Standardized methods to quantify thrombogenicity of blood‐contacting materials via thromboelastography

Abstract

Blood coagulation is the most significant complication of vascular biomaterials. A straightforward, sensitive, and standard measure of the compatibility of these materials with whole blood (hemocompatibility) is necessary to avoid coagulation. Current techniques used quantify only individual clotting components and are poor predictors of coagulation. The thromboelastograph (TEG) provides a measure of overall clot formation from whole blood. Although TEG is very common in clinical settings, its application to biomaterials is limited partly due to difficulty in sample preparation. In this protocol, whole blood samples are incubated with (1) biomaterials (tube with clamped ends) and (2) endothelial cells cultured on biomaterial surfaces (12-well plate) under controlled shearing conditions (10 rpm on rocker, at 37°C), and then the blood is transferred to the TEG to measure clot formation. TEG clearly discriminates among the R-times (time until initial clot formation) of expanded poly(tetrafluoroethylene), poly(urethane), and Tygon tubing. Marked differences in R-time are also seen when endothelial cells are cultured on various extracellular matrix proteins and proteoglycans. Thus, R-time provides a robust metric of overall thrombogenicity of biomaterials, and these procedures provide a standardized method for TEG to facilitate direct comparison among candidate biomaterials undergoing in-vitro testing.

Thromboelastometric and platelet responses to silk biomaterials

“…VETs are also increasingly used for experimental research151618, but its implication in assessing the thrombogenicity of biomaterials is at its neo-natal stage19 However, the use of VETs in biomaterial science is gaining rapid popularity due to real-time comprehensive overview of clotting kinetics, minimal artefacts in coagulation activation, ease in sample preparation and relatively small sample volume19. The small sample volume (300 μl) for one measurement allows using the blood of a single donor for a wide range of biomaterials, consequently eliminating the variation in blood sample from different donors and providing more reliable information of haemocompatibility of the biomaterials.…”

“…TEG is already in use to evaluate the thrombogenicity (i.e. the ability of a material to induce the formation of clot or thrombus when coming in contact with blood) of insoluble biomaterials19. In line with these TEG experiments and for the purpose of the present study, the use of the NATEM-assay of ROTEM1518, which is a re-calcified, non-activated test of citrated blood, is chosen to investigate the haemocompatibility of nonmulberry silk biomaterials.…”

Gelatin Effects on the Physicochemical and Hemocompatible Properties of Gelatin/PAAm/Laponite Nanocomposite Hydrogels

“…8 It is wellknown that protein adsorption is the first step involved in the initiation of thrombosis on biomaterial surfaces, and thus decreasing BSA adsorption clearly implies a better antithrombotic effect, which can further be confirmed by higher values of blood-clotting index and lower degrees of hemolysis. 48 Figure 9 shows that the amount of BSA adsorbed decreased with increasing gelatin content in the NC gels. This is because gelatin is a hydrophilic and biocompatible polymer in nature, which confers an increased hydrophilicity and wettability on the NC gels and a resulting BSA adsorption resistance.…”

Strategies and Processes to Decellularize and Recellularize Hearts to Generate Functional Organs and Reduce the Risk of Thrombosis

“…They demonstrated that flow of the blood in a circuit can also activate platelets. Shankarraman et al 116 have utilized thromboelastography to quantify thrombogenicity of blood-contacting surfaces. In vitro blood flow models have been used to assess thrombosis and thromboembolism associated with artificial hearts and vascular implants such as stents.…”