Abstract

Leaf-Inspired Microvascular Patterns

Kara McCloskey, Assistant Professor, Universily of California

The vascularization of tissue grafts is critical for maintaining viability of the cells within a transplanted graft.  A number of strategies are currently being investigated including very promising microfluidics systems. We explored the potential for generating a vasculature-patterned endothelial cells (EC) that could be integrated into distinct layers between sheets of primary cells.  Bioinspired from the leaf veins, we generated a reverse mold with a fractal vascular-branching pattern that models the unique spatial arrangement over multiple length scales that precisely mimic branching vasculature. By coating the reverse mold with 50µg/ml of fibronectin and stamping enabled selective adhesion of the human umbilical vein endothelial cells (HUVECS) to the patterned adhesive matrix, we show that a vascular-branching pattern can be transferred by microcontact printing.  Moreover, this pattern can be maintained transferred to a 3D hydrogel matrix and remains stable for up to 4 days. After 4 days, HUVECs can be observed migrating and sprouting into Matrigel. These printed vascular branching patterns, especially after transfer to 3D hydrogels, provide a viable alternative strategy to the prevascularization of complex tissues.