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Title: Microfluidic devices for integrated bio/chemical systems
Author: Schabmüller, Christian Georg Johann
ISNI:       0000 0001 3554 8445
Awarding Body: University of Southampton
Current Institution: University of Southampton
Date of Award: 2001
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This project contributes to the area of microfluidics and BioMEMS (Micro-Electro-Mechanical-Systems) by developing and improving discrete fluidic devices, realising an interconnection method to obtain entire microfluidic systems and by combining microfluidic with BioMEMS. Bubbles severely degrade most micropumps and gases cannot be pumped at all in many cases. A novel self-aligning micropump, which is able to pump gas and liquid was developed. It is also tolerant to gas bubbles of up to three times the pump chamber volume. The pump rate for ethanol is 1500 ml/min with a maximum backpressure of 1000 Pa and the pump rate for air is 700 ml/min. To realise fluidic systems a flow sensor measuring and controlling the output of the micropump was most desirable. Technical problems experienced with a previous attempt are specified and solutions for obtaining a working flow sensor are presented. Initial experiments for water are described where flow rates of up to 30 ml/min were measured. With the novel approach of a microfluidic circuitboard the aspect of interconnection by adapting the principle of the printed electrical circuitboard has been addressed. The concept has been proven functional with tests comprising a micropump and by a system consisting of various devices. A system combining biotechnology with microfluidics results in a micromachined chip for the polymerase chain reaction (PCR). Integrated aspects of this device are incorporated heaters, temperature sensors and novel optical detection approaches. Optical fibres and pn-diodes have been included in the design for light input and fluorescent detection rendering the system immune from ambient light and eliminating the need of bulk optical components. Experiments show that the water filled chip with 1 ml volume can be cycled 30 times stepping through three temperature levels in 2.2 min. This makes it the smallest and fastest silicon micromachined PCR chip presented so far. Furthermore, this device could be used in connection with a system formed by the earlier described micromachined devices realised on the fluidic circuitboard, e.g. mixing the various chemicals for the PCR.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available