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PhD Defence Magdalena Malankowska

Membrane integration in biomedical microdevices

Magdalena Malankowska is a PhD Student in the Research Group MESOSCALE CHEMICAL SYSTEM. Her Supervisor is professor Han Gardeniers from the faculty Sciences and Technology. This doctoral degree program was undertaken jointly with the de Universidad de Zaragoza and the Universidade Nova de Lisboa. Her defence will be at the Universidad de Zaragoza. 

The present work has been performed under the Erasmus Mundus Doctorate in Membrane Engineering program. The home institute was the Chemical Engineering and Environmental Technologies Department at the University of Zaragoza, within the Nanostructured Films and Particles (NFP) group. The NFP is a member of the Nanoscience Institute of Aragon (INA). Two host universities were:  Faculdade de Ciências e Tecnologia at the University Nova de Lisboa (Portugal) and Mesoscale Chemical Systems group at the University of Twente (The Netherlands). This research has been carried out for approximately 4 years (2013-2017) and it was part of the research project EUDIME, which was funded by the European Union.

The target of the research presented in this thesis is a design, development and fabrication of a microfluidic device with integrated membrane in the form of a membrane contactor for various biological applications. The microfluidic devices are fabricated and tested for oxygenation of blood and separation of anaesthetic gas.

In the first part of the work, the microfluidic system for blood oxygenation, so called lung-on-a-chip, is introduced. In such system, one chamber is devoted to pure oxygen, and the other chamber is designed for blood and they are separated by a dense permeable membrane. Computer modelling is performed in order to design the liquid chamber with homogenous liquid flow, low pressure drop of the system and low shear stress without compensation of high oxygenation. Two different microdevice geometries are proposed: alveolar and meander type design with vertical membrane arrangement. Fabricated devices as well as integrated membranes are made of PDMS by soft-lithography and their surface is modified in order to make them more hydrophilic. The experiments of blood oxygenation are performed and the oxygen concentration is measured by an oximeter electrode and compared to the mathematically modelled values. The parameter sensitivity and the possible improvements of the proposed architectures based on the mathematical simulations are presented as well.

The second part of the thesis, introduces the concept of an alveolar microfluidic device as gas-ionic liquid micro-contactor for removal of CO2 from anaesthesia gas, containing Xe. The working principle involves the transport of CO2 through a flat PDMS membrane followed by the capture and enzymatic bioconversion in the ionic liquid solvent. As proof of concept demonstration, simple gas permeability experiments are performed followed by the experiments with ionic liquid and ionic liquid with the enzyme.

Finally, an alternative concept of a microfluidic device with an integrated membrane in the form of a fractal geometry with nanonozzles as pores at the vertices of the third-level octahedra for the controlled addition of gaseous species is introduced. Fractal geometry, that is a three-dimensional repetitive unit, is fabricated by a combination of anisotropic etching of silicon and corner lithography. As a proof of concept, simple gas permeation experiments are performed, and the achieved results are compared to the gas permeation obtained by a dense PDMS membrane.