Engineering a multiplexed blood-brain barrier on a chip with integrated electrodes to monitor barrier formation
Mariia Zakharova is a PhD student in the research group Biomedical and Environmental Sensorsystems. Supervisors are prof.dr.ir. L.I. Segerink and prof.dr.ir. A. van den Berg from the Faculty of Electrical Engineering, Mathematics and Computer Science. Co-supervisor is dr. K. Broersen from the Faculty of Science & Technology.
A variety of platforms were developed since the first introduction of the organ-on-chip (OOC) concept. The ability of OOCs to closely recapitulate the micro physiological environment and organ-specific functions allows them to be a potential replacement for static in vitro models and partially experimental animal models for drug studies. In this thesis, the first step toward optimization and scale-up of OOC devices is shown. The aim of the research was the development of a blood-brain barrier (BBB) on-chip with increased throughput and integrated readouts. The design, fabrication protocol, and characterization of the BBB model are presented. Chapter 2 focuses on the fabrication and characterization of novel thinner PDMS membranes acting as a cell scaffold allowing for across-membrane cell-cell interaction. A parallel comparison of PDMS and PC membranes in Transwells is presented. The possibility to increase the throughput of the BBB-on-chip is discussed in Chapter 3. Here, the design, development, and characterization of the multiplexed chip are described. The presented chip contains eight parallel channels branching from a common inlet, that can be addressed simultaneously or individually. The BBB is recapitulated by co-culturing brain endothelial cells and human astrocytes. Another important limitation is the lack of sensors integrated into OOC. Measurement of TEER is an important feature for many barrier models on-chip, however, electrode integration in such devices is not always straightforward. Therefore, in Chapters 4 and 5 we discuss the different methodologies to integrate the electrodes for online monitoring of BBB development. Chapter 4 presents a cleanroom-free method to integrate electrodes inside the OOC and discusses the data analysis for extracting the TEER values from the impedance spectra. In Chapter 5, the parallel integration of the electrodes in the Quadro-channel chip is discussed. Finally, in Chapter 6, the ultrasound-mediated transient disruption of the BBB using monodisperse microbubbles is presented in OOC. To conclude, Chapter 7 provides the discussion and future perspectives on the development of OOC.
