Fig. 1.

Concept of the present study: VEGF-induced angiogenesis-on-a-chip for gene and inhibitor study.

(Top) In vivo, the DLL4/NOTCH1 pathway orients the endothelial cell fate within an angiogenic sprout. The tip-cell migrates and expresses DLL4, while the stalk-cell is inhibited in its migration by the DLL4/NOTCH1 interaction which rather triggers cell proliferation. (VE-Cad: VE-cadherin) (Bottom) Concept of the model: a human microvessel is fabricated on a PDMS chip within a collagen gel scaffold and used to study VEGF-A-induced angiogenesis, permeability and angiogenic inhibitors effects.