Water-soluble modifications of fullerene C60 easy penetrate through cellular membranes

I. Andreeva, A. Petrukhinab, A. Garmanovab, V. Romanovac, P. Troshind, O. Troshinad, L. DuBuskee, and S. Andreevb

aTimiryazev Institute of Plant Physiology, 127276 Moscow, Russia

NRC Institute of Immunology, 115478 Moscow, Russia

cNesmeyanov Institute of Organoelement Compounds, 119991 Moscow, Russia

Institute of Problems of Chemical Physics, 142432 Chernogolovka, Russia

eImmunology Research Institute of New England, Fitchburg, MA, USA

Fullerene C60 and its derivatives (FDs) exert substantial biological activity in a variety of cells and tissues However, mechanism of interaction of FDs with the cellular membranes are poorly understood, and the reports available reflect largely visual observations or their effects on artificial membranes.

In this work, a penetration dynamics of fullerene C60 in hydrated molecular colloidal form (FMC) and various C60 water-soluble derivatives (FDs) through membranes of human erythrocytes and platelets and plant symbiosomes were assayed. FDs bearing amino acid were capable of resulting in pronounced depolarization of symbiosomal membrane energized with the Mg-ATP. In human erythrocytes and platelets incubated in K+-free medium in the presence of FCCP, a known protonophore, FDs with malonic acid pendants promoted acidification of intracellular medium thereby simulating an effect of the K+-ionophore valinomycin. Dissipation of ApH artificially induced on the plasma membrane of these cells was observed in the presence of C60-?-amino-butiric acid, with the latter compound strongly stimulated Mg-ATP-dependent generation of membrane potential on the symbiosomal membrane. C60-Arg was shown to dissipate K+-diffusion potential on the erythrocyte membrane induced by valinomycin. Fullerene used as FMC also entered symbiosomes and platelets as evidenced by quenching the fluorescence of Ca2+ indicator chlorotetracycline which is exclusively localized within Ca-stores of these cells. These findings provide evidence for easy permeation of fullerene-based compounds through biological membranes of different type cells that may be important for our understanding the molecular mechanisms responsible for delivery of such compounds to their cellular targets.