ИСТИНА

Introduction We explore the potentialities of various light scattering modalities and laser tweezers techniques to measure the parameters of red blood cells (RBCs) related to their intrinsic microrheologic properties, deformability and aggregation, determining the microcirculation of blood in conditions of norm and pathologic alterations and, also, at incubation with nanoparticles applied for diagnostic or therapeutic purposes. Materials and Methods We performed serial measurements of scattering phase functions of single cells trapped with single and/or double channel laser tweezers, low-angle light scattering from diluted suspensions of RBCs in Couette shear flow, and diffuse backscattering from whole blood samples. We also conducted experiments with single RBCs and RBC aggregates suspended in authologous plasma and/or solutions of various macromolecules manipulating the cells with laser tweezers and measuring the interaction forces. All measurements were conducted in vitro at room temperature with blood samples freshly drawn from human individuals (healthy ones and suffering various diseases) and laboratory animals - white rats (healthy controls and those with experimentally induces pathologies: brain ischemia, diabetes, hypertension). Incubation with nanoparticles was performed in vitro or, in case of rats, in vivo. Results We demonstrate that the measured elastic light scattering distributions reveal changes in the RBC’s orientation and shape, the latter being related with their ability to deform and to reversibly aggregate. Microrheologic properties of RBCs depend on the cells’ age, time of storage, environment, pathologic alterations, and different external factors (like incubation with nanoparticles). In particular, we studied the effect of pathologies and certain drugs (e.g. semax) as well as of nanodiamonds and fullerens on RBC deformability and aggregation parameters. As for the latter we characterized this property with characteristic times of linear and 3D aggregates formation, hydrodynamic strength of the aggregates, force of interaction of individual cells in the process of aggregation. The obtained results were related to the particular conditions characteristic of the donors (human individuals and animals), sample preparation protocols and the measurement modalities. Conclusion Though the techniques that we used are adequate for studying the microrheologic properties of RBCs from basic science to clinical application perspectives, their further development may raise the efficiency of the measurements and informativity of the obtained data. We propose the directions of further research in this relation.