Controlled cell-cell interaction assay

A kit comprising:

• a microfluidic device, wherein the microfluidic device comprises:
• 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.

A method of making a microfluidic device, comprising:

• (a) generating a plurality of electrodes on a substrate and comprising a ground electrode, a first signal electrode, and a second signal electrode;
• (b) generating a microwell array on the substrate and the plurality of electrodes and comprising a plurality of microwells;
• (c1) providing a first patterning device comprising a plurality of first parallel flow channels with a first pattern;
• (c2) aligning the first patterning device with the microwell array, thereby microwells of the microwell array in a first group are aligned to one of the plurality of first parallel flow channels;
• (c3) introducing into each of the plurality of first parallel flow channels a solution comprising a plurality of first barcode molecules, wherein the plurality of first barcode molecules in one solution comprises an identical first microwell barcode sequence, wherein the pluralities of first barcode molecules in different solutions comprise different first microwell barcode sequences, thereby attaching first barcode molecules of the plurality of first barcode molecules to the microwells of the microwell array in the first group aligned to the first parallel flow channel;
• (d1) providing a second patterning device comprising a plurality of second parallel flow channels with a second pattern;
• (d2) aligning the second patterning device with the microwell array, thereby microwells of the microwell array in a second group are aligned to one of the plurality of second parallel flow channels;
• (d3) introducing into each of the second parallel flow channels a solution comprising a plurality of second barcode molecules, wherein the plurality of second barcode molecules in one solution comprises an identical second microwell barcode sequence, wherein the pluralities of second barcode molecules in different solutions comprise different second microwell barcode sequences, thereby attaching second barcode molecules of the plurality of second barcode molecules to the first barcode molecules attached to the microwells of the microwell array in the first group aligned to the second parallel flow channel.