Visualizing Hg2+ ions in living cells using a FRET-based fluorescent sensor.

Area of Science:

• Analytical Chemistry
• Biomedical Engineering
• Molecular Imaging

Background:

• Mercury ions (Hg2+) are toxic environmental pollutants and intracellular contaminants.
• Sensitive and selective detection methods for Hg2+ in biological systems are crucial for diagnostics and research.

Purpose of the Study:

• To design and synthesize a novel Förster Resonance Energy Transfer (FRET) fluorescent sensor for Hg2+.
• To evaluate the sensor's performance in aqueous solutions and for imaging Hg2+ in living cells.

Main Methods:

• Rational design of a coumarin-rhodamine based FRET platform (RBC1).
• Spectroscopic analysis (absorbance and fluorescence) to determine Hg2+ detection capabilities.
• Cellular imaging experiments using A375 cells to demonstrate in situ Hg2+ detection.

Main Results:

• RBC1 exhibited high selectivity and sensitivity for Hg2+ detection in aqueous solution.
• Hg2+ addition caused a decrease in coumarin emission and an increase in rhodamine emission, characteristic of FRET.
• The sensor responded to Hg2+ within 2 minutes with no interference from other common metal ions.
• Successful fluorescent imaging of intracellular Hg2+ in A375 cells was achieved.

Conclusions:

• The coumarin-rhodamine based FRET sensor (RBC1) is effective for selective and sensitive Hg2+ detection.
• The developed sensor enables real-time imaging of Hg2+ in living cells.
• The FRET design strategy using dual fluorophore switching offers a promising approach for developing advanced fluorescent sensors.