Synthesis of [sup 14]C-labeled C[sub 60], its suspension in water, and its uptake by human keratinocytes

We describe how, in order for us to determine whether unfunctionalized parent C[sub 60] had any biological activity, we synthesized [sup 14]C-labeled C[sub 60], developed a method to produce a fine aqueous suspension of the labeled material, and then monitored the uptake of the labeled C[sub 60] by human cells. The C[sub 60] became rapidly cell-associated, though it did not affect the proliferation of human keratinocytes or human fibroblasts, indicating that the rapid accumulation of C[sub 60] in human cells does not result in acute toxicity. 17 refs., 1 fig.