The effect of carbon nanoparticles of various nature on the microviscosity of erythrocyte membranes in experimental animals

The microviscosity of erythrocyte membranes is directly related to their integrity, the violation of which in the presence of foreign objects manifests itself in a sharp increase in the microviscosity index, which certainly indicates the degree of cytotoxic effect of objects in contact with cells of a living organism. Using the spin probe method, a comparative study was made of the effect of a number of carbon nanoparticles on the microviscosity of rat erythrocyte membranes. It has been found that the presence of oxidized graphene (OG) in suspension of red blood cells practically does not affect the microviscosity index of membranes. In the presence of carbon nanotubes (CNTs) of various structures during prolonged (24 h) incubation with erythrocytes, an increase in the microviscosity of erythrocyte membranes is 1.5–2 times. Oxidized multi-walled nanotubes exert the greatest effect. Hydrophobic multi-walled CNTs have a smaller effect, and single-walled nanotubes are characterized by a slight effect on the membranes. Incubation of erythrocytes with carbon nanochorns (CNCh) leads to a significant increase in the microviscosity of erythrocyte membranes by 60 % and higher; after 1 h of incubation, the polarity of the surface of the lipid layer of the membranes increases stepwise, apparently due to the destruction of the membrane and the ingress of water molecules there, as well as the disorder of phospholipids. The introduction of detonation nanodiamond (DND) nanoparticles into a suspension of erythrocytes at a concentration of 25 μg/ml produced no noticeable change in the membrane microviscosity index. An increase in the concentration of DND in suspension of red blood cells to 50 and 75 μg/ml led to a decrease in the microviscosity of erythrocyte membranes (increase in fluidity of the membranes) by 20 and 28 %, respectively. Thus, among carbon nanoparticles, nanotubes and nanochorns can exhibit cytotoxicity, which is mainly due to their structure, size, and shape.