Figure 2.

Primary technologies used to culture cells in 3D. (A) Formation of 3D micro‐tissues using hanging drop approach. Droplets of cell suspension are placed on the lid of a Petri dish, which is gently inverted and placed on top of the dish containing media to maintain a humid atmosphere. Suspended cells come together in the apex of the droplet, forming a compact 3D aggregate. (B) 3D culture using hydrogel technology. The cartoon shows cells within a matrix of protein molecules that create a nano‐scale micro‐environment mimicking the structure of the extracellular matrix. Cells are embedded within the proteinous 3D framework within an aqueous‐based gel. (C) Porous solid scaffold supporting 3D cultured cells. Cells enter the porous framework of the solid scaffold where they do not flatten, they maintain their 3D structure, and they bind to one another forming 3D tissue‐like masses.