Endothelialized microrods for minimally invasive in situ neovascularization

Despite the significant advancements in fabricating various scaffolding systems over the past decades, generation of functional tissues towards vascularization remains challenging for the currently available biofabrication approaches. On the other hand, the applicability of traditional surgical transplantation of vascularized tissue constructs is sometimes limited due to the sophisticated surgical procedures, which are invasive, leading to increased risks of scar formation and infection. Considering these facts, we present an innovative platform, the angiogenic microrods composed of sodium alginate/gelatin harboring proliferating endothelial cells using a specially designed double T-junction microfluidic device with an expansion chamber, for achieving minimally invasive neovascularization in situ. Such vessel-like microarchitectures could be derived through controlled penetration of the crosslinker genepin for the gelatin phase, ensuing differential degrees in crosslinking of peripheral and central portions of the microstructures, thus resulting in the formation of vascular lumen-like hollow cavities via endothelial cell migration and proliferation during culture in vitro. Furthermore, in vivo performance of the microrods was explored. We believe that the development of these modular microrods for minimally invasive delivery is of great interest and offers a convenient approach for vascularization in situ.