What Is a Microtissue?

A microtissue is a small, three-dimensional cluster of living cells that forms by self-assembly: when cells are placed in an environment they cannot stick to, they stick to each other instead, and cell-to-cell adhesion pulls them into a compact 3D structure. Unlike cells grown flat on plastic, a microtissue has the cell–cell contacts, geometry, and gradients of real tissue — which is why microtissues (and their spherical form, spheroids) are widely used as more physiologically relevant models in cancer research, toxicology, tissue engineering, and drug discovery.

How microtissues form in the 3D Petri Dish®

The 3D Petri Dish® is a reusable micro-mold used to cast a small gel of agarose — a material cells cannot attach to. The mold’s pillars form an array of round-bottom micro-wells in the gel. Mono-dispersed cells are pipetted into a single seeding chamber above the wells; they settle into the recesses within about 10–20 minutes, and over the next 1–2 days each group of cells self-assembles into one microtissue per well. One pipetting step yields up to 256 uniform microtissues — no scaffold, no animal products, just cells.

Because the agarose gel is optically clear, microtissues can be followed in place with a standard inverted microscope — brightfield, phase contrast, or fluorescence — without harvesting them first.

Microtissues vs. scaffold-based 3D culture

Scaffold- and matrix-based methods embed cells in an animal-derived or synthetic material that becomes part of the model. Scaffold-free microtissues contain only the cells and what those cells make themselves — one less variable in the experiment, and no animal-derived products in the culture. Both approaches are used across 3D biology; scaffold-free self-assembly is the natural fit when the goal is maximal cell–cell interaction and a fully defined system.