Three-dimensional cell culture systems as an in vitro platform for cancer and stem cell modeling

Table 2 Proposed advantages, disadvantages, and research stage of different three-dimensional cell culture methods

Techniques	Advantages	Disadvantages	Research stage
Liquid overlay cultures and Hanging drops	(1) Easy-to-use protocol; (2) No added materials; (3) Consistent spheroid formation; control over size Co-culture ability; (4) Transparent; (5) High reproducibility; (6) Inexpensive; (7) Easy to image/harvest samples	(1) No support or porosity; (2) Limited flexibility; (3) Limited spheroid size; (4) Heterogeneity of cell lineage; (5) Lack of matrix interaction	(1) Basic research; (2) Drug discovery; (3) Personalized medicine
Hydrogel	(1) Large variety of natural or synthetic materials; (2) Customizable; (3) Co-culture possible; (4) Inexpensive; (5) High reproducibility	(1) Gelling mechanism; (2) Gel-to-gel variation and structural changes over time; (3) Undefined constituents in natural gels; (4) May not be transparent	(1) Basic research; (2) Drug discovery
Bioreactors	(1) Simple to culture cells; (2) Large-scale production easily achievable; (3) Motion of culture assists nutrient transport; (4) Spheroids produced are easily accessible	(1) Specialized equipment required; (2) No control over cell number/size of spheroid; (3) Cells possibly exposed to shear force in spinner flasks (may be problematic for sensitive cells)	(1) Basic research; (2) Tissue engineering; (3) Cell expansion
Scaffolds	(1) Large variety of materials possible for desired properties; (2) Customizable; (3) Co-cultures possible; (4) Medium cost	(1) Possible scaffold-to-scaffold variation; (2) May not be transparent; (3) Cell removal may be difficult	(1) Basic research; (2) Drug screening; (3) Drug discovery; (4) Cell expansion
3D bioprinting	(1) Custom-made architecture; (2) Chemical, physical gradients; (3) High-throughput production; (4) Co-culture ability	(1) Require expensive 3D bioprinting machine; (2) Challenges with cells/materials	(1) Cancer pathology; (2) Anticancer drug screening; (3) Cancer treatment; (4) Tissue engineering

Modified from Breslin et al[64]; Fang et al[47]; Leong et al[109].