Ethanol Fermentation as the Basis for Autonomous, Long-term and High-pressure Fluid Transport in Microfluidics

We present a concept for autonomous, long-term and high-pressure fluid transport on disposable microfluidic chips, which are fully bio-compatible and compostable. The actuation principle is based on ethanol fermentation, a well-known biological process in which yeast cells convert molecules like sucrose into cellular energy and thereby produce ethanol and carbon dioxide (CO2) as metabolic waste products. A two-chamber fluidic system separated by a flexible membrane is suggested for active fluid transport utilizing a bio-reactor. One chamber, connected to the outside via a pressure-sensitive valve, contains the fluid to be actuated, the other one the culture medium for the yeast cells. Once the yeast cells are injected into the culture medium, ethanol fermentation and thus the production of CO2 starts, which builds up pressure on the membrane and hence also on the fluid chamber. As soon as the switching point of the pressure sensitive valve is reached, fluid transport at a predefined and constant flow rate starts.