Reduction of CuO butterfly wing scales generates Cu SERS substrates for DNA base detection

We prepare three-dimensional Cu plasmonic structures via a reduction of CuO photonic crystals replicated from butterfly wing scales. These Cu superstructures with high purity provide surface-enhanced Raman scattering (SERS) substrates for the label-free detection of DNA bases down to a micromolar level, which is achieved for the first time on Cu and even comparable to the detection-sensitivity for DNA bases on some Ag substrates. The generation of such superstructures has provided a substantial step for the biotemplated SERS substrates with high sensitivity, high reproducibility, and ultra-low cost to detect biomolecules, and presented affordable high-quality routine SERS consumables for corresponding biolaboratories.