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. Author manuscript; available in PMC: 2009 Dec 16.
Published in final edited form as: Langmuir. 2008 Dec 16;24(24):14282–14288. doi: 10.1021/1a8029243

Figure 4.

Figure 4

SECM images obtained for DNA monolayers modified with NB at the top (A, C) and NB at the bottom (B, D). The tip was polarized to 1 V, and the scans were performed in 80 mM NaCl, 20 mM NaPi, pH = 7.2, 5 mM K4Fe(CN)6 at a speed of 10 μm/s. The substrate bias was −400 mV (green in A, B) and 0 mV (blue in A, B). The switching ratios (the current obtained at −400 mV divided by the current obtained at 0 mV) are shown for monolayers with NB at the top (C) and monolayers with NB at the bottom (D). The poorly covered areas of the DNA monolayer are in the rear corners of A, B, C, and D.