ИСТИНА

Nanoparticles (NP) have strong potential for diagnostic and therapeutic applications in all industries, especially in medicine. Commonly it is intended to administer NP into human body by injecting them into the bloodstream. For the time being there is no sufficient evidence confirming that it will not negatively influence the blood components and circulation and therefore the patient’s health. In this respect it is vital to assess the interaction of NP with blood cells in in vitro conditions before conducting the in vivo experiments and clinical applications. The aim of this work is to evaluate the effect of different concentrations of titanium oxide NP on red blood cells (RBC) microrheologic properties. Blood samples were drawn from a healthy donor and were stabilised with EDTA to prevent blood clotting. After that they were incubated with different amounts of TiO2 NP (15-100 µg/ml). All experiments were performed within 2 hours after blood sampling. Two laser methods described in detail in were used in our experiments: laser diffractometry technique and laser aggregometry technique based on diffuse light scattering from whole blood samples. The essence of laser diffractometry is in obtaining the diffraction patterns from highly diluted suspensions of RBCs and evaluating their ability to deform (elongate) in shear flow characterized by the elongation index. With laser aggregometry, the RBC aggregation properties, in particular, the spontaneous aggregation rate and the hydrodynamic strength of the aggregates were measured. Based on the obtained results we can conclude that safe usage of TiO2 NP administered into the blood can be achieved at concentrations not exceeding 15 µg/ml, at which the NP effect is not or very slightly (within the measurement error of 10,8%) pronounced. After surpassing this concentration our results demonstrate a dramatic impairment of aggregation parameters. For example, the aggregation rate of RBC in whole blood sample incubated with Rutile TiO2 NP at the concentration of 15 µg/ml decreased by 21±7% compared to the control sample. No statistically significant differences in the deformability properties of RBCs were found at any used concentration of TiO2 NP.