Research Article The Effect of Highly Hydroxylated Fullerenol C 60 (OH) 36 on Human Erythrocyte Membrane Organization Jacek Grebowski and Anita Krokosz Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 141/143 Pomorska Street, 90-236 Lodz, Poland Correspondence should be addressed to Anita Krokosz; krokosz@biol.uni.lodz.pl Received 31 October 2014; Revised 24 February 2015; Accepted 25 February 2015 Academic Editor: Luciano Bachmann Copyright © 2015 J. Grebowski and A. Krokosz. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. he mechanism of the interaction of highly hydroxylated fullerenol C 60 (OH) 36 with erythrocyte membranes was studied by electron spin resonance spectroscopy (ESR) of stearic acid derivatives labeled with a nitroxyl radical at C-12 or C-16 and with a nitroxyl derivative of maleimide covalently attached to sulhydryl groups of membrane proteins. A signiicant increase in membrane luidity in the hydrophobic region of the lipid bilayer was observed for 12-doxylstearic acid at fullerenol concentrations of 100mg/L or 150 mg/L, while for 16-doxylstearic acid signiicant increase in luidity was only observed at 150 mg/L. Fullerenol at 100 mg/L or 150 mg/L caused conformational changes in membrane proteins, expressed as an increase in the h  /h  parameter, when fullerenol was added before the maleimide spin label (MSL) to the membrane suspension. he increase of the h  /h  parameter may be caused by changes in lipid-protein or protein-protein interactions which increase the mobility of the MSL label and as a result increase the membrane luidity. Incubation of the membranes with the MSL before the addition of fullerenol blocked the available membrane protein –SH groups and minimized the interaction of fullerenol with them. his conirms that fullerenol interacts with erythrocyte membrane proteins via available protein –SH groups. 1. Introduction Fullerenes and their derivatives can penetrate the cells of living organisms. However, the mechanism of penetration into cells and the possible efects on the plasma membrane are still unclear [1]. A water soluble derivative of fullerene C 60 (CO 2 H) 2 has been shown to penetrate the cell membrane and immunolu- orescence microscopy conirmed the presence of the fullerene derivative inside the cell. Diferential centrifugation showed the presence of radiolabeled nanoparticles in the cytoplasm, plasma membrane, mitochondria, and microsomes [2]. he probable mechanism of penetration into the cell is related to the structural similarity of the carbon cage of fullerene derivatives to clathrin. Clathrin is a component of the coat of endocytic vesicles [2]. Additionally, nanoparticles of fullerenol C 60 (OH) 24 can be taken up by cells via endocytosis resulting in their intracellular localization [3]. Fullerenol can interact with polar groups of phosphatidyl- glycerol via hydrogen bonds. his leads to disruption of the structural organization of the lipid bilayer which, in turn, causes a change in membrane luidity [4]. Moreover, the hydrophilic molecules of C 60 (OH)  (Figure 1) can adsorb to membrane phospholipid heads and may also interact with membrane proteins, afecting their structure and function [1]. Changes in the activities of ATPases caused by fullerenol could be the result of direct and/or indirect (via membrane luidity changes) interaction with the enzymes. he amount of fullerenol associated with the membranes was proportional to its concentration in the incubation medium and inversely proportional to the concentration of the membrane proteins. his is probably connected to the fact that at higher concentrations of membrane proteins, the increased viscosity of the suspension can afect the difusion of fullerenol inside the membrane [5]. Our previous work has shown that fullerenol C 60 (OH) 36 , by associating with band 3 protein, not only prevents its degradation, but can also inluence the binding sites of spectrin; bands 4.1 and 4.2 proteins; and actin, Hindawi Publishing Corporation Journal of Spectroscopy Volume 2015, Article ID 825914, 6 pages http://dx.doi.org/10.1155/2015/825914