Figure 1.

(a) Schematic illustration of UO₂²⁺-specific DNAzyme and cleavage of DNAzyme induced by UO₂²⁺ (b) Schematic illustration of UO₂²⁺ detection by a PNI sensor combined with a DNAzyme-cleaved reaction. The left panel shows the SERS spectra measured from PNI sensors in the absence of (blue spectrum) and the presence of 10 nM UO₂²⁺ (red spectrum).