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

Abstract

Catalytic micropumps consisting of Ti/Cr/Pt microtubes with diameters of 5–10 μm and tunable lengths in the range of 20–1000 μm 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 μm 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.