Influence of the pH value and the surfactant concentration on the pumping performance of magnesium fuel based Janus micropumps

Micropumps are in animal and human bodies and on cellular levels vital for the life functions. In case of critical problems like diseases, artificial micropumps are candidates to take over important functions. These functions are ranging from release of substances over removing toxics to stirring stomach fluids, helping to disperse medicine. We hereby present a Janus micropump, powered by hydrogen bubbles, which is able to operate in a gastric pH environment. This Janus micropump consumes hydrochloric acid as an external fuel and releases magnesium ions , which act as micronutrients . The presented Janus micropumps do display significant pumping power by moving external tracer particles and stop after exhausting their magnesium or alternatively acid fuel. The pumping properties depend significantly on the surrounding pH environment and the amount of external surfactant added. Analysis of tracer particle motion shows, that the cause of this movement are the bubbles generated that drag the liquid along after bubble release.