Bacterial biofilms are structured, surface‑attached communities of microorganisms embedded within a self‑produced matrix of extracellular polymers. This architecture enhances the resilience of resident cells against environmental stressors and increases their tolerance to antibiotics, making biofilm‑associated infections persistent and difficult to treat. Biofilms formed by Pseudomonas aeruginosa are particularly problematic in cystic fibrosis, where effective therapeutic options remain limited. Hybrid nitroxide–antibiotic conjugates have been proposed as a strategy to disperse P. aeruginosa biofilms by combining traditional antibacterial activity with the biofilm‑modulating properties of nitroxides.[1] As metabolites play a central role in coordinating biofilm maturation and virulence, the ability to study metabolomic changes following exposure to nitroxide–ciprofloxacin hybrid compounds is of significant value. The presentation will report our investigations into the use of desorption electrospray ionization mass spectrometry imaging (DESI‑MSI) to map metabolomic changes within the biofilm upon exposure to nitroxide-antibiotic conjugates.
DESI‑MS is an ambient ionization method that allows direct analysis of surface‑bound molecules under atmospheric conditions without extensive sample preparation or extraction. When coupled with spatially resolved sampling, DESI‑MS imaging (DESI‑MSI) generates two‑dimensional chemical maps that depict the distribution of metabolites, lipids, and other small molecules across biological samples, including tissues and microbial biofilms.[2]
Overall, this work provides spatially resolved metabolomic insight into how nitroxide‑modified antibiotics influence P. aeruginosa biofilms and contributes to a deeper understanding of their mechanisms of biofilm disruption.