A Dissipative Particle Dynamics Analysis to Study the Kinetics of Platelets in Microscale

Abstract

Platelet-mediated thrombosis is an extremely complex process. We have recently developed a computational analysis to study the motion, aggregation and adhesion of platelets in microscale. Unlike the traditional continuum-based approach, we employ a dissipative particle dynamics (DPD) approach that recently emerged from molecular dynamics (MD). Briefly, in our analysis, the mechanics of each individual platelet is modeled by the behavior of a mesoscale DPD particle driven by conservative, viscous and random interaction forces. Additionally, activated platelets exhibit attractive forces, modeled with springs attached to its surface. The springs can bind either to another platelet or to a vessel wall. The values of the effective spring constant characterize the bond stiffness of the adhesion interaction. To test this model, we simulated the platelet deposition in a perfusion chamber performed by Hubbell and McIntire (Rev. Sci. Instrum. 57(5):892–897, 1986). They measured platelet accumulation on a collagen wall after 120s from human blood under steady conditions with wall shear rates of 1500 s-1 and 500 s-1 and an entrance point platelet concentration of 2.0×108 ml-1. By fitting the simulations to the experiments, the effective platelet adhesion spring constant was determined to be 50N/m, which is considered to be within a reasonable range. We conclude that our new DPD analysis provides the capability of simulating the time-dependent adhesion of platelets, with an insight into the events on the micro time- and length- scale, such as kinetics of platelet activation and binding. Supported by NIH HL054885, and HL075426.