Bioconjugated nanoparticles for attachment and penetration into pathogenic bacteria

Mei, Lin; Lu, Zhentan; Zhang, Wei; Wu, Zhongming; Zhang, Xinge; Wang, Yanan; Luo, Yuting; Li, Chaoxing; Jia, Yulin

doi:10.1016/j.biomaterials.2013.09.045

Cited by 107 publications

(92 citation statements)

References 47 publications

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“…The somewhat higher values of RSC% in DPPH than in lipid peroxidation indicated that the nanoparticles were more likely to ET-based reaction rather than HAT-based reaction. This behavior was different from that of some organic antioxidants such as rutin, which could react quickly with lipid peroxyl radicals but not nitrogen radicals [42]. The discussion about the difference between Se and organic antioxidants was not discussed because it was beyond the scope of this work.…”

Section: Resultsmentioning

confidence: 90%

“…After 6 h of exposure, biopsy samples from the small intestines and dorsal skin were immediately obtained for SEM observation. The ultrathin sections were made as following [42]. The small intestines and dorsal skin were quickly sliced into small pieces (1 mm × 1 mm), and then washed and fixed with 2.5% glutaraldehyde in PBS buffer (pH 7.4, 10 mmol/L).…”

Section: Methodsmentioning

confidence: 99%

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Antioxidant capacities of the selenium nanoparticles stabilized by chitosan

et al. 2017

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BackgroundsSelenium (Se) as one of the essential trace elements for human plays an important role in the oxidation reduction system. But the high toxicity of Se limits its application. In this case, the element Se with zero oxidation state (Se0) has captured our attention because of its low toxicity and excellent bioavailability. However, Se0 is very unstable and easily changes into the inactive form. By now many efforts have been done to protect its stability. And this work was conducted to explore the antioxidant capacities of the stable Se0 nanoparticles (SeNPs) stabilized using chitosan (CS) with different molecular weights (Mws) (CS-SeNPs).ResultsThe different Mws CS-SeNPs could form uniform sphere particles with a size of about 103 nm after 30 days. The antioxidant tests of the DPPH, ABTS, and lipid peroxide models showed that these CS-SeNPs could scavenge free radicals at different levels. And the 1 month old SeNPs held the higher ABTS scavenging ability that the value could reach up to 87.45 ± 7.63% and 89.44 ± 5.03% of CS(l)-SeNPs and CS(h)-SeNPs, respectively. In the cell test using BABLC-3T3 or Caco-2, the production of the intracellular reactive oxygen species (ROS) could be inhibited in a Se concentration-dependent manner. The topical or oral administration of CS-SeNPs, particularly the Se nanoparticles stabilized with low molecular weight CS, CS(l)-SeNPs, and treated with a 30-day storage process, could efficiently protect glutathione peroxidase (GPx) activity and prevent the lipofusin formation induced by UV-radiation or d-galactose in mice, respectively. Such effects were more evident in viscera than in skin. The acute toxicity of CS(l)-SeNPs was tenfold lower than that of H2SeO3.ConclusionsOur work could demonstrate the CS-SeNPs hold a lower toxicity and a 30-day storage process could enhance the antioxidant capacities. All CS-SeNPs could penetrate the tissues and perform their antioxidant effects, especially the CS(l)-SeNPs in mice models. What’s more, the antioxidant capacities of CS-SeNPs were more evident in viscera than in skin.

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Section: Resultsmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Antioxidant capacities of the selenium nanoparticles stabilized by chitosan

et al. 2017

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“…The species-specific antibacterial mechanism may be caused by structural differences in the organization of the bacterial cell wall. Some studies found that the thicker cell wall of G+ bacteria acts as a barrier protecting the cell from penetration of silver nanoparticles and ions into the cytoplasm 19, 20 . This may be part of the reason CSS-Ag NPs exhibited a better antibacterial effect on G− bacteria rather than G+ bacteria.…”

Section: Resultsmentioning

confidence: 99%

Catechol-Functional Chitosan/Silver Nanoparticle Composite as a Highly Effective Antibacterial Agent with Species-Specific Mechanisms

Huang

Bao

Liu

et al. 2017

Sci Rep

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In this study, silver nanoparticles (Ag NPs) coated with catechol-conjugated chitosan (CSS) were prepared using green methods. Interestingly, we uncovered that CSS-coated Ag NPs (CSS-Ag NPs) exhibited a higher toxicity against gram-negative Escherichia coli (E. coli) bacteria than against gram-positive Staphylococcus aureus (S. aureus) bacteria. The differences revealed that the CSS-Ag NPs killed gram bacteria with distinct, species-specific mechanisms. The aim of this study is to further investigate these underlying mechanisms through a series of analyses. The ultrastructure and morphology of the bacteria before and after treatment with CSS-Ag NPs were observed. The results demonstrated the CSS-Ag NPs killed gram-positive bacteria through a disorganization of the cell wall and leakage of cytoplasmic content. In contrast, the primary mechanism of action on gram-negative bacteria was a change in membrane permeability, induced by adsorption of CSS-Ag NPs. The species-specific mechanisms are caused by structural differences in the cell walls of gram bacteria. Gram-positive bacteria are protected from CSS-Ag NPs by a thicker cell wall, while gram-negatives are more easily killed due to an interaction between a special outer membrane and the nanoparticles. Our study offers an in-depth understanding of the antibacterial behaviors of CSS-Ag NPs and provides insights into ultimately optimizing the design of Ag NPs for treatment of bacterial infections.

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“…The cell suspension was sampled at 0, 5, 30 and 60 min of incubation, stained with fluorescent dye using the LIVE/DEAD kit for 15 min in the dark, and smeared on glass slides. Fluorescence images were taken under a fluorescence microscope using excitation and emission wavelengths of 494 and 515 nm for Sytox® Green and 528 and 617 nm for propidium iodide, respectively [28]. …”

Section: Methodsmentioning

confidence: 99%

Two-Phase Bactericidal Mechanism of Silver Nanoparticles against Burkholderia pseudomallei

et al. 2016

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Silver nanoparticles (AgNPs) have a strong antimicrobial activity against a variety of pathogenic bacteria. The killing mechanism of AgNPs involves direct physical membrane destruction and subsequent molecular damage from both AgNPs and released Ag+. Burkholderia pseudomallei is the causative agent of melioidosis, an endemic infectious disease primarily found in northern Australia and Southeast Asia. B. pseudomallei is intrinsically resistant to most common antibiotics. In this study, the antimicrobial activity and mechanism of AgNPs (10–20 nm) against B. pseudomallei were investigated. The MIC and MBC for nine B. pseudomallei strains ranged from 32–48 μg/mL and 96–128 μg/mL, respectively. Concentrations of AgNPs less than 256 μg/mL were not toxic to human red blood cells. AgNPs exhibited a two-phase mechanism: cell death induction and ROS induction. The first phase was a rapid killing step within 5 min, causing the direct damage of the cytoplasmic membrane of the bacterial cells, as observed by a time-kill assay and fluorescence microscopy. During the period of 5–30 min, the cell surface charge was rapidly neutralized from -8.73 and -7.74 to 2.85 and 2.94 mV in two isolates of B. pseudomallei, as revealed by zeta potential measurement. Energy-dispersive X-ray (EDX) spectroscopy showed the silver element deposited on the bacterial membrane, and TEM micrographs of the AgNP-treated B. pseudomallei cells showed severe membrane damage and cytosolic leakage at 1/5 MIC and cell bursting at MBC. During the killing effect the released Ag+ from AgNPs was only 3.9% from the starting AgNPs concentration as observed with ICP-OES experiment. In the second phase, the ROS induction occurred 1–4 hr after the AgNP treatment. Altogether, we provide direct kinetic evidence of the AgNPs killing mechanism, by which cell death is separable from the ROS induction and AgNPs mainly contributes in the killing action. AgNPs may be considered a potential candidate to develop a novel alternative agent for melioidosis treatment with fast action.

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Bioconjugated nanoparticles for attachment and penetration into pathogenic bacteria

Cited by 107 publications

References 47 publications

Antioxidant capacities of the selenium nanoparticles stabilized by chitosan

Antioxidant capacities of the selenium nanoparticles stabilized by chitosan

Catechol-Functional Chitosan/Silver Nanoparticle Composite as a Highly Effective Antibacterial Agent with Species-Specific Mechanisms

Two-Phase Bactericidal Mechanism of Silver Nanoparticles against Burkholderia pseudomallei

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