Techniques for high-throughput fluid exchange in droplets

摘要

Techniques include a substrate having a microchannel, first and second microchannel branches, and a fork joining the microchannel upstream and the branches downstream. The microchannel passes a continuous stream of droplets, having a first fluid with magnetic particles, separated by a spacer fluid. A picoinjector, disposed along the microchannel, includes both: a supply channel connected to the microchannel by an aperture on a first side of the microchannel; and, a pair of electrodes on an opposite side. The picoinjector injects a volume of a second fluid into a first droplet when the pair of electrodes carries a certain voltage difference. A first magnet introduces a magnetic field into the microchannel between the picoinjector and the fork to move magnetic particles in the first droplet toward the first side of the microchannel before the droplet is split at the fork to produce output droplets of the second fluid with magnetic particles.