Lipophilic halogen-free ionic liquid with antibacterial and anti-biofilm activities against Pseudomonas aeruginosa

A halogen-free ionic liquid (IL) designed with long alkyl chain anion is reported. 1-methylimidazolium stearate (MIM stearate) synthesized through Bronsted acid-base reaction has shown improved lipophilic character and is able to penetrate bacterial cell walls. Antimicrobial activities against Gram-negative bacteria, Escherichia coli, and Pseudomonas aeruginosa were observed. Anti-biofilm assays showed effectivity against the biofilm of Pseudomonas aeruginosa. At 50 µg/mL the %biofilm inhibition of MIM stearate towards P. aeruginosa biofilm formation is comparable to the Bromofuran positive control. Brine shrimp lethality assay showed weak toxicity indicating the IL to be safe and benign. The synthesized MIM stearate showed good promise as an antimicrobial and anti-biofilm agent.