A Long Fluorescence Lifetime Probe for Labeling of Gram-Negative Bacteria

Area of Science:

• Microbiology
• Biochemistry
• Analytical Chemistry

Background:

• Antibiotic resistance is a significant global health threat, driven by factors like misdiagnosis and overuse of antimicrobials.
• Accurate and rapid bacterial detection is crucial for effective treatment and combating resistance.
• Existing detection methods can be limited by autofluorescence in biological samples.

Purpose of the Study:

• To develop a novel fluorescent probe with a long fluorescence lifetime for sensitive bacterial detection.
• To create a probe that specifically targets Gram-negative bacteria.
• To enable bacterial imaging and detection with reduced interference from biological autofluorescence.

Main Methods:

• Synthesis of a polymyxin-based fluorescent probe (ADOTA-PMX) utilizing a red-emitting azadioxatriangulenium fluorophore.
• Evaluation of the probe's specificity and efficacy in labeling Gram-negative bacteria.
• Application of fluorescence lifetime imaging microscopy (FLIM) and benchtop fluorimetry for bacterial detection and characterization.

Main Results:

• ADOTA-PMX demonstrated high specificity for Gram-negative bacteria.
• The probe exhibited a fluorescence lifetime of 4.5 ns when bound to bacteria, suggesting outer membrane interaction.
• Bacterial detection and lifetime measurements were achievable with a benchtop fluorimeter, simplifying the process.

Conclusions:

• ADOTA-PMX is the first targeted probe for fluorescence lifetime imaging, offering sensitive detection of Gram-negative bacteria.
• The probe's long fluorescence lifetime overcomes autofluorescence limitations, enhancing imaging capabilities.
• This technology holds potential for multiplexed bacterial detection and improved diagnostics.