Immobilized optical fiber microprobe for selective and sensitive Escherichia coli detection

Area of Science:

• Biotechnology
• Biosensing
• Optical Physics

Background:

• Escherichia coli (E. coli) outbreaks pose significant public health risks via contaminated food and water.
• Accurate and rapid detection methods for E. coli are essential for effective public health protection.

Purpose of the Study:

• To propose and demonstrate a fast-response, label-free biosensor for E. coli detection.
• To utilize a multimode microfiber probe for sensitive E. coli quantification.

Main Methods:

• A multimode microfiber probe was engineered to excite guided modes with an evanescent field.
• The interaction of the evanescent field with E. coli causes spectral shifts.
• Bacteriophage immobilization on the microfiber surface facilitates specific E. coli binding.

Main Results:

• The proposed method achieved label-free detection of E. coli.
• Sensitive detection of E. coli concentrations as low as 10^3 CFU/mL was demonstrated.
• The detection range spanned from 10^3 to 10^7 CFU/mL with high sensitivity and fast response.

Conclusions:

• The bacteriophage-based microfiber probe provides a highly sensitive and rapid method for E. coli detection.
• This biosensing technology holds significant potential for environmental monitoring and food safety applications.