What is the difference between 3D culture and 2D hydrogel coating culture?

In 3D cell culture, cells are embedded inside the hydrogel matrix and grow in a three-dimensional structure.

2D hydrogel coating culture adds a layer of hydrogel at the bottom of the culture plate. Cells are added to the surface of the hydrogel. If using the thick 2D hydrogel coating, the stiffness and functional ligands on the substance are changed, and cell behavior (morphology, mobility, etc.) may be different when using the thin 2D gel coating, where only a very thin layer of hydrogel was applied to the plate surface to change the functional properties without adjusting the stiffness of the plastic surface.