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We present the development and application of a microfluidic device that can efficiently and reproducibly isolate a programmable number of cells into microwells. The chip consists of a 3x4 array of 100 µm microwells drilled through a flex-PCB substrate along microchannels. Negative DEP focusing of particles is used to axially centre particles within the channel and also to shield the microwell entrance for flowing particles. An optical detection routine analyses and selects the cells to be delivered with single cell resolution. Cell viability results based on a calcein release assay performed on single cells are within the range of physiological loss of fluorescence intensity.

We present a novel method for the isolation, functional analysis and sorting of single cells or small cellular aggregates. In- verted open microwells featuring a microchannel on top, an open air-fluid interface on bottom side and embedded electrodes were implemented on flexible-PCB technology. Microwell arrays in pitch with standard microtiter plates were implemented. K562 cells were delivered to the microwells and trapped at the air-flow interface. Cell delivery and aggregate formation were controlled by dielectrophoresis. Continuous fluid replacement around the cells during the experiment was demonstrated. After analysis, live cells were easily recovered to standard plates where cell growth was demonstrated.

We present here an innovative architecture based on negative-dielectrophoresis (nDEP) to perform the controlled isolation and patterning of a programmable number of cells inside microwells. The high efficiency solution we propose features electrodes placed on the floor and sidewalls of the microfluidic channels where microwells are realized and allows for the successful isolation, patterning and live-cell imaging of both single cells and cell clusters, with single cell resolution. Cell viability was assessed after delivery performing a calcein release assay in the microwells.