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

Self-diffusion of water-soluble fullerene derivative (WSFD) C60[S(CH2)3SO3Na]5H in mouse red blood cells (RBC) was characterized by 1H pulsed field gradient NMR technique. It was found that a fraction of fullerene molecules (~13% of the fullerene derivative added in aqueous RBC suspension) shows a self-diffusion coefficient of (5.5 ± 0.8)·10-12 m2/s, which is matching the coefficient of the lateral diffusion of lipids in the erythrocyte membrane (DL = (5.4 ± 0.8)·10-12 m2/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 m2/s and (7.7 ± 1.2)·10-12 m2/s, which are also close to the lateral diffusion coefficients of (6.5 ± 1.0)·10-12 m2/s and (8.5 ± 1.3)·10-12 m2/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.