Microfluidics Core Facility Droplet-based Microfluidics
Droplet-based microfluidics is a big sub topic in microfluidics. Water-in-Oil droplets or micrometer-sized Oil-in-Water droplets can be produced on chip or by means of glass-capillary nested devices. Water-in-oil droplets are widely used to encapsulate any wanted cargo which can then be analyzed in small compartments. The droplets find applications in single cell sequencing, antibody screening, cell-cell interactions and many more because the content is restricted to the droplet size and not diluted in a bigger volume. This also allows the study of single cells without interference of surrounding cells. Another application of droplet-based microfluidics is for the production of e.g.: beads or capsules consisting of proteins and/or hydrogels. Within the µFlu CF, we prepare the microfluidic chip with the appropriate design, tailored to the project needs of the user. We further offer guidance and help in the generation process of such droplets. Further, we also generate oil-in-water droplets, which are handed to the user to be used for further experiments. Mostly we fabricate the devices by photolithography, however, depending on the design dimensions, droplet fabrication devices can also be fabricated using a high precision 3D printer.
Besides producing water-in-oil droplets it is sometimes necessary to inject various cargo into already established droplets. Therefore we make use of an electrical field on chip to inject proteins, drugs, as well as living organisms into such droplets. To facilitate the injection, we prepare electrodes in the microfluidic device and attach it to a picoinjection module to generate a field of several hundred volts. Depending on the application this system allows to introduce previously produced droplets into the device, as well as to produce droplets on the same device containing the electrodes. The injection occurs in the millisecond range, which is why cell viability is not effected by the electrical field. The image shows the injection with the field on, compared to the generation of daughter droplets when there is no electrical field present.
Picoinjection Device
