TABLE I.

Comparison between conventional two-dimensional cell culturing technique and three-dimensional cell culturing technique.^1–76

Parameters	Two-dimensional	Three-dimensional
	Monolayer Petri dish culture	Liver organoids	Liver-on-a-chip
General characteristics	Cells grow on rigid tissue culture plastic in monolayer fashion	Usually cultured with hydrogel or as suspension culture where the cell mass is clustered	Gas permeable polymeric membrane usually used as culturing chamber material where cells are encouraged to reconstruct extracellular matrix (ECM); multicellular interactions can be easily encouraged
Cell morphologies	Unnatural cell spreading, limited ECM secretion and limited cell–cell interaction	Possess similar hepatic physiological architecture and excellent cell–cell and ECM interactions	Can achieve close resemblance of physiological and pathological hepatic architecture, high level of ECM production and cell–cell/cell–surface interactions
Flow characteristics	Cannot induce flow parameters; regular replenishing of culture media is required	Can induce flow depending on the design of the bioreactor	Controllable flow parameters, such as shear stress and recirculation of metabolites
Signaling molecules and mass transfer	Short range	Due to formation of spheroids, inner cell mass experience limited mass transfer which could result in cell apoptosis	Accurate control of signaling molecules and nutrients spatially and over time. Incorporations of non-parenchymal cells can more accurately mimic physiological conditions and produce clinically relevant data
High throughput screening (HTS)	A widespread model for HTS	Depending on the platforms used, the throughput levels may vary	Depending on the designed platform, it could be achieved but is limited by the technical challenges
Experimental data	Ease of operation but single time-point data	Difficult to obtain homogenous data	Able to perform real-time monitoring of metabolites over the entire course of the experiment