Stimuli-responsive discriminative detection of Cu2+ and Hg2+ with concurrent sensing of S2- from aqueous medium and bio-fluids by C-N fused azophenine functionalized smart hydrogel assay @A potential biomarker sensor for Wilson's disease

A multi-functional azophenine based colorimetric chemosensor, CN-1 has been reported by catalytic FeCl3 mediated facile oxidative C-N bond fusion of o-anisidine. The chemosensor, characterized by single crystal X-ray crystallography, can be exploited towards 'naked-eye' discriminative detection of Cu2+ and Hg2+ (LOD = 30 and 480 ppb respectively) from purely aqueous medium through colorimetric and electrochemical (CV) readouts. It is equally responsive towards intoxicated real water specimen, like river water, industrial sewage water, demonstrating its practical applicability. Along with detection, CN-1 exhibited metal ion sequestration capability, leading to the removal of similar to 74 % and similar to 40 % removal of Cu2+ and Hg2+ respectively from contaminated water bodies. Moreover, the unprecedented uniqueness of the synthesized azophenine based chemosensor levies in its capability towards ppb level Cu2+ detection colorimetrically from target-specific bio-fluids to monitor aberrant unbound copper levels, thereby highlighting it as a potential biomarker sensor as well as a pathological non-invasive diagnostic tool of Wilson's disease, which has been explored for the first time in the domain of azophenine based host-guest chemistry. The reversible spectrochemical response in presence of aqueous S2- could efficiently formulate Write-Read-Erase-Read nature of a memory element and four-input complex logic circuitry for molecular level information storage, which is also hitherto unexplored in the azophenine family. One step ahead, fabrication of functionalized smart hydrogel assay escalates the reliability and practical applicability of the present work through simple 'naked eye' colorimetric-optical readouts.

Automated summary

CN-1 is a multi-functional azophenine based colorimetric chemosensor capable of detecting and distinguishing Cu2+ and Hg2+ through colorimetric and electrochemical readouts, with responsiveness to contaminated water samples and metal ion sequestration capability. Furthermore, it has the ability to monitor Cu2+ levels in biological fluids and store molecular level information.