In-air microfluidic sorting of single cells on multiple paths

Sorting of desired single cells from a cell population is crucial for many applications in biology and biomedicine that require analysis at the cellular level. Microfluidic dielectrophoresis (DEP)-based single-cell sorting method has been demonstrated as a powerful technology to enable high-throughput and accurate sorting of single cells. However, conventional DEP sorting is mainly performed in the oil phase constrained by solid channels, which restricts the capacity and tunability of the sorting path. Here, we describe an approach to sort single cells on multiple paths in air. Our device allows for tunable ejection of droplets containing single cells in air, which are interrogated and sorted by a microfluidic DEP sorter with a cylindrical electrode, showing a sorting accuracy of >99% for all paths with high survival rates. We demonstrate the utility of our device by isolating multiple subpopulations from a cell sample with three types of cells. Our technology holds the potential to perform sorting on numerous paths, making it applicable for multipurpose sorting from complex heterogeneous cell populations.