Genipin crosslinked collagen microfluidic scaffolds form stable microvessels in vitro using human endothelial cells

Abstract

Reconstituted collagen gels represent an ideal choice for the development of clinically relevant engineered vascularized scaffolds, but are typically too mechanically weak to resist deformation. The chemical crosslinker, genipin, has been used to increase the mechanical strength, reduce immunogenicity of tissues in vivo, and protect collagen against enzymatic degradation in vivo. It is not fully clear what effects genipin fixation of type I collagen gels has on human endothelial cell functionalized in vascularized scaffolds in vitro. We compared the vascular leakage of fluorescent solutes, lifespan, and viability of control, 1, and 20 mM genipin treated scaffolds under stable perfusion conditions and found no negative effects due to the genipin fixation of scaffolds. We subjected microvessels to two stressful perfusion conditions by reducing shear stress and by eliminating a positive transmural pressure. Interestingly the genipin treated scaffolds supported vessels with superior morphological stability and lifespan compared to control scaffolds. This study demonstrates that genipin fixed collagen scaffolds permit normal endothelial cell physiology and stabilize endothelial microvessels subjected to stressful perfusion conditions in vitro.