title: Role of flow for the deposition of platelets.
abstract: Implants inside the cardiovascular system are subjected to blood flow. Platelet deposition usually takes place, eventually leading to thrombus formation. Tests must be performed in order to select a suitable biomaterial, but no generally accepted test method exists for biomaterials in contact with blood. At a first glance, the flow appears to play only a minor role in the complex interaction between platelets and biomaterials. However, experiments and models have indeed demonstrated the importance of flow. Flow is the mechanism by which platelets are transported to the site of deposition, enabling deposition and forming the shape of a growing thrombus. This interaction is investigated here by means of two experimental models. The first model generates the simplest shear flow, the plane Couette flow. It serves to quantify the role of the shear rate. The second model, the stagnation point flow model, features a more complex shear flow. This model is used to understand the influence of a changing flow field along the wall over which the platelets travel. The platelet deposition is observed using the two experimental models, and a numerical model is developed to reproduce and simulate the experimental results. In the numerical model, the movement of platelets is computed with a combination of convective and stochastic movements due to diffusion. The combined motion brings some platelets close to the wall. The deposition of the platelet at the wall is modeled by a stochastic model. Probability determines whether the individual platelet deposits or flows onwards. This probability is the product of three different probabilities, which are the properties of the platelet, the wall, and the flow. The results of the models are compared with the experimental results and are used to understand the experiments.
authors.affiliation: Charité - Universitätsmedizin Berlin, Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Labor für Biofluidmechanik Augustenburger Platz 1 Forum 4, 13353 Berlin, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Affeld
authors.affiliation: Charité - Universitätsmedizin Berlin, Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Labor für Biofluidmechanik Augustenburger Platz 1 Forum 4, 13353 Berlin, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Schaller
authors.affiliation: Charité - Universitätsmedizin Berlin, Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Labor für Biofluidmechanik Augustenburger Platz 1 Forum 4, 13353 Berlin, Germany.
authors.forename: Thies
authors.initials: T
authors.lastname: Wölken
authors.affiliation: DHZB, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Krabatsch
authors.affiliation: Charité - Universitätsmedizin Berlin, Institut für Laboratoriumsmedizin, Klinische Chemie und Pathobiochemie, Labor für Biofluidmechanik Augustenburger Platz 1 Forum 4, 13353 Berlin, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kertzscher
mesh_terms: D001792:Blood Platelets / Q000502:physiology*; D002448:Cell Adhesion; D018056:Hemorheology; D013927:Thrombosis