title: Single-cell printing based on impedance detection.
abstract: Label-free isolation of single cells is essential for the growing field of single-cell analysis. Here, we present a device which prints single living cells encapsulated in free-flying picoliter droplets. It combines inkjet printing and impedance flow cytometry. Droplet volume can be controlled in the range of 500 pl-800 pl by piezo actuator displacement. Two sets of parallel facing electrodes in a 50 μm × 55 μm channel are applied to measure the presence and velocity of a single cell in real-time. Polystyrene beads with <5% variation in diameter generated signal variations of 12%-17% coefficients of variation. Single bead efficiency (i.e., printing events with single beads vs. total number of printing events) was 73% ± 11% at a throughput of approximately 9 events/min. Viability of printed HeLa cells and human primary fibroblasts was demonstrated by culturing cells for at least eight days.
authors.forename: J
authors.initials: J
authors.lastname: Schoendube
authors.affiliation: Zurich Instruments AG , Technoparkstrasse 1, 8005 Zurich, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Wright
authors.forename: R
authors.initials: R
authors.lastname: Zengerle
authors.forename: P
authors.initials: P
authors.lastname: Koltay