Microfabricated devices for adherent stem cell culture

• Main Author: Macown, R. J.
• Published: University College London (University of London) 2015
• Subjects: 660.6
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654660

This thesis details the development of a system of microfabricated devices for the adherent culture of stem cells. The multipotency and self renewal of stem cells make them a potentially abundant source of valuable human cells, for both drug screening and regenerative medicine. However, processing stem cells is challenging due to the complexity of whole cell products, the number of process parameters, and the typical use of adherent culture. It is hypothesised that a microfabricated adherent culture system could facilitate process development with minimal use of resources. Furthermore, microfluidic systems offer advantages in spatial and temporal control over the microenvironment that would benefit process development. An existing prototype culture system is critically evaluated by: assessing the design, modelling fluid flow and dissolved oxygen, and successfully co-culturing human embryonic stem cells, on inactivated mouse embryonic fibroblasts, under perfused conditions. The utilisation of reversible seals facilitates the use of standard tissue-culture polystyrene culture surfaces and manual seeding techniques. The evaluation of the prototype system is used to inform improvements to the design, making it easier to use, increasing the robustness, allowing monitoring of whole culture chambers by microscopy, and improving control over mean pericellular dissolved oxygen. Modelling shows the improved culture system also achieves more uniform distribution of both pericellular dissolved oxygen and fluid velocity. The improved culture system shows similar mouse embryonic stem cell seeding behaviour to tissue culture flasks, but, with medium perfused at 300 μl.h 1, mouse embryonic stem cells reach full confluency in less than 48 h, compared with 72 hours for cells maintained statically in flasks. There is also inconclusive data suggesting that the growth rate is limited by pericellular dissolved oxygen and is, therefore, increased and made more uniform by the inclusion of a gas permeable lid system. The reliability, ease of use, comparability with traditional culture systems, and control over process parameters of the improved system should make it a useful tool for stem cell process development.