Abstract
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 nanoparticles 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.
Highlights
Pseudomonas aeruginosa is a Gram-negative opportunistic bacterium that causes chronic lung infections in patients with cystic fibrosis, ventilator-associated respiratory diseases, and catheter-associated urinary tract infections [1]
This study highlighted the potential of carvacrol loaded into chitosan nanoparticles as an effective treatment for P. aeruginosa biofilm-related infections
The alkylation of chitosan nanoparticles was studied for their ability to eradicate biofilms and avoid biofilm formation
Summary
Pseudomonas aeruginosa is a Gram-negative opportunistic bacterium that causes chronic lung infections in patients with cystic fibrosis, ventilator-associated respiratory diseases, and catheter-associated urinary tract infections [1]. P. aeruginosa has become more challenging to treat and eradicate due to its capacity to resist antibiotics [2,3,4]. P. aeruginosa infections involve biofilm formation and the presence of embedded persistent multidrugtolerant cells [3,5]. Biofilms are surface-attached communities of bacterial cells enclosed in a matrix of self-produced extracellular polymeric substances (EPS) composed of carbohydrates, proteins, and nucleic acids [5]. EPS form a highly complex network with a three-dimensional structure that supports cellular attachment and acts as a protective barrier against conventional antibiotics [3,6,7]. There has been a surge in scientific interest in the development of agents with effective antibiofilm properties that affect bacterial viability, attenuate motility, cellular adhesion, and quorum sensing (QS) [8,9]
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