Effect of engineered TiO2 and ZnO nanoparticles on erythrocytes, platelet-rich plasma and giant unilamelar phospholipid vesicles

Washed erythrocytes, platelet-rich plasma and suspensions of giant unilamelar phospholipid vesicles were incubated with samples of EPs. These samples were observed by different microscopic techniques. We found that TiO2 and ZnO EPs adhered to the membrane of washed human and canine erythrocytes. TiO2 and ZnO EPs induced coalescence of human erythrocytes. Addition of TiO2 and ZnO EPs to platelet-rich plasma caused activation of human platelets after 24 hours and 3 hours, respectively, while in canine erythrocytes, activation of platelets due to ZnO EPs occurred already after 1 hour. To assess the effect of EPs on a representative sample of giant unilamelar phospholipid vesicles, analysis of the recorded populations was improved by applying the principles of statistical physics. TiO2 EPs did not induce any notable effect on giant unilamelar phospholipid vesicles within 50 minutes of incubation, while ZnO EPs induced a decrease in the number of giant unilamelar phospholipid vesicles that was statistically significant (p？<？0,001) already after 20 minutes of incubation.These results indicate that TiO2 and ZnO EPs cause erythrocyte aggregation and could be potentially prothrombogenic, while ZnO could also cause membrane rupture.With increasing industrial production of engineered nano and microparticles, questions have been raised on their effects on humans and animals [1-4]. Engineered particles enter the body by inhalation [5], ingestion [6] and by corrosion of implants [7,8], while possibilities of injection of engineered nanoparticles for imaging and therapeutic purposes are being explored [9,10]. In order to protect ourselves from their (potentially) harmful effects and use them beneficially, their interactions with living beings should be well studied and the underlying biochemical and biophysical mechanisms which take place on the mesoscopic and nanoscopic level [11-17] should be better understood.It was observed that engineered nanoparticles can cross the plasma me