Red Blood Cells Morphology Depending on Potential of Optically Transparent Electrode
Authors: Khubutiya Mogely Sh. , Evseev Anatoly K. , Mirzaeian Mojtaba , Borovkova Natalia V , Goroncharovskaya Irina V , Goldin Mark M 
Published: February 2020

It is known that normal erythrocytes (discocytes) may undergo transformation in degenerative forms (e.g. echinocytes or stomatocytes) due to changes in temperature, electrolyte concentration, pH, and the addition of certain agents [1]. It is also important that the morphology of red blood cells depends on transmembrane potential [2].
On the other hand, direct contact with the charged solid surfaces, such as the wall of the vessel or foreign materials (such as metal stents or carbon hemosorbents during the detoxification of the body) can lead to the morphological changes of red blood cells.
For the first time the influence of the surface potential of the solid phase to the behavior of blood cells have been proposed in the investigation of thrombus formation. This hypothesis was confirmed by the data of [3], it was found a direct correlation between the decrease of blood cells and the potential magnitude of activated carbon for process of hemosorption.
The goal of this work was to study the effect of potential of an optically transparent ITO electrode on the morphology of red blood cells in real time.
The three-electrode cell was used, the bottom of it was optically transparent ITO working electrode (Sigma-Aldrich, USA), area of the electrode was 28.3 mm2, auxiliary electrode was a carbon black electrode, a reference electrode was silver chloride electrode. Potentiostat IPC Pro L (ZAO «Kronas», Russia) was used in the potentiodynamic mode, the scanning rate was 10 mV/s. The suspension of erythrocytes was prepared by diluting volunteer red blood cells in isotonic saline (0.15 M NaCl), concentration of erythrocyte was 8∙109 cells/L. The morphology of erythrocytes was examined by an inverted light microscope Eclipse TS100 (Nikon, Japan), the lens CFI Achromat LWD 40x/0.55 (Nikon, Japan) in real time depending on the electrode potential.
It was found that the morphological forms of red blood cells have been changed depending on ITO electrode potential. It turned out that, initial normal erythrocytes (discocytes) transformed into various degenerative forms (echinocytes, spherocytes, stomatocytes) depending on value of ITO electrode potential (Fig. 1). It is important that each of morphological form formed and existed in certain ranges of potentials. For example at potentials around - 250 mV discocytes turned into echinocytes, than at more negative potential values echinocytes turned into spherocytes. The mentioned cathodic morphological changes of erythrocytes occurred in the cathode potential region from -250 mV to -400 mV.
The anodic transformation of red blood cells was not obtained to the potential of about 600 mV. A very important effect was found in a potential range 600 mV to 1200 mV. At the region transformation echinocytes in discocytes occurred. In the positive potential more 1200 mV the transformation discocytes into stomatocytes was observed.
Finally, it was found that the potential ranges more negative than -400 mV and more positive than 1300 correspond to cell destruction. It is very important that the transformation discocytes into degenerative forms are usually reversible.
The most likely reason of obtained transformations of morphological forms of red blood cells in the cell/electrode system at different electrode potentials may be the processes of electroreduction or electrooxidation of functional groups on the surface of erythrocyte membranes. Undoubtedly electron transfer cell from electrode to membrane or opposite direction is due to sign and ratio of charge density of cell membrane and electrode. It was proposed the breakdown of the membrane at potentials more negative than -400 mV and a positive 1300 mV lead to destruction of cell
Thus, the observed in reversible and irreversible changes in morphological forms of erythrocytes and cell destruction for different values of electrode potential was obtained. These effects can be used to develop diagnostic methods of erythrocytes state and perhaps to improve their quality during prolonged storage.
1. Tachev K.D., Danov K.D., Kralchevsky P.A. Colloids Surf B Biointerfaces 2004 34:123–140.
2. Glaser R. Stud Biophys 1978 74: 57-58.
3. Goldin Mark M., Volkov A.G., Goldfarb Yu.S., Goldin Mikhail M. J Electrochem Soc 2006 153(8): J91-J99.
Fig. 1. Erythrocyte morphology depending on electrode potential. The arrows identified three initial echinocytes and their morphological change depending on electrode potential.

Figure 1