Hydrophobic Chitosan Nanoparticles Loaded with Carvacrol against Pseudomonas aeruginosa Biofilms

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.

Enhanced antimicrobial, antibiofilm and ecotoxic activities of nanoencapsulated carvacrol and thymol as compared to their free counterparts

“…Classical cleaning and disinfection strategies have shown decreased efficiency towards biofilms removal due to the increased microbial resistance, in addition to the reduced diffusion owing to the extrapolymeric matrix that acts as a protective barrier for biofilms [1,6,14]. Therefore, alternative strategies such as the use of nano-based delivery systems encapsulating biosourced terpenes from essential oils (EOs) such as thymol (THY) have aroused as impressive control strategies with remarkable antibiofilm effectiveness against a wide range of pathogenic microorganisms [5,7,[15][16][17]. THY is recognized as safe to be used in food industries by the Food and Drug Administration (FDA) [18,19].…”

Investigation of the effects of antimicrobial and anti‐biofilm peptide IDR1018 and chitosan nanoparticles on ciprofloxacin‐resistant Escherichia coli

“…Peptide IDR1018 and CNs alone efficiently inhibited and eradicated the biofilms of clinical isolates in a concentration‐dependent manner ( p < 0.05). Biofilm inhibition and dispersion of the mature biofilm by peptide IDR1018 and CNs have been reported in the other studies [11, 43, 44]. In one research, peptide IDR1018 effectively prevented biofilm formation and eradicated mature biofilms in concentrations lower than the MIC that had effect on planktonic growth [11].…”

Nanomaterials Regulate Bacterial Quorum Sensing: Applications, Mechanisms, and Optimization Strategies

“…[ 64 ] Moreover, chitosan can destabilize the bacterial cell membrane, thereby enhancing the drug efficacy. [ 198 ] However, a previous study has shown that the net negative charge of NPs can prevent them from accumulating on biofilm surfaces, and when the NPs are weakly alkaline and positively charged, they cannot penetrate the biofilm to reach its core where resistant bacterial subpopulations exist. [ 199 ] Therefore, it is still a challenge to reasonably design the surface charge of nanomaterials to achieve the best balance between adsorption and penetration of bacterial defensive barriers.…”