Colorimetric Sensing by Using Allosteric‐DNAzyme‐Coupled Rolling Circle Amplification and a Peptide Nucleic Acid–Organic Dye Probe

Target detection by the naked eye: The action of an RNA-cleaving allosteric DNAzyme in response to ligand binding was coupled to a rolling circle amplification process to generate long single-stranded DNA molecules for colorimetric sensing (see scheme). Upon hybridization of the resulting DNA with a complementary PNA sequence in the presence of a duplex-binding dye, the color of the dye changed from blue to purple.