β-Cyclodextrin Encapsulation of Synthetic AHLs: Drug Delivery Implications and Quorum-Quenching Exploits

Area of Science:

• Microbiology
• Biochemistry
• Molecular Biology

Background:

• Bacteria like Pseudomonas aeruginosa use quorum sensing (QS) for population density-dependent regulation.
• QS in Gram-negative bacteria involves N-acyl-l-homoserine lactones (AHLs) as signaling molecules.
• Synthetic AHL analogues (SAHLAs) are developed to disrupt QS but suffer from poor water solubility.

Purpose of the Study:

• To evaluate the affinity of SAHLAs and their hydrolysis products for beta-cyclodextrin (β-CD) inclusion complexes.
• To assess the efficacy of these β-CD/SAHLA complexes in inhibiting Pseudomonas aeruginosa virulence in a Caenorhabditis elegans infection model.

Main Methods:

• Fluorescence spectroscopy, NMR spectrometry, and mass spectrometry were used to determine binding affinities.
• A Caenorhabditis elegans host infection study was conducted to evaluate anti-virulence activity.

Main Results:

• The study quantified the binding affinities of various SAHLAs and their hydrolysis products to β-CD.
• Complexation with β-CD enhanced the anti-virulence potential of SAHLAs against P. aeruginosa in vivo.

Conclusions:

• Beta-cyclodextrins show potential for improving the delivery and efficacy of SAHLAs.
• This strategy offers a novel approach for probing and controlling bacterial quorum sensing and virulence.