In Vitro Perfused Human Capillary Networks

Abstract

Replicating in vitro the complex in vivo tissue microenvironment has the potential to transform our approach to medicine and also our understanding of biology. In order to accurately model the 3D arrangement and interaction of cells and extracellular matrix, new microphysiological systems must include a vascular supply. The vasculature not only provides the necessary convective transport of oxygen, nutrients, and waste in 3D culture, but also couples and integrates the responses of organ systems. Here we combine tissue engineering and microfluidic technology to create an in vitro 3D metabolically active stroma (*1 mm 3 ) that, for the first time, contains a perfused, living, dynamic, interconnected human capillary network. The range of flow rate (mm/s) and shear rate (s -1 ) within the network was 0-4000 and 0-1000, respectively, and thus included the normal physiological range. Infusion of FITC dextran demonstrated microvessels (15-50 mm) to be largely impermeable to 70 kDa. Our high-throughput biology-directed platform has the potential to impact a broad range of fields that intersect with the microcirculation, including tumor metastasis, drug discovery, vascular disease, and environmental chemical toxicity.

Human 3D vascularized organotypic microfluidic assays to study breast cancer cell extravasation

“…However, in that system, the vascular wall was represented by an endothelial monolayer on the side of a central gel region. With the recent attempts in inducing vasculogenesis (27,28), vascular networks have been generated inside the gel region either by coculture with human lung fibroblasts in separate gel regions or by interstitial flow. Despite the tremendous advances in modeling angiogenesis and vasculogenesis, these models have not previously been used to study metastasis organ specificity and investigate the role of human organ-specific microenvironments.…”

Principles of the Kenzan Method for Robotic Cell Spheroid-Based Three-Dimensional Bioprinting

“…When this was attempted within the confines of the current technology, often rudimentary 'channels' were implemented 6,20 . Some success had the 'organs-on-chip' microfluidic devices 26 , but their scaling-up and integration into functional bioprinted constructs need more efforts to succeed. The same issues apply to the innervation of the bioprinted constructs 27 .…”

Digital biomanufacturing supporting vascularization in 3D bioprinting

“…Significantly, the smaller elements of the vasculature, the microvasculature, pose unique challenges in a biomanufacturing process. A stereotypical microvessel is comprised of multiple cell types (endothelial cells, smooth muscle/contractile cells, perivascular mesenchymal cells, and immune cells) assembled in a very structured way critical to the microvessel's function [26] . In addition, many individual microvessels are needed (perhaps thousands in some applications) to assemble and effective perfusion circuit.…”

“…Here, the channels serve as a perfusion source which, when contiguously connected to a neighboring microvasculature, help to drive the formation of a microcirculation. Often, vascular cells are used to form the initial, native microvasculature to be connected to the channel system [37] . In contrast, Advanced Solutions Life Sciences is using isolated microvessels to form the native microcirculation [36] .…”