Microfabricated fluorescence-activated cell sorter through hydrodynamic flow manipulation

In this paper, we present a novel flow manipulation and signal detection scheme for a microfabricated fluorescence-activated cell sorter (mu FACS). Optics setup was built on an inverted fluorescence microscope (IX71, Olympus, USA) and microchips were made of PDMS using soft lithography. Perfectly aligned axial illumination setup of the commercial microscope ensures effective signal detection. Hydrodynamic flow manipulation scheme is adopted for both flow focusing and cell sorting. Fast and robust sorting function is utilized by a nozzle flow from wide actuation channel. The sorting function is verified through real-time high-speed imaging. The captured images are used for adjusting delays between signal detection and sorting activation. The system automatically adjusts itself to any flow conditions, and so no adjustment is made to the flow parameters between runs. We believe that the proposed techniques will help breaking through the obstacles of mu FACS system development.