Use of microfluidics to assess the platelet-based control of coagulation

Abstract

This paper provides an overview of the various types of microfluidic devices that are employed to study the complex processes of platelet activation and blood coagulation in whole blood under flow conditions. We elaborate on how these devices are used to detect impaired platelet-dependent fibrin formation in blood from mice or patients with specific bleeding disorders. We provide a practical guide on how to assess formation of a platelet-fibrin thrombus under flow, using equipment that is present in most laboratories. In addition, we describe current insights on how blood flow and shear rate alter the location of platelet populations, von Willebrand factor, coagulation factors, and fibrin in a growing thrombus. Finally, we discuss possibilities and limitations for the clinical use of microfluidic devices to evaluate a hemostatic or prothrombotic tendency in patient blood samples.

In vitro studies show synergistic effects of a procoagulant bispecific antibody and bypassing agents

“…The T‐TAS is a microchip‐based flow‐chamber system that measures thrombus formation under physiological blood flow conditions , and was used to confirm the effects of the aPCC–SIA and rFVIIa–SIA combinations. Shear rates of 600 s −1 and 240 s −1 on collagen/TF‐coated AR‐chips were used to represent average‐sized arteries and veins, respectively .…”

“…blood flow conditions [21], and was used to confirm the effects of the aPCC-SIA and rFVIIa-SIA combinations. Shear rates of 600 s À1 and 240 s À1 on collagen/TF-coated AR-chips were used to represent average-sized arteries and veins, respectively [22][23][24]. The time of onset of thrombus formation (T10 kPa) in WB at a shear rate of 600 s À1 was 6.3 AE 1.0 min.…”

Imaging Platelet Processes and Function—Current and Emerging Approaches for Imaging in vitro and in vivo

“…A syringe pump either pulls or pushes antibody-or fluorescently labeled blood, PRP or washed platelets in the presence of anticoagulant (generally trisodium citrate and PPACK), through the channel at constant shear rates which are determined by the velocity of the flow and viscosity values that are appropriate for the sample being evaluated. If the contribution of coagulation to the hemostatic process is to be assessed, then the sample must be carefully recalcified to overcome the anticoagulant (105,106). The whole process is captured using a high-resolution objective lens with a highspeed photodetector or high-sensitivity camera (usually confocal or widefield/fluorescence).…”

In vitro flow based systems to study platelet function and thrombus formation: Recommendations for standardization: Communication from the SSC on Biorheology of the ISTH

“…Blood flow assays also shaped our thinking around additional functions of key platelet receptors that may have been overlooked in classical assays, most notably glycoprotein (GP)Ib‐IX‐V and integrin αIIbβ3 proposed to act as mechanoreceptors . Finally, blood flow assays have the potential to: (a) screen for hereditary or acquired platelet‐related pathologies, (b) assess the effectiveness of novel anti‐platelet therapies, and (c) evaluate the importance of the coagulation cascade in hemostasis and thrombosis …”

“…5,6 Finally, blood flow assays have the potential to: (a) screen for hereditary or acquired platelet-related pathologies, (b) assess the effectiveness of novel anti-platelet therapies, and (c) evaluate the importance of the coagulation cascade in hemostasis and thrombosis. [7][8][9][10] The so named "in vitro thrombosis model" is a frequently used assay to study the formation of 3D aggregates under flow. 11 It involves perfusing anticoagulated whole blood over fibrillar collagen in a flow geometry of rectangular cross-section, such as glass microcapillaries or parallel-plate flow chambers.…”