Biogenic selenium nanoparticles as dual-action antithrombotic agents: Targeting platelet activation cascades and thrombus formation.

Platelet hyperactivation is a central driver of thrombotic disorders, yet current antithrombotic therapies remain constrained by bleeding risk and other limitations. Here, we investigated protein-capped selenium nanoparticles (SeNPs, ~40 nm) as a potential antithrombotic nanoplatform. SeNPs were synthesized and characterized using spectroscopic and microscopic approaches, demonstrating spherical morphology and protein-associated stabilization. Hemocompatibility and metabolic viability studies showed no hemolysis and no significant reduction in viability at concentrations up to 100 μg/ml under the tested conditions. SeNPs inhibited platelet aggregation and attenuated thrombin-induced cytoskeletal remodeling, integrin αIIbβ3 activation, P-selectin externalization and intracellular Ca2⁺ elevation. Mechanistically, SeNP treatment reduced global tyrosine phosphorylation and Akt phosphorylation, together with decreased mitochondrial superoxide detected by MitoSOX, consistent with attenuation of platelet activation-associated signaling and altered mitochondrial redox status. Ex vivo thromboelastography demonstrated delayed clot initiation and reduced clot strength, while fibrin polymerization assays showed prolonged lag time and reduced polymerization rate, indicating platelet-independent modulation of fibrin formation. In vivo, intravenous SeNP administration prolonged tail bleeding time but significantly attenuated FeCl₃-induced carotid artery thrombosis and preserved arterial blood flow. These findings demonstrate that biogenic SeNPs exert complementary effects on platelet activation and fibrin-dependent coagulation processes, while also highlighting the need to define an appropriate therapeutic window between antithrombotic efficacy and bleeding liability.