A highly selective quinolizinium-based fluorescent probe for cysteine detection

Area of Science:

• Analytical Chemistry
• Biochemistry
• Chemical Biology

Background:

• Cysteine is a crucial amino acid involved in various biological processes.
• Selective and sensitive detection methods for cysteine are essential for biological and clinical research.
• Existing detection methods may lack selectivity or require complex procedures.

Purpose of the Study:

• To develop a novel fluorescent turn-off probe for the selective detection of cysteine.
• To evaluate the probe's selectivity, sensitivity, and performance in complex biological matrices.
• To assess the probe's applicability for real-time cysteine monitoring in living cells and biological fluids.

Main Methods:

• Synthesis of a novel quinolizinium-based fluorescent compound.
• Spectroscopic analysis (fluorescence) to determine probe performance.
• Testing probe selectivity against various amino acids, including homocysteine and glutathione.
• Cellular imaging studies to assess cysteine detection in living cells.
• Quantitative analysis of cysteine in spiked mouse serum samples.

Main Results:

• The developed probe exhibits a 'turn-off' fluorescence response upon binding to cysteine.
• High selectivity and sensitivity towards cysteine were achieved, with a detection limit of 0.18 μM (S/N = 3).
• The probe demonstrated excellent performance in detecting cysteine in living cells with minimal cytotoxicity.
• Accurate quantitative analysis of cysteine in mouse serum samples yielded moderate to good recovery rates (96-109%).

Conclusions:

• A novel, selective, and sensitive fluorescent quinolizinium-based probe for cysteine detection has been successfully developed.
• The probe is suitable for real-time cysteine monitoring in biological systems, including living cells.
• This tool offers a promising approach for biochemical research and potential diagnostic applications involving cysteine levels.