A dual-function styryl pyridinium dye platform for targeting bacteria and biofilms

Area of Science:

• Medicinal Chemistry
• Microbiology
• Biotechnology

Background:

• Bacterial infections, particularly those involving biofilms and antibiotic-resistant strains, necessitate advanced diagnostic and therapeutic strategies.
• Cationic fluorescent molecules offer potential as dual-action agents due to their imaging and membrane-targeting properties.

Purpose of the Study:

• To develop and evaluate novel alkyl chain-modified styryl pyridinium dyes as theragnostic agents for bacterial infections.
• To assess the imaging capabilities, antimicrobial activity, and biofilm disruption potential of these novel compounds.

Main Methods:

• Synthesis and characterization of styryl pyridinium dyes with varying alkyl chain lengths (1C, 6C, 8C, 16C).
• Evaluation of membrane interaction (NPN uptake, zeta potential), bacterial imaging (confocal microscopy), antimicrobial activity (MIC), biofilm inhibition/disruption assays, and cytotoxicity studies.
• Assessment of bacterial resistance development.

Main Results:

• Dye 8C demonstrated potent antimicrobial activity against *E. coli* and *S. aureus*, efficient bacterial membrane disruption, and effective cellular imaging.
• 8C successfully inhibited and disrupted bacterial biofilms with minimal observed resistance development after prolonged exposure.
• The compound exhibited low cytotoxicity against mammalian cells, indicating a favorable safety profile.

Conclusions:

• Alkyl chain modification is a viable strategy for tuning the bioactivity and theragnostic potential of styryl pyridinium dyes.
• Dye 8C represents a promising dual-function agent for the diagnosis and treatment of bacterial infections, including those involving biofilms.