DNAzyme sensors for detection of metal ions in the environment and imaging them in living cells

•DNAzymes are an emerging class of metal ions sensors with high selectivity.•Recent progress has been made in using DNAzymes for environmental detection of metal ions with high sensitivity.•Cellular imaging of metal ions in living cells using DNAzymes with high temporal control has also been reported.

The on-site and real-time detection of metal ions is important for environmental monitoring and for understanding the impact of metal ions on human health. However, developing sensors selective for a wide range of metal ions that can work in the complex matrices of untreated samples and cells presents significant challenges. To meet these challenges, DNAzymes, an emerging class of metal ion-dependent enzymes selective for almost any metal ion, have been functionalized with fluorophores, nanoparticles and other imaging agents and incorporated into sensors for the detection of metal ions in environmental samples and for imaging metal ions in living cells. Herein, we highlight the recent developments of DNAzyme-based fluorescent, colorimetric, SERS, electrochemical and electrochemiluminscent sensors for metal ions for these applications.