Effect of detonation nanodiamond surface composition on physiological indicators of mitochondrial functions

For the first time, an effect of detonation nanodiamonds (NDs) with different surface compositions on the main functional characteristics of isolated rat liver mitochondria was studied. The response of membrane potential, calcium retention capacity, and redox state of pyridine nucleotides have been monitored upon the administration of NDs functionalized with carboxyl, hydroxyl, amine, hydrogen, and chlorine surface groups. Hydrogenated and chlorinated NDs caused reduction of the membrane potential and calcium retention capacity of mitochondria. An aminated ND caused an even greater decrease in calcium retention capacity (at a concentration of 0.75 mg/ml), reducing it to 65% of the control. The use of cyclosporine A prevented a decrease in membrane potential and calcium retention capacity indicating the induction of non-specific mitochondrial membrane pores during the NDs incubation with mitochondria. Hydrogenated and chlorinated NDs had no significant effect on the redox state of mitochondrial pyridine nucleotides. Other NDs studied had no effects on functional characteristics of mitochondria, even at high concentrations (up to 1.5 mg/ml). High activity of chlorinated and hydrogenated NDs may be due to the greater hydrophobicity of their surface and its interaction with mitochondrial pores components. Thus, isolated rat liver mitochondria can be used as a biomodel for initial testing of ND samples to assess the possibility of their use in drug delivery systems.