Nanowire intensity fluctuations and thickness variations. In (a), a fluorescence image of a biofunctionalized nanowire is shown. In (b), the intensity plot along the dotted line is shown. The intensity value is fluctuating along the wire axis and even disappearing at two points. Images (c) and (d) show SEM images of a typical nanowire used in this study. With the larger magnification in (d), the nanowire thickness variation is clearly visible.