INVESTIGATION OF ANTITHROMBOGENICITY OF MAGNETITE

Abstract

In examining the antithrombogenicity of magnetite, we investigated the interaction between platelets and magnetite, Methods 1) The coagulation onset times (COTS) of platelet-rich plasma (PRP) anti platelet-free plasma (PFP) in glass tubes coated with magnetite were determined with a rheometer, which yields COTs of 20 min and more for materials considered antithrombogenic. 2) Platelet activation was investigated by scanning electron microscopy (SEM) 20 min after PRP, in the absence of calcium, was plated on magnetite and segmented polyurethane (SPU) sheets (N = 4). Results 1) The COTs of PRP in 11 magnetite and plain glass tubes were 27.1 ± 8.9 and 2.3 ± 0.6 min, respectively (p < 0.0001). 2) The COTS of PFP in 4 glass tubes were 5.5 ± 1.0 min, hut the PFP experiment in 4 magnetite tubes was stopped at 140 min because PFP did not coagulate at all. 3) SEM study showed that hardly any platelets adhered to the magnetite and SPU sheets, covering only 0.55 ± 0.14% and 0.60 ± 0.30%, respectively, of the entire surface area (NS). Approximately 60 ± 70% of the adhering platelets protruded pseudo-pods. Conclusions Our findings indicate that magnetite does not activate the clotting factors of the contact phase at all, but may activate platelets to a very small extent. In conclusion, these findings indicate that magnetite has excellent antithrombogenicity.