A method for producing multicellular aggregates, in a microfluidic device comprising at least one row having at least one microwell, for each row, a supplying channel spanning along a length of the row and each microwell is in flow connection with the supplying channel, the method comprising the steps of: introducing a first wetting agent comprising a liquid immiscible in water into the supplying channel and corresponding microwells of at least one row of the microfluidic device; introducing a solution comprising an aqueous suspension of cells and a hydrogel precursor into the supplying channel and corresponding at least one microwell of the at least one row of the microfluidic device to replace the first wetting agent within the supplying channel and the at least one microwell with the solution; introducing a second wetting agent comprising a liquid immiscible in water into the supplying channel of the at least one row of the microfluidic device to replace the solution within the supplying channel with the second wetting agent, wherein replacing the solution in the supplying channel with the second wetting agent induces the formation of a droplet containing the aqueous suspension of cells and the hydrogel precursor within each one of the at least one microwell of the at least one row of the microfluidic device, wherein the formation of the droplet is confined in the microwell; inducing the gelation of the hydrogel precursor within the droplet to form a hydrogel seeded with the suspension of cells, wherein the gelation is induced after the droplet has formed and is being confined within the microwell; and introducing a cell culture medium into the supplying channel of the at least one row of the microfluidic device to replace the second wetting agent in the supplying channel. introducing a first wetting agent comprising a liquid immiscible in water into the supplying channel and corresponding microwells of at least one row of the microfluidic device; introducing a solution comprising an aqueous suspension of cells and a hydrogel precursor into the supplying channel and corresponding at least one microwell of the at least one row of the microfluidic device to replace the first wetting agent within the supplying channel and the at least one microwell with the solution; introducing a second wetting agent comprising a liquid immiscible in water into the supplying channel of the at least one row of the microfluidic device to replace the solution within the supplying channel with the second wetting agent, wherein replacing the solution in the supplying channel with the second wetting agent induces the formation of a droplet containing the aqueous suspension of cells and the hydrogel precursor within each one of the at least one microwell of the at least one row of the microfluidic device, wherein the formation of the droplet is confined in the microwell; inducing the gelation of the hydrogel precursor within the droplet to form a hydrogel seeded with the suspension of cells, wherein the gelation is induced after the droplet has formed and is being confined within the microwell; and introducing a cell culture medium into the supplying channel of the at least one row of the microfluidic device to replace the second wetting agent in the supplying channel.