A 3D cell culture is an artificially created environment in which biological cells are permitted to grow or interact with their surroundings in all three dimensions. Unlike 2D environments such as the Petri dish, a 3D cell culture allows cells in vitro to grow in all directions, similar to how they would in living systems.
These three-dimensional cultures are usually grown in bioreactors, small capsules in which the cells can grow into spheroids, or 3D cell colonies.
Scaffold-free cell culture approaches use freely floating cell aggregates, typically referred to as spheroids.