The Role of Surface Chemistry on the Toxicity of Ag Nanoparticles

Xiong, Yujie; Brunson, Mark W.; Huh, Juyoung; Huang, Aaron Y.; Coster, Adam; Wendt, K.; Fay, Justin C.; Qin, Dong

doi:10.1002/smll.201202476

Cited by 35 publications

(40 citation statements)

References 40 publications

(46 reference statements)

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“…As yeast cell walls were rigid, it could be supposed that under typical conditions nanoparticles cannot enter the cell (23,43,60). TEM observation also confirmed that no particles were inside yeast cells when cells were cultivated with CuO-NPs in our study (data not shown).…”

Section: Figsupporting

confidence: 77%

“…After being cultivated with CuO-NPs, copper salt, and bCuO in 5 ml of SD medium for 4 h, the yeast cells were harvested by centrifugation at 8,000 ϫ g for 10 min and washed with PBS (pH 7.2) two times to remove copper adsorbed to the surface of the yeast (41,42). The process of separating nanoparticles from cells followed a method described previously (43). Briefly, 2 ml of ferric nitrate (1 mol/liter) was added into the sample as etchant solution; after 5 min of etching, the solution was removed by centrifugation, and samples were washed two times again with PBS.…”

Section: Methodsmentioning

confidence: 99%

“…To investigate whether the differences in cytotoxicity levels could be explained by the differences in cellular uptake of nanoparticles, i.e., a Trojan horse mechanism, we followed the method described by Xiong et al (43) to measure the copper content inside yeast cells. By carefully etching with ferric nitrate and washing samples with PBS, free particles and copper ions in medium as well as those absorbed on the cells were removed.…”

Section: Intracellular Ros Generationmentioning

confidence: 99%

See 2 more Smart Citations

Assessment of the Toxicity of CuO Nanoparticles by Using Saccharomyces cerevisiae Mutants with Multiple Genes Deleted

Bao

Fang

et al. 2015

Appl Environ Microbiol

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bTo develop applicable and susceptible models to evaluate the toxicity of nanoparticles, the antimicrobial effects of CuO nanoparticles (CuO-NPs) on various Saccharomyces cerevisiae (S. cerevisiae) strains (wild type, single-gene-deleted mutants, and multiple-gene-deleted mutants) were determined and compared. Further experiments were also conducted to analyze the mechanisms associated with toxicity using copper salt, bulk CuO (bCuO), carbon-shelled copper nanoparticles (C/Cu-NPs), and carbon nanoparticles (C-NPs) for comparisons. The results indicated that the growth inhibition rates of CuO-NPs for the wild-type and the single-gene-deleted strains were comparable, while for the multiple-gene deletion mutant, significantly higher toxicity was observed (P < 0.05). When the toxicity of the CuO-NPs to yeast cells was compared with the toxicities of copper salt and bCuO, we concluded that the toxicity of CuO-NPs should be attributed to soluble copper rather than to the nanoparticles. The striking difference in adverse effects of C-NPs and C/Cu-NPs with equivalent surface areas also proved this. A toxicity assay revealed that the multiple-gene-deleted mutant was significantly more sensitive to CuO-NPs than the wild type. Specifically, compared with the wild-type strain, copper was readily taken up by mutant strains when cell permeability genes were knocked out, and the mutants with deletions of genes regulated under oxidative stress (OS) were likely producing more reactive oxygen species (ROS). Hence, as mechanism-based gene inactivation could increase the susceptibility of yeast, the multiple-gene-deleted mutants should be improved model organisms to investigate the toxicity of nanoparticles. With recent developments in nanotechnology around the world, there are mounting concerns regarding the potential environmental and human health risks caused by exposure to engineered nanomaterials (ENMs). Relative to the rapid development of nanotechnology, ecotoxicology and environmental hazard assessments have obviously fallen behind and still represent huge knowledge gaps (1). It is thus urgent to establish approaches to speed up safety analysis, and the insights gained from these approaches could give us a better understanding of the hazardous effects ENMs at the biological level and assist the development of safe-design approaches.As one of the increasingly used metal oxide nanoparticles (NPs), CuO-NPs have been applied to superconducting materials, sensing materials, glass, and ceramics and in other primarily antimicrobial applications (2). The extensive production and usage of CuO-NPs increase the harmful effects to organisms. Investigators have demonstrated that CuO-NPs are toxic to Escherichia coli HB101 (3, 4), prokaryotic alga Microcystis aeruginosa (5), airway epithelial (HEp-2) cells (6), the crustacean Thamnocephalus platyurus (7), Lemna gibba (8), mice (9), and other organisms. A considerable amount of research has been done about the toxicity of CuO-NPs, and comparative interspecies sensitivity was found to vary...

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Section: Figsupporting

confidence: 77%

Section: Methodsmentioning

confidence: 99%

Section: Intracellular Ros Generationmentioning

confidence: 99%

See 1 more Smart Citation

Assessment of the Toxicity of CuO Nanoparticles by Using Saccharomyces cerevisiae Mutants with Multiple Genes Deleted

Bao

Fang

et al. 2015

Appl Environ Microbiol

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“…It was widely reported that AgNP-induced biological effects or toxicities were mainly involved with silver ion release or intracellular ROS generation, 7,11,39 although some studies emphasized that AgNPs could efficiently induce oxidative stress through excessive ROS production, which was distinct from silver ions. 17 The results obtained herein revealed the concurrence of Ag + and ROS in AgNP-exposed bacterial system, showing the complexity of the antibacterial effects induced by AgNPs.…”

mentioning

confidence: 57%

“…The biologically active radical species are capable of attacking the cell membrane, posing oxidative stress, or even causing death to the cells. [15][16][17] Meanwhile, the released silver ions can approach negatively charged cell membrane and interfere with its integrity. 1 Moreover, the internalized AgNPs through endocytosis or pinocytosis may pose a Trojan-horse-type effect, releasing silver ions in the cytoplasm through the reactions with organelles such as mitochondria.…”

Section: Long Et Almentioning

confidence: 99%

Surface ligand controls silver ion release of nanosilver and its antibacterial activity against <em>Escherichia coli</em>

Long¹,

Hu²,

Yan³

et al. 2017

IJN

121

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Understanding the mechanism of nanosilver-dependent antibacterial activity against microorganisms helps optimize the design and usage of the related nanomaterials. In this study, we prepared four kinds of 10 nm-sized silver nanoparticles (AgNPs) with dictated surface chemistry by capping different ligands, including citrate, mercaptopropionic acid, mercaptohexanoic acid, and mercaptopropionic sulfonic acid. Their surface-dependent chemistry and antibacterial activities were investigated. Owing to the weak bond to surface Ag, short carbon chain, and low silver ion attraction, citrate-coated AgNPs caused the highest silver ion release and the strongest antibacterial activity against Escherichia coli , when compared to the other tested AgNPs. The study on the underlying antibacterial mechanisms indicated that cellular membrane uptake of Ag, NAD + /NADH ratio increase, and intracellular reactive oxygen species (ROS) generation were significantly induced in both AgNP and silver ion exposure groups. The released silver ions from AgNPs inside cells through a Trojan-horse-type mechanism were suggested to interact with respiratory chain proteins on the membrane, interrupt intracellular O 2 reduction, and induce ROS production. The further oxidative damages of lipid peroxidation and membrane breakdown caused the lethal effect on E. coli . Altogether, this study demonstrated that AgNPs exerted antibacterial activity through the release of silver ions and the subsequent induction of intracellular ROS generation by interacting with the cell membrane. The findings are helpful in guiding the controllable synthesis through the regulation of surface coating for medical care purpose.

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3D Printed Dry Electrodes for Electrophysiological Signal Monitoring: A Review

Alsharif

Cucuri

Mishra

et al. 2023

Adv Materials Technologies

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EP electrodes are classified into two main categories: invasive (internal) and non-invasive (external). Non-invasive electrodes involve a harmless approach that detects EP signals from the surface of the human skin. [13,14] Human skin is divided into two main layers: the epidermis and dermis. The outer layer of human skin, the stratum corneum on the epidermis, has outstanding electrode-skin impedance features. [15] Therefore, while employing noninvasive electrodes for EP signal detection, it is essential to minimize the effect of the stratum corneum completely and thoroughly. Majority of the non-invasive electrodes are used in medical monitoring systems and are composed of silver/silver chloride (Ag/AgCl) electrodes, [16][17][18][19] which have been utilized for many years. [20,21] In fact, state-of-the-art non-invasive electrodes are traditionally classified into three types based on the proportion of electrolytes present at the electrodeskin interface: wet electrodes, semi-dry electrodes, and dry electrodes. [22] Traditional wet electrodes setup includes Ag/AgCl electrodes and conductive gels that lowers the electrode-skin impedance between the electrodes and the epidermal layer of the human skin. The introduction of the gel plays an important role in establishing a non-polarized electrode-electrolyte interface and a stable electrode-skin interface. However, conductive gels or pastes limit the long-term monitoring of electrodes because of its tendency to cause skin irritation. [23] They can dehydrate and coagulate after prolonged use, thereby increasing the signal detection noise and degrading the signal quality. [24] In recent decades, several approaches have been developed to fabricate dry electrodes that do not require wet gels, making them a promising alternative as they have enhanced signal quality, portability, and ease of use. [25] Dry electrodes have clearly demonstrated several advantages, including rapid setup as well as user comfort due to the absence of conductive gels, skin preparation, and post-monitor cleaning. However, due to a lack of electrolytes, dry electrodes typically produce high electrode-skin impedance values that are substantially greater than those of wet electrodes. Furthermore, dry electrodes are prone to ambient noise and movement artifacts, making them unsuitable for mobile applications such as sports and where movement is required due to the noise produced in the EP signal. [22] The semi-dry electrode came out to be the most promising option. Although this term is out of the scope of this paper, semi-dry electrodes replaced the conductive gels 3D printed on-skin electrodes are of notable interest because, unlike traditional wet silver/silver chloride (Ag/AgCl) on-skin electrodes, they can be personalized and 3D printed using a variety of materials with distinct properties such as stretchability, conformal interfaces with skin, biocompatibility, wearable comfort, and, finally, low-cost manufacturing. Dry on-skin electrodes, in particular, have the additional advantage of replacing...

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The Role of Surface Chemistry on the Toxicity of Ag Nanoparticles

Cited by 35 publications

References 40 publications

Assessment of the Toxicity of CuO Nanoparticles by Using Saccharomyces cerevisiae Mutants with Multiple Genes Deleted

Assessment of the Toxicity of CuO Nanoparticles by Using Saccharomyces cerevisiae Mutants with Multiple Genes Deleted

Surface ligand controls silver ion release of nanosilver and its antibacterial activity against <em>Escherichia coli</em>

3D Printed Dry Electrodes for Electrophysiological Signal Monitoring: A Review

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