ИСТИНА

Iron (iii) oxide nanoparticles (Fe2O3) have been proposed for using in various biological and bio-medical applications. For example, the particles are promising for biomedical imaging and photodynamic therapy (PDT) of oncology diseases. Recently, the Fe2O3 nanoparticles with surface functionalization by porphyrins (Fe2O3-POR) were proposed as more efficient for PDT since they strongly absorb light, which is then converted to energy and heat in the illuminated areas. It is presumed that in order to reach the target these particles would be administered into blood. Although Fe2O3 nanoparticles are considered as biocompatible and non-toxic, so far there is little information on the interaction of the particles with major blood components. The aim of this work was to estimate the in vitro effect of Fe2O3 particles on blood microrheology properties. The ability of red blood cells (RBCs) to deform in shear flow was characterized by shear stress dependence of the deformability index. The ability to spontaneously aggregate in whole blood was characterized by the time of aggregates formation and aggregation amplitude (the number of aggregated RBC at rest in percents). The hydrodynamic strength of aggregates was assessed also. In this work, all measurements were performed by means of the laser diffractometry and aggregometry techniques by using the commercially available Rheoscan system (Rheomeditech, Korea). These techniques are convenient, fast and relatively simple for in vitro measuring the deformability and aggregation properties of RBC in blood samples. The essence of laser diffractometry is in obtaining and subsequent analysis of the obtained diffraction pattern from a highly diluted suspension of RBCs at rest and shear flow. Laser aggregometry technique allows to register the kinetics of the spontaneous aggregation (time dependence of light intensity forward scattered from a sample of whole blood at rest) and shear-induced disaggregation (shear stress dependence of light intensity backscattered from a sample of whole blood under shear flow) of RBCs for obtaining the characteristic time of aggregates formation (aggregation rate), as well as hydrodynamic strength of RBC aggregates.