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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Microfabrication of Bio-Analytical Devices: Microelectrode Array and Traveling-Wave Electrophoresis

Draper, Neil 01 May 2015 (has links)
The need for potable water is increasing with the ever-increasing world population. Further development of fast, portable, and cost effective analytical tools is necessary in order to create diagnostic techniques capable of supporting the water needs of the world’s population. Within the last decade microfluidics and Lab-on-a-Chip (LOC) technologies have increased the portability and speed of detection for aqueous samples. Photolithography techniques serve as a cost effective fabrication tool to create LOC electrodes on the micron scale. An in-depth look at the fabrication process is undertaken in this paper in order to further the development of micro-scale detection techniques. An electrode array capable of detecting multiple targets within one aqueous sample was designed and fabricated. The electrode array was assessed for performance characteristics to determine if reproducibility is possible. The fabrication process was also detailed for a new chemical separation technique, traveling-wave electrophoresis (TWE). TWE could serve as a separation tool capable of separating out specific charged molecules for biological and chemical samples. The TWE device was assessed on the capabilities to move charged molecules.
2

Design and production of polymer based miniaturised bio-analytical devices

Garst, Sebastian, n/a January 2007 (has links)
The aim to provide preventive healthcare and high quality medical diagnostics and treatment to an increasingly ageing population caused a rapidly increasing demand for point-of-care diagnostic devices. Disposables have an advantage over re-usable units as cross-contamination is avoided, no cleaning and sterilising of equipment is required and devices can be used out of centralised laboratories. To remain cost-effective, costs for disposables should be kept low. This makes polymer materials an obvious choice. One method for the realisation of fluidic micro devices is the stacking of several layers of microstructured polymer films. Reel-to-reel manufacturing is a promising technique for high-volume manufacturing of disposable polymer bio-analytical devices. Polyethylene terephthalate (PET) and cycloolefin copolymer (COC) were selected as suitable polymer substrate materials and polydimethyl siloxane (PDMS) as membrane layer. Bonding of polymer films with the help of adhesives carries the risk of channel blocking. Despite this drawback, no other method of bonding PDMS to a structural layer could be identified. Bonding with solvents avoids channel blocking issues, but adversely affects biocompatibility. Thermal diffusion processes enable bonding of COC and PET without the use of any auxiliary material. The extensive process times requires for thermal diffusion bonding can be considerably shortened by pre-treating the material with plasma or UV exposure. Welding with the use of a laser energy absorbing dye was demonstrated to be particularly suitable for selective bonding around channels and reservoirs. None of the assessed bonding methods provide a generic solution to all bonding applications. Instead, the selection of an appropriate technique depends on the intended application and the required level of biocompatibility. Since this selection has implications on the feasibility and reliability of microfluidic structures on the device, design rules which ensure design for production have to be established and followed.

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