Laser-actuated micro-valves and micro-pumps

This paper describes a micro-pumping technology using laser induced thermal bubbles, which offers greater flexibility for selective control of flow directions in microfluidic chips. Without complicated fabrication, the bubble in the microchannel could be created by focusing a continuous-wave laser onto the patterned metal pad. Experiments demonstrate that the flow direction can be freely chosen at a T-junction and the flow velocity could be adjusted from 100 to 400 μm/s in real time by adjusting the laser power. This technology can be readily incorporated into the lab-on-a-chip systems for flexible microfluidic manipulation.