scholarly journals An N-Halamine/Graphene Oxide-Functionalized Electrospun Polymer Membrane That Inactivates Bacteria on Contact and by Releasing Active Chlorine

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2784
Author(s):  
Shi Lan ◽  
Jinghua Zhang ◽  
Jie Li ◽  
Yanan Guo ◽  
Xianliang Sheng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Antibacterial Properties ◽  
Polymer Membrane ◽  
Water Disinfection ◽  
Fibrous Membrane ◽  
Active Chlorine ◽  
Public Health Issue ◽  
Emerging Pathogens ◽  
Electrospinning Technique ◽  
E Coli

The emergence of antibiotic-resistant “superbugs” in recent decades has led to widespread illness and death and is a major ongoing public health issue. Since traditional antimicrobials and antibiotics are in many cases showing limited or no effectiveness in fighting some emerging pathogens, there is an urgent need to develop and explore novel antibacterial agents that are both powerful and reliable. Combining two or more antibiotics or antimicrobials has become a hot topic in antibacterial research. In this contribution, we report on using a simple electrospinning technique to create an N-halamine/graphene oxide-modified polymer membrane with excellent antibacterial activity. With the assistance of advanced techniques, the as-obtained membrane was characterized in terms of its chemical composition, morphology, size, and the presence of active chlorine. Its antibacterial properties were tested with Escherichia coli (E. coli) as the model bacteria, using the colony-counting method. Interestingly, the final N-halamine/graphene oxide-based antibacterial fibrous membrane inactivated E. coli both on contact and by releasing active chlorine. We believe that the synergistic antimicrobial action of our as-fabricated fibrous membrane should have great potential for utilization in water disinfection, air purification, medical and healthcare products, textile products, and other antibacterial-associated fields.

scholarly journals Disinfection properties of the tea polyphenol epigallocatechin gallate in the presence of calcium ions

2021 ◽  
Author(s):  
Zhen Xu ◽  
Xuanqi Liu ◽  
Cuimin Feng ◽  
Shu Zhu ◽  
Ying Li ◽  
...  
Keyword(s):  
Calcium Ions ◽  
Calcium Ion ◽  
Antibacterial Properties ◽  
Epigallocatechin Gallate ◽  
Water Disinfection ◽  
Tea Polyphenols ◽  
Surface Structures ◽  
Tea Polyphenol ◽  
E Coli ◽  
Drinking Water Disinfection

Abstract The antibacterial properties of tea polyphenols make them suitable for drinking water disinfection, but it is necessary to clarify the influence of metal ions on the sterilization efficacy. Epigallocatechin gallate (EGCG) was selected as a representative tea polyphenol, and the effects of calcium ion (Ca2+) concentration on its disinfection properties in Escherichia coli cultures were investigated. Changes in bacterial growth and structures were detected. The presence of low concentration Ca2+ (1–5 mM) inhibited the disinfection effect of EGCG but higher concentrations (6–10 mM) enhanced its effects. As Ca2+ concentration increased, the proportion of damaged bacteria also increased (15–43%). The presence of Ca2+ lessened the damaging effects of EGCG on the surface structures of E. coli but may have facilitated the entry of EGCG into the bacteria, enhancing its antibacterial efficacy. Tea polyphenols may be useful additives for the disinfection of groundwater and other raw waters containing calcium ions.

scholarly journals Preparation of Electrospun Gelatin Mat with Incorporated Zinc Oxide/Graphene Oxide and Its Antibacterial Activity

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1043 ◽  
Author(s):  
Honghai Li ◽  
Yu Chen ◽  
Weipeng Lu ◽  
Yisheng Xu ◽  
Yanchuan Guo ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Graphene Oxide ◽  
Antibacterial Properties ◽  
Degradation Process ◽  
Antimicrobial Activities ◽  
Wound Dressings ◽  
X Ray ◽  
E Coli ◽  
Potential Applicability ◽  
Electrospun Gelatin

Current wound dressings have poor antimicrobial activities and are difficult to degrade. Therefore, biodegradable and antibacterial dressings are urgently needed. In this article, we used the hydrothermal method and side-by-side electrospinning technology to prepare a gelatin mat with incorporated zinc oxide/graphene oxide (ZnO/GO) nanocomposites. The resultant fibers were characterized by field emission environment scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR). Results indicated that the gelatin fibers had good morphology, and ZnO/GO nanocomposites were uniformly dispersed on the fibers. The loss of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) viability were observed to more than 90% with the incorporation of ZnO/GO. The degradation process showed that the composite fibers completely degraded within 7 days and had good controllable degradation characteristics. This study demonstrated the potential applicability of ZnO/GO-gelatin mats with excellent antibacterial properties as wound dressing material.

Antibacterial properties of Ag and Ag/AgCl nanoparticles from radish and tea extracts for water treatment applications

2015 ◽  
Vol 16 (1) ◽  
pp. 171-179
Author(s):  
Yuphada Boonto ◽  
Jirapat Ananpattarachai ◽  
Puangrat Kajitvichyanukul
Keyword(s):  
Antibacterial Activity ◽  
Water Treatment ◽  
Microwave Irradiation ◽  
Green Synthesis ◽  
Plant Extracts ◽  
Antibacterial Properties ◽  
Water Disinfection ◽  
E Coli ◽  
High Antibacterial Activity ◽  
Complete Inactivation

Silver nanoparticles (AgNPs) have antibacterial properties and are widely used for water disinfection. This technology is commercially applied in point-of-use water treatment as a post-treatment for filtrate water. However, the current process of synthesizing AgNPs has several disadvantages including the use of hazardous chemicals, consumption of a large amount of energy and the formation of hazardous byproducts. Here, we report an alternative and green synthesis using plant extracts. In this work, the plant extracts came from radish (R) and tea (T), and the AgNPs were derived from a microwave irradiation method. The AgNPs synthesized by chemical-based microwave irradiation (Ag-C) were also used as a control material. The novel method produced a smaller size of nanostructures with good dispersion ability and less agglomeration than those from chemical synthesis. The antibacterial properties of AgNPs on Gram-negative bacteria Escherichia coli (E. coli) and Gram-positive bacteria Staphylococcus aureus (S. aureus) were investigated. The results revealed that AgNPs from both green synthesis and chemical-based methods inactivated both types of bacteria. The green-synthesized AgNPs from radish juice provided a higher percentage of inhibition of E. coli than that of S. aureus. The inactivation rates of the AgNPs increased with increasing concentration of AgNPs. As the concentration of the Ag/AgCl-R and Ag-R increased from 150 μg/mL to 300 μg/mL, complete inactivation required a reduced time for the reaction from 300 minutes to only 30 minutes. Finally, the Ag/AgCl-R and Ag-R offered high antibacterial activity while the Ag-T provided the lowest antibacterial activity. This work provides an alternative method for the eco-synthesis of antibacterial nanomaterials for water treatment.

An Experimental Study of the Silver-Loading Diatomite on the Water Disinfection

2014 ◽  
Vol 955-959 ◽  
pp. 166-170
Author(s):  
Fen E Hu ◽  
Huiping Wang ◽  
You Ming Shi
Keyword(s):  
Water Samples ◽  
Decomposition Method ◽  
Ph Value ◽  
Silver Content ◽  
Antibacterial Properties ◽  
Water Disinfection ◽  
E Coli ◽  
Antibacterial Material ◽  
Effects Of Temperature ◽  
Vacuum Heating

The silver-loading diatomite prepared by the vacuum heating decomposition method was applied to the water disinfection. The inactivation effects of the silver-loading diatomite on the Escherichia coli (E. coli) in water were investigated. The effects of temperature and pH value on the bactericidal activity of the silver-loading diatomite against E. coli were investigated. The concentration of Ag+ in water samples was tested for safety. The results show that the silver-loading diatomite with the silver content of 1.46% can kill E. coli in experiment water in 30 minutes. The higher the temperature and the greater the PH value of the water samples, the stronger the antibacterial properties of the silver-loading diatomite. The concentration of Ag+ is less than 50ug/L in the disinfected and treated water samples. The silver-loading diatomite is a safe, effective antibacterial material.

scholarly journals The Biology of Colicin M and Its Orthologs

2021 ◽  
Author(s):  
Dimitri Chérier ◽  
Delphine Patin ◽  
Didier Blanot ◽  
Thierry Touzé ◽  
Hélène Barreteau
Keyword(s):  
Pathogenic Bacteria ◽  
Antibacterial Properties ◽  
Multidrug Resistant ◽  
Public Health Issue ◽  
Sequence Alignments ◽  
Food Preservatives ◽  
E Coli ◽  
Peptidoglycan Biosynthesis ◽  
Lipid Ii ◽  
Colicin M

The misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Consequently, the discovery of new antibacterials in the short term is crucial. Colicins, due to their antibacterial properties, thus constitute good candidates. These toxin proteins, produced by E. coli to kill enteric relative competitors, exhibit cytotoxicity through ionophoric activity or essential macromolecule degradation. Among the 25-colicin types known to date, colicin M (ColM) is the only one colicin interfering with peptidoglycan biosynthesis. Accordingly, ColM develops its lethal activity in E. coli periplasm by hydrolyzing the last peptidoglycan precursor, lipid II, into two dead-end products, thereby leading to cell lysis. Since the discovery of its unusual mode of action, several ColM orthologs have also been identified based on sequence alignments; all of the characterized ColM-like proteins display the same enzymatic activity of lipid II degradation and narrow antibacterial spectra. This publication aims at being an exhaustive review about what is currently known on this new family of antibacterial enzymes as well as on their potential use of food preservatives or therapeutic agents.

Antibacterial properties and mechanism of graphene oxide-silver nanocomposites as bactericidal agents for water disinfection

2016 ◽  
Vol 604 ◽  
pp. 167-176 ◽  
Author(s):  
Biao Song ◽  
Chang Zhang ◽  
Guangming Zeng ◽  
Jilai Gong ◽  
Yingna Chang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Antibacterial Properties ◽  
Water Disinfection ◽  
Silver Nanocomposites

scholarly journals The Biology of Colicin M and Its Orthologs

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1109
Author(s):  
Dimitri Chérier ◽  
Delphine Patin ◽  
Didier Blanot ◽  
Thierry Touzé ◽  
Hélène Barreteau
Keyword(s):  
Pathogenic Bacteria ◽  
Current Knowledge ◽  
Antibacterial Properties ◽  
Multidrug Resistant ◽  
Public Health Issue ◽  
Sequence Alignments ◽  
Food Preservatives ◽  
E Coli ◽  
Lipid Ii ◽  
Colicin M

The misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Consequently, the discovery of new antibacterials in the short term is crucial. Colicins, due to their antibacterial properties, thus constitute good candidates. These toxin proteins, produced by E. coli to kill enteric relative competitors, exhibit cytotoxicity through ionophoric activity or essential macromolecule degradation. Among the 25 colicin types known to date, colicin M (ColM) is the only one colicin interfering with peptidoglycan biosynthesis. Accordingly, ColM develops its lethal activity in E. coli periplasm by hydrolyzing the last peptidoglycan precursor, lipid II, into two dead-end products, thereby leading to cell lysis. Since the discovery of its unusual mode of action, several ColM orthologs have also been identified based on sequence alignments; all of the characterized ColM-like proteins display the same enzymatic activity of lipid II degradation and narrow antibacterial spectra. This publication aims at being an exhaustive review of the current knowledge on this new family of antibacterial enzymes as well as on their potential use as food preservatives or therapeutic agents.

scholarly journals Medium-Dependent Antibacterial Properties and Bacterial Filtration Ability of Reduced Graphene Oxide

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1454 ◽  
Author(s):  
Alexander Gusev ◽  
Olga Zakharova ◽  
Dmitry S. Muratov ◽  
Nataliia S. Vorobeva ◽  
Mamun Sarker ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Antibacterial Properties ◽  
Physiological Saline ◽  
Complete Removal ◽  
E Coli ◽  
Reduced Graphene ◽  
Biological Contaminants ◽  
Physiological Saline Solution ◽  
Nutrition Medium

Toxicity of reduced graphene oxide (rGO) has been a topic of multiple studies and was shown to depend on a variety of characteristics of rGO and biological objects of interest. In this paper, we demonstrate that when studying the same dispersions of rGO and fluorescent Escherichia coli (E. coli) bacteria, the outcome of nanotoxicity experiments also depends on the type of culture medium. We show that rGO inhibits the growth of bacteria in a nutrition medium but shows little effect on the behavior of E. coli in a physiological saline solution. The observed effects of rGO on E. coli in different media could be at least partially rationalized through the adsorption of bacteria and nutrients on the dispersed rGO sheets, which is likely mediated via hydrogen bonding. We also found that the interaction between rGO and E. coli is medium-dependent, and in physiological saline solutions they form stable flocculate structures that were not observed in nutrition media. Furthermore, the aggregation of rGO and E. coli in saline media was observed regardless of whether the bacteria were alive or dead. Filtration of the aggregate suspensions led to nearly complete removal of bacteria from filtered liquids, which highlights the potential of rGO for the filtration and separation of biological contaminants, regardless of whether they include live or dead microorganisms.

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

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1207 ◽  
Author(s):  
Thi Truong ◽  
Selvaraj Kumar ◽  
Yu-Tzu Huang ◽  
Dave Chen ◽  
Yu-Kuo Liu ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Graphene Oxide ◽  
Membrane Integrity ◽  
Antibacterial Properties ◽  
Ag Nps ◽  
E Coli ◽  
Size Dependent ◽  
Transmission Electron ◽  
Combined Action ◽  
Bacterial Cell Membrane

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.

scholarly journals A novel Aloe Vera-Loaded Ethylcellulose/Hydroxypropyl Methylcellulose Nanofibrous Mat Designed For Wound Healing Application

2021 ◽  
Author(s):  
Leila Yavari ◽  
Marjan Ghorbani
Keyword(s):  
Thermal Stability ◽  
Chemical Structure ◽  
Pathogenic Bacteria ◽  
Hydroxypropyl Methylcellulose ◽  
Aloe Vera ◽  
Antibacterial Properties ◽  
Wound Dressings ◽  
Electrospinning Technique ◽  
E Coli ◽  
Rapid Healing

Abstract Newly, the usage of nanofibers (NFs) as wound dressings with the aim of their rapid healing and prevention of bacterial infection has been considered by researchers. In this regard, we produced the ethylcellulose/hydroxypropyl methylcellulose NFs incorporated with Aloe-vera (EC/HPMC/Alv) by the electrospinning technique. The produced NFs were investigated for their chemical structure, morphological, mechanical, thermal stability, degradation, swelling, cell viability, and antibacterial properties. Amongst the produced NFs, the NF samples containing 10% Alv illustrated the appropriate thermal stability and tensile properties. The produced NFs did not show any cell cytotoxicity which indicates their good compatibility. Also, NFs containing Alv significantly (P<0.05) increased cell proliferation and adhesion. In addition, the NFs/Alv sample was indicated antibacterial ability against S. aureus (10.21 ± 1.21 mm) and E. coli (5.06 ± 1.3 mm) pathogenic bacteria. As a result, these findings suggest that the produced NFs could be applied as an active mat for wound dressing application.

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