The protective effects three fullerene derivatives Gd@C82(OH)22, C60(OH)22, and C60(C(COOH)2)2. against H2O2-induced mitochondrial damage in A549 cells, and rBCECs cells. The cells were treated with 100 μM fullerene derivatives before incubation with 50 μM H2O2. Aggregation of the dye, JC-1, seen as red fluorescence, indicates integrity of the mitochondrial membrane.