Microfluidics is a multidisciplinary field at the intersection of engineering sciences, physics, chemistry, biochemistry, nanotechnology and biotechnology, and deals with the behavior, the precise control and manipulation of liquids and gases in a narrow space, typically in the submillimeter range.
In this range, other physical laws play a role than in macrofluidics. The smaller the batch, the larger the ratio of surface to volume. Capillary forces and surface charges dominate gravity and allow a passive flow, which is utilized, for example, in lateral flow tests (e.g., pregnancy test). In addition, small channels allow turbulent-free flow (laminar flow) to create stable interfaces between liquids. Cells in such a liquid flow can be counted or sorted (flow cytometry).
External drive mechanisms e.g. Rotary actuators are also used to enable fluid transport on the passive chip in CD-player-like systems. This allows a directed flow. In the case of active microfluidics, micropumps or microvalves are used, which ensure a continuous or dosed fluid transport. The flow direction can be controlled by microvalves. This makes it possible to miniaturize processes on a single chip that are normally performed in a laboratory or to develop completely new processes.
The methodical focus of the Microfluidics Unit, a new facility within BioSupraMol, is to provide the infrastructure to design and produce tailor-made microfluidic chips for a variety of research questions. Currently these include chips for droplet-based approaches that provide picoliter-volume compartments in high-throughput analytics, and applications in biology such as single-cell observations of bacteria and fungi.
The central method is the production of microfluidic devices, usually made of PDMS (cross-linked polydimethylsiloxane), using soft lithography. This involves designing the size and pattern of the flow channels to provide a casting mask for the particular application. This mold can then be used to produce chips for experimental work. The chip can be connected to injector pumps via tubings to inject solutions e.g. with polymers or microorganisms, cells and nutrients. Processes in the chip can be visualized and recorded via optical microscopy.
The equipment and expertise from design to chip are all available within the unit. Above, the unit provides services related to microscopy monitoring of microfluidics, droplet-based particle synthesis, single cell response of bacteria against antimicrobials, cell encapsulation with microgels, and biological data analysis. An expansion of the unit is currently being planned, which provides solutions for the processing and analysis of large amounts of data generated in microfluidics.