Controlled cell-cell interaction assay

A microfluidic device, comprising:

• a substrate;
• a plurality of electrodes on the substrate and comprising a ground electrode, a first signal electrode, and a second signal electrode;
• a microwell array on the substrate and the plurality of electrodes and comprising a plurality of microwells,
• wherein each of the plurality of microwells comprises a plurality of barcode molecules attached thereto, wherein each barcode molecule of the plurality of barcode molecules comprises a molecular barcode sequence, a first microwell barcode sequence, and a second microwell barcode sequence, wherein first microwell barcode sequences of the pluralities of barcode molecules are predetermined and are identical in microwells in each row of the microwell array and different in microwells in different rows of the microwell array, and wherein second microwell barcode sequences of the pluralities of barcode molecules are predetermined and are identical in microwells in each column of the microwell array and different in microwells in different columns of the microwell array,
• wherein a surface of each of the plurality of electrodes is on a bottom of at least one microwell of the plurality of microwells, wherein a space between the first signal electrode and the ground electrode in the microwell is capable of trapping a first cell when a first signal is applied to the first signal electrode and the ground electrode, wherein a space between the second signal electrode and the ground electrode in a microwell of the plurality of microwells is capable of trapping a second cell when a second signal is applied to the second signal electrode and the ground electrode;
• and
• a flow channel comprising an inlet and an outlet and in fluidic communication with the microwell array.