In this thesis, a multiplexed micro-fabricated cell culture device is presented to probe the soluble micro-environment of stem cells. A large number of biological, physical and chemical variables determine the micro-environment of stem cells and affect therefore their fate. The soluble micro-environment is believed to play a pivotal role in controlling stem cell fate and its optimisation may therefore allow exploitation of applications such as regenerative medicine or drug discovery. However, novel tools are required to probe and optimise the soluble micro-environment. The ability to move small volumes of liquid and the minimal use of resources are important characteristics of microfluidic systems and thus, they are perfectly suited to study the micro-environment of stem cells. A microfluidic cell culture device must ful fil three important requirements to be of utility in stem cell bioprocess development. The first aspect addresses the need for adaptability and flexibility to implement changes in microfluidic designs to take account of the rapid progress in stem cell research. To this end, a packaging solution specifi cally designed for a microfluidic cell culture device has been developed. The packaging system has thus been complemented with a rapid fabrication method using a micro-milling machine to quickly fabricate disposable and easily reconfi gurable microfluidic chips. The packaging solution has a maximum burst pressure of approximately 7.5 bar and the fabrication method has a dimensional fidelity with less than 10% deviation from the nominal value. The second aspect focuses on the scalability and comparability of results and the feasibility of continuous culture of stem cells - both critical elements for the success of a microfluidic cell culture system for stem cell bioprocess development. A novel cell seeding method has been developed using a pipette to directly and carefully seed cells into a culture chamber within a microfluidic cell culture device. To prevent a wash-out of viable cells during continuous culture, a low hydrodynamic shear stress microfluidic chip has been developed. The cell culture device has been successfully tested using human embryonic stem cells (hESC) on feeder cells. The third aspect concerns the automated monitoring of stem cell bioprocesses in the cell culture device. A multiplexed micro fluidic bioreactor platform with time-lapse imaging has been developed to obtain data-rich experimental sets. The platform consisting of a cooled media reservoir and a pumping mechanism has been characterised and tested using mouse embryonic stem cells (mESC) as a proof of concept. The combination of these three aspects provides a basis towards a multiplexed microfabricated cell culture device, which allows data-rich experimentation and comparability with current benchscale culture vessels for stem cell expansion and di fferentiation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:565656 |
| Date | January 2012 |
| Creators | Reichen, M. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1349012/ |
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