A Luminescent Cocaine Detection Platform Using a Split G‑Quadruplex-Selective Iridium(III) Complex and a Three-Way DNA Junction Architecture

In this study, a series of 10 in-house cyclometalated iridium­(III) complexes bearing different auxiliary ligands were tested for their selectivity toward split G-quadruplex in order to construct a label-free switch-on cocaine detection platform employing a three-way junction architecture and a G-quadruplex motif as a signal output unit. Through two rounds of screening, we discovered that the iridium­(III) complex <b>7</b> exhibited excellent selectivity toward the intermolecular G-quadruplex motif. A detection limit as low as 30 nM for cocaine can be achieved by this sensing approach with a linear relationship between luminescence intensity and cocaine concentration established from 30 to 300 nM. Furthermore, this sensing approach could detect cocaine in diluted oral fluid. We hope that our simple, signal-on, label-free oligonucleotide-based sensing method for cocaine using a three-way DNA junction architecture could act as a useful platform in bioanalytical research

An Iridium(III) Complex Inhibits JMJD2 Activities and Acts as a Potential Epigenetic Modulator

A novel iridium­(III) complex was synthesized and evaluated for its ability to target JMJD2 enzymatic activity. The iridium­(III) complex <b>1</b> can inhibit JMJD2 activity and was selective for JMJD2 activity over JARID, JMJD3, and HDAC activities. Moreover, <b>1</b> suppressed the trimethylation of the p21 promoter on H3K9me3 and interrupted the JMJD2D–H3K9me3 interactions in human cells, suggesting that it could act as an epigenetic modulator. To our knowledge, <b>1</b> represents the first metal-based JMJD2 inhibitor reported in the literature