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A Selective and Sensitive Method for Colistin Detection by G-Quadruplex Ligand Competition.
Shijiong Wei1, Dehui Qiu1, Xinrong Yan1
1State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P.R. China.
Analytical Chemistry
|July 31, 2025
Summary
A new chemiluminescence method detects colistin (COL), a last-resort antibiotic, in environmental samples. This simple, label-free technique quantifies COL using its interaction with a G-quadruplex DNAzyme, offering a rapid detection solution.
Area of Science:
- Analytical Chemistry
- Environmental Science
- Biochemistry
Background:
- Colistin (COL) is a critical last-resort antibiotic for multidrug-resistant Gram-negative infections.
- Widespread COL use leads to environmental accumulation, posing ecological and health risks.
- Existing methods for COL quantification lack speed and specificity.
Purpose of the Study:
- To develop a rapid, specific, and simple method for quantifying colistin (COL) in various samples.
- To leverage the interaction between COL and G-quadruplex (G4) DNA for detection.
- To establish a reliable method for monitoring environmental COL levels.
Main Methods:
- A chemiluminescence detection strategy based on the specific binding of COL to a parallel G-quadruplex (G4).
- Utilized the catalytic activity of the G4/hemin DNAzyme, inhibited by COL's stronger affinity for G4.
- Optimized G4 sequence (F3TC), oxidation substrate (luminol), and reaction conditions.
Main Results:
- Achieved sensitive COL detection over a wide concentration range (0.5–2,500 ng/mL).
- Established a low detection limit of 0.4 ng/mL for COL.
- Demonstrated excellent selectivity for COL against other antibiotics and validated the method in real samples.
Conclusions:
- The developed G4-based chemiluminescence method offers a simple, label-free, and efficient approach for COL quantification.
- This method addresses the need for rapid and specific antibiotic detection, particularly for environmental monitoring.
- The validated technique holds potential as a standard method for colistin detection.
