A process for producing a 3D tissue culture model by (a) printing a drop of bio-ink to a substrate； (b) printing a drop of activator to the drop of bio-ink to form a hydrogel droplet； (c) repeating steps (a) and (b) in any order to form a hydrogel mold adapted to receive a drop containing cells； (d) printing a drop containing cells to the hydrogel mold； and (e) repeating steps (a) and (b) in any order to form a 3D tissue culture model comprising the cells encapsulated in the hydrogel mold.
