Plan-view SEM images, acquired with secondary electron detection (SED), of virus-free (a,b) and virus-containing (c,d,e) bioaffinity layers. (a,b) Control VBR bioaffinity layer prepared by electrodeposition from a solution containing no virus particles. Micron scale protrusions from the surface of this film are characteristic of electrodeposited PEDOT. These protrusions are not seen at PEDOT-PSS films prepared by spin-coating. We refer to these structures as “PEDOT stalagmites”. (c,d,e) VBR bioaffinity layers containing M13 virus particles. Filamentous M13 virus particles comprise the dark regions of these images. Lighter gray regions contain no virus. PEDOT stalagmites are also observed. Enhanced contrast (e) exposes tangles of M13, again distributed nonuniformly inside a virus-PEDOT bioaffinity layer.