Researchers from Tsinghua University have created a microfluidic device that can trap single cells and release them in a deterministic order. It has an array of trapping sites, a main channel, a trigger channel and an air channel. The capillary valves present along the channels can be opened and closed in a predetermined pattern to trap the cell. They can be released in a in a last-trapped-first-release order.
This video (link) shows the device in action on MCF-7 cells.
Source: A microfluidic device enabling deterministic single cell trapping and release
