Tunable catalytic tubular micro-pumps operating at low concentrations of hydrogen peroxide

Catalytic micropumps consisting of Ti/Cr/Pt microtubes with diameters of 5-10 mm and tunable lengths in the range of 20-1000 mu m are reported. Micropumps were fabricated by rolling up metallic nanomembranes into microtubes with an inner platinum layer. When immersed into a solution of hydrogen peroxide, the micropumps are activated by the catalytic decomposition of peroxide into oxygen microbubbles and water. Fluid pumping is demonstrated by the movement of polystyrene particles with a diameter of 1 mu m through the catalytic microtubes. Concentrations from 0.009 to 11% H2O2 were employed to study the catalytic generation of microbubbles in micropumps with different lengths. A minimum concentration of 0.06% fuel was determined to be sufficient to actuate the micropumps. Such devices based on rolled-up nanomembranes hold great promise for the integration into Lab-on-a-chip systems for sensing, sorting of particles and drug delivery.