The in situ synthesis of silver nanoclusters inside a bacterial cellulose hydrogel for antibacterial applications

2020 ◽  
Vol 8 (22) ◽  
pp. 4846-4850 ◽  
Author(s):  
Yong Liu ◽  
Shanshan Wang ◽  
Ziping Wang ◽  
Qiaofeng Yao ◽  
Shasha Fang ◽  
...  
Keyword(s):  
Bacterial Cellulose ◽  
In Situ Synthesis ◽  
Silver Nanoclusters ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Cellulose Hydrogel ◽  
Ag Nanoclusters ◽  
Ag Ncs

An antibacterial hydrogel is developed through in situ formation of Ag nanoclusters on bacterial cellulous, which shows better and longer-lasting killing efficacy than that of pristine Ag NCs against both Gram-positive and Gram-negative bacteria.

scholarly journals Asymmetric one-pot synthesis of cyclopropanes

2016 ◽  
Vol 35 (1) ◽  
pp. 45
Author(s):  
Naoufel Ben Hamadi ◽  
Ahlem Guesmi ◽  
Wided Nouira
Keyword(s):  
Escherichia Coli ◽  
Water Soluble ◽  
Gram Negative Bacteria ◽  
Protecting Group ◽  
Gram Positive ◽  
One Pot ◽  
Gram Negative ◽  
Activity Screening ◽  
High Yields

Cycloaddition of the diazoalkanes to electron-deficient olefins (in situ) affords polysubstituted cyclopropanes in high yields (up to 85%). Deprotection of the ketal protecting group provided water-soluble cyclopropane-bearing carbohydrate in good yields. Antimicrobial activity screening of the synthesized compounds 8 and 9, utilizing a variety of Gram-positive (Staphylococcus aureus and Enterococcus fecalis), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and yeast (Candida albicans), exhibited that all the prepared analogues acquire promising activities against both Gram-positive and Gram-negative bacteria especially compounds 9b and 9c (antimicrobial active agents against Gram-negative bacteria).

scholarly journals Physiochemical synthesis of Silver/Kaolinite nanocomposites and study their antibacterial properties

2021 ◽  
Vol 1 (1) ◽  
pp. 1-11
Author(s):  
Salmah Moosa ◽  
Anis Nadia Mohd Faisol Mahadeven ◽  
Kamyar Shameli
Keyword(s):  
Gamma Irradiation ◽  
Ambient Pressure ◽  
Synthesis Method ◽  
Antibacterial Properties ◽  
Gram Negative Bacteria ◽  
Zone Of Inhibition ◽  
Gram Positive ◽  
Gram Negative ◽  
Physical Synthesis ◽  
Ag Ncs

Silver nanocomposites (Ag NCs) were prepared by two methods, chemical and physical synthesis using sodium borohydride and gamma irradiation as a reducing tool. A one-step silver/kaolinite nanocomposite (Ag/Kln NCs) synthesis method has been developed successfully by irradiation technique at room temperature and under ambient pressure. The Ag/Kln NCs produced by the ?-irradiation technique is pure without chemical residues, has a good distribution with enhanced antibacterial properties, and environmentally friendly. The effects of various experimental parameters on the formation of NCs, such as the concentration of Ag+ and the irradiation dose, have been investigated. A study on antimicrobial susceptibility was undertaken to determine the antibacterial properties of Ag NCs in the presence of gram-positive and gram-negative bacteria. The susceptibility of the microorganisms to varying concentrations of Ag NCs synthesized via physical synthesis using gamma irradiation was compared to those synthesized chemically. Concentrations of Ag NCs used were 0.5, 1.0, 2.0, 5.0, and 10 % for chemical synthesis and irradiation doses used for physical synthesis were 7, 13, 20, 30, 40, 50, 65 and 80 kGy. Observation on well diffusion variant showed a significantly large zone of inhibition for physically synthesized NCs, (63 to 107% relative to control) which indicates high antimicrobial activity. Chemically synthesized NCs using the same experimental set up however showed a significantly smaller zone of inhibition. The Ag/Kln NCs in 20kGy showed higher antibacterial activity against Enterococcus faecalis and Escherichia coli as gram-positive and gram-negative bacteria. These suggest that Ag/Kln NCs can be employed as an effective bacteria inhibitor and can be applied in the medical field.

scholarly journals In-situ catalytic upgrading of heavy oil using dispersed bionanoparticles supported on gram-positive and gram-negative bacteria

2017 ◽  
Vol 203 ◽  
pp. 807-819 ◽  
Author(s):  
Jacob B. Omajali ◽  
Abarasi Hart ◽  
Marc Walker ◽  
Joseph Wood ◽  
Lynne E. Macaskie
Keyword(s):  
Heavy Oil ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Catalytic Upgrading

SYNTHESIS OF NANOCOMPOSITES OF POLYVINYL ALCOHOL WITH SILVER NANOPARTICLES AND THEIR USE

2013 ◽  
Vol 12 (04) ◽  
pp. 1350029 ◽  
Author(s):  
N. V. BHAT ◽  
N. S. KARMAKAR ◽  
D. C. KOTHARI
Keyword(s):  
Silver Nanoparticles ◽  
Polyvinyl Alcohol ◽  
Quantitative Methods ◽  
In Situ Synthesis ◽  
Gram Negative Bacteria ◽  
Structure And Properties ◽  
Gram Negative ◽  
Synthesis Of Nanoparticles ◽  
Vis Spectroscopy

Composites of polyvinyl alcohol (PVA) containing silver nanoparticles were prepared using in situ synthesis of nanoparticles. Structure and properties of these composites were investigated using UV-Vis spectroscopy, XRD, DSC, SEM and AFM. The studies show that PVA can reduce the AgNO 3 to yield silver nanoparticles and in the process forms bonds with PVA chains. The anti-bacterial properties of these films were studied by qualitative as well as quantitative methods which gave the values of 98% for gram positive and 89% for gram negative bacteria.

Design of a Nanostructured Active Surface against Gram-Positive and Gram-Negative Bacteria through Plasma Activation and in Situ Silver Reduction

2015 ◽  
Vol 8 (1) ◽  
pp. 64-73 ◽  
Author(s):  
Joan Gilabert-Porres ◽  
Sara Martí ◽  
Laura Calatayud ◽  
Victor Ramos ◽  
Antoni Rosell ◽  
...  
Keyword(s):  
Active Surface ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Plasma Activation

Development of a Fluorescence In Situ Hybridization protocol for analysis of Gram-positive and Gram-negative bacteria

2016 ◽  
Vol 33 (3) ◽  
pp. 434
Author(s):  
Marina González-Pérez ◽  
Rafaela Fernandes ◽  
Ricardo Vieira ◽  
António Pereira ◽  
António Candeias ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Hybridization Protocol

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

In-vitro Antioxidant and Antibacterial Activity of Methanolic Extract of Shorea robusta Gaertn. F. Resin

2016 ◽  
Vol 6 (4) ◽  
pp. 68
Author(s):  
Sushma Vashisht ◽  
Manish Pal Singh ◽  
Viney Chawla
Keyword(s):  
Antibacterial Activity ◽  
Methanolic Extract ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Gram Positive ◽  
Gram Negative ◽  
Shorea Robusta ◽  
Dose Dependent ◽  
Resin Extract

The methanolic extract of the resin of Shorea robusta was subjected to investigate its antioxidant and antibacterial properties its utility in free radical mediated diseases including diabetic, cardiovascular, cancer etc. The methanol extract of the resin was tested for antioxidant activity using scavenging activity of DPPH (1,1-diphenyl-2-picrylhydrazil) radical method, reducing power by FeCl3 and antibacterial activity against gram positive and gram negative bacteria using disc diffusion method. The phytochemical screening considered the presence of triterpenoids, tannins and flavoniods. Overall, the plant extract is a source of natural antioxidants which might be helpful in preventing the progress of various oxidative stress mediated diseases including aging. The half inhibition concentration (IC50) of resin extract of Shorea robusta and ascorbic acid were 35.60 µg/ml and 31.91 µg/ml respectively. The resin extract exhibit a significant dose dependent inhibition of DPPH activity. Antibacterial activity was observed against gram positive and gram negative bacteria in dose dependent manner.Key Words: Shorea robusta, antioxidant, antibacterial, Disc-diffusion, DPPH.

Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Elaf Ayad Kadhem ◽  
Miaad Hamzah Zghair ◽  
Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽  
Hussam H. Tizkam ◽  
Shoeb Alahmad
Keyword(s):  
Antibacterial Activity ◽  
Magnesium Oxide ◽  
Diffusion Method ◽  
Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Magnesium Oxide Nanoparticles ◽  
Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

Antimicrobial Activity of Iron-Halide Complexes Against Gram-Positive and Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Resistance ◽  
Extracellular Dna ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Substances ◽  
Mammalian Cell Lines

Antimicrobial resistance (AMR) has become one of the more serious threats to the global health. The emergence of bacteria resistant to antimicrobial substances decreases the potencies of current antibiotics. Consequently, there is an urgent and growing need for the developing of new classes of antibiotics. Three prepared novel iron complexes have a broad-spectrum antimicrobial activity with minimum bactericidal concentration (MBC) values ranging from 3.5 to 10 mM and 3.5 to 40 mM against Gram-positive and Gram-negative bacteria with antimicrobial resistance phenotype, respectively. Time-kill studies and quantification of the extracellular DNA confirmed the bacteriolytic mode of action of the iron-halide compounds. Additionally, the novel complexes showed significant antibiofilm activity against the tested pathogenic bacterial strains at concentrations lower than the MBC. The cytotoxic effect of the complexes on different mammalian cell lines show sub-cytotoxic values at concentrations lower than the minimum bactericidal concentrations.

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