A cysteine and Hg²⁺ detection method based on transformation supramolecular assembly of cyanine dye by AGRO100

ETC (3,3'-di(3-sulfopropyl)-4,5,4',5'-dibenzo-9-ethylthiacarbocyanine triethylammonium salt), as a derivative of thiazole, is capable of forming various aggregates by the short-range noncovalent interaction forces under specific conditions, accompanying with significant absorbance and fluorescence characteristics. In this work, a label-free probe (ETC) for the detection of Cys (Cysteine) and Hg²⁺ was developed based on transformation between monomers and J-aggregations by AGRO100. AGRO100 can transform between single-stranded DNA and G-quadruplex to realize recognition of Cys and Hg²⁺ in dual-channel mode. These recognitional signals can be captured by UV-visible absorption spectra and fluorescence spectroscopy. ETC exhibits high sensitivity and selectivity with the detection limit of 0.197 nM in a wide range of 0-15 μM, which can apply of Cys and Hg²⁺ detection in human serum.