Chemically immobilized T4-bacteriophage for specific Escherichia coli detection using surface plasmon resonance

Area of Science:

• Biotechnology
• Biosensing
• Microbiology

Background:

• Accurate and rapid detection of bacterial pathogens is crucial for public health.
• Bacteriophage-based biosensors offer high specificity for target bacteria.

Purpose of the Study:

• To develop and characterize a bioassay platform for detecting Escherichia coli K12 using T4 bacteriophage and SPR.
• To optimize phage immobilization for enhanced bacterial capture and sensor performance.

Main Methods:

• Covalent immobilization of T4 bacteriophages onto gold surfaces via dithiobis(succinimidyl propionate) (DTSP) self-assembled monolayers.
• Characterization of phage-immobilized substrates using scanning electron microscopy (SEM).
• Detection and specificity analysis using surface plasmon resonance (SPR) with Escherichia coli K12 and non-host strains.

Main Results:

• Uniform T4 phage immobilization achieved using DTSP, confirmed by SEM.
• High specificity demonstrated for Escherichia coli K12 detection against non-host strains using SPR.
• Optimal T4 phage concentration for immobilization determined as 1.5 × 10(11) plaque-forming units/mL.
• Regenerable sensor surface capable of detecting bacteria in the range of 7 × 10(2) to 7 × 10(8) colony-forming units/mL.

Conclusions:

• The developed T4 phage-SPR bioassay platform provides a sensitive and specific method for Escherichia coli K12 detection.
• The platform's regenerability and broad detection range support its potential for real-time pathogen monitoring.
• This approach has significant implications for developing online bioassays for food and waterborne pathogens.