endothelial cells plated on the surface of a two-dimensional substratum ( gelatin-coated dishes , dishes coated with native type i collagen or collagen gels ) form a cobblestone monolayer at confluence , whereas cells plated within a three-dimensional gel matrix elongate into a sprouting morphology and self-associate into tube-like structures .
C0041455
type i collagen
C0009325
collagen