Ratiometric fluorescence sensor for Escherichia coli detection using fluorescein isothiocyanate-labeled metal-organic...

Area of Science:

• Materials Science
• Analytical Chemistry
• Biotechnology

Background:

• Escherichia coli (E. coli) contamination poses significant risks to public health.
• Accurate and rapid detection methods for E. coli are crucial for food safety and clinical diagnostics.
• Existing detection methods often face challenges with sensitivity, selectivity, or complex procedures.

Purpose of the Study:

• To develop a ratiometric fluorescence sensor for sensitive and selective detection of E. coli.
• To utilize metal-organic frameworks functionalized with fluorescein isothiocyanate for enhanced detection.
• To demonstrate the practical application of the sensor in real-world samples like juice.

Main Methods:

• Fabrication of a ratiometric fluorescence sensor (ZTMs@FITC) using zirconium-tetraphenylporphyrin tetrasulfonic acid hydrate and fluorescein isothiocyanate.
• Exploitation of E. coli's metabolic activity to influence Cu2+ concentration, which quenches red fluorescence from ZTMs.
• Monitoring the ratio of fluorescence intensities at 683 nm (ZTMs) and 515 nm (FITC) for quantitative detection.

Main Results:

• The ZTMs@FITC probe exhibited a ratiometric response to E. coli concentration.
• Detection range achieved was 1.0 × 10^1 to 5.0 × 10^5 CFU/mL with a limit of detection of 6 CFU/mL.
• The sensor demonstrated high selectivity for E. coli and successful application in detecting E. coli in juice samples, with a visible color change from yellow to red.

Conclusions:

• The developed ratiometric fluorescence sensor provides a rapid, sensitive, and selective method for E. coli detection.
• The dual-signal approach minimizes environmental interference and enhances detection precision.
• The sensor shows significant potential for practical applications in food safety analysis and microbial detection.