Simple and Cost-effective Fluoride Riboswitch-Based Whole-Cell Biosensor for the Determination of Fluoride in...

Area of Science:

• Environmental Science
• Biotechnology
• Analytical Chemistry

Background:

• Elevated fluoride levels in drinking water present significant health risks.
• Accurate and reliable detection methods are essential for monitoring fluoride concentrations.
• Existing methods may lack specificity or require complex procedures.

Purpose of the Study:

• To develop a highly selective whole-cell biosensor for fluoride detection.
• To utilize a fluoride riboswitch (FRS) and a lacZ reporter gene system.
• To enable accurate quantification of fluoride in water samples.

Main Methods:

• Engineered an E. coli mutant with a recombinant plasmid containing the FRS fused to the lacZ reporter gene.
• Fluoride binding to the FRS aptamer induced β-galactosidase expression.
• Quantified fluoride using a colorimetric assay and a calibration curve (R² > 0.9).

Main Results:

• The developed biosensor exhibited narrow specificity and high selectivity for fluoride.
• Minimal interference was observed from common ions (e.g., Cl⁻, OH⁻, Na⁺, Ca²⁺).
• Fluoride concentrations in Sri Lankan water samples were accurately determined within the range of 0.15-0.90 ppm.

Conclusions:

• The FRS-based whole-cell biosensor is a sensitive and selective tool for fluoride detection.
• This biosensor offers a reliable method for monitoring fluoride levels in drinking water.
• The findings contribute to improved water quality assessment and public health protection.