Dendrimer-induced leukocyte procoagulant activity depends on particle size and surface charge

Aims: Thrombogenicity associated with the induction of leukocyte procoagulant activity (PCA) is a common complication in sepsis and cancer. Since nanoparticles are increasingly used for drug delivery, their interaction with coagulation systems is an important part of the safety assessment. The purpose of this study was to investigate the effects of nanoparticle physicochemical properties on leukocyte PCA, and to get insight into the mechanism of PCA induction. Materials & Methods: A total of 12 formulations of polyamidoamine (PAMAM) dendrimers, varying in size and surface charge, were studied in vitro using recalcification time assay. Results: Irrespective of their size, anionic and neutral dendrimers did not induce leukocyte PCA in vitro. Cationic particles induced PCA in a size- and charge-dependent manner. The mechanism of PCA induction was similar to that of doxorubicin. Cationic dendrimers were also found to exacerbate endotoxin-induced PCA. Conclusion: PAMAM dendrimer-induced leukocyte PCA depends on particle size, charge and density of surface groups.