Table 2.

A summary of the ECM used on tumor chips.

Category	Gel condition	Concentration range	Advantages	Disadvantages	References
Rat tail collagen type I	At a neutral pH	1.3–10.0 (mg/mL)	Similar to the ECM of tumors, biodegradability, containing cell adhesive domains, commercially available	Derived from animals, weak stability, monocomponent	[55,[149], [150], [151], [152], [153], [154], [155]]
Matrigel	Above room temperature	2.5%–10% (v/v)	A variety of protein components, biodegradability, commercially available	Derived from animals, undefined compositions, poor mechanical properties	[[156], [157], [158], [159], [160], [161]]
Bovine fibrinogen	Mixed with bovine thrombin	2.5–10.0 (mg/mL)	Promoting the self-assembly of HUVECs, enzymatical degradability, occurring RGD adhesion domains, commercially available	Risks of immunogen and pathogen, monocomponent	[56,140,[162], [163], [164], [165]]
GelMA	Exposure to light with the assistance of a photoinitiator	3%–10% (v/v)	Customized components, easy to pattern, rapid prototyping, good biocompatibility and bioactivity, commercially available	Risk of cell death induced by photoinitiators, lack of microscale pores to accommodate tumor cell migration, difficult to degrade	[133,156,166,167]
Cultrex BME	Above room temperature	2.5%–10% (v/v)	Similar to an early developmental basement membrane, commercially available	Risks of immunogen and pathogen, undefined compositions, poor mechanical properties	[[168], [169], [170]]
dECM	Chemical, biological and physical methods	–	Reconstituted native ECM, customized components	Expensive cost, risk of cytotoxicity, require a different protocol to ensure efficient decellularization	[145,155]