Chelerythrine as a fluorescent light-up ligand for an i-motif DNA structure

A fluorescent light-up ligand for an i-motif structure has been reported in this study. Chelerythrine (CHE) could bind to i-motif and show a significant increase in the fluorescence intensity, while exhibiting weak response towards single-stranded (ssDNA), double-stranded (dsDNA), and G-quadruplexes. This feature makes CHE advantageous in the label-free fluorescence sensing systems.