Figure 12.

(a) SEM cross-section of an NAA bilayer. The inset shows a magnified view of the interface region between the two layers with different porosities to show the difference in pore diameter; (b) SEM top view of the sample showing the self-ordering of the pores and the uniformity of the pore distribution; (c) Schematic view of the sensing and self-referencing procedure, where the protein to be sensed can infiltrate Layer 1, but not Layer 2. Layer 3 corresponds to the union of Layers 1 and 2. Reprinted with permission from [55]. Copyright 2013 American Chemical Society.