitoring the DNA denaturation profile to determine the genotype. Multiplexing based on single-bead analysis was achieved at heating rates more than 20 times faster than conventional DASH provides.QC 20101008
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Samel, Björn. "Novel Microfluidic Devices Based on a Thermally Responsive PDMS Composite." Doctoral thesis, KTH, Mikrosystemteknik, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4470.
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The field of micro total analysis systems (μTAS) aims at developments toward miniaturized and fully integrated lab-on-a-chip systems for applications, such as drug screening, drug delivery, cellular assays, protein analysis, genomic analysis and handheld point-of-care diagnostics. Such systems offer to dramatically reduce liquid sample and reagent quantities, increase sensitivity as well as speed of analysis and facilitate portable systems via the integration of components such as pumps, valves, mixers, separation units, reactors and detectors. Precise microfluidic control for such systems has long been considered one of the most difficult technical barriers due to integration of on-chip fluidic handling components and complicated off-chip liquid control as well as fluidic interconnections. Actuation principles and materials with the advantages of low cost, easy fabrication, easy integration, high reliability, and compact size are required to promote the development of such systems. Within this thesis, liquid displacement in microfluidic applications, by means of expandable microspheres, is presented as an innovative approach addressing some of the previously mentioned issues. Furthermore, these expandable microspheres are embedded into a PDMS matrix, which composes a novel thermally responsive silicone elastomer composite actuator for liquid handling. Due to the merits of PDMS and expandable microspheres, the composite actuator's main characteristic to expand irreversibly upon generated heat makes it possible to locally alter its surface topography. The composite actuator concept, along with a novel adhesive PDMS bonding technique, is used to design and fabricate liquid handling components such as pumps and valves, which operate at work-ranges from nanoliters to microliters. The integration of several such microfluidic components promotes the development of disposable lab-on-a-chip platforms for precise sample volume control addressing, e.g. active dosing, transportation, merging and mixing of nanoliter liquid volumes. Moreover, microfluidic pumps based on the composite actuator have been incorporated with sharp and hollow microneedles to realize a microneedle-based transdermal patch which exhibits on-board liquid storage and active dispensing functionality. Such a system represents a first step toward painless, minimally invasive and transdermal administration of macromolecular drugs such as insulin or vaccines. The presented on-chip liquid handling concept does not require external actuators for pumping and valving, uses low-cost materials and wafer-level processes only, is highly integrable and potentially enables controlled and cost-effective transdermal microfluidic applications, as well as large-scale integrated fluidic networks for point-of care diagnostics, disposable biochips or lab-on-a-chip applications. This thesis discusses several design concepts for a large variety of microfluidic components, which are promoted by the use of the novel composite actuator. Results on the successful fabrication and evaluation of prototype devices are reported herein along with comprehensive process parameters on a novel full-wafer adhesive bonding technique for the fabrication of PDMS based microfluidic devices.QC 20100817
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Lee, Michael. "Développement de micro-outils pour la biodétection, les micromélangeurs et les microfiltres." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10119.
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Ce travail de thèse est consacré au développement de micro-outils pour des applications dans le domaine biomédical. Il se compose de trois volets: le premier volet est dédié au développement et caractérisation d’un immunocapteur pour la détection d'une cytokine anti-inflammatoire (Interleukine-10 (IL-10)) en utilisant le transistor EOS (Electrolyte-Oxide-Semiconductor) à base d’un nouveau diélectrique à haute constante diélectrique (high-k): l’oxyde d'hafnium (HfO2) utilisé comme transducteur. Le deuxième et le troisième volet sont consacrés respectivement à la conception et réalisation d’une part d’un micro-mélangeur ‘passif’ et d’autre part d’un micro-filtre totalement flexible par des méthodes douces de microfabrication. Des moules souples en poly(diméthylsiloxane) (PDMS) micro-structurés sont préparés à partir d'un moule mère en silicium qui a été préalablement structuré par lithographie électronique et gravure ionique réactive (RIE). Un procédé de collage direct a été mis au point pour fabriquer ces dispositifs «PDMS-sur-Polymère» suffisamment résistants en pression pour permettre des études de mélange de fluides ou pour filtrer des microparticulesThe work in this thesis is devoted to the develoment of micro-tools for the application in the biomedical domain. It is composed of three main chapters. The first chapter is devoted on the development and characterization of an immunosensor for the detection of an anti-inflammatory cytokine (Interleukin-10 (IL-10) and applied as an EOS (Electrolyte-Oxide-Semiconductor) transistor as a base for a new dielectric material with a high dielectric (high-k): hafnium oxide used as a transducer. The second and third main chapters are dedicated respectively to the conception and realization of a passive micromixer and microfilter that are both flexible using soft lithography microfabrication. The flexible micro-structured molds in poly(dimethylsiloxane) (PDMS) were prepared to peel from the master silicon mold which was beforehand structured by electron beam lithography and reactive ion etching (RIE). A process for direct covalent bonding was worked out for the fabrication of devices “PDMS bonded to Polymers” that were sufficiently resistant in pressure and permitted the studies of mixing liquids or to filter microparticles
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Kick, Alfred. "Oberflächenplasmonenresonanz-basierte DNA-Chips und Nucleobasen-Sequenzentwurf." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-126339.
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Die vorliegende Dissertation beschreibt die Erarbeitung anwendbarer Methoden zum Aufbau Oberflächenplasmonenresonanz (SPR)-basierter DNA-Mikroarrays. Es werden die Beziehungen zwischen allen Teilschritten der Entwicklung eines DNA-Biosensors aufgezeigt. Die Sondendichte auf der Sensoroberfläche ist entscheidend für die Leistungsfähigkeit eines DNA-Chips. In dieser Arbeit werden thiolmodifizierte Sonden und solche mit Phosphorothioatgruppen verwendet und verglichen.
Der Aufbau selbstorganisierender Monoschichten, bestehend aus Mercaptoalkoholen und thiolmodifizierten DNA-Einzelsträngen, wird mittels Röntgenphotoelektronenspektroskopie untersucht. Es werden bis zu 180 Spots auf einem SPR-Chip aufgetragen. Eine weitere Erhöhung der Anzahl an Sondenorten pro Chip wird mit einer hydrophil/hydrophoben Strukturierung der Arrayoberfläche erreicht. Dies erfolgt durch das Mikrokontaktdrucken mit Alkanthiolen.
Die selektiven Hybridisierungen der Produkte der Polymerase-Kettenreaktion (PCR) werden bei SPR-Messungen auf DNA-Mikroarrays detektiert. Eine schnelle markierungsfreie Echtzeitanalyse wird bei Hybridisierungen im mikrofluidischen Kanal innerhalb weniger Minuten erzielt. Die Anwendbarkeit dieser Methoden wurde anhand der Mutationsanalyse der Fusionsgene AML1-ETO und CBFB-MYH11 bei der akuten myeloischen Leukämie bestätigt.
Die Hybridisierungseffizienz auf DNA-Mikroarrays hängt stark von der Sodensequenz ab. SPR-Experimente zeigen, dass die Ausbildung der Haarnadelstrukturen die Ursache dafür ist. Ein Computerprogramm (EGNAS) auf Grundlage eines neu entwickelten Nucleobasen-Sequenzentwurf-Algorithmus, ermöglicht die Generierung vollständiger Sequenzsätze. Die Intra- und Interstrangeigenschaften dieser Sequenzen können kontrolliert werden, um Haarnadelstrukturen und Kreuzhybridisierungen zu vermeiden. Dadurch können optimierte Sequenzen für Anwendungen auf DNA-Chips oder in der DNA-Nanobiotechnologie entworfen werden.
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Usov, Denys. "Switching of surface composition and morphology of binary polymer brushes." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2004. http://nbn-resolving.de/urn:nbn:de:swb:14-1085656171515-51343.
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Switching of surface composition and morphology of binary polymer brushes in response to changes in solvent selectivity, heating above glass transition temperatures, and contact with a rubbery stamp was studied. The binary brushes: polystyrene/poly(2-vinyl pyridine) (PS/P2VP), poly(styrene-co-2,3,4,5,6-pentafluorostyrene)/poly(methyl (meth)acrylate) (PSF/P(M)MA), and PS/PMMA were synthesized via two-step surface-initiated radical polymerization. Wetting experiments show that switching of brushes? surface composition upon exposure to solvents of various thermodynamic quality occurs faster than in 6 s. It takes longer time (5-10 min), if rate of solvent diffusion into the brush film is low. Discontinuous switching of surface composition of binary brushes is found upon exposure to binary solvents with gradually changed selectivity. X-ray Photoelectron Spectroscopy (XPS) shows quantitatively that the top brush layer (1) is dominated by respective favourite polymers after exposure to solvents of opposite selectivity and (2) comprises both brush constituents in almost symmetric ratio after exposure to non-selective solvents. Morphologies of binary brushes obtained after exposure to the solvents were studied with Atomic Force Microscopy (AFM). Local top layer composition was sensed with X-ray Photoemission Electron Microscopy (XPEEM). The morphologies are relevant to the particular solvents, reproducible, and independent on previous solvents. Phase segregation beneath the brush top layers was visualized with plasma etching. Qualitative agreement of the experimentally observed morphologies and predicted with self-consistent field theory is found. Enrichment of a binary brush top layer with the polymer providing lower surface energy takes place after annealing. Perpendicular segregation of binary brush constituents was sensed with XPEEM on perpendicular walls of imprinted elevations after wet microcontact printing.
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Usov, Denys. "Switching of surface composition and morphology of binary polymer brushes." Doctoral thesis, Technische Universität Dresden, 2003. https://tud.qucosa.de/id/qucosa%3A24340.
Full textAbstract:
Switching of surface composition and morphology of binary polymer brushes in response to changes in solvent selectivity, heating above glass transition temperatures, and contact with a rubbery stamp was studied. The binary brushes: polystyrene/poly(2-vinyl pyridine) (PS/P2VP), poly(styrene-co-2,3,4,5,6-pentafluorostyrene)/poly(methyl (meth)acrylate) (PSF/P(M)MA), and PS/PMMA were synthesized via two-step surface-initiated radical polymerization. Wetting experiments show that switching of brushes? surface composition upon exposure to solvents of various thermodynamic quality occurs faster than in 6 s. It takes longer time (5-10 min), if rate of solvent diffusion into the brush film is low. Discontinuous switching of surface composition of binary brushes is found upon exposure to binary solvents with gradually changed selectivity. X-ray Photoelectron Spectroscopy (XPS) shows quantitatively that the top brush layer (1) is dominated by respective favourite polymers after exposure to solvents of opposite selectivity and (2) comprises both brush constituents in almost symmetric ratio after exposure to non-selective solvents. Morphologies of binary brushes obtained after exposure to the solvents were studied with Atomic Force Microscopy (AFM). Local top layer composition was sensed with X-ray Photoemission Electron Microscopy (XPEEM). The morphologies are relevant to the particular solvents, reproducible, and independent on previous solvents. Phase segregation beneath the brush top layers was visualized with plasma etching. Qualitative agreement of the experimentally observed morphologies and predicted with self-consistent field theory is found. Enrichment of a binary brush top layer with the polymer providing lower surface energy takes place after annealing. Perpendicular segregation of binary brush constituents was sensed with XPEEM on perpendicular walls of imprinted elevations after wet microcontact printing.
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Casimirius, Stéphane. "Croissance localisée de nanotubes de carbone aux échelles micrométrique et nanométrique." Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00136052.
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La réalisation de dispositifs nanotechnologiques comportant des nanotubes de carbone (NTC) repose essentiellement sur l'intégration contrôlée des NTC sur substrat. Nous avons développé cette thématique en choisissant, plutôt que la manipulation de NTC synthétisés, l'approche de la croissance localisée de NTC par dépôt chimique catalytique en phase vapeur (CCVD) sous mélange de gaz H2-CH4. Nos travaux nous ont permis de synthétiser sélectivement des NTC à partir de sites catalytiques définis, sur des substrats de silicium. Notre étude a porté sur la synthèse de NTC à partir de dépôts de nanoparticules (NP) catalytiques de cobalt préparées selon trois voies distinctes : formation in situ de NP sur support oxyde par réduction sélective de la solution solide Mg0,95Co0,05O préparée par voie sol-gel ; NP de Co préformées par voie chimique, déposées directement sur un substrat SiO2/Si ; NP formées par le recuit de couche mince métallique Co également déposée sur substrat SiO2/Si. Nous avons démontré que la CCVD sous CH4 pur ou sous mélange H2-CH4, avec montée en température sous gaz inerte, aboutit à la formation de NTC dès 850°C, à partir de dépôts catalytiques non structurés. En particulier, le choix du système catalytique adéquat permet (1) de produire des films denses de NTC (environ 1 NTC/µm²) ; (2) de favoriser la formation de NTC mono- ou biparois, dont le diamètre est généralement compris entre 0,8 et 4 nm, et la longueur de l'ordre de quelques dizaines de µm. Des techniques de structuration ont été développées dans le but de localiser les dépôts de NP catalytiques. Le tamponnage (technique de lithographie molle) d'un précurseur catalytique liquide (sol ou suspension de NP Co) à l'aide d'un timbre apparaît comme une technique adéquate pour la production de motifs catalytiques micrométriques (1 - 100 µm). En revanche, la lithographie électronique associée au dépôt en couche mince (lift-off) demeure l'outil privilégié pour localiser des motifs catalytiques de dimensi ons nanométriques (jusqu'à 50 nm) par rapport aux structures prédéfinies du substrat de silicium. Nos travaux démontrent l'adéquation de la croissance localisée pour la production de motifs de NTC avec un certain contrôle de la densité surfacique des NTC, compatible avec la formation d'interconnexions entre motifs voisins. La dimension ultime des motifs produits varie entre 50 nm et 100 µm, selon la nature du catalyseur et de la technique de structuration employée. Notre étude ne met pas en évidence l'influence nette de l'organisation des motifs catalytiques sur l'orientation des NTC, qui reste majoritairement aléatoire à la surface des substrats SiO2/Si, et ce quelle que soit la nature du catalyseur mis en Suvre.
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LIU, CHUAN-SHENG, and 劉權昇. "A Study of the MicroContact Printing." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/77188443434348911437.
Full textAbstract:
碩士國立臺灣大學
化學工程學研究所
90
If a liquid drop is placed on a solid surface, the contact angle would be affected by the surface energy. If a liquid drop is placed on a specific surface consisting of alternating and parallel hydrophobic and hydrophilic stripes, the contact angle of the liquid drop would be determined by the three-phase contact line normal or parallel to the stripes. The three-phase contact line would be contorted or smooth along different directions of the stripe. The microcontact printing was applied to fabricate alternating and parallel hydrophobic and hydrophilic stripes of thiol self-assembled monolayers on gold surface . We found that the aggregation of silane molecules in the solvent would affect the quality of contact inking procedure , especially the stripe width is small. We also explored the effect of stripe width on the contact angle. It was found that when the three-phase contact line is parallel to the stripes, the contact angle is independent of the stripe width. On the other when the three-phase contact line is perpendicular to the stripes, the contact angle would be affected by the stripes width. Key words: self assembled monolayer、microcontact printing 、three-phase contact line
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Lin, Yu-Ling, and 林于令. "Surface Patterning of Collagen with Microcontact Printing." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/73787320514181623866.
Full textAbstract:
碩士國立陽明大學
醫學工程研究所
91
Patterning techniques used to control both the size and shape of the proteins on surface to which the cell is attached, are useful tools for understanding the behavior of cells at the cell-material interface. In this study, we focus on the patterning of collagen fibrils using microcontact printing techniques. Because the motion of monomeric collagen molecules is restricted to a 2-D surface, they can not polymerize into microfibrils on the patterned surface. Instead, we have prepared fibrous collagen by raising the solution temperature to 20℃, allowing the collagen monomers reassemble into fibrils . Thus we have successfully created homogeneous patterns of collagen fibrils by using solutions of collagen fibrils as ink. We also used polyHEMA as material of soft lithography. PolyHEMA hydrogels are prepared by using photo-sensitive initiator to polymerize HEMA in the presence of TMPTMA cross-linking agent. An optically transparent polymer is formed and has a patterned relief structure. The dimensions of polyHEMA stamps are as small as 3μm. Although the polyHEMA stamps could be used in microcontact printing, but the swelling behavior of polyHEMA would caused the resulting pattern inhomogeneous.
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Lin, Jyun-Hong, and 林俊宏. "Fabrication of Magnetic Patterns via Microcontact Printing." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/83980186609940201585.
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