Endothelial cells patterning by ultrasound standing wave for micro-vascular network generation in 3D engineered tissue

Abstract

The development of functional and perfusable micro-vascular networks stands as a crucial role in the regeneration of tissues, particularly for the creation of large-scale, three-dimensional tissues. In recent years, the fabrication of micro- vascular networks has been a complicated multitask involving several different factors, such as time-consuming processes, cell survival, micro-diameter vasculature, and strict alignment requirements. In response to these challenges, an innovative approach that integrates multi-material extrusion with ultrasound standing wave forces to create a network structure of human umbilical vein endothelial cells within a composite matrix of calcium alginate and decellularized extracellular matrix was proposed. Through the improvement of cell-cell adhesion, the angiogenesis process, and perfusion tests using microparticles, FITC-dextran, and whole mouse blood, the functioning of the matured microvasculature networks was proven. Furthermore, animal experiments were conducted to assess the implantability and integration of the pre-formed vascular networks. The results showed that the pre-existing blood vessels of the host sprout towards the preformed vessels of the scaffold over time, and the micro-vessels inside the implanted scaffold matured from empty tubular structures to functional blood-carrying micro-vessels within two weeks. This approach was also employed for generating artificial liver scaffolds, which are the fundamental building blocks of liver tissue. Liver function and vascularization were both improved by the co-cultivation of two cell types. These findings highlight the potential of the proposed technique for the fabrication of large and complex tissue constructs with functional micro- vascular networks.