Positive-Charge-Based Small Molecule Dyes for Gut Microbiota Fluorescent Imaging

Area of Science:

• Microbiology
• Biotechnology
• Medical Imaging

Background:

• Gut microbiota research is a rapidly growing field with significant implications for host health.
• Challenges remain in precisely localizing and tracking gut microbial populations.
• Existing imaging techniques may lack specificity or biocompatibility for gut microbiota studies.

Purpose of the Study:

• To develop novel fluorescent small molecule probes for effective gut microbiota imaging.
• To evaluate the labeling efficiency, toxicity, and biocompatibility of the new probes.
• To compare the performance of the new probes against established imaging agents.

Main Methods:

• Optimization of a positron salt small molecule probe (F16) to create two new probes, EF and 6F.
• In vitro bacterial labeling experiments with Gram-positive and Gram-negative bacteria.
• In vivo imaging studies in mice to assess intestinal microbiota labeling and tissue compatibility.
• Comparative analysis with commercial fluorescent dyes like MitoTracker and FITC.

Main Results:

• EF and 6F successfully labeled both Gram-positive (Staphylococcus aureus, Lactobacillus reuteri) and Gram-negative bacteria (Escherichia coli, Salmonella pullorum).
• Probes exhibited low bacterial toxicity, with effective use up to 200 μM.
• 6F demonstrated superior hydrophilicity and fluorescence in aqueous solutions compared to EF.
• In vivo imaging showed EF and 6F could label intestinal microbiota without damaging host tissue.
• The new probes displayed better biocompatibility than MitoTracker and FITC.

Conclusions:

• EF and 6F are novel, effective small molecule probes for gut microbiota imaging.
• These probes offer improved hydrophilicity, fluorescence, and biocompatibility for biological applications.
• The developed probes provide a valuable new option for researchers investigating complex gut microbiota ecosystems.