scholarly journals Synthesis of Gold Nanoparticles by using Batch Method and Study its Antibacterial Activity

2020 ◽  
Vol 17 (2(SI)) ◽  
pp. 0633
Author(s):  
Ahmed Mohammed et al.
Keyword(s):  
Gold Nanoparticles ◽  
Dilution Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
E Coli ◽  
Inhibition Concentration ◽  
Uv Visible ◽  
Average Size ◽  
Broth Dilution ◽  
Initial Heating

The research involves preparing gold nanoparticles (AuNPs) and studying the factors that influence the shape, sizes and distribution ratio of the prepared particles according to Turkevich method. These factors include (reaction temperature, initial heating, concentration of gold ions, concentration and quantity of added citrate, reaction time and order of reactant addition). Gold nanoparticles prepared were characterized by the following measurements: UV-Visible spectroscopy, X-ray diffraction and scanning electron microscopy. The average size of gold nanoparticles was formed in the range (20 -35) nm. The amount of added citrate was changed and studied. In addition, the concentration of added gold ions was changed and the calibration curve was calculated used to estimate Au ions in different samples. The effectiveness of gold nanoparticles prepared according to Turkevich method was studied as antibacterial agents against E. coli bacteria. The minimum inhibition concentration of gold nanoparticles that inhibit bacterial growth was calculated using the broth dilution method, which is based on several dilutions to determine the inhibition concentration.

scholarly journals Optical, Structural, and Antimicrobial Study of Gold nanoparticles Synthesized Using an Aqueous Extract of Mimusops elengi Raw Fruits

2020 ◽  
Vol 10 (6) ◽  
pp. 7085-7096
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Extract ◽  
X Ray Diffraction ◽  
X Ray ◽  
Green Route ◽  
Infra Red ◽  
Hazardous Condition ◽  
Uv Visible ◽  
Mimusops Elengi ◽  
Positive Results

Gold nanoparticles (AuNPs) has been synthesized via a green route using an aqueous extract of Mimusops elengi raw fruits. The phytochemicals of the fruit help in stabilizing and capping of the nanoparticles. The formation and stability of the synthesized samples has been explained based on results that we obtain from UV-Visible spectroscopy, Fourier Transform Infra-Red (FTIR) spectroscopy, Dynamic Light Scattering (DLS), X-ray diffraction (XRD), scanning electron microscopy (SEM). Further, the positive results of the antimicrobial test add one more novelty to this work. The axiom of this work is the synthesis of stable AuNPs without using any external stabilizing or reducing agents. The formation of AuNPs with the help of photochemical present in Mimusops elengi is yet another important aspect of this work, which provides an eco-friendly method for the synthesis of AuNPs, which can be used extensively because of its non-hazardous condition.

Sunlight-Driving Formation and Characterization of Size-Controlled Gold Nanoparticles

2007 ◽  
Vol 7 (2) ◽  
pp. 708-711 ◽  
Author(s):  
Yonglan Luo
Keyword(s):  
Gold Nanoparticles ◽  
Sodium Citrate ◽  
Noble Metal Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron Microcopy ◽  
Uv Visible ◽  
Size Controlled

Exposing a sodium citrate-HAuCl4 aqueous solution to sunlight results in the formation of size-controlled, citrate-capped gold nanoparticles. The gold nanoparticles were characterized by UV-visible, transmission electron microscopy (TEM), scanning electron microcopy (SEM), and X-ray diffraction (XRD) spectroscopic methods. It provides a general methodologyfor the economic, convenient, mild preparation of citrate-capped noble metal nanoparticles.

scholarly journals Biogenic Gold Nanoparticles as Potent Antibacterial and Antibiofilm Nano-Antibiotics against Pseudomonas aeruginosa

Antibiotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 100 ◽  
Author(s):  
Syed Ghazanfar Ali ◽  
Mohammad Azam Ansari ◽  
Mohammad A. Alzohairy ◽  
Mohammad N. Alomary ◽  
Sami AlYahya ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pseudomonas Aeruginosa ◽  
Gold Nanoparticles ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Tinospora Cordifolia ◽  
Confocal Laser ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Size

Abstract: Plant-based synthesis of eco-friendly nanoparticles has widespread applications in many fields, including medicine. Biofilm—a shield for pathogenic microorganisms—once formed, is difficult to destroy with antibiotics, making the pathogen resistant. Here, we synthesized gold nanoparticles (AuNPs) using the stem of an Ayurvedic medicinal plant, Tinospora cordifolia, and studied the action of AuNPs against Pseudomonas aeruginosa PAO1 biofilm. The synthesized AuNPs were characterized by techniques such as ultraviolet-visible spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, energy-dispersive X-ray diffraction, X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy. The AuNPs were spherically shaped with an average size of 16.1 nm. Further, the subminimum inhibitory concentrations (MICs) of AuNPs (50, 100, and 150 µg/mL) greatly affected the biofilm-forming ability of P. aeruginosa, as observed by crystal violet assay and SEM, which showed a decrease in the number of biofilm-forming cells with increasing AuNP concentration. This was further justified by confocal laser scanning microscopy (CLSM), which showed irregularities in the structure of the biofilm at the sub-MIC of AuNPs. Further, the interaction of AuNPs with PAO1 at the highest sub-MIC (150 µg/mL) showed the internalization of the nanoparticles, probably affecting the tendency of PAO1 to colonize on the surface of the nanoparticles. This study suggests that green-synthesized AuNPs can be used as effective nano-antibiotics against biofilm-related infections caused by P. aeruginosa.

scholarly journals Synthesis of gold nanoparticles using Platycodon grandiflorum extract and its antipathogenic activity under optimal conditions

2020 ◽  
Vol 10 ◽  
pp. 184798042096169
Author(s):  
Periasamy Anbu ◽  
Subash CB Gopinath ◽  
S Jayanthi
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Plant Extracts ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Platycodon Grandiflorum ◽  
Transmission Electron ◽  
Flower Plant ◽  
Average Size

Gold nanoparticles have many applications in the biomedical field, mainly for drug delivery, cancer therapy, and detection of pathogenic microorganisms. In this study, gold nanoparticles synthesized using Platycodon grandiflorum (Balloon flower plant) extracts were evaluated for their antibacterial potential. Gold nanoparticles were synthesized at 20–50°C using different volumes of the leaf extract. Biosynthesis of gold nanoparticles was confirmed by ultraviolet–visible spectral absorption at 545 nm by surface plasmon resonance. The morphology and size of the P. grandiflorum gold nanoparticles were further characterized as spherical in shape with an average size of 15 nm in diameter by scanning electron microscopy and transmission electron microscopy. Energy-dispersive X-ray analysis clearly displayed the presence of gold particles. The structural analysis results with face central cubic crystalline nature and elemental composition, including gold, were confirmed by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. In addition, Fourier transform infrared results identified the functional group in P. grandiflorum that is involved in the reduction of metal ions to gold nanoparticles. The synthesized P. grandiflorum gold nanoparticles exhibited efficient antibacterial activity against Escherichia coli (16 mm) and Bacillus subtilis (11 mm). This report confirms the synthesis of gold nanoparticle from balloon flower plant extracts, which can be used as a reducing and stabilizing agent and demonstrates its antibacterial applications.

Ultrasonic-hydrothermal Synthesis and Characterization of Mesoporous Anatase TiO2 Microspheres

2011 ◽  
Vol 239-242 ◽  
pp. 2323-2326 ◽  
Author(s):  
Hai Bin Li ◽  
Shu Guang Chen ◽  
Wei Ming Lu ◽  
Qi Cheng Liu
Keyword(s):  
Diffuse Reflectance Spectroscopy ◽  
Tetrabutyl Titanate ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Uv Visible ◽  
Average Size ◽  
Adsorption Desorption

Mesoporous TiO2 microspheres with a combination of large surface and high crystallinity were fabricated by an ultrasonic-hydrothermal method with Octadecylamine as a structure-directing agent and tetrabutyl titanate as a precursor. The mesoporous materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption measurements, and UV–visible diffuse reflectance spectroscopy (UV-vis). Low-angle XRD and TEM images indicated that the disordered wormhole-like mesoporous architecture of TiO2 microspheres with diameters of about 200-400 nm were actually formed by agglomerization of nanoparticles with an average size of about 10nm. The analysis from N2 adsorption–desorption isotherms showed that the surface area of mesoporous sample was 204.7 m2g-1, with a pore size of 4.3 nm and pore volume of 0.263 cm3g-1 after calcined at 673 K.

A Preliminary Study on the Effect of Pandanus amaryllifolius Extract as Green Stabilizer to the Growth of Nanostructured ZnO

2020 ◽  
Vol 990 ◽  
pp. 277-282
Author(s):  
Rabiatuladawiyah Md Akhir ◽  
Siti Zulaikha Umbaidilah ◽  
Nurul Afaah Abdullah ◽  
Mohamad Rusop Mahmood ◽  
Zuraida Khusaimi
Keyword(s):  
Cost Effective ◽  
Hexagonal Wurtzite Structure ◽  
Zno Nanoparticle ◽  
X Ray Diffraction ◽  
Green Method ◽  
Visible Absorption ◽  
X Ray ◽  
Preliminary Study ◽  
Uv Visible ◽  
Average Size

Nanostructured zinc oxide (ZnO) were successfully prepared by using phyto assisted solution immersion process. ZnO were grown on a glass substrate coated with ZnO nanoparticle thin-film as seed layer at annealing temperature of 450°C. The fabricated nanostructured ZnO exhibit absorption at ∼375 nm as revealed from the UV-visible absorption spectrum, and it is comparable with ZnO nanostructured synthesized from hexamethylenetetramine (HMTA). X-ray diffraction (XRD) measurement revealed a sharp peak corresponding to the hexagonal wurtzite structure of nanostructured ZnO. Field emission scanning electron microscopy (FESEM) showed average size of ZnO at 24.15 nm slightly smaller compared to synthesized from HMTA; 30.54 nm. It should also be highlighted that the needs of using this alternative green method are due to the advantages of low working temperature and cost-effective, and with the least possible damage to the environment.

Eco-Friendly Synthesis of Gold Nanoparticles by Bacillus subtilis and Their Environmental Applications

2018 ◽  
Vol 24 (8) ◽  
pp. 5942-5946 ◽  
Author(s):  
B. S Srinath ◽  
K Namratha ◽  
K Byrappa
Keyword(s):  
Gold Nanoparticles ◽  
Bacillus Subtilis ◽  
Color Change ◽  
Cost Effective ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gold Mines ◽  
The Earth ◽  
Transmission Electron ◽  
Uv Visible

Biosynthesis of gold nanoparticles (GNPs) is an eco-friendly, cost effective and nontoxic alternative to chemical and physical methods. The microbe which inhabits nearly all surfaces on the earth, an attainment typically attributed to their metabolic adaptability. The organism which resides in gold mines would be having more capability to resist against soluble gold toxicity and produce gold nanoparticles efficiently. In the present study, we report for the synthesis of GNPs by a member of Bacillus subtilis isolated from Hutti gold mine, India. The synthesis of GNPs was observed by a color change from yellow to pink and confirmed by a peak around 545 nm using a UV–visible spectroscopy. The synthesized GNPs were further characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The results show that synthesized GNPs are well dispersed and their size ranges 20–25 nm. The present work is aimed to use green synthesized GNPs as catalyst to degrade Methylene blue (MB) and these GNPs could be used to degrade toxic dyes in the environment.

scholarly journals Green Synthesis, Characterization and Cholinesterase Inhibitory Potential of Gold Nanoparticles

2021 ◽  
Vol 65 (3) ◽  
Author(s):  
Zainab ◽  
Khalid Saeed ◽  
Ammara ◽  
Shujaat Ahmad ◽  
Hanif Ahmad ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Green Synthesis ◽  
X Ray Diffraction ◽  
Au Nps ◽  
X Ray ◽  
Sem Study ◽  
Gold Nps ◽  
Uv Visible ◽  
Inhibitory Potential

Abstract. The green synthesis of gold nanoparticles (Au NPs) from their precursor was carried out using Delphinium uncinatum and Erythrophyleum guineense plants extracts. The Au NPs obtained were characterized by various instrumental techniques such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and UV/Visible (UV/VIS) spectrophotometer. The SEM study presented that E. guineense (GE) and D. uncinatum (GN) synthesized gold nanoparticles was below 100 and 300 nm, respectively.  The micrographs also presented that E. guineense (GE) synthesized gold particles had irregular round shaped while the D. uncinatum (GN) synthesized nanoparticles had cylindrical shaped. The XRD spectra presented peaks at about 38.1°, 44.43°, 64.6° and 77.64° can be indexed to (111), (200), (220) and (311) orientation, respectively, which confirmed the presence of gold nanoparticles. It means that both E. guineense (GE) and D. uncinatum (GN) synthesized gold nanoparticles are highly crystalline.  The UV/VIS analysis presented that both plant extracts significantly reduced the gold slat and as a result high quantity of gold nanoparticles were formed. The E. guanense gold NP and D. uncinatum gold NPs were investigated for their in-vitro cholinesterases inhibitory potentials in 62.5-1000 µg/mL concentrations range. The bioactivity results presented that the loading of the test samples in gold NPs enhanced their AChE and BChE inhibitory potentials.   Resumen. La síntesis verde de nanopartículas de oro (NP de Au) se llevó a cabo mediante extractos de plantas de Delphinium uncinatum y Erythrophyleum guineense. Las NP de Au obtenidas se caracterizaron mediante diversas técnicas instrumentales como microscopía electrónica de barrido (SEM), dispersión de energía de rayos X (EDX), difracción de rayos X (XRD) y espectrofotómetro UV / Visible (UV / Vis). El estudio SEM reveló tamaños de las nanopartículas de oro sintetizadas por E. guineense (GE) y D. uncinatum (GN) por debajo de 100 y 300 nm, respectivamente. Las micrografías también mostraron que las partículas de oro sintetizadas por E. guineense (GE) tenían una forma redonda irregular, mientras que las nanopartículas sintetizadas por D. uncinatum (GN) tenían una forma cilíndrica. Los patrones XRD presentaron picos a aproximadamente 38.1 °, 44.43 °, 64.6 ° y 77.64 ° pueden indexarse ​​a la orientación (111), (200), (220) y (311), respectivamente, lo que confirmó la presencia de nanopartículas de oro cristalinas. El análisis UV / Vis mostró que ambos extractos de plantas formaron nanopartículas de oro. Se investigaron las NP de oro como inhibidores de colinesterasas in vitro en un intervalo de concentraciones de 62.5 a 1000 µg / ml. Los resultados de la bioactividad mostraron que la carga de las muestras de prueba en NP de oro mejoró sus potenciales inhibidores de AChE y BChE.

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

RNA polymerase: Preparation and structural analysis of helical polymers

1984 ◽  
Vol 42 ◽  
pp. 152-153
Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi
Keyword(s):  
Structural Analysis ◽  
Rna Polymerase ◽  
Molecular Level ◽  
X Ray Diffraction ◽  
Helical Polymers ◽  
X Ray ◽  
E Coli ◽  
The Past ◽  
Ordered Arrays ◽  
Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

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