01682nas a2200229   4500000000100000008004100001260001500042653001300057653002100070653001500091653001800106653002100124100001900145700002100164700001800185245009200203856005000295300001200345490000700357520107400364022001401438       2023                            d  c2023-12-3110aBleeding10aendothelial cell10ahemostasis10amicrofluidics10avessel-on-a-chip1 aYumiko Sakurai1 aElaissa T. Hardy1 aWilbur A. Lam00aHemostasis-on-a-chip / incorporating the endothelium in microfluidic models of bleeding  uhttps://doi.org/10.1080/09537104.2023.2185453  a21854530 v343 aCurrently, point-of-care assays for human platelet function and coagulation are used to assess bleeding risks and drug testing, but they lack intact endothelium, a critical component of the human vascular system. Within these assays, the assessment of bleeding risk is typically indicated by the lack of or reduced platelet function and coagulation without true evaluation of hemostasis. Hemostasis is defined as the cessation of bleeding. Additionally, animal models of hemostasis also, by definition, lack human endothelium, which may limit their clinical relevance. This review discusses the current state-of-the-art of hemostasis-on-a-chip, specifically, human cell-based microfluidic models that incorporate endothelial cells, which function as physiologically relevant in vitro models of bleeding. These assays recapitulate the entire process of vascular injury, bleeding, and hemostasis, and provide real-time, direct observation, thereby serving as research-enabling tools that enhance our understanding of hemostasis and also as novel drug discovery platforms.  a0953-7104