Spheroid cultures are 3D cell cultures that consist of cell aggregates generated from a single type or from a multicellular mix of cells that arrange themselves into sphere-like formations during proliferation. Spheroid cultures develop primarily via cell-to-cell adhesion. Low-adhesion culture conditions are typically used to promote cell self-aggregation into sphere-shaped 3D structures.

Spheroid cultures generally contain layers of cells, with some exposed on the surface and others buried within the sphere. They usually include proliferating, non-proliferating, and necrotic cells, which can be well oxygenated or hypoxic.

These cultures offer a better understanding of cells in their microenvironment and provide researchers with a more realistic cellular scenario for research.