Imaging Endogenous Metal Ions in Living Cells Using a DNAzyme-Catalytic Hairpin Assembly Probe.

Research paper by Zhenkun Z Wu, Huanhuan H Fan, Nitya Sai Reddy NSR Satyavolu, Wenjing W Wang, Ryan R Lake, Jian-Hui JH Jiang, Yi Y Lu

Indexed on: 31 May '17Published on: 31 May '17Published in: Angewandte Chemie International Edition


DNAzymes have been shown as a promising platform for metal ions detection and a few DNAzyme-based sensors have been reported to detect metal ions inside cells. However, these methods required an influx of metal ions to increase their concentrations for detection. To address this major issue, we herein report the design of a catalytic hairpin assembly (CHA) reaction to amplify the signal from photocaged Na+-specific DNAzyme to detect endogenous Na+ inside cells. Upon light activation and in the presence of Na+, NaA43 DNAzymes cleave the substrate strands and release initiator DNA that trigger the followed CHA amplification reaction. This strategy has allowed detection of endogenous Na+ inside cells, which has been demonstrated by both fluorescent imaging of individual cells and flow cytometry of the whole cell population. This method can be generally applied to detect other endogenous metal ions and thus contribute to deeper understanding of the role of metal ions in biological systems.