Bacterial lipase triggers the release of antibiotics from digestible liquid crystal nanoparticles

Chelsea R. Thorn, Andrew J. Clulow, Ben J. Boyd, Clive A. Prestidge, Nicky Thomas

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14 Citations (Scopus)


In the advent of the post-antibiotic era, new strategies are urgently required to improve the efficacy of antimicrobials and outsmart multi-drug resistant bacteria. Exploiting a basic survival mechanism of bacteria, lipase production, monoolein liquid crystal nanoparticles (MO-LCNPs) were investigated as a bacterial-triggered drug delivery system for three different antimicrobial compounds and compared with model sn-1/3 regiospecific and non-regiospecific lipases via pH-stat titration, proton nuclear magnetic resonance and in situ synchrotron small-angle X-ray scattering. The release of model hydrophobic (rifampicin) and macromolecular (alginate lyase) antimicrobials were triggered from MO-LCNPs at 82-fold and 7-fold higher rates (respectively) due to bacterial lipase digestion of MO-LCNPs, which could not be stimulated with a small hydrophilic antibiotic (ciprofloxacin HCl) or non-digestible, phytantriol-LCNPs. While sn-1/3 regiospecific lipase rapidly digested MO-LCNPs in a two-phase process, the single-phase digestion kinetics of the non-regiospecific lipase steadily digested the cubic Im3m structure and gave rise to lamellar structures that ultimately stimulated the triggered antibiotic release. Accordingly, MO-LCNPs have an application for localised Pseudomonas aeruginosa and Staphylococcus aureus infections that produce non-regiospecific lipases and for concentration-dependent antibiotics that have macromolecular (MW ~ 30 kDa) or hydrophobic (logP ~ 4) chemistries, as a triggered bolus release would be clinically efficacious for improved bacterial eradication.

Original languageEnglish
Pages (from-to)168-182
Number of pages15
JournalJournal of Controlled Release
Publication statusPublished - 10 Mar 2020


  • Antimicrobials
  • Liquid crystalline nanoparticles
  • Triggered drug delivery

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