Figure 6.
Nanopore experiments indicating the effect of graphene layers on double-stranded DNA translocation. A) Schematic of graphene–dielectric–graphene membrane used in studying translocation of 850bp dsDNA. A 6 nm pore is used in this experiment. B,C) Translocation histograms for dsDNA translocations at transmembrane voltages of 300 mV and 500 mV, respectively. All experiments were performed in 1 M KCl, 10 × 10−3 M Tris, 1 × 10−3 M EDTA at pH 7. Insets: Sample current traces of dsDNA blockade events for both values of transmembrane voltages. The smaller timescale of translocation of a much longer dsDNA (compared to ssDNA used in this study) indicates significantly reduced hydrophobic interactions in between graphene and dsDNA as compared to graphene and ssDNA.