Hydrophobic Chitosan Nanoparticles Loaded with Carvacrol against Pseudomonas aeruginosa Biofilms

Ariadna Thalia Bernal-Mercado, Josué Juarez, Miguel Angel Valdez, Jesus Fernando Ayala-Zavala, Carmen Lizette Del-Toro-sánchez, David Encinas-Basurto*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


Pseudomonas aeruginosa infections have become more challenging to treat and eradicate due to their ability to form biofilms. This study aimed to produce hydrophobic nanoparticles by grafting 11-carbon and three-carbon alkyl chains to a chitosan polymer as a platform to carry and deliver carvacrol for improving its antibacterial and antibiofilm properties. Carvacrol–chitosan nanoparticles showed ζ potential values of 10.5–14.4 mV, a size of 140.3–166.6 nm, and an encapsulation efficiency of 25.1–68.8%. Hydrophobic nanoparticles reduced 46–53% of the biomass and viable cells (7–25%) within P. aeruginosa biofilms. Diffusion of nanoparticles through the bacterial biofilm showed a higher penetration of nanoparticles created with 11-carbon chain chitosan than those formulated with unmodified chitosan. The interaction of nanoparticles with a 50:50 w/w phospholipid mixture at the air–water interface was studied, and values suggested that viscoelasticity and fluidity properties were modified. The modified nanoparticles significantly reduced viable P. aeruginosa in biofilms (0.078–2.0 log CFU·cm−2) and swarming motility (40–60%). Furthermore, the formulated nanoparti-cles reduced the quorum sensing in Chromobacterium violaceum. This study revealed that modifying the chitosan polarity to synthesize more hydrophobic nanoparticles could be an effective treatment against P. aeruginosa biofilms to decrease its virulence and pathogenicity, mainly by increasing their ability to interact with the membrane phospholipids and penetrate preformed biofilms.

Original languageEnglish
Article number699
Issue number3
StatePublished - 1 Feb 2022

Bibliographical note

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© 2022 by the authors. Licensee MDPI, Basel, Switzerland.


  • Anti-quorum-sensing agents
  • Bacterial biofilms
  • Langmuir balance
  • Nanotechnology
  • Plant compounds


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