Self-diffusion of water-soluble fullerene derivatives in mouse erythrocytes

Self-diffusion of water-soluble fullerene derivative (WSFD) C-60[S(CH2)(3)SO3Na](5)H in mouse red blood cells (RBC) was characterized by H-1 pulsed field gradient NMR technique. It was found that a fraction of fullerene molecules (similar to 13% of the fullerene derivative added in aqueous RBC suspension) shows a self-diffusion coefficient of (5.5 +/- 0.8).10(-12) m(2)/s, which is matching the coefficient of the lateral diffusion of lipids in the erythrocyte membrane (D-L = (5.4 +/- 0.8).10(-12) m(2)/s). This experimental finding evidences the absorption of the fullerene derivative by RBC. Fullerene derivative molecules are also absorbed by RBC ghosts and phosphatidylcholine liposomes as manifested in self-diffusion coefficients of (7.9 +/- 1.2).10(-12) m(2)/s and (7.7 +/- 1.2).10(-12) m(2)/s, which are also close to the lateral diffusion coefficients of (6.5 +/- 1.0).10(-12) m(2)/S and (8.5 +/- 1.3).10(-12) m(2)/s, respectively. The obtained results suggest that fullerene derivative molecules are, probably, fixed on the RBC surface. The average residence time of the fullerene derivative molecule on RBC was estimated as 440 +/- 70 ms. Thus, the pulsed field gradient NMR was shown to be a versatile technique for investigation of the interactions of the fullerene derivatives with blood cells providing essential information, which can be projected on their behavior in-vivo after intravenous administration while screening as potential drug candidates.