Microfluidic Array Chip with Parallel Channels for Fast Preparation of Sample Droplet Array

We present a parallel microfluidic array chip for the fast preparation of microdroplets to provide droplet arrays of a sample using the hydrodynamics of immiscible fluids as they flow in a microchamber and bypass channel. The microfluidic chip has eight channels that are parallel from the inlet to the outlet of the device. Each channel has 13 microchambers and bypass channels to trap the droplets from the sample plugs. Because samples can be arrayed simultaneously in eight parallel channels, the arrays of sample droplets can form quickly. After filling the microchannel and chambers with the sample, oil is injected into the device. As the oil fills the microchannel, owing to the difference in the flow resistance between the microchamber and bypass channel, the oil flows through the bypass channel, trapping the sample in the microchamber. A total of 104 microdroplets of an aqueous sample could be successfully trapped in 8 x 13 arrays of microchambers using one simple injection of sequential plugs of mineral oil, the aqueous sample, and mineral oil with surfactant. Sample droplets were successfully formed at all chambers at flow rates of less than 0.06 mL/h, and a trapping efficiency of greater than 90% was achieved at 0.15 mL/h.