Highly selective, sensitive and biocompatible rhodamine-based isomers for Al³⁺ detection: A comparative study

Area of Science:

• Materials Chemistry
• Analytical Chemistry
• Biophysical Chemistry

Background:

• Selective metal ion detection is crucial for understanding chemical and biological processes.
• Rhodamine derivatives are widely used as fluorescent probes due to their favorable optical properties.

Purpose of the Study:

• To synthesize and characterize novel rhodamine-based isomers for selective aluminum ion (Al3+) sensing.
• To evaluate the sensing performance and potential applications of these isomers in biological systems.

Main Methods:

• Synthesis and characterization of two rhodamine-based isomers (L-2-oxy and L-4-oxy).
• Spectroscopic analysis (absorbance and fluorescence) to assess Al3+ sensing capabilities.
• Determination of Limit of Detection (LOD) and quantum yield.
• Density Functional Theory (DFT) studies to elucidate the sensing mechanism.
• Cell imaging studies using L6 cell line.

Main Results:

• Both L-2-oxy and L-4-oxy isomers exhibited enhanced absorbance and fluorescence in the presence of Al3+.
• Low LOD values (∼1.0 nM) were achieved for Al3+ detection.
• DFT studies indicated spirolactam ring opening and potential Chelation Enhanced Fluorescence (CHEF) effect.
• L-2-oxy showed superior sensing performance compared to L-4-oxy.
• The probes were successfully applied in cell imaging of Al3+.

Conclusions:

• The developed rhodamine-based isomers are effective fluorescent probes for selective Al3+ detection.
• L-2-oxy isomer offers enhanced sensitivity and better performance for Al3+ sensing.
• These probes hold promise for applications in chemical analysis and biological imaging.