Rhodamine based sensor for naked-eye detection and live cell imaging of fluoride ions

Area of Science:

• Analytical Chemistry
• Chemical Sensing
• Biophysical Chemistry

Background:

• Fluoride ion detection is crucial in environmental monitoring and biological studies.
• Existing methods for fluoride sensing often lack selectivity or sensitivity.
• Rhodamine derivatives offer potential as signaling units in chemosensors due to their photophysical properties.

Purpose of the Study:

• To design and synthesize a novel rhodamine-based probe for selective colorimetric and fluorescent detection of fluoride ions.
• To investigate the sensing mechanism and confirm the probe's response to fluoride.
• To evaluate the probe's applicability in real sample analysis and biological imaging.

Main Methods:

• Synthesis of a rhodamine-based chemosensor.
• Spectroscopic analysis (colorimetric and fluorescence) for fluoride detection.
• Density functional theory (DFT) calculations and proton nuclear magnetic resonance (¹H NMR) titrations to elucidate the sensing mechanism.
• Application of the probe in real water samples and HeLa cell imaging.

Main Results:

• The synthesized probe exhibits high selectivity and sensitivity towards fluoride ions.
• Fluoride triggers a distinct colorimetric and fluorescence change via spirolactam ring opening.
• DFT calculations and ¹H NMR titrations support the proposed sensing mechanism.
• The probe successfully detected fluoride in real water samples and enabled imaging of fluoride ions within HeLa cells.

Conclusions:

• A highly selective rhodamine-based colorimetric and fluorescent probe for fluoride has been developed.
• The probe's mechanism involves fluoride-induced spirolactam ring opening.
• The sensor demonstrates practical utility for environmental monitoring and biological applications, including cellular imaging.