The Effect of Charge at the Surface of Silver Nanoparticles on Antimicrobial Activity against Gram‐Positive and Gram‐Negative Bacteria: A Preliminary Study

Abbaszadegan, Abbas; Ghahramani, Yasamin; Gholami, Ahmad; Hemmateenejad, Bahram; Dorostkar, Samira; Nabavizadeh, Mohammadreza; Sharghi, Hashem

doi:10.1155/2015/720654

Cited by 437 publications

(338 citation statements)

References 30 publications

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“…This is consistent with previous reports using surface functionalized silver nanoparticles of positive and neutral charge. 39 The extent of cytotoxicity towards mammalian cells was dependent on the ratio of positively charged ligands, which is consistent with previous findings that positively charged AuNPs depolarize membrane potential and disrupt cell membrane lipid bilayers. 32 We found evidence for cytotoxicity, but interestingly there was no disruption of cell membrane integrity by positively charged AuNPs.…”

Section: Discussionsupporting

confidence: 91%

Targeting bacterial biofilms via surface engineering of gold nanoparticles

et al. 2015

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Bacterial biofilms are associated with persistent infections that are resistant to conventional antibiotics and substantially complicate patient care. Surface engineered nanoparticles represent a novel, unconventional approach for disruption of biofilms and targeting of bacterial pathogens. Herein, we describe the role of surface charge of gold nanoparticles (AuNPs) on biofilm disruption and bactericidal activity towards Staphylococcus aureus and Pseudomonas aeruginosa which are important ventilator associated pneumonia (VAP) pathogens. In addition, we study the toxicity of charged AuNPs on human bronchial epithelial cells. While 100% positively charged AuNP surface was uniformly toxic to both bacteria and epithelial cells, reducing the extent of positive charge on the AuNP surface at moderate concentrations prevented epithelial cell toxicity. Reducing surface charge was however also less effective in killing bacteria. Conversely, increasing AuNP concentration while maintaining a low level of positivity continued to be bactericidal and disrupt the bacterial biofilm and was less cytotoxic to epithelial cells. These initial in vitro studies suggest that modulation of AuNP surface charge could be used to balance effects on bacteria vs. airway cells in the context of VAP, but the therapeutic window in terms of concentration vs. surface positive charge may be limited. Additional factors such as hydrophobicity may need to be considered in order to design AuNPs with specific, beneficial effects on bacterial pathogens and their biofilms.

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Section: Discussionsupporting

confidence: 91%

Targeting bacterial biofilms via surface engineering of gold nanoparticles

et al. 2015

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“…Mycosynthesis of nano-Ag affected by the interaction of Ag NPs with biomolecules released by microorganism metabolism, likely proteins will influence surface chemistry of nanoparticles and modify their electronic charge and agglomeration state leading to the improvement of their biological activity82. Phytochemical analysis is carried out in plant species but only few reports are available in endophytes47.…”

Section: Discussionmentioning

confidence: 99%

Applying Taguchi design and large-scale strategy for mycosynthesis of nano-silver from endophytic Trichoderma harzianum SYA.F4 and its application against phytopathogens

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et al. 2017

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100

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Development of reliable and low-cost requirement for large-scale eco-friendly biogenic synthesis of metallic nanoparticles is an important step for industrial applications of bionanotechnology. In the present study, the mycosynthesis of spherical nano-Ag (12.7 ± 0.8 nm) from extracellular filtrate of local endophytic T. harzianum SYA.F4 strain which have interested mixed bioactive metabolites (alkaloids, flavonoids, tannins, phenols, nitrate reductase (320 nmol/hr/ml), carbohydrate (25 μg/μl) and total protein concentration (2.5 g/l) was reported. Industrial mycosynthesis of nano-Ag can be induced with different characters depending on the fungal cultivation and physical conditions. Taguchi design was applied to improve the physicochemical conditions for nano-Ag production, and the optimum conditions which increased its mass weight 3 times larger than a basal condition were as follows: AgNO3 (0.01 M), diluted reductant (10 v/v, pH 5) and incubated at 30 °C, 200 rpm for 24 hr. Kinetic conversion rates in submerged batch cultivation in 7 L stirred tank bioreactor on using semi-defined cultivation medium was as follows: the maximum biomass production (Xmax) and maximum nano-Ag mass weight (Pmax) calculated (60.5 g/l and 78.4 g/l respectively). The best nano-Ag concentration that formed large inhibition zones was 100 μg/ml which showed against A.alternate (43 mm) followed by Helminthosporium sp. (35 mm), Botrytis sp. (32 mm) and P. arenaria (28 mm).

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“…The positive surface charge of the AgNPs is crucial for the adhesion (Abbaszadegan et al, 2015). The positive charge confers electrostatic attraction between AgNPs and negatively charged cell membrane of the microorganisms, thereby facilitates AgNPs attachment onto cell membranes.…”

Section: Effects Of Nanoscale and Physico-chemical Properties On Antimentioning

confidence: 99%

Mechanistic Basis of Antimicrobial Actions of Silver Nanoparticles

et al. 2016

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Multidrug resistance of the pathogenic microorganisms to the antimicrobial drugs has become a major impediment toward successful diagnosis and management of infectious diseases. Recent advancements in nanotechnology-based medicines have opened new horizons for combating multidrug resistance in microorganisms. In particular, the use of silver nanoparticles (AgNPs) as a potent antibacterial agent has received much attention. The most critical physico-chemical parameters that affect the antimicrobial potential of AgNPs include size, shape, surface charge, concentration and colloidal state. AgNPs exhibits their antimicrobial potential through multifaceted mechanisms. AgNPs adhesion to microbial cells, penetration inside the cells, ROS and free radical generation, and modulation of microbial signal transduction pathways have been recognized as the most prominent modes of antimicrobial action. On the other side, AgNPs exposure to human cells induces cytotoxicity, genotoxicity, and inflammatory response in human cells in a cell-type dependent manner. This has raised concerns regarding use of AgNPs in therapeutics and drug delivery. We have summarized the emerging endeavors that address current challenges in relation to safe use of AgNPs in therapeutics and drug delivery platforms. Based on research done so far, we believe that AgNPs can be engineered so as to increase their efficacy, stability, specificity, biosafety and biocompatibility. In this regard, three perspectives research directions have been suggested that include (1) synthesizing AgNPs with controlled physico-chemical properties, (2) examining microbial development of resistance toward AgNPs, and (3) ascertaining the susceptibility of cytoxicity, genotoxicity, and inflammatory response to human cells upon AgNPs exposure.

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The Effect of Charge at the Surface of Silver Nanoparticles on Antimicrobial Activity against Gram‐Positive and Gram‐Negative Bacteria: A Preliminary Study

Cited by 437 publications

References 30 publications

Targeting bacterial biofilms via surface engineering of gold nanoparticles

Targeting bacterial biofilms via surface engineering of gold nanoparticles

Applying Taguchi design and large-scale strategy for mycosynthesis of nano-silver from endophytic Trichoderma harzianum SYA.F4 and its application against phytopathogens

Mechanistic Basis of Antimicrobial Actions of Silver Nanoparticles

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