A microdroplet-based shift register

A microfluidic device is presented for the serial formation, storage and retrieval of water microdroplets in oil. The principle of operation is similar to that of an electronic shift register. Droplets, considered as units of information, can be arrayed and serially shifted within the device, allowing the controllable positioning of the emulsions and the creation of interfaces between drops. Using this passive system, by exploiting the balance between hydrodynamic pressure and surface tension across a drop due to the device design, droplet networks can be readily arrayed in a series of elements and cascaded within the microchannels in an automatable and high throughput fashion. The results showed the suitability of the system to be used for the formation of artificial lipid bilayers and for the study of biological dynamic processes based on the diffusion of molecules through interfaces.