Krek JL, Šimundić M, Drab M, Pajnič M, Šuštar V, Štukelj R, Drobne D, Kralj-Iglič V
[ site ] Slovenian Veterinary Research, 2015

The effect of carbon black agglomerated nanomaterial on biophysical properties of canine red blood cell and platelet membranes that are reflected in changes of cell shape, was studied. Samples of canine blood diluted with citrated and phosphate buffered saline were incubated with carbon black nanomaterial and observed by scanning electron microscope and optical microscope. Interaction of agglomerated nanomaterial with erythrocyte membrane was observed. The relative abundance of different erythrocyte shape types (discocytes, echinocytes, spherically shaped erythrocytes) was determined on populations of cells, in suspensions with added carbon black nanomaterial and in control suspensions. Ensembles composed of representative images of cell populations were assessed by statistical methods. A two dimensional mathematical model of the erythrocyte shape was constructed to illustrate and explain erythrocyte swelling of intially discocytic/echinocytic shape to the final spherical shape, which preceeds membrane rupture. Micrometre-sized agglomerates were formed in the blood and interacted with erythrocyte membrane without evidently disturbing local membrane curvature or global cell shape. Incubation of blood with citrated and phosphate buffered saline caused a time dependent decrease of the number of intact erythrocytes in samples that was ascribed to a disintegration of erythrocyte membranes. The presence of carbon black nanomaterial in the samples suppressed this effect. Relative proportions of cell shape types remained largely unchanged within 24 hours of observation of the test and the control sample. The observed effects of carbon black nanomaterial can be described as originating from osmosis. Incubation of canine platelets with carbon black nanomaterial within 24 hours preserved the disc-like shape that is characteristic for resting platelets. It was concluded that carbon black nanomaterial interacts with membranes of blood cells but does not have a direct effect on the local or global membrane shape. However, large size of carbon black agglomerates, that can be formed in blood plasma could present mechanical obstacles in the cardiovascular system.