Selective retrieval of individual cells from microfluidic arrays combining dielectrophoretic force and directed hydrodynamic flow

Hydrodynamic-based microfluidic platforms enable single-cell arraying and analysis over time. Despite the advantages of established microfluidic systems, long term analysis and proliferation of cells selected in such devices require off-chip recovery of cells as well as an investigation of on-chip analysis on cell phenotype; requirements still largely unmet. Here, we introduce a device for single-cell isolation, selective retrieval and off-chip recovery. To this end, singularly addressable three-dimensional electrodes are embedded within a microfluidic channel, allowing, through application of a negative dielectrophoretic (DEP) force, the selective release of single cells from their trapping site. Selective capture and release is carried out in standard culture medium and cells can be subsequently single cell mitigated towards a recovery well using hybrid SU-8/PDMS pneumatic valves. Importantly, transcriptional analysis of recovered cells revealed only marginal alteration of the molecular profile upon DEP application, underscored by equivocal minor transcriptional changes induced upon injection into the microfluidics device. Therefore, the established microfluidic system combining targeted DEP manipulation with down-stream hydrodynamic coordination of single cells, provides the means to handle and manipulate individual cells within one device. Overall design: Jurkat T-cells were injected and either passed through the microfluidics setup in absence or in the presence of DEP forces. After retrieval, cells were collected and cultured for three hours to permit potential alterations by the DEP field or the fluidic forces to be represented transcriptionally. Input cells solely cultured served as negative control (Input), whilst cells cultured for three hours under Phorbol-12-myristate 13-acetate and Ionomcyin activation (PMA/Iono), globally activating transcription based on protein kinase C (PKC) activation and calcium ion influx 29, served as positive control. The chip associated conditions encompassed DEP (Chip-DEP) or solely injected in the chip (Chip-Ctrl).