Comparative Assessment of Biocidal Activity of Different RGO/Ceramic Oxide-Ag Nanocomposites

2017 ◽  
Vol 47 ◽  
pp. 89-95 ◽  
Author(s):  
Agnieszka Maria Jastrzębska ◽  
Adrianna Derecka ◽  
Ewa Karwowska ◽  
Aneta Pląsek ◽  
Tomasz Wojciechowski ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Antimicrobial Properties ◽  
Comparative Assessment ◽  
Biocidal Activity ◽  
Ceramic Oxides ◽  
Nanocomposite Structure ◽  
E Coli ◽  
Ceramic Oxide ◽  
Biocidal Properties

The aim of this study was to compare the bioactivity of RGO/ceramic oxide-Ag nanocomposites. Different ceramic oxides (MexOy) i.e.: Al2O3, TiO2, SiO2 and ZnO2 were in situ co-deposited with Ag nanoparticles on the surface of RGO resulting in the formation of a nanocomposite structure of stacked flakes. The results of our investigations indicate that it is possible to obtain the targeted biocidal properties of the RGO/Ag system by choosing the appropriate ceramic oxide as a modificator of Ag nanoparticles. The strongest antimicrobial properties against E. coli, S. aureus and Bacillus sp. strains were achieved for RGO/SiO2-Ag nanocomposite whereas for Sarcina sp. bacteria the most effective biocide was RGO/TiO2-Ag nanocomposite.

Antibacterial Activity of Surface-Modified Fabric with Ag/AgCl-Doped Quaternary Ammonium-Modified Silicate Hybrid

2019 ◽  
Vol 19 (11) ◽  
pp. 7285-7293 ◽  
Author(s):  
Kuo-Hui Wu ◽  
Yin-Chiung Chang ◽  
Ken-Fa Cheng ◽  
Je-Chuang Wang
Keyword(s):  
Colloidal Suspension ◽  
Sol Gel ◽  
Antimicrobial Properties ◽  
Woven Fabrics ◽  
Dipolar Interactions ◽  
Zone Of Inhibition ◽  
E Coli ◽  
Antibacterial Material ◽  
Surface Modified

An organic–inorganic hybrid antibacterial material based on Ag/AgCl and quaternary ammoniummodified silicate (Ormosil (NR+4 Cl-)) was prepared by sol–gel processes and an in situ reduction method, in which silver nitrate, tetraethoxysilane (TEOS), N-trimethoxysilylpropyl-N,N,Ntrimethylammonium chloride (TMAPS) and N-[3-(trimethoxysilyl)propyl]diethylenetriamine (ATS) acted as precursor, linker and colloidal suspension stabilizer, respectively. The physical properties of the Ormosil (NR+4 Cl-) and Ormosil (NR+4 Cl-)/Ag hybrids were examined using XPS and TGA spectroscopy, the results of which indicated that Ag/AgCl was immobilized in channels by dipolar interactions with the Ormosil (NR+4 Cl-) matrix. Ormosil (NR+4 Cl-) and Ormosil (NR+4 Cl-)/Ag sol solutions were used to functionalize non-woven fabrics by simply immersing the textiles into the dispersions in order to obtain antimicrobial fabrics. The antibacterial effects of the Ormosil/Ag- and Ormosil (NR+4 Cl-)/Ag-modified fabrics against Gram-negative P. aeruginosa and E. coli, and Grampositive S. aureus and B. subtilis, were assessed using the zone of inhibition and the plate-counting method. The antibacterial efficacy was maintained even after 20 laundry cycles. The results indicated that the Ormosil/Ag and Ormosil (NR+4 Cl-)/Ag hybrids are useful as non-leaching agents imparting durable antimicrobial properties to fabrics.

Disinfection of Fruits with Activated Water

2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova
Keyword(s):  
Antimicrobial Activity ◽  
Aqueous Solutions ◽  
Antimicrobial Properties ◽  
The Other ◽  
Gram Negative Bacteria ◽  
High Antimicrobial Activity ◽  
Gram Negative ◽  
E Coli ◽  
Number Of Microorganisms ◽  
Lower Effect

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.

Optics-Free Visualization of Proteins in Single Cells by Time of Flight-Secondary Ion Mass Spectrometry Coupled with Genetically Encoded Chemical Tags

2020 ◽  
Author(s):  
Feifei Jia ◽  
Jie Wang ◽  
Yanyan Zhang ◽  
Qun Luo ◽  
Luyu Qi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Single Cells ◽  
Time Of Flight ◽  
E Coli ◽  
Tof Sims ◽  
Ion Mass Spectrometry ◽  
Chemical Tags ◽  
Secondary Ion

<p></p><p><i>In situ</i> visualization of proteins of interest at single cell level is attractive in cell biology, molecular biology and biomedicine, which usually involves photon, electron or X-ray based imaging methods. Herein, we report an optics-free strategy that images a specific protein in single cells by time of flight-secondary ion mass spectrometry (ToF-SIMS) following genetic incorporation of fluorine-containing unnatural amino acids as a chemical tag into the protein via genetic code expansion technique. The method was developed and validated by imaging GFP in E. coli and human HeLa cancer cells, and then utilized to visualize the distribution of chemotaxis protein CheA in E. coli cells and the interaction between high mobility group box 1 protein and cisplatin damaged DNA in HeLa cells. The present work highlights the power of ToF-SIMS imaging combined with genetically encoded chemical tags for <i>in situ </i>visualization of proteins of interest as well as the interactions between proteins and drugs or drug damaged DNA in single cells.</p><p></p>

scholarly journals Physicochemical and Antimicrobial Properties of Cocoa Pod Husk Pectin Intended as a Versatile Pharmaceutical Excipient and Nutraceutical

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Ofosua Adi-Dako ◽  
Kwabena Ofori-Kwakye ◽  
Samuel Frimpong Manso ◽  
Mariam EL Boakye-Gyasi ◽  
Clement Sasu ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Antimicrobial Properties ◽  
Microbiological Quality ◽  
Elemental Content ◽  
Moderate Activity ◽  
Pharmaceutical Excipient ◽  
E Coli ◽  
Swelling Capacity ◽  
Weak Activity ◽  
Cocoa Pod Husk

The physicochemical and antimicrobial properties of cocoa pod husk (CPH) pectin intended as a versatile pharmaceutical excipient and nutraceutical were studied. Properties investigated include pH, moisture content, ash values, swelling index, viscosity, degree of esterification (DE), flow properties, SEM, FTIR, NMR, and elemental content. Antimicrobial screening and determination of MICs against test microorganisms were undertaken using agar diffusion and broth dilution methods, respectively. CPH pectin had a DE of 26.8% and exhibited good physicochemical properties. Pectin had good microbiological quality and exhibited pseudoplastic, shear thinning behaviour, and high swelling capacity in aqueous media. The DE, FTIR, and NMR results were similar to those of previous studies and supported highly acetylated low methoxy pectin. CPH pectin was found to be a rich source of minerals and has potential as a nutraceutical. Pectin showed dose-dependent moderate activity against gram positive and gram negative microorganisms but weak activity against Listeria spp. and A. niger. The MICs of pectin ranged from 0.5 to 4.0 mg/mL, with the highest activity against E. coli and S. aureus (MIC: 0.5–1.0 mg/mL) and the lowest activity against A. niger (MIC: 2.0–4.0 mg/mL). The study has demonstrated that CPH pectin possesses the requisite properties for use as a nutraceutical and functional pharmaceutical excipient.

In Situ Formation of Ag Nanoparticles for Fiber Strain Sensors: Toward Textile-Based Wearable Applications

2021 ◽  
Author(s):  
Hwajoong Kim ◽  
Ammar Shaqeel ◽  
Solbi Han ◽  
Junseo Kang ◽  
Jieun Yun ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Strain Sensors ◽  
In Situ Formation

scholarly journals Sputter-Deposited Ag Nanoparticles on Electrospun PCL Scaffolds: Morphology, Wettability and Antibacterial Activity

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 345
Author(s):  
Daniele Valerini ◽  
Loredana Tammaro ◽  
Roberta Vitali ◽  
Gloria Guillot ◽  
Antonio Rinaldi
Keyword(s):  
Ag Nanoparticles ◽  
Food Packaging ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Deposition Process ◽  
Polymer Fibers ◽  
Antibacterial Action ◽  
Porous Scaffolds ◽  
Electrospinning Technique ◽  
Sputtering Deposition

Porous scaffolds made of biocompatible and environmental-friendly polymer fibers with diameters in the nano/micro range can find applications in a wide variety of sectors, spanning from the biomedical field to textiles and so on. Their development has received a boost in the last decades thanks to advances in the production methods, such as the electrospinning technique. Conferring antimicrobial properties to these fibrous structures is a primary requirement for many of their applications, but the addition of antimicrobial agents by wet methods can present a series of drawbacks. In this work, strong antibacterial action is successfully provided to electrospun polycaprolactone (PCL) scaffolds by silver (Ag) addition through a simple and flexible way, namely the sputtering deposition of silver onto the PCL fibers. SEM-EDS analyses demonstrate that the polymer fibers get coated by Ag nanoparticles without undergoing any alteration of their morphological integrity upon the deposition process. The influence on wettability is evaluated with polar (water) and non-polar (diiodomethane) liquids, evidencing that this coating method allows preserving the hydrophobic character of the PCL polymer. Excellent antibacterial action (reduction > 99.995% in 4 h) is demonstrated against Escherichia coli. The easy fabrication of these PCL-Ag mats can be applicable to the production of biomedical devices, bioremediation and antifouling systems in filtration, personal protective equipment (PPE), food packaging materials, etc.

scholarly journals DnaA, the Initiator of Escherichia coliChromosomal Replication, Is Located at the Cell Membrane

2000 ◽  
Vol 182 (9) ◽  
pp. 2604-2610 ◽  
Author(s):  
Gillian Newman ◽  
Elliott Crooke
Keyword(s):  
Cell Membrane ◽  
Spatial Organization ◽  
Active Form ◽  
Chromosomal Replication ◽  
E Coli ◽  
Dnaa Protein ◽  
Section Electron ◽  
Acidic Phospholipids

ABSTRACT Given the lack of a nucleus in prokaryotic cells, the significance of spatial organization in bacterial chromosome replication is only beginning to be fully appreciated. DnaA protein, the initiator of chromosomal replication in Escherichia coli, is purified as a soluble protein, and in vitro it efficiently initiates replication of minichromosomes in membrane-free DNA synthesis reactions. However, its conversion from a replicatively inactive to an active form in vitro occurs through its association with acidic phospholipids in a lipid bilayer. To determine whether the in situ residence of DnaA protein is cytoplasmic, membrane associated, or both, we examined the cellular location of DnaA using immunogold cryothin-section electron microscopy and immunofluorescence. Both of these methods revealed that DnaA is localized at the cell membrane, further suggesting that initiation of chromosomal replication in E. coli is a membrane-affiliated event.

Antimicrobial Screening, in Silico Studies and QSAR of Chalcone-based 1,4-disubstituted 1,2,3-triazole Hybrids

Drug Research ◽  
2020 ◽  
Author(s):  
Pinki Yadav ◽  
Kashmiri Lal ◽  
Ashwani Kumar
Keyword(s):  
Topoisomerase Ii ◽  
Antimicrobial Properties ◽  
Qsar Model ◽  
Quantitative Structure Activity Relationship ◽  
Binding Modes ◽  
E Coli ◽  
Structure Activity ◽  
In Silico Studies ◽  
Microbial Strains

AbstractThe in vitro antimicrobial properties of some chalcones (1a–1c ) and chalcone tethred 1,4-disubstituted 1,2,3-triazoles (2a–2u) towards different microbial strains viz. Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Aspergillus niger and Candida albicans are reported. Compounds 2g and 2u exhibited better potency than the standard Fluconazole with MIC values of 0.0063 µmol/mL and 0.0068 µmol/mL, respectively. Furthermore, molecular docking was performed to investigate the binding modes of two potent compounds 2q and 2g with E. coli topoisomerase II DNA gyrase B and C. albicans lanosterol 14α-demethylase, respectively. Based on these results, a statistically significant quantitative structure activity relationship (QSAR) model was successfully summarized for antibacterial activity against B. subtilis.

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