Size-Dependent Antibacterial Activity of Silver Nanoparticle-Loaded Graphene Oxide Nanosheets

A series of graphene oxide (GO) suspensions with different particle sizes (<100 nm, ~100 nm, ~1 µm and >1 µm) were successfully fabricated after 0, 30, 60 and 120 min of sonication, respectively. The antibacterial properties of GO suspensions showed that >1 µm GO size resulted in a loss of nearly 50% of bacterial viability, which was higher than treatment by ~100 nm GO size (25%) towards Escherichia coli (E. coli). Complete entrapment of bacteria by the larger GO was observed in transmission electron microscopy (TEM). Silver nanoparticles (Ag NPs) were doped onto GO samples with different lateral sizes to form GO–Ag NP composites. Resulting larger GO–Ag NPs showed higher antibacterial activity than smaller GO–Ag NPs. As observed by Fourier transform infrared spectroscopy (FTIR), the interaction between E. coli and GO occurred mainly at the outer membrane, where membrane amino acids interact with hydroxyl and epoxy groups. The reactive oxygen species (ROS) and the considerable penetration of released Ag+ into the inner bacterial cell membrane result in loss of membrane integrity and damaged morphology. The present work improves the combined action of GO size effect with constant Ag loadings for potential antibacterial activity.

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Antibacterial Property of Composites of Reduced Graphene Oxide with Nano-Silver and Zinc Oxide Nanoparticles Synthesized Using a Microwave-Assisted Approach

International Journal of Molecular Sciences ◽

10.3390/ijms20215394 ◽

2019 ◽

Vol 20 (21) ◽

pp. 5394 ◽

Cited By ~ 4

Author(s):

Yi-Huang Hsueh ◽

Chien-Te Hsieh ◽

Shu-Ting Chiu ◽

Ping-Han Tsai ◽

Chia-Ying Liu ◽

...

Keyword(s):

Zinc Oxide ◽

Antibacterial Activity ◽

Graphene Oxide ◽

Reductase Activity ◽

Chemical Reduction ◽

Membrane Integrity ◽

Zno Nps ◽

Nano Silver ◽

E Coli ◽

Microwave Assisted

Graphene oxide (GO) composites with various metal nanoparticles (NPs) are attracting increasing interest owing to their broad scope in biomedical applications. Here, microwave-assisted chemical reduction was used to deposit nano-silver and zinc oxide NPs (Ag and ZnO NPs) on the surface of reduced GO (rGO) at the following weight percentages: 5.34% Ag/rGO, 7.49% Ag/rGO, 6.85% ZnO/rGO, 16.45% ZnO/rGO, 3.47/34.91% Ag/ZnO/rGO, and 7.08/15.28% Ag/ZnO/rGO. These materials were tested for antibacterial activity, and 3.47/34.91% Ag/ZnO/rGO and 7.08/15.28% Ag/ZnO/rGO exhibited better antibacterial activity than the other tested materials against the gram-negative bacterium Escherichia coli K12. At 1000 ppm, both these Ag/ZnO/rGO composites had better killing properties against both E. coli K12 and the gram-positive bacterium Staphylococcus aureus SA113 than Ag/rGO and ZnO/rGO did. RedoxSensor flow cytometry showed that 3.47/34.91% Ag/ZnO/rGO and 7.08/15.28% Ag/ZnO/rGO decreased reductase activity and affected membrane integrity in the bacteria. At 100 ppm, these two composites affected membrane integrity more in E. coli, while 7.08/15.28% Ag/ZnO/rGO considerably decreased reductase activity in S. aureus. Thus, the 3.47/34.91% and 7.08%/15.28% Ag/ZnO/rGO nanocomposites can be applied not only as antibacterial agents but also in a variety of biomedical materials such as sensors, photothermal therapy, drug delivery, and catalysis, in the future.

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Structure-Function Relationship of Antibacterial Synthetic Peptides Homologous to a Helical Surface Region on Human Lactoferrin against Escherichia coli Serotype O111

Infection and Immunity ◽

10.1128/iai.66.6.2434-2440.1998 ◽

1998 ◽

Vol 66 (6) ◽

pp. 2434-2440 ◽

Cited By ~ 72

Author(s):

Daniel S. Chapple ◽

David J. Mason ◽

Christopher L. Joannou ◽

Edward W. Odell ◽

Vanya Gant ◽

...

Keyword(s):

Electron Microscopy ◽

Escherichia Coli ◽

Transmission Electron Microscopy ◽

Flow Cytometry ◽

Antibacterial Activity ◽

Synthetic Peptides ◽

Membrane Integrity ◽

E Coli ◽

Transmission Electron ◽

Helical Region

ABSTRACT Lactoferricin includes an 11-amino-acid amphipathic alpha-helical region which is exhibited on the outer surface of the amino-terminal lobe of lactoferrin. Synthetic peptides homologous to this region exhibited potent antibacterial activity against a selected range of both gram-negative and gram-positive bacteria. An analog synthesized with methionine substituted for proline at position 26, which is predicted to disrupt the helical region, abolished antibacterial activity against Escherichia coli and considerably reduced antibacterial activity against Staphylococcus aureus and anAcinetobacter strain. The mode of action of human lactoferrin peptide (HLP) 2 against E. coli serotype O111 (NCTC 8007) was established by using flow cytometry, surface plasmon resonance, and transmission electron microscopy. Flow cytometry was used to monitor membrane potential, membrane integrity, and metabolic processes by using the fluorescent probes bis-1,3-(dibutylbarbituric acid)-trimethine oxonol, propidium iodide, and carbonyl cyanide m-chlorophenylhydrazone, respectively. HLP 2 was found to act at the cell membrane, causing complete loss of membrane potential after 10 min and of membrane integrity within 30 min, with irreversible damage to the cell as shown by rapid loss of viability. The number of particles, measured by light scatter on the flow cytometer, dropped significantly, showing that bacterial lysis resulted. The peptide was shown to bind toE. coli O111 lipopolysaccharide by using surface plasmon resonance. Transmission electron microscopy revealed bacterial distortion, with the outer membrane becoming detached from the inner cytoplasmic membrane. We conclude that HLP 2 causes membrane disruption of the outer membrane, resulting in lysis, and that structural considerations are important for antibacterial activity.

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Synergistic Antibacterial Activity of Silver-Loaded Graphene Oxide towards Staphylococcus Aureus and Escherichia Coli

Nanomaterials ◽

10.3390/nano10020366 ◽

2020 ◽

Vol 10 (2) ◽

pp. 366 ◽

Cited By ~ 8

Author(s):

Truong Vi ◽

Selvaraj Kumar ◽

Jong-Hwei Pang ◽

Yu-Kuo Liu ◽

Dave Chen ◽

...

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Bactericidal Effect ◽

Catalytic Performance ◽

Redox Activity ◽

Ag Nps ◽

E Coli ◽

Transmission Electron ◽

Physicochemical Effect

In this study, the physicochemical and surface properties of the GO–Ag composite promote a synergistic antibacterial effect towards both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. Aureus) bacteria. GO–Ag NPs have a better bactericidal effect on E. coli (73%) and S. Aureus (98.5%) than pristine samples (pure Ag or GO). Transmission electron microscopy (TEM) confirms that the GO layers folded entire bacteria by attaching to the membrane through functional groups, while the Ag NPs penetrated the inner cell, thus damaging the cell membrane and leading to cell death. Cyclic voltammetry (CV) tests showed significant redox activity in GO–Ag NPs, enabling good catalytic performance towards H2O2 reduction. Strong reactive oxygen species (ROS) in GO–Ag NPs suggests that ROS might be associated with bactericidal activity. Therefore, the synergy between the physicochemical effect and ROS production of this material is proposed as the mechanism of its antibacterial activity.

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In Vitro Antibacterial Activity of Biological-Derived Silver Nanoparticles: Preliminary Data

Veterinary Sciences ◽

10.3390/vetsci7010012 ◽

2020 ◽

Vol 7 (1) ◽

pp. 12

Author(s):

Gabriele Meroni ◽

Joel F. Soares Filipe ◽

Piera A. Martino

Keyword(s):

Silver Nanoparticles ◽

Antibacterial Activity ◽

Curcuma Longa ◽

Antibacterial Properties ◽

Antibacterial Activities ◽

E Coli ◽

Transmission Electron ◽

Disk Diffusion Assay ◽

Biological Methods

Silver nanoparticles (AgNPs) are promising alternatives to antibiotics. The aims of this study were to produce AgNPs using two biological methods and determine their antibacterial activity against Pseudomonas aeruginosa and Staphylococcus pseudintermedius. AgNPs were biosynthesized from an infusion of Curcuma longa (turmeric) and the culture supernatant of E. coli. Characterization was achieved by ultraviolet-visible spectroscopy and by Transmission Electron Microscopy (TEM). The antibacterial properties of NPs from C. longa (ClAgNPs) and E. coli (EcAgNPs), alone and in combination with carbenicillin and ampicillin, were investigated through the Kirby-Bauer disk diffusion assay and the minimum inhibitory concentration (MIC). Dimensions of NPs ranged from 11.107 ± 2.705 nm (ClAgNPs) to 27.282 ± 2.68 nm (EcAgNPs). Kirby-Bauer and MIC assays showed great antibacterial abilities for both NPs alone and in combination with antibiotics. EcAgNPs alone showed the most powerful antibacterial activities, resulting in MIC values ranging from 0.438 ± 0.18 µM (P. aeruginosa) to 3.75 ± 3.65 µM (S. pseudintermedius) compared to those of ClAgNPs: 71.8 ± 0 µM (P. aeruginosa) and 143.7 ± 0 µM (S. pseudintermedius). The antibiofilm abilities were strain-dependent, but no statistical differences were found between the two NPs. These results suggest the antibacterial potential of AgNPs for the treatment of infectious diseases.

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Preparation of bioactive and antibacterial PMMA-based bone cement by modification with quaternary ammonium and alkoxysilane

Journal of Biomaterials Applications ◽

10.1177/08853282211004413 ◽

2021 ◽

pp. 088532822110044

Author(s):

Haiyang Wang ◽

Toshinari Maeda ◽

Toshiki Miyazaki

Keyword(s):

Antibacterial Activity ◽

Methyl Methacrylate ◽

Bone Cement ◽

Setting Time ◽

Antibacterial Properties ◽

The Body ◽

Apatite Formation ◽

Gram Positive ◽

E Coli ◽

Gram Positive Bacteria

Bone cement based on poly(methyl methacrylate) (PMMA) powder and methyl methacrylate (MMA) liquid is a very popular biomaterial used for the fixation of artificial joints. However, there is a risk of this cement loosening from bone because of a lack of bone-bonding bioactivity. Apatite formation in the body environment is a prerequisite for cement bioactivity. Additionally, suppression of infection during implantation is required for bone cements to be successfully introduced into the human body. In this study, we modified PMMA cement with γ-methacryloxypropyltrimetoxysilane and calcium acetate to introduce bioactive properties and 2-( tert-butylamino)ethyl methacrylate (TBAEMA) to provide antibacterial properties. The long-term antibacterial activity is attributed to the copolymerization of TBAEMA and MMA. As the TBAEMA content increased, the setting time increased and the compressive strength decreased. After soaking in simulated body fluid, an apatite layer was detected within 7 days, irrespective of the TBAEMA content. The cement showed better antibacterial activity against Gram-negative E. Coli than Gram-positive bacteria; however, of the Gram-positive bacteria investigated, B. subtilis was more susceptible than S. aureus.

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Green Synthesized Silver Nanoparticles Immobilized on Activated Carbon Nanoparticles: Antibacterial Activity Enhancement Study and Its Application on Textiles Fabrics

Molecules ◽

10.3390/molecules26133790 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3790

Author(s):

Pratama Jujur Wibawa ◽

Muhammad Nur ◽

Mukhammad Asy’ari ◽

Wijanarka Wijanarka ◽

Heru Susanto ◽

...

Keyword(s):

Silver Nanoparticles ◽

Antibacterial Activity ◽

Activated Carbon ◽

Aloe Vera ◽

Particle Size Analysis ◽

Size Analysis ◽

E Coli ◽

Transmission Electron ◽

Average Size ◽

Green Synthesized Silver Nanoparticles

This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs–ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis’s spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).

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Temperature Dependent On Activated Carbon For Their Biological Activity And Photocatalytical Degradation of Methylene Blue: A Novel Approach To Green Synthesis

10.21203/rs.3.rs-792713/v1 ◽

2021 ◽

Author(s):

Amalanathan.M ◽

Aravind.M ◽

Sony Michael Mary.M ◽

Razan A. Alshgari ◽

Asma A. Alothman ◽

...

Keyword(s):

Methylene Blue ◽

Antibacterial Activity ◽

Activated Carbon ◽

Hydrothermal Carbonization ◽

Microbial Pathogens ◽

X Ray Diffraction ◽

E Coli ◽

Novel Approach ◽

Transmission Electron ◽

Ft Ir

Abstract In this work, jasmine flower derived activated carbon were successfully synthesized by hydrothermal carbonization process at the different annealing temperature. The Crystallinity, phase, structural, morphological and optical properties of activated carbon were investigated using X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Transmission electron microscope (TEM), and UV-visible spectroscopy analysis. The graphitic phase of carbon was obtained from the XRD pattern. Surface morphology reveals irregular-shaped nanoparticles. The photodegradation of methylene blue (MB) was carried out under the visible light irradiation technique to study its photocatalytic activity. The activated carbon obtained at 400oC, 500oC and 600oC shows a photocatalytic degradation efficiency of 86%, 90%, and 94%, respectively. Antibacterial activity of activated carbon was examined against S. Aureus (MTCC-737) and E-Coli (MTCC- 443) microbial pathogens, and their potent antibacterial activity was examined from the zone of inhibition layer.

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Microwave-Assisted Green Synthesis of Silver Nanoparticles Using Juglans regia Leaf Extract and Evaluation of Their Physico-Chemical and Antibacterial Properties

Antibiotics ◽

10.3390/antibiotics7030068 ◽

2018 ◽

Vol 7 (3) ◽

pp. 68 ◽

Cited By ~ 8

Author(s):

Mahsa Eshghi ◽

Hamideh Vaghari ◽

Yahya Najian ◽

Mohammad Najian ◽

Hoda Jafarizadeh-Malmiri ◽

...

Keyword(s):

Silver Nanoparticles ◽

Leaf Extract ◽

Juglans Regia ◽

Antibacterial Properties ◽

Infrared Analysis ◽

Ag Nps ◽

Stabilizing Agents ◽

Agno3 Solution ◽

Transmission Electron ◽

Vis Spectroscopy

Silver nanoparticles (Ag NPs) were synthesized using Juglans regia (J. regia) leaf extract, as both reducing and stabilizing agents through microwave irradiation method. The effects of a 1% (w/v) amount of leaf extract (0.1–0.9 mL) and an amount of 1 mM AgNO3 solution (15–25 mL) on the broad emission peak (λmax) and concentration of the synthesized Ag NPs solution were investigated using response surface methodology (RSM). Fourier transform infrared analysis indicated the main functional groups existing in the J. regia leaf extract. Dynamic light scattering, UV-Vis spectroscopy and transmission electron microscopy were used to characterize the synthesized Ag NPs. Fabricated Ag NPs with the mean particle size and polydispersity index and maximum concentration and zeta potential of 168 nm, 0.419, 135.16 ppm and −15.6 mV, respectively, were obtained using 0.1 mL of J. regia leaf extract and 15 mL of AgNO3. The antibacterial activity of the fabricated Ag NPs was assessed against both Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria and was found to possess high bactericidal effects.

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Susceptibility of Escherichia coli and Clostridium perfringens to sucrose monoesters of capric and lauric acid

Czech Journal of Animal Science ◽

10.17221/7588-cjas ◽

2014 ◽

Vol 59 (No. 8) ◽

pp. 374-380

Author(s):

E. Skřivanová ◽

Š. Pražáková ◽

O. Benada ◽

P. Hovorková ◽

MarounekM

Keyword(s):

Escherichia Coli ◽

Antibacterial Activity ◽

Clostridium Perfringens ◽

Lauric Acid ◽

Cytoplasmic Membrane ◽

E Coli ◽

Enteropathogenic Bacteria ◽

Viable Cells ◽

Transmission Electron ◽

Cytoplasmic Structures

The sucrose monoesters of capric and lauric acid were tested for their antibacterial activity towards two foodborne enteropathogenic bacteria – Escherichia coli (CCM 3954 – serotype O6 and E22 – serotype O103) and Clostridium perfringens (CNCTC 5459 and CIP 105178). Antibacterial activity was evaluated by the plating technique. Sucrose monocaprate significantly decreased the number of viable cells of E. coli at all tested concentrations (0.1–5 mg/ml). The overnight incubation of C. perfringens with the sucrose ester of lauric acid at 0.1–5 mg/ml reduced the number of viable cells below the detection limit (2 log<sub>10</sub> CFU/ml). Incubating E. coli CCM 3954 and C. perfringens CNCTC 5459 with monoesters (0.1 and 2 mg/ml) did not influence the K<sup>+</sup> permeability of the cytoplasmic membrane in cells during a 2.5-minute treatment. A 30-minute incubation of E. coli CCM 3954 and C. perfringens CNCTC 5459 with esters (0.1 and 2 mg/ml) revealed damage to cytoplasmic structures, as observed by transmission electron microscopy.  

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Green Synthesis and Antibacterial Activity of HAp@Ag Nanocomposite Using Centella asiatica (L.) Urban Extract and Eggshell

International Journal of Biomaterials ◽

10.1155/2020/8841221 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Xuan Nui Pham ◽

Hoa Thi Nguyen ◽

Ngan Thi Pham

Keyword(s):

Electron Microscopy ◽

Antibacterial Activity ◽

Green Synthesis ◽

Antibacterial Properties ◽

Centella Asiatica ◽

Diffusion Method ◽

Ag Nps ◽

X Ray ◽

Synthesis Of Nanoparticles ◽

Green Approach

In recent years, the green synthesis of nanoparticles via biological processes has attracted considerable attention. Herein, we introduce a facile and green approach for the synthesis of poriferous silver nanoparticles (Ag-NPs) decorated hydroxylapatite (HAp@Ag) nanoparticles with excellent antibacterial properties. All the nanocomposites were fully characterized in the solid state via various techniques such as X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectrometer (EDX), in which the synthesized Ag-NPs (24 nm in diameter) and their homogeneous incorporation on HAp have been studied by ultraviolet-visible (UV-vis) technique, transmission electron microscopy (TEM), and dynamic light scattering (DLS) analysis. The obtained results indicate that the structure and morphology of HAp have no significant changes after the incorporation of Ag-NPs on its surface. Moreover, an impressive antibacterial activity of HAp@Ag nanocomposite against Gram-positive bacterium Staphylococcus aureus and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa has been recorded by using the agar well diffusion method. As a result, the HAp@Ag nanocomposite promises to be a great biomedical material with high antibacterial properties.

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