Table 1.

Key differences between 2D and 3D cell cultures for modeling in vivo conditions.

S.No	Characteristics	2D Cell Cultures	3D Cell Cultures	Ref
1	Cell morphology	Cell shape is elongated and grows on a flat 2D surface.	Natural cell shape is preserved with spheroids or organoids structures and with other 3D models	[11]
2	Cell proliferation	Cell growth in 2 dimensions is rapid and does not mimic in vivo	Cell growth is realistic under 3D culture conditions	[12]
3	Cell and ECM interactions	Growing on a flat surface is not mimicking the native tissue environment. There is no cell and ECM interactions.	Cells and ECM interact with each other and make a 3D environment such as the existing interactions in native tissues. These models reduce the cost of in vivo testing.	[1,13]
4	Cell–Cell Interactions	Multi-cell interactions cannot mimic the native organ environment.	Multi-cell interactions in different 3D tissue models can mimic the native environment.	[14]
5	Cell differentiation	Less resemblance to the native tissue.	Mimics native tissue-like differentiation and markers expression are close to the native tissues.	[15]
6	Vasculature	2D co-culture vasculature studies do not mimic the native vascular system.	Ability to incorporate complex vasculature in the 3D model	[16]
7	Protein and gene expression	Lack of 3D culture conditions, the expression levels may not show much resemblance to in vivo	Show resemblance with in vivo environment	[3]
8	Drug response efficacy	Low or sometimes not predictable due to cells growing on plastic substrate	Predictable as structure is—in vivo environment.	[3,17]
9	Apoptosis and viability (tumor models)	Sensitive to study the target drugs	High resistance to the anti-cancer drugs, which replicates the in vivo environment.	[12,18]
10	Mechanical stimulation	Mechanical stimulation may not mimic the native tissue	We can apply mechanical stimulus according to the native environment and it is an accurate representation of cells in vivo.	[14]
11	Physiological relevance	Highly non-relevant to the physiological environment.	Feasible to make physiologically relevant nutritional and oxygen conditions.	[1]
12	Exposure to culture condition	All cells receive nutrients and growth supplements equally.	The core site of the models will not obtain enough nutrients. Different approaches are explored to improve upon the nutrient and oxygen diffusion to the core site.	[13]
13	Experimentation and analysis	Easy to handle and highly reproducible.	Handling is difficult when compared to 2D cultures, less reproducible, and difficult to handle.	[19]
14	Characterizations	Easy to characterize the cells for experiment with any instrument. Well-established characterization techniques are available.	Difficult to characterize the 3D models. Specific instrumentation is required. Time consuming and not so well-established.	[20]
15	Cost	Inexpensive and well established	Expensive and requires further standardization.	[18]