Fig. 4.

Schematic of electron flow through a bacterial nanowire. The labels L, B and R stand for Left electrode, Bridge and Right electrode, respectively. Here, L is the conductive AFM tip of the experiment, B is the bacterial pilus and R is the gold grid shown in Fig. 3. The arrow gives the path of the electrons, with direction depending on the sign of the chemical potential difference between the electrodes. The star symbols on the pilus represent charge carriers on the surface. The “…” represents the pilus extending in length far to the left. The segment length of the pilus between the electrodes is 600 nm. The height and width of the ellipsoidal pilus is approximated by a diameter of 10 nm.