Digital microfluidics for microchip-based cell sorting

Within the framework of the scientific project MINAPSO (Mikrochip Navigierte Parallel Sortieranlage), a device has been developed that is intended to separate specific biological cells out of heterogeneous cell suspensions on chip level. The process relies on parallel splitting of cell containing droplets, accomplished by the effect of electrowetting and recognition of fluorescently labelled cells. We present an automatic cell sorting platform consisting of a silicon based electrowetting chip and a fluorescence microscope. Based on the device, all relevant fluid operations like drop extraction, drop transport and drop splitting were verified by parameter variations. Measurements of particle distributions support the technical feasibility of the sorting concept and the proof of principle is conducted by a complete sorting experiment.