A thioether-rich crown-based highly selective fluorescent sensor for Hg(2+) and Ag(+) in aqueous solution

Area of Science:

• Analytical Chemistry
• Materials Science
• Biomedical Engineering

Background:

• Development of selective and sensitive fluorescent sensors is crucial for environmental monitoring and biological analysis.
• Naphthalimide derivatives and crown ethers are widely used building blocks for chemosensors.
• Simultaneous detection of multiple metal ions remains a challenge in sensing applications.

Purpose of the Study:

• To design and synthesize a novel fluorescent sensor for the selective detection of Hg(2+) and Ag(+) ions.
• To investigate the sensing mechanism and performance of the sensor in aqueous solutions.
• To evaluate the sensor's applicability for metal ion imaging in living cells.

Main Methods:

• Synthesis of a naphthalimide-based fluorescent sensor incorporating a thioether-rich crown receptor.
• Spectroscopic studies (fluorescence and UV-Vis absorption) to analyze sensor-analyte interactions.
• Quantum yield calculations and limit of detection determination.
• Live cell imaging experiments using fluorescence microscopy.

Main Results:

• The sensor exhibited dual signaling behavior for Hg(2+) and Ag(+) in aqueous media.
• Hg(2+) ion detection resulted in a significant fluorescence enhancement (approx. 5-fold increase in quantum yield) with a linear response.
• The pre-formed sensor-Hg(2+) complex showed a distinct fluorescence quenching response upon addition of Ag(+).
• Successful fluorescent visualization of Hg(2+) ions in living cells was demonstrated.

Conclusions:

• The developed sensor provides a sensitive and selective method for detecting Hg(2+) and Ag(+) ions.
• The dual signaling mechanism allows for potential ratiometric or sequential detection strategies.
• The sensor's utility in biological systems highlights its potential for practical applications in environmental and biomedical fields.