Rapid tissue perfusion using sacrificial percolation of anisotropic networks

Tissue engineering has long sought to rapidly generate perfusable vascularized tissues with vessel sizes spanning those seen in humans. Current techniques such as biological 3D printing (top-down) and cellular self-assembly (bottom-up) are resource intensive and have not overcome the inherent tradeoff between vessel resolution and assembly time, limiting their utility and scalability for engineering tissues. We present a flexible and scalable technique termed SPAN (sacrificial percolation of anisotropic networks), where a network of perfusable channels is created throughout a tissue in minutes, irrespective of its size. Conduits with length scales spanning arterioles to capillaries are generated using pipettable alginate fibers that interconnect above a percolation density threshold and are then degraded within constructs of arbitrary size and shape. SPAN is readily used within common tissue engineering processes, can be used to generate endothelial cell-lined vasculature in a multi-cell type construct, and paves the way for rapid assembly of perfusable tissues. [Display omitted] •Scalable strategy that enables rapid perfusion of large, engineered tissues•Sacrificial anisotropic elements percolated to form a perfusion network•Pipettable process readily applicable to diverse manufacturing processes•Cell mixtures self-assemble into vascularized tissues Despite 3 decades of significant progress in tissue engineering, a persistent challenge remains to generate rapidly perfusable vascular networks to support thick engineered tissues. We report a facile and scalable approach to rapidly assemble networks of hollow channels within cell-laden hydrogels and demonstrate its utility in generating high cell density engineered constructs. Plastic dishes and bulk gel formats have long served as universal standards for 2D and 3D cell culture, and yet, despite being highly sought after, there is no such standard format for perfused cell culture in 3D gels. The fabrication strategy reported here is compatible with a wide range of established tissue engineering methods and cell culture in general. As such, the SPAN platform could be readily adopted as a standard approach to generating perfusable cultures of 3D tissues for both research and translational communities. Tissue engineering has faced a persistent challenge to generate rapidly perfused microvascular networks at scale to support metabolic demands of resident cells. We overcome this challenge by developing a simple a