A comprehensive toolkit for manipulation and analysis of sprouting capillary networks based on magnetic ordering of multiple EC-coated microcarriers and their use in tissue modelling and drug testing

: Despite significant developments in endothelial-cell (EC) manipulation techniques, an in vitro model of a functional microvasculature with controlled local interconnectivity (<1 mm length scale) under well-defined global architecture (∼1 cm length scale) is still lacking. Here, we report the generation of such controlled multi-scale vascular networks via manipulation of tens of sprouting EC microcarriers. We exploit magnetic patterning to assemble superparamagnetic microbeads coated with human umbilical vein endothelial cells (HUVECs) into ordered arrays and establish effective growth rules governing the directionality of sprouting and the development of interconnections between the neighboring beads depending on the applied bead-bead spacing. The microcarrier-based approach offers a range of advantages over conventional EC-manipulation techniques including: (i) expedited sprouting, (ii) spatial control over the interconnections, (iii) reduction in cell consumption by even >100×, and (iv) a native high-throughput format. We co-develop a multiparametric morphometric analysis tool and demonstrate high-content assessment of drug-induced vascular remodeling in 3D tumor microenvironments. Overall, we propose a uniquely precise and standardized vascular tissue-engineering and imaging toolkit with applications, e.g., in angiogenesis/anastomosis research as well as high-throughput drug testing including personalized therapies.