Nano-silver-modified PQC/DNA biosensor for detecting E. coli in environmental water

Sun, Hui; Choy, Tsj; Zhu, Ding; Yam, WC; Fung, YS

doi:10.1016/j.bios.2008.08.008

Cited by 69 publications

(30 citation statements)

References 33 publications

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“…4,5 Compared with other metals, silver nanoparticles show higher toxicity to microorganisms while exhibiting lower toxicity to mammalian cells. 6 To date, the most promising applications have been shown in the medical or pharmacological fields, such as biosensors 7 and wound treatment for infection. 8,9 Silver nanoparticles are available as an antimicrobial gel formulation for conventional topical antimicrobial agents, especially for burn treatment.…”

Section: Introductionmentioning

confidence: 99%

Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

Wu¹

2011

IJN

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Purpose:The purpose of the present study was to elucidate the antimicrobial activity and mechanism of silver nanoparticles incorporated into thermosensitive gel (S-T-Gel) on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Patients and methods: This study investigated the growth, permeability, and morphology of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa cells in order to observe the action of S-T-Gel on the membrane structure of these three bacteria. The cell morphology of normal and treated bacteria cells was assessed by transmission electron microscopy (TEM), and the effects of S-T-Gel on genome DNA of bacterial cells were evaluated by agarose gel electrophoresis. Results: S-T-Gel showed promising activity against Staphylococcus aureus and moderate activity against Escherichia coli and Pseudomonas aeruginosa. The observation with TEM suggested that S-T-Gel may destroy the structure of bacterial cell membranes in order to enter the bacterial cell. S-T-Gel then condensed DNA and combined and coagulated with the cytoplasm of the damaged bacteria, resulting in the leakage of the cytoplasmic component and the eventual death of these three bacteria. In addition, the analysis of agarose gel electrophoresis demonstrated that S-T-Gel could increase the decomposability of genome DNA. Conclusion: These results about promising antimicrobial activity and mechanism of S-T-Gel may be useful for further research and development in in-vivo studies.

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Section: Introductionmentioning

confidence: 99%

Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

Wu¹

2011

IJN

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“…This might be attributable to the presence of the thick cell wall of Mu50 (VISA) compared to that of Mu3 (hVISA) (3). Studies using atomic force microscopy and transmission electron microscopy with aerogel-generated nano-magnesium oxide against E. coli showed that the cell wall of this bacterium was extensively damaged, allowing the contents to leak out and nanoparticles to gain entry (14,33). Likewise, Ag NPs have been shown to attach to the microbial cell surface and penetrate inside, where intracellular targets, including respiratory enzymes, were disrupted (34).…”

Section: Discussionmentioning

confidence: 99%

Antibiofilm and Membrane-Damaging Potential of Cuprous Oxide Nanoparticles against Staphylococcus aureus with Reduced Susceptibility to Vancomycin

Singh

Ahmed

Prasad

et al. 2015

Antimicrob Agents Chemother

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The antimicrobial effects of copper ions and salts are well known, but the effects of cuprous oxide nanoparticles (Cu 2 O-NPs) on staphylococcal biofilms have not yet been clearly revealed. The present study evaluated Cu 2 O-NPs for their antibacterial and antibiofilm activities against heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and vancomycin-intermediate S. aureus (VISA). Nanoscaled Cu 2 O, generated by solution phase technology, contained Cu 2 O octahedral nanoparticles. Field emission electron microscopy demonstrated particles with sizes ranging from 100 to 150 nm. Cu 2 O-NPs inhibited the growth of S. aureus and showed antibiofilm activity. The MICs and minimum biofilm inhibitory concentrations ranged from 625 g/ml to 5,000 g/ml and from 2,500 g/ml to 10,000 g/ml, respectively. Exposure of S. aureus to Cu 2 O-NPs caused leakage of the cellular constituents and increased uptake of ethidium bromide and propidium iodide. Exposure also caused a significant reduction in the overall vancomycin-BODIPY (dipyrromethene boron difluoride [4,4-difluoro-4-bora-3a,4a-diaza-s-indacene] fluorescent dye) binding and a decrease in the viable cell count in the presence of 7.5% sodium chloride. Cu 2 O-NP toxicity assessment by hemolysis assay showed no cytotoxicity at 625 to 10,000 g/ml concentrations. The results suggest that Cu 2 O-NPs exert their action by disruption of the bacterial cell membrane and can be used as effective antistaphylococcal and antibiofilm agents in diverse medical devices. Biofilm formation, one of the defense mechanisms of Staphylococcus aureus, represents a structural community of bacterial cells embedded in a self-produced polymeric matrix adherent to an artificial surface (1). Biofilms can be associated with a variety of complications, the worst being the risk of bacterial and fungal infections in surgical implanted devices. Bacteria embedded in biofilms are hard to eradicate with standard antibiotics and are intrinsically resistant to host immune responses (2). S. aureus strains with reduced susceptibility to vancomycin, such as heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) and vancomycin-intermediate Staphylococcus aureus (VISA), are being reported increasingly worldwide (3). The emergence of such strains is attributed to excess or irrational use of vancomycin and poor tissue penetration (4). Biofilm formation also plays an important role in the pathogenesis of staphylococcal infections, especially with prosthetic materials (5). It is presumed to be a significant initial step in the pathway to development of vancomycin resistance (6, 7). Biofilm infections are difficult to treat due to their inherent antibiotic resistance (8). Only limited numbers of antibiotics, such as daptomycin, quinupristin-dalfopristin, linezolid, and tigecycline, are active against the vancomycin-nonsusceptible S. aureus strains (9). Interestingly, daptomycin nonsusceptibility is also being reported for some hVISA and VISA isolates (10, 11). Despite antimicrobial therapy, the ...

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“…The local concentration of surface probe is much higher than it would otherwise be in the homogenous reaction, and thus, the hybridization usually reaches equilibrium in 10-15 min (Dell'Atti et al 2007, Uludag et al 2008, Liao and Ho 2009, Sun et al 2009, Li et al 2013). This time is true when C T in the nanomolar to micromolar concentration range.…”

Section: Considerations For Probe Immobilization and Hybridization Stmentioning

confidence: 99%

Nucleic acid electrochemical and electromechanical biosensors: a review of techniques and developments

Rosario

Mutharasan

2014

Reviews in Analytical Chemistry

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This review comprises the last decade's development on experimental techniques for electrochemical and electromechanical sensing of nucleic acids, which originate from pathogenic bacteria, parasites, and viruses commonly found in food, water, and medical context. The electrochemical devices that are of primary interest are those that use voltammetry for detecting DNA and RNA-associated electrochemically active molecules at the working electrode. Attograms of nucleic acids have been reported to be detectable with electrochemical sensors in a batch-mode measurement arrangement. The masssensing electromechanical devices sense nucleic acids at the femtogram levels in a flow format without a molecular technique for amplifying target strand using polymerase chain reaction. Both underlying physics and methods of various studies are summarized, with discussion on limitations and potentials. We call attention to the need for sensors that not only detect but also confirm detection, as false negatives are not acceptable when one measures pathogenic species.

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Nano-silver-modified PQC/DNA biosensor for detecting E. coli in environmental water

Cited by 69 publications

References 33 publications

Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

Antimicrobial activity and the mechanism of silver nanoparticle thermosensitive gel

Antibiofilm and Membrane-Damaging Potential of Cuprous Oxide Nanoparticles against Staphylococcus aureus with Reduced Susceptibility to Vancomycin

Nucleic acid electrochemical and electromechanical biosensors: a review of techniques and developments

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