Electrochemical immunoassay on a microfluidic device with sequential injection and flushing functions.

An integrated microfluidic device with injecting, flushing, and sensing functions was realized using valves that operate based on direct electrowetting. The device consisted of two substrates: a glass substrate with driving and sensing electrodes and a poly(dimethylsiloxane) (PDMS) substrate. Microfluidic transport was achieved using the spontaneous movement of solutions in hydrophilic flow channels formed with a dry-film photoresist layer.