Abstract

High-Throughput Microfluidic Platform for Drug Screening of Vascularized 3D Tissues

Sara Previdi, Scientist, University Medical Center Leiden

3D tissues such as spheroids or organoids derived from human pluripotent stem cells (PSCs) represent a new type of three-dimensional in vitro model for understanding organ development, disease mechanism and drug testing. Despite the success in generating 3D cultures resembling different tissue types (brain, heart, intestine, liver, lung and kidney), these mini-organs show limited growth potential and an immature phenotype due to lack of vascularization. Several groups have attempted to improve vascularization of organoids by transplanting them into a host (i.e. mouse, chick). However, the low predictivity of animal models, boost the development of in vitro alternative strategies. In this regard, microfluidic techniques are increasingly recognized as important toolbox able to add physiologically relevant cues to traditional cell culture models. We recently described the use of the OrganoPlate® for generating 3D perusable angiogenic vessels. Here, we present the use of a high-throughput 'grafting' platform which allows vessels co-culture with 3D tissue aggregates and tissue vascularization. One unit of the Mimetas OrganoPlate® Graft is made of two microfluidic channels in which endothelial cells can be patterned against ECM through the use of the PhaseGuide® technology. Gradient of pro-angiogenic factors (VEGF, PMA, S1P and FGF-b) allows the formation of a perfused vascular bed on top of which tissue fragments (i.e. organoids or spheroids) can be added to enable vascularization. Tissue dependent vessels remodeling and stabilization can be monitored overtime by real time imaging and barrier integrity. When liver spheroids are used, vessels became leaktight to dextran 150 kDa after 14 days of co-culture. Moreover, expression of CD31+ cells around and in within the spheroids proves that endothelial cells migration and tissue envelopment occurred during co-culture. The high number of units (up to 64 chips in 384 well format) enables functionality studies and compound screening in a robust and automated way. We propose the use of the OrganoPlate® Graft as a vessels grafting platform for multiple 3D tissues allowing drug screening and disease modeling in a more physiological environment.