Site-specific biochemical functionalization along the height of vertically aligned carbon nanofiber arrays

Flexible strategies for the biochemical functionalization of synthetic nanoscale materials can enhance their impact upon a broader range of devices and applications. Here we report approaches for the heterogeneous functionalization of vertically aligned carbon nanofibers, a nanostructured material increasingly used to provide nanoscale components in microfabricated devices. Photoresist blocking strategies are developed for site-specific physical, chemical, and electrochemical functionalization of nanofiber arrays both spatially across regions of the device as well as along the length of the vertical nanofibers. These approaches are explored for the functionalization of nanofiber surfaces with gold, conductive polymers, and DNA and for the biotinylation and subsequent capture of active enzyme- and quantum-dot-conjugated (strept)avidins. Functionalizations are visualized with both fluorescent and electron microscopy and characterized using dye and enzyme assays.