Antimicrobial Photothermal Treatment of Pseudomonas Aeruginosa by a Carbon Nanoparticles-Polypyrrole Nanocomposite

Abstract

Background: Nowadays, it is needed to explore new routes to treat infectious bacterial pathogens due to prevalence of antibiotic-resistant bacteria. Antimicrobial photothermal therapy (PTT), as a new strategy, eradicates pathogenic bacteria.Objective: In this study, the antimicrobial effects of a carbon nanoparticles-polypyrrole nanocomposite (C-PPy) upon laser irradiation were investigated to destroy the pathogenic gram-negative Pseudomonas aeruginosa. Material and Methods:In this experimental study, the bacterial cells were incubated with 50, 100 and 250 µg mL -1 concentrations of C-PPy and irradiated with a 808-nm laser at two power densities of 0.5 and 1.0 W cm -2 . CFU numbers were counted for the irradiated cells, and compared to an untreated sample (kept in dark). To explore the antibacterial properties and mechanism(s) of C-PPy, temperature increment, reactive oxygen species formation, and protein and DNA leakages were evaluated. Field emission scanning electron microscopy was also employed to investigate morphological changes in the bacterial cell structures. Results:The results showed that following C-PPy attachment to the bacteria surface, irradiation of near-infrared light resulted in a significant decrement in the bacterial cell viability due to photothermal lysis. Slightly increase in protein leakage and significantly increase intracellular reactive oxygen species (ROS) were observed in the bacteria upon treating with C-PPy. Conclusion:Photo-ablation strategy is a new minimally invasive and inexpensive method without overdose risk manner for combat with bacteria.

Pseudomonas aeruginosa Biofilms

“…PTT involves the use of the near-infrared (NIR) light in a wavelength ranging from 700 to 1100 nm for irradiation of nanomaterials to generate localized heat which causes irreversible damage to nearby bacterial cells [ 207 ]. Various photothermal nanomaterials, including carbon-based nanocomposites [ 208 , 209 , 210 ], gold and silver nanoparticles [ 211 , 212 ] and conducting polymers [ 207 , 213 ], have been optimized for PTT. For example, gold nanorods (AuNR) surface engineered with phospholipid-polyethylene (PEG) have been developed and utilized against P. aeruginosa suspension and biofilm cultures [ 173 ].…”

Emerging Trends in Nanomaterials for Antibacterial Applications

“…The photothermal effect results in membrane damage followed by protein inactivation and/or leakage leading to bacterial death. 194 , 195 PTT against bacteria is efficacious on both gram-positive and gram negative types and regardless of antibiotic resistance. In addition to its efficiency, it is fast, noninvasive, and can be modulated by the laser intensity and time of irradiation.…”

Non-antibiotic methods against Pseudomonas aeruginosa include QS inhibitors: a narrative review

“…ROS also reacts with enzymes, proteins, lipids, and other cellular components in bacterial cells, resulting in cell death. Photoablation is a new minimally invasive and inexpensive antibacterial therapy without any excessive risk to normal cells (47). Other, 50-100 nm long gold nanorods presented on heteromultivalent and 3D display of 2 types of glycomimetic polymers can prevent the colonization of the bacteria and potential the formation of the biofilm by targeting LecA and LecB lectins on PA specifically, and they have shown the photothermal characteristics of killing pathogenic cells upon NIR light irradiation (48).…”