scholarly journals Microwave-Assisted Rapid Synthesis of Eu(OH)3/RGO Nanocomposites and Enhancement of Their Antibacterial Activity against Escherichia coli

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 43
Author(s):  
Kun-Yauh Shih ◽  
Shiou-Ching Yu

Nanomaterials with high antibacterial activity and low cytotoxicity have attracted extensive attention from scientists. In this study, europium (III) hydroxide (Eu(OH)3)/reduced graphene oxide (RGO) nanocomposites were synthesized using a rapid, one-step method, and their antibacterial activity against Escherichia coli (E. coli) was investigated using the synergistic effect of the antibacterial activity between Eu and graphene oxide (GO). The Eu(OH)3/RGO nanocomposites were prepared using a microwave-assisted synthesis method and characterized using X-ray diffraction, scanning electron microscopy, photoluminescence spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. Raman sprectroscopy and X-ray diffraction confirmed the pure hexagonal phase structure of the nanocomposites. Further, the antibacterial properties of Eu(OH)3/RGO were investigated using the minimum inhibitory concentration assay, colony counting method, inhibition zone diameter, and optical density measurements. The results revealed that the Eu(OH)3/RGO exhibited a superior inhibition effect against E. coli and a larger inhibition zone diameter compared to RGO and Eu(OH)3. Further, the reusability test revealed that Eu(OH)3/RGO nanocomposite retained above 98% of its bacterial inhibition effect after seven consecutive applications. The high antibacterial activity of the Eu(OH)3/RGO nanocomposite could be attributed to the release of Eu3+ ions from the nanocomposite and the sharp edge of RGO. These results indicated the potential bactericidal applications of the Eu(OH)3/RGO nanocomposite.

2021 ◽  
Vol 869 (1) ◽  
pp. 012033
Author(s):  
D R Utami ◽  
I Irwan ◽  
S Agustina ◽  
S Karina ◽  
S Afriani

Abstract Squid is one of the export commodities in Indonesia. In general, the use of squid meat, while the ink is only as waste. In fact, Squid ink contain bioactive compound that potential as anti-inflammatory, antihypertensive, anti-diabetic,anti-microbial and anti-malaria agents. The purpose of the study is to determine the types of secondary metabolite compounds contained in n-hexane extract of Loligo sp. ink using maceration method to determine its antibacterial activity against Escherichia coli. The results of secondary metabolite compounds obtained from the n-hexane extract of Loligo sp. ink are alkaloid, saponins, glycosides and phenol. The results of antibacterial test against E. coli using the disc method obtained the average of inhibition zone diameter at the concentration of 4% is 6.3 mm (intermediate), concentration of 8% is 7.83 mm (intermediate), concentration of 16% is 14.5 mm (susceptible) and concentration of 32% is 10.83 mm (intermediate). The antibacterial activity in n-hexane extract of Loligo sp. ink is optimal at the concentration of 16% against E. coli bacteria.


2020 ◽  
Author(s):  
Leyla Mojtabavi ◽  
Amir Razavi

AbstractIn this work, we studied the effects of copper incorporation in the composition of bioactive glass. Three different glass compositions were synthesized with 0, 3, and 6 mol% of copper addition. X-Ray Diffraction (XRD) patterns confirmed that an amorphous microstructure was obtained for all three glass compositions. Results from Differential Thermal Analysis (DTA) showed that the copper addition in the glass lowers the glass transition temperature, from 646°C to 590°C when added at 6 mol%. X-ray Photoelectron (XPS) survey and high-resolution scans were performed to study the structural effects of copper addition in the glass. Results indicated that the incorporation of copper changes the ratio of bridging to non-birding oxygens in the structure. Glasses were further analyzed for their structure with Nuclear Magnetic Resonance (NMR) spectroscopy, which indicated that copper acts as a network modifier in the glass composition and copper-containing glasses show a less connected microstructure. Antibacterial efficacy of the glasses was analyzed against E. coli and S. epidermis. Copper-containing glasses showed a significantly higher inhibition zone compared to control glass. The glass with 6 mol% copper, exhibited inhibition zones of 9 and 16mm against E. coli and S. epidermis bacteria, respectively.


Author(s):  
Selma M.H. AL-Jawad ◽  
Zahraa S. Shakir ◽  
Duha S. Ahmed

ZnO/MWCNTs hybrid and doped with different concentration of Nickel element prepared by using Sol-gel been technique reported. All samples were prepared and characterized by X-Ray Diffraction Analysis (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM), and UV-Vis spectroscopy have been identified the structural, optical and morphological properties. X-ray diffraction showed the polycrystalline nature with hexagonal wutzite structure of hybrid and doped with Nickel. The crystalline size of the hybrid nanostructure was increasing from 23.73 nm to 34.59 nm. Besides, the UV-Vis spectroscopy showed a significant decrease in the band gap values from 2.97 eV to 2.01 eV. Whereas the FE-SEM analysis confirm the formation spherical shapes of ZnO NPs deposited on cylindrical tubes representing the MWCNTs. The antibacterial activity reveals that the inhibition zone of Ni doped-ZnO/MWCNTs hybrid was 28.5 mm, 26.5 mm toward E. coli and S. aureus bacteria, respectively.


Author(s):  
Jansen Silalahi ◽  
Petrika Situmorang ◽  
Popi Patilaya ◽  
Yosy Ce Silalahi

ABSTRACTObjective: The purpose of this study was to evaluate the antibacterial activity of chitosan, hydrolyzed coconut oil and their combination againstBacillus cereus and Escherichia coli.Methods: The materials used in this study were powder of chitosan (obtained from prawn shell produced by Laboratory of Research Centre FMIPAUniversity of Sumatera Utara) and virgin coconut oil (VCO) product of Siti Nurbaya-Indonesia. VCO was partially hydrolyzed by Lipozyme TL IM(active at sn-1,3 position) and the result called hydrolyzed virgin coconut oil (HVCO). The bacteria used in this study were B. cereus and E. coli. Theantibacterial activity of chitosan in 1% acetic acid and HVCO in dimethylsulfoxide was tested by Kirby–Bauer agar diffusion method using paper discwith diameter of 6 mm.Results: The results showed that the minimum inhibitory concentration of chitosan against B. cereus and E. coli is at concentration of 0.05% withinhibition zone diameter of 6.86 mm and 7.56 mm, respectively. MIC of HVCO against B. cereus is at concentration of 0.25% with inhibition zonediameter of 6.40 mm, and against E. coli is at a concentration of 0.50% with inhibition zone diameter of 6.20 mm. The inhibition zone diameter ofchitosan 0.05% and HVCO 0.25% in combination against B. cereus is 8.33 mm which is higher than half the sum of chitosan 0.05% and HVCO 0.25%(6.63 mm). The inhibition zone diameter of chitosan 0.05% and 0.5% HVCO in combination against E. coli is 8.53 mm which is higher than half thesum of chitosan 0.05% and HVCO 0.5% (6.53 mm).Conclusion: The findings of this study indicate that chitosan is more antibacterial than HVCO, and the interaction between chitosan and HVCO incombination demonstrated to be synergistic against B. cereus and E. coli.Keywords: Antibacterial, Chitosan, Coconut oil, Combination, Bacillus cereus, Escherichia coli.®


2021 ◽  
Vol 18 (4) ◽  
pp. 119-123
Author(s):  
Doaa Kaduim ◽  
Zaid Mahmoud ◽  
Falah Mousa

The biosynthesis of iron oxide (Fe2O3, also known as haematite) nano particles (NPs) using Hydra helix and Beta vulgaris aqueous extracts were adduced, respectively, where the extracts act as a stabiliser and reductant reagent. The crystal structure and size of particles were investigated using X-ray diffraction (XRD), while the morphology was examined using field emission scanning electron microscopy (FESEM), XRD patterns showed the synthesised nanoparticles with well-crystallised structure from Beta vulgaris extract with size 12 nm, while the results by using Hydra helix showed many peaks back to Goethite phase with 16 nm. The antibacterial and antifungal activity were examined using Staphylococcus (showed inhibition zone diameter 23 mm, 16 mm using Hydra helix and Beta vulgaris, respectively), E. coli (showed no inhibition) and Candida fungi (showed inhibition zone 16 mm, 11 mm using Hydra helix and Beta vulgaris, respectively).


2020 ◽  
Vol 12 (4) ◽  
pp. 542-547
Author(s):  
Shikha Sharma ◽  
Fehmeeda Khatoon

An environmental technique of herbal mediated blend of Ag nanoparticles is a substantial stage in the ground of nanotechnology. Chitosan (CS) is a polymer which is biocompatible and antibacterial. In this work, we have synthesized CS–Ag Nano hydrogel which is form with chitosan-based hydrogel merged in the herbal synthesized Ag nanoparticles. These green synthesized Ag-nanoparticles made from Polygonum bistorta plant leaves and described with the assistance of UV-vis spectrophotometer, and Dynamic Light Scattering (DLS). In this work our main focus to synthesized CS–Ag Nano hydrogel. These hydrogel was described by Fourier transform infrared (FTIR) spectroscopic method, X-ray diffraction (XRD) method, and contact angle. Nanoparticle size distribution was within 1 to 100 nm by DLS and the optimum wavelength was noted in 400 to 450 nm by UV-vis spectroscopic readings. A good antibacterial behavior has been displayed by these synthesized CS–Ag Nano hydrogel films against both E. coli (gram –ve) and S. aureus (gram +ve) with the maximum 7 mm inhibition zone.


2021 ◽  
Vol 6 (1) ◽  
pp. 59-68
Author(s):  
Sutomo Sutomo ◽  
◽  
Arnida Arnida ◽  
Fahriah Fahriah

Racun ayam is one of the plants which has several activities in its fruits, one of which is an antibacterial. This study aims to determine the antibacterial activity of ethanol extract of racun ayam leaves. The extraction was done by maceration method using ethanol as a solvent. Antibacterial activity assay was carried out on S. aureus, E. coli, and P. aeruginosa bacteria by disk diffusion method at the concentrations of 80, 100, and 120 ppm. The results showed that the ethanol extract of B. javanica leaves had the greatest inhibition zone on E. coli with inhibition zone diameter values ​​at 80, 100, and 120 ppm were 11.7 mm, 14.5 mm and 19.67 mm respectively. Inhibition zones in S. aureus could only be seen at 100 and 120 ppm which had inhibition zone diameters at 1.17 mm and 2.17 mm respectively, whereas in P. aeruginosa they did not have any inhibitory zone values. The results of statistical analysis showed a significance of the inhibition zone diameter values ​​of E. coli bacteria starting at 80 ppm with a sig value of 0.034. Due to a sig value was <0.05, it was categorized as significantly different from the negative control. The bacteria of S. aureus which had ​​<0.05 for sig values only found on 100 ppm and 120 ppm. Bacteria P. aeruginosa which had sig value >0.05 was not significantly different at all concentrations


2020 ◽  
Vol 13 (2) ◽  
pp. 99-113
Author(s):  
Kindu Geta ◽  
Mulugeta Kibret

Medicinal plants offer a major and accessible source of health care to people living in developing countries. Increasing drug resistant microbial infections intensified the search for new, safer, and more efficacious agents against microbial infections. Acanthus sennii is one of the medicinal plants used traditionally for the treatment of different infectious diseases in Ethiopia. Therefore, this study was carried out to evaluate antibacterial activity of A. sennii against pathogenic bacteria. Plant materials were extracted by maceration technique with chloroform, ethanol and water solvents. The antibacterial activities of the crude extracts of the plant were carried out by the agar well diffusion method. Broth dilution method was used to determine minimum inhibitory and streak plate bactericidal concentration of extracts. The results revealed that ethanol extracts of leaves revealed high antibacterial activity against standard strains of Staphylococcus aureus with inhibition zone of 14±0.6 mm at 25 mg/ml and 17±0.7 mm at 50 mg/ml. Ethanol extracts of buds showed high antibacterial activity against standard strains of S. aureus with inhibition zone of 25.7±0.7 mm at 100 mg/ml, also against standard strains of E. coli with inhibition zone of 16 mm at 50 mg/ml and 23.7 mm at 100 mg/ml. The mean minimum inhibitory concentration of 5.2±1.8 and 2.6±0.5 mg/ml was recorded for ethanol extract of leaves against standard strains of E. coli and clinical isolates of S. aureus; the mean minimum bactericidal concentration of 4.2±1.0 mg/ml with ethanol extract of leaves against standard strains of S. aureus; and the mean minimum bactericidal concentration of 12.5 mg/ml against standard strains and clinical isolates of E. coli. The result showed that A. sennii could be a candidate in the search for new antibacterial agents against these bacteria and its use in ethnomedicinal treatment of infectious diseases used by local communities may be validated. Isolating bio-active components and determining toxicity are future agenda. Keywords: Acanthus sennii, Antibacterial activity, E. coli, Minimum inhibition concentration, Minimum bactericidal concentration, S. aureus  


2016 ◽  
Vol 73 (8) ◽  
pp. 1910-1919 ◽  
Author(s):  
Zhong-Hua Huang ◽  
Yan-Na Yin ◽  
Gu-li-mi-la Aikebaier ◽  
Yan Zhang

A novel positively charged N-[(2-hydroxy-3-trimethylammonium)propyl] chloride chitosan (HTCC)-Ag/polyethersulfone (PES) composite nanofiltration membrane was easily prepared by coating the active layer, HTCC, onto PES as the support through epichlorohydrin as the cross-linking reagent and nano-Ag particles as the introduced inorganic components. Scanning election microscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and X-ray diffraction were employed to characterize the morphology of the resultant membranes, of which the molecular weight cut-off was about 941 Da. At 25 °C, the pure water permeability is 16.27 L/h·m2·MPa. Our results showed that the rejection of pharmaceuticals and personal care products (PPCPs) followed the sequence: atenolol &gt; carbamazepine &gt; ibuprofen, confirming that the membranes were positively charged. The antibacterial properties of the membranes were compared to elucidate the existence of Ag nanoparticles which help to improve antibacterial activity against Gram-negative Escherichia coli (DH5α, Rosetta) and Gram-positive Bacillus subtilis. The inhibition zone diameters of HTCC-Ag/PES membranes towards E. coli DH5α, E. coli Rosetta and Bacillus subtilis were 17.77, 16.18, and 15.44 mm, respectively. It was found that HTCC-Ag/PES membrane has a better antibacterial activity against E. coli than against Bacillus subtilis, especially for E. coli DH5α.


BIOEDUKASI ◽  
2019 ◽  
pp. 17
Author(s):  
Wahyu Nur Sulistyanto ◽  
Guntur Trimulyono

The phenomenon of increasing human bacterial infections and increased resistance to antibiotics encourages the exploration of more antibiotic producers. One source of antibiotics comes from the Actinomycetes bacteria, the source of isolation comes from the rhizosphere of sugarcane plants because it is known in the rhizosphere to produce exudates that are beneficial to bacteria. The purpose of this study was to obtain Actinomycetes isolates and determine the antibacterial abilities of selected isolates. Initial isolation was carried out using Starch Casein Agar (ScA) media, then color grouping, Gram test and cell morphology observation. The next stage is testing the antibacterial activity carried out using the well method. Data obtained in the form of basic characters Actinomycetes, inhibition zone diameter and antibacterial activity count. The results showed that 4 isolates had antibacterial ability against test bacteria, among others, ACB34a isolates, ACB44c isolates, ACB44c isolates and ACB55c isolates. Based on the results of measurement and calculation of antibacterial activity against E. coli, it can be known in succession, among others, ACB44c isolates (9.62 mm2 / 10µl) and ACB54c (0.38 mm2 / 10µl), then antibacterial activity against S. aureus. among others, ACB44c (27.33 mm2 / 10µl), ACB54c (26.41 mm2 / 10µl), ACB55c (8.04 mm2 / 10µl), and ACB34a (8.04 mm2 / 10µl).


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