Fig. 2. (a) I–V curves of a graphene device before (black) and after (red) cutting. (b) Device characteristics of a representative DNAzyme-reconnected device after DNA connection (black) and further Cu²⁺ treatments (0.5 nM, 5 min) in the presence of 50 μM ascorbate (red). (c) I–V curves of a graphene device reconnected by control DNA, after DNA connection (black) and after further Cu²⁺ treatment for 5 min (red) (0.5 nM with 50 μM ascorbate).