Penetration of Fullerene C₆₀ Derivatives Through Biological Membranes

Abstract

Penetration of fullerene C₆₀ in hydrated molecular‐colloidal form (FMC) and various C₆₀ water‐soluble derivatives (FDs) through membranes of human erythrocytes, platelets and symbiosomes (subcellular organelles of plant origin) were tested. The FDs bearing amino acids induced pronounced depolarization of symbiosome membranes energized with Mg‐ATP. In erythrocytes and platelets incubated in K⁺‐free medium in the presence of FCCP, FDs with malonic acid pendants promoted acidification of the intracellular medium thereby simulating an effect of the K⁺ ionophore valinomycin. Dissipation of ΔpH artificially induced on the plasma membrane of these cells was observed in the presence of C₆₀‐γ‐aminobutiric acid which, in addition, strongly stimulated Mg‐ATP‐dependent generation of membrane potential on symbiosome membranes. C₆₀‐Arg was shown to dissipate K⁺‐diffusion potential on erythrocyte membranes induced by valinomycin. Fullerene C₆₀ used in hydrated molecular‐colloidal form (FMC) also entered symbiosomes and platelets as evidenced by the quenching of the fluorescence of the Ca²⁺ indicator chlorotetracycline localized in the interior of these cells. These findings provide evidence for ease of permeation of these fullerene‐based compounds through biological membranes from different type cells.

Keywords:

• Fullerene C₆₀
• C₆₀ amino acid derivatives
• fluorescent probe
• membrane potential

Acknowledgments

The authors thank Dr. V. V. Krylova and P. N. Dubrovo from the Timiryazev Institute of Plant Physiology for their help in isolation and purification of symbiosomes from yellow lupin root nodules and Dr. G. Andrievsky from the Institute for Therapy of Ukrainian Academy of Medical Science for generously providing for the molecular colloidal dispersion of C₆₀ in water.