Electrochemical bidirectional micropump for processing of liquid plugs

An electrochemical micropump based on the production and shrinkage of hydrogen bubbles was fabricated. Bidirectional movement of a solution in a microfluidic channel was realized by producing and shrinking hydrogen bubbles on a platinum black electrode. The pump could also be operated autonomously by changing the mixed potential, which was realized by coupling the reduction and oxidation of protons/hydrogen with the oxidation (dissolution) of zinc and deposition of silver on electrodes connected to the platinum black electrode. The pump could withdraw an external solution through a microneedle. Also, two integrated pumps could manipulate solution plugs in microfabricated flow channels.