Organoid arrays

A method for making an array of organoids, comprising:

• i. seeding stem cells on a surface;
• ii. culturing the stem cells of step i. in situ to allow their aggregation into multicellular stem cell containing aggregates,
• iii. overlaying the multicellular aggregates of step ii. with an overlay comprising an overlay hydrogel;
• and
• iv. culturing the multicellular stem cell containing aggregates of step
• ii. in situ in conditions suitable for organoid development, wherein the array of organoids is within a single focal plane and the surface may be overlaid with a regular tessellation, such that the organoids are uniquely positioned within adjacent tiles of the tessellation;
• wherein the organoids are composed of organ specific cells that are self-organized
• wherein the surface is a biofunctional hydrogel imprinted with cavities or microwells of various sizes, shapes and depths;
• wherein steps ii., iii., and iv. occur in situ such that the stem cells containing aggregates and the multicellular stem cell containing aggregates remain in the same position and/or culture environment from initiation to formation of the array of organoids;
• and
• wherein the biofunctional hydrogel of the surface has a stiffness between 150 Pa and 50 kPa and the hydrogel of the overlay is diluted such that it forms a viscous solution or semi-solid media.