A method of producing 3D cell structures, comprising the steps of: forming an array of separated homogenous aqueous fluid microdroplets of a desired shape and size in a desired spatial pattern, wherein the separated homogenous aqueous fluid microdroplets comprise cells, wherein the forming of the array comprises: (a) providing a patterned substrate with a solid support coated with a layer or film comprising (i) hydrophilic areas having the desired shape and size; surrounded by (ii) hydrophobic areas separating the hydrophilic areas into the desired spatial pattern; and (b) applying the aqueous fluid comprising the cells to a multitude of the hydrophilic areas at the same time; turning the patterned substrate with the solid support upside down such that the separated homogeneous aqueous fluid microdroplets form hanging separated homogeneous aqueous fluid microdroplets; agglomerating the cells comprised in the hanging separated homogeneous aqueous fluid microdroplets to form 3D cell structures; and further comprising a step between step and: providing the turned patterned substrate with the solid support comprising the hanging separated homogeneous aqueous fluid microdroplets on a holder, wherein the holder comprises a plate having an opening which is adjusted to hold the turned patterned substrate with the solid support; wherein a cell-culture dish comprising a liquid is provided below the holder, wherein the volume of one hanging separated homogenous aqueous fluid microdroplet is in the range from 5 nL to 100 nL, and wherein the holder is a table comprising a tabletop with an opening which is adjusted to hold the turned patterned substrate with the solid support and comprises legs which extend from the surface of the plate facing downwards to the ground. forming an array of separated homogenous aqueous fluid microdroplets of a desired shape and size in a desired spatial pattern, wherein the separated homogenous aqueous fluid microdroplets comprise cells, wherein the forming of the array comprises: (a) providing a patterned substrate with a solid support coated with a layer or film comprising (i) hydrophilic areas having the desired shape and size; surrounded by (ii) hydrophobic areas separating the hydrophilic areas into the desired spatial pattern; and (b) applying the aqueous fluid comprising the cells to a multitude of the hydrophilic areas at the same time; (a) providing a patterned substrate with a solid support coated with a layer or film comprising (i) hydrophilic areas having the desired shape and size; surrounded by (ii) hydrophobic areas separating the hydrophilic areas into the desired spatial pattern; and (i) hydrophilic areas having the desired shape and size; surrounded by (ii) hydrophobic areas separating the hydrophilic areas into the desired spatial pattern; and (b) applying the aqueous fluid comprising the cells to a multitude of the hydrophilic areas at the same time; turning the patterned substrate with the solid support upside down such that the separated homogeneous aqueous fluid microdroplets form hanging separated homogeneous aqueous fluid microdroplets; agglomerating the cells comprised in the hanging separated homogeneous aqueous fluid microdroplets to form 3D cell structures; and providing the turned patterned substrate with the solid support comprising the hanging separated homogeneous aqueous fluid microdroplets on a holder, wherein the holder comprises a plate having an opening which is adjusted to hold the turned patterned substrate with the solid support; wherein a cell-culture dish comprising a liquid is provided below the holder, wherein the volume of one hanging separated homogenous aqueous fluid microdroplet is in the range from 5 nL to 100 nL, and wherein the holder is a table comprising a tabletop with an opening which is adjusted to hold the turned patterned substrate with the solid support and comprises legs which extend from the surface of the plate facing downwards to the ground.