This thesis is focused on the manipulation of solid spheres and droplets with a particular focus on medium exchange and size based sorting. Two novel microfluidic devices are demonstrated. Firstly, a medium exchanger capable of transferring spheres and droplets between two miscible liquids was developed. The primary phase was extracted via a series of narrow perpendicular channels using a pressure differential created by mismatched input flow rates. Complete exchange of mineral oil phases has been demonstrated along with the use of the device to create a buffer region for chemical sphere curing of alginate droplets for use in stem cell encapsulation. This device offers simple passive exchange at greater throughput than previously demonstrated. The second device is a tuneable sphere focusing device that focuses spheres via inertial lift forces. Through the compression of the device the channel width is reduced such that the spheres are moved from an unfocused state into two focused streams. Focusing of 12μm spheres into two streams is achieved through channel dimension deformation. The device is shown to be capable of up to 88% ±1.1% focusing when compressed whilst the uncompressed device only focuses 51.4% ±2.1% of the spheres. The deformation of the device offers the potential for a greater range of tuning than previously possible with inertial lift based sorting.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:637117 |
| Date | January 2014 |
| Creators | Morgan, Alex John Lewis |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/69902/ |
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