Table 1.

Comparisons of different lymph node-mimicking models.

	Dish culture	Animal model	Hydrogel	Organoid	Microfluidic device
Spatial feature	2D	3D	3D	3D	3D
Cost	Low	High	Low	Medium	Medium
Operation time	Short	Long	Short	Medium	Medium
Scalability	High	Medium	Medium	Medium	Medium
Organ-level function	Absent	High	Low	Medium	High
Physiological relevance	Low	High	Medium	Medium	High
Structural variability	Low	Low	High	High	Medium
Cell-cell/tissue communication	Low	High	Low	Medium	High
Dynamic flow	Absent	High	Absent	Absent	High
Real-time read-out	High	Low	Medium	Medium	High
Environment control	High	low	Medium	Medium	High
Portability	Medium	Hard	Medium	Medium	Easy
Ethical issuea	Possible	Yes	Possible	Possible	Possible

^aEthical considerations of cell experiment are largely dependent on the source of cells.