Development of a highly sensitive bacteria detection assay using fluorescent pH-responsive polymeric micelles

Area of Science:

• Biotechnology
• Materials Science
• Analytical Chemistry

Background:

• Bacterial detection is crucial for food safety and healthcare.
• Conventional methods for bacterial detection are time-consuming and costly.
• There is a need for rapid, sensitive, and cost-effective bacterial detection assays.

Purpose of the Study:

• To develop a novel, sensitive bioassay for detecting Escherichia coli (E. coli).
• To utilize pH-responsive polymeric micelles for enhanced bacterial detection.
• To provide a faster and more efficient alternative to traditional microbiological methods.

Main Methods:

• Synthesized poly(ethylene glycol-b-trimethylsilyl methacrylate) and self-assembled it into micelles.
• Loaded micelles with a fluorescent dye (1-methylpyrene) and bioconjugated them with anti-E. coli antibodies.
• Utilized pH-triggered cleavage of silicon protecting groups to release the dye upon bacterial attachment.
• Measured changes in fluorescence emission spectra to detect bacterial presence.

Main Results:

• Developed a bioassay capable of detecting as few as 15 E. coli bacteria per milliliter.
• Achieved high sensitivity through an amplification effect from released fluorophores.
• Demonstrated that dye release and signal generation are dependent on micelle-bacterium interaction and pH changes.
• Observed a distinct change in fluorescence spectra (disappearance of excimer band) indicating successful dye encapsulation.

Conclusions:

• The developed bioassay is a simple, sensitive, and rapid method for E. coli detection.
• pH-responsive polymeric micelles offer a promising platform for sensitive bioanalytical applications.
• This technology has potential applications in food safety and clinical diagnostics, improving upon conventional methods.