Biomimicking Leaf-Vein Engraved Soft and Elastic Membrane Promotes Vascular Reconstruction

Hierarchical vasculature reconstruction is fundamental for tissue regeneration. The regeneration of functional vascular network requires a proper directional guidance, especially in case of large-size defects. To provide the "running track" for vasculature, a leaf-vein mimetic membrane using soft and elastic poly(lactide-co-propylene glycol-co-lactide) dimethacrylate is developed. Engraved with an interconnected and perfusable leaf-vein micropattern, the membrane can guide human umbilical vein endothelial cells (HUVECs) to form vasculature in vitro. In particular, the "running track" upregulates the angiogenesis-related gene expression and promotes the HUVECs to differentiate into tip cells and stalk cells via tuning vascular endothelial growth factor receptor 2 signaling transduction. As a proof of concept, its revascularization capability using a rat calvarial defect model in vivo is evaluated. The in vivo results demonstrate that the leaf-vein engraved membrane accelerates the formation and maturation of vasculature, leading to a hierarchical blood vessel network. With the superior pro-vasculature property, it is believed that the leaf-vein engraved membrane is not only an ideal candidate for the reconstruction of calvarial vasculature but also a promising solution for more complicated vasculature reconstruction, such as muscle, skin, and heart.