TABLE I.

Types of vascularization methods.

Vascularization method	Benefits	Limitations
Fluid flow through constructed, endothelial cell-lined channel that connects to the culture chamber	• Relatively simple and easy to implement • Allows for modeling of flow effects • Allows for greater control of perfusion medium	• Does not recapitulate complex, branched geometries present in vasculature in vivo
Self-assembled microvasculature formed by endothelial cells under static conditions	• Self-assembly and de novo vessel formation recreates processes that occur in vivo • Greater likelihood of faithfully modeling in vivo vasculature	• Lacks effects of fluid flow that influence endothelial cell orientation and morphology in vivo • May be difficult to control flow in certain chip formats
Artificial method to create a biomimetic network	• Allows greater degree of researcher control over the vascularized network • More complex geometries can be recapitulated • Greater resemblance to in vivo vasculature than flow through microfluidic channels	• Vessel formation is not de novo and may not possess complete fidelity to in vivo vasculature • If synthetic material used is not sacrificial, its interactions with cells may influence results
Self-assembled microvasculature formed by endothelial cells under flow conditions	• Closest to recapitulating in vivo vasculature • Models flow effects and self-assembly ensures recapitulation of in vivo vessel formation processes	• May be difficult to successfully implement • In multi-organ chips, it may be difficult to control perfusion of multiple media types