In this thesis a lab on a chip platform is described which is capable of electrofusing cells in a picoliter droplet. The platform consist out of glass part containing recessed platinum electrodes plasma bonded to a PDMS slab containing microchannels. First the two cell populations are introduced separately into two YinYang shaped channel structures. These structures prevent the cells from clogging the microchannels by acting as elongated funnels, introducing the cells gradually into the microchannels. Once the cells enter the microchannels, each population flows through spiral shaped channel, forcing the cells with a combination of an inertial and a Dean force to take place into a single equilibrium position on the inside of the curve. The two spirals shaped channels are connected to a double T-junction. The double T-junction produces droplets alternatingly with a frequency of 1600 droplets per second per junction, enabling single cell encapsulation of two different cells after one another into two different droplets with a 77% efficiency. Next the two different droplet are forced to electrocoalesce, with 95% success yield, due to an electric field created by the electrode pair that is located directly after the double T-junction. The larger droplet containing two different cells is shrunken down to 15% of its original volume by six perpendicular channels, which are half the width of the main channel. To prevent cell removal, small pillars are placed ate the intersection between the main and the perpendicular channel. Droplet volume reduction is necessary to enable cell-cell contact which is required for cell electrofusion. The smaller droplets pass over six electrode pairs that are responsible for electroporating the cell membranes of the two cells. Once the electroporated regions of the two cell membranes touch each other the cells can fuse. The platform was tested by introducing two differently dyed cell populations. One had a blue dyed cell nucleus and green dyed cell membrane, the other had red dyed cell nucleus. 5% of the droplets coming out of the chip contained a larger cell which a green membrane, blue and red nuclei. This indicates successful cell electrofusion.
|Award date||11 Sep 2015|
|Place of Publication||Enschede|
|Publication status||Published - 11 Sep 2015|