scholarly journals Controlled Synthesis of Gold Nanoparticles UsingAspergillus terreusIF0 and Its Antibacterial Potential against Gram Negative Pathogenic Bacteria

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Eepsita Priyadarshini ◽  
Nilotpala Pradhan ◽  
Lala B. Sukla ◽  
Prasanna K. Panda
Keyword(s):  
Gold Nanoparticles ◽  
Pathogenic Bacteria ◽  
Particle Diameter ◽  
Weight Fraction ◽  
Xrd Analysis ◽  
Controlled Synthesis ◽  
Chloroauric Acid ◽  
Gram Negative ◽  
Fungal Extract ◽  
Vis Spectroscopy

Biosynthesis of monodispersed nanoparticles, along with determination of potential responsible biomolecules, is the major bottleneck in the area of bionanotechnology research. The present study focuses on an ecofriendly, ambient temperature protocol for size controlled synthesis of gold nanoparticles, using the fungusAspergillus terreusIF0. Gold nanoparticles were formed immediately, with the addition of chloroauric acid to the aqueous fungal extract. Synthesized nanoparticles were characterized by UV-Vis spectroscopy, TEM-EDX, and XRD analysis. Particle diameter and dispersity of nanoparticles were controlled by varying the pH of the fungal extract. At pH 10, the average size of the synthesized particles was in the range of 10–19 nm. Dialysis to obtain high and low molecular weight fraction followed by FTIR analysis revealed that biomolecules larger than 12 kDa and having –CH, –NH, and –SH functional groups were responsible for bioreduction and stabilization. In addition, the synthesized gold nanoparticles were found to be selectively bactericidal against the pathogenic gram negative bacteria,Escherichia coli.

Seed-mediated synthesis and PEG coating of gold nanoparticles for controlling morphology and sizes

MRS Advances ◽  
2020 ◽  
Vol 5 (63) ◽  
pp. 3353-3360
Author(s):  
Susana Helena Arellano Ramírez ◽  
Perla García Casillas ◽  
Christian Chapa González
Keyword(s):  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Infrared Spectrometry ◽  
Ammonium Bromide ◽  
Chloroauric Acid ◽  
Vis Spectroscopy ◽  
Seed Mediated ◽  
Peg Coating

AbstractA significant area of research is biomedical applications of nanoparticles which involves efforts to control the physicochemical properties through simple and scalable processes. Gold nanoparticles have received considerable attention due to their unique properties that they exhibit based on their morphology. Gold nanospheres (AuNSs) and nanorods (AuNRs) were prepared with a seed-mediated method followed of polyethylene glycol (PEG)-coating. The seeds were prepared with 0.1 M cetyltrimethyl-ammonium bromide (CTAB), 0.005 M chloroauric acid (HAuCl4), and 0.01 M sodium borohydride (NaBH4) solution. Gold nanoparticles with spherical morphology was achieved by growth by aggregation at room temperature, while to achieve the rod morphology 0.1 M silver nitrate (AgNO3) and 0.1 M ascorbic acid solution were added. The gold nanoparticles obtained by the seed-mediated synthesis have spherical or rod shapes, depending on the experimental conditions, and a uniform particle size. Surface functionalization was developed using polyethylene glycol. Morphology, and size distribution of AuNPs were evaluated by Field Emission Scanning Electron Microscopy. The average size of AuNSs, and AuNRs was 7.85nm and 7.96 x 31.47nm respectively. Fourier transform infrared spectrometry was performed to corroborate the presence of PEG in the AuNPs surface. Additionally, suspensions of AuNSs and AuNRs were evaluated by UV-Vis spectroscopy. Gold nanoparticles were stored for several days at room temperature and it was observed that the colloidal stability increased once gold nanoparticles were coated with PEG due to the shield formed in the surface of the NPs and the increase in size which were 9.65±1.90 nm of diameter for AuNSs and for AuNRs were 29.03±5.88 and 8.39±1.02 nm for length and transverse axis, respectively.

Optimization of Gold Nanoparticles Synthesis using Design of Experiments Technique

2017 ◽  
Vol 68 (7) ◽  
pp. 1518-1423
Author(s):  
Adina Turcu Stiolica ◽  
Mariana Popescu ◽  
Maria Viorica Bubulica ◽  
Carmen Nicoleta Oancea ◽  
Claudiu Nicolicescu ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Zeta Potential ◽  
Design Of Experiments ◽  
Process Model ◽  
Sodium Citrate ◽  
Drug Carriers ◽  
Chloroauric Acid ◽  
Gold Colloids ◽  
Citrate Concentration ◽  
Vis Spectroscopy

Gold nanoparticles are considered the newest drug carriers for different diseases. Therefore it is appropriate continuous optimization of their preparation. In this study, gold colloids with an average size of 1 - 26 nm were obtained by the reduction of tetrachloroauric acid with trisodium citrate. The nanomaterials were characterized by UV-Vis spectroscopy and dynamic light scattering technique. In addition, zeta potential was measured for samples synthesized in order to determine the stability of the colloids. A Two-level Full Factorial design was chosen to determine the optimum set of process parameters (chloroauric acid concentration and sodium citrate concentration) and their effect on various gold nanoparticles characteristics (size and zeta potential). These effects were quantified using Design of Experiments (DoE) with 5 runs and 1 centerpoint. The selected objective and process model in this investigation are screening and interaction. Findings from this research show that to obtain particles larger than 35 nm, it is recommended to increase sodium citrate concentration, at low chloroauric acid values. These conditions will help to achieve smaller zeta potential, too.

Green synthesis of gold nanoparticles using Tribulus terrestris extract and antibacterial activity against Gram-negative bacteria

2021 ◽  
Vol 7 (2) ◽  
Keyword(s):  
Gold Nanoparticles ◽  
Green Synthesis ◽  
Tribulus Terrestris ◽  
Chloroauric Acid ◽  
X Ray Diffraction ◽  
Inhibitory Effects ◽  
Plant Metabolites ◽  
Sem Images ◽  
Gram Negative ◽  
Human Blood Cells

Aqueous extract of the plant Tribulus terrestris was used to reduce chloroauric acid for synthesizing gold nanoparticles (AuNPs). In this green synthesis, the reaction proceeded to give a red/purple color that was monitored by UV-vis spectrophotometry, where the formed AuNPs had an absorption band with max of 550 nm. In terms of the highest absorbance at 550 nm, reaction conditions were optimized at a temperature of 75°C, at pH 7 and using a reaction time of 4 h. The integrity of the synthesized AuNPs was confirmed and their physical properties were characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM), which also showed evidence that plant metabolites contributed to capping or stabilization of the AuNPs. XRD spectra suggested a particle size of around 40 nm and SEM images revealed spherical and relatively uniform and disperse particles with a size of less than 0.1 m. In a broth microdilution assay, the AuNPs showed inhibitory effects against Gram-negative Escherichia coli, but not against Gram-positive Enterococcus faecalis. The AuNPs showed no hemagglutination activity or cytotoxic activity against human blood cells, which is important for them to be explored as therapeutic antibacterial agents.

scholarly journals Role of Surfactant in the Formation of Gold Nanoparticles in Aqueous Medium

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Abhishek Das ◽  
Ridhima Chadha ◽  
Nandita Maiti ◽  
Sudhir Kapoor
Keyword(s):  
Gold Nanoparticles ◽  
Aqueous Medium ◽  
Sodium Dodecyl ◽  
Chloroauric Acid ◽  
Synthesis Mechanism ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
The Stability ◽  
Mediated Reduction

The stability of gold nanoparticles is a major issue which decides their impending usage in nanobiotechnological applications. Often biomimetically synthesized nanoparticles are deemed useless owing to their instability in aqueous medium. So, surfactants are used to stabilize the nanoparticles. But does the surfactant only stabilize by being adsorbed to the surface of the nanoparticles and not play significantly in moulding the size and shape of the nanoparticles? Keeping this idea in mind, gold nanoparticles (GNPs) synthesized by l-tryptophan (Trp) mediated reduction of chloroauric acid (HAuCl4) were stabilized by anionic surfactant, sodium dodecyl sulphate (SDS), and its effect on the moulding of size and properties of the GNPs was studied. Interestingly, unlike most of the gold nanoparticles synthesis mechanism showing saturation growth mechanism, inclusion of SDS in the reaction mixture for GNPs synthesis resulted in a bimodal mechanism which was studied by UV-Vis spectroscopy. The mechanism was further substantiated with transmission electron microscopy. Zeta potential of GNPs solutions was measured to corroborate stability observations recorded visually.

Synthesis of L-Phenylalanine Stabilized Gold Nanoparticles and Their Thermal Stability

2006 ◽  
Vol 6 (11) ◽  
pp. 3512-3516 ◽  
Author(s):  
Nimai C. Nayak ◽  
Kwanwoo Shin
Keyword(s):  
Thermal Stability ◽  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Ambient Condition ◽  
Synthesis Methods ◽  
Chloroauric Acid ◽  
Borohydride Reduction ◽  
Thermal Stabilities ◽  
Transmission Electron ◽  
Vis Spectroscopy

Here we described the two synthesis methods of L-phenylalanine (L-phe) coated gold nanoparticles through a reduction of aqueous chloroaurate ions directly by L-phe, and also the borohydride reduction of chloroauric acid followed by capping with L-phe molecules. Phenylalanine reduced gold nanoparticles and the phenylalanine capped gold nanoparticles were evaluated by transmission electron microscope and UV-vis spectroscopy, and then their thermal stabilities were compared. We found that the phenylalanine reduced gold nanoparticles were unstable and form linearly arranged aggregates on aging, while as the phenylalanine capped gold nanoparticles were stable for months in ambient condition.

scholarly journals Biosynthesis of Silver and Gold Nanoparticles Using Aqueous Extract of Codonopsis pilosula Roots for Antibacterial and Catalytic Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Van-Dat Doan ◽  
Bao-An Huynh ◽  
Thanh-Danh Nguyen ◽  
Xuan-Thang Cao ◽  
Van-Cuong Nguyen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Aqueous Extract ◽  
Metal Ion ◽  
Metallic Nanoparticles ◽  
Ion Concentration ◽  
Gram Negative ◽  
X Ray ◽  
Codonopsis Pilosula ◽  
Vis Spectroscopy

In this study, biogenic silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were synthesized by a green approach using an aqueous extract from Codonopsis pilosula (CP) roots as a reducing and stabilizing agent. The formation of CP-AgNPs and CP-AuNPs was confirmed and optimized by UV-Vis spectroscopy. The CP-AgNPs and CP-AuNPs obtained under optimum conditions of metal ion concentration, reaction temperature, and reaction time were characterized by high-resolution transition electron microscopy (HR-TEM), selected area electron diffraction (SAED) analysis, field-emission scan electron microscopy (FE-SEM), powder X-ray diffraction (XRD) analysis, Fourier transform infrared (FTIR) spectroscopy, dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS) method. It has been found that the biosynthesized CP-AgNPs and CP-AuNPs were formed in spherical shape with an average size of 10±2.5 nm and 20±3.2 nm, respectively. The biosynthesized metallic nanoparticles exhibited selective bacterial activity against three bacterial strains including two Gram-positive bacteria of Bacillus subtilis and Staphylococcus aureus and one Gram-negative bacteria of Escherichia coli. Meanwhile, there was no antibacterial activity detected toward Gram-negative Salmonella enteritidis. CP-AgNPs and CP-AuNPs also manifested an excellent catalytic performance in the reduction of 1,4-dinitrobenzene, 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol.

scholarly journals Green and Economic Fabrication of Zinc Oxide (ZnO) Nanorods as a Broadband UV Blocker and Antimicrobial Agent

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 530 ◽  
Author(s):  
Seyedeh-Masoumeh Taghizadeh ◽  
Neha Lal ◽  
Alireza Ebrahiminezhad ◽  
Fatemeh Moeini ◽  
Mostafa Seifan ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Large Scale ◽  
Average Length ◽  
Zno Nanorods ◽  
Waste Product ◽  
Antibacterial Properties ◽  
Xrd Analysis ◽  
Controlled Synthesis ◽  
Vis Spectroscopy ◽  
Prepared Nanorods

Zinc oxide (ZnO) nanoparticles have gained widespread interest due to their unique properties, making them suitable for a range of applications. Several methods for their production are available, and of these, controlled synthesis techniques are particularly favourable. Large-scale culturing of Chlorella vulgaris produces secretory carbohydrates as a waste product, which have been shown to play an important role in directing the particle size and morphology of nanoparticles. In this investigation, ZnO nanorods were produced through a controlled synthesis approach using secretory carbohydrates from C. vulgaris, which presents a cost-effective and sustainable alternative to the existing techniques. Fourier transform infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD) analysis, transmission electron microscopy (TEM), and UV-Vis spectroscopy were used to characterise the nanorods. The prepared nanorods exhibited a broad range of UV absorption, which suggests that the particles are a promising broadband sun blocker and are likely to be effective for the fabrication of sunscreens with protection against both UVB (290–320 nm) and UVA (320–400 nm) radiations. The antimicrobial activity of the prepared nanorods against Gram-positive and Gram-negative bacteria was also assessed. The nanostructures had a crystalline structure and rod-like appearance, with an average length and width of 150 nm and 21 nm, respectively. The nanorods also demonstrated notable antibacterial activity, and 250 μg/mL was determined to be the most effective concentration. The antibacterial properties of the ZnO nanorods suggest its suitability for a range of antimicrobial uses, such as in the food industry and for various biomedical applications.

scholarly journals Synthesis and Characterization of about 20nm Gold Nanoparticles

2021 ◽  
Vol 37 (5) ◽  
pp. 1187-1191
Author(s):  
Arpita Biswas
Keyword(s):  
Gold Nanoparticles ◽  
Electron Diffraction ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Trisodium Citrate ◽  
Average Diameter ◽  
Chloroauric Acid ◽  
X Ray ◽  
Vis Spectroscopy

The synthesis of spherical gold nanoparticles (AuNPs) by the chemical reduction process and the characterization of the synthesized nanoparticles is the main aim of this article. Reduction of Chloroauric acid by trisodium citrate salt was performed to get AuNPs of average diameter 20nm. Trisodium citrate is not only the reducing reagent but also the stabilizer of the synthesized AuNPs. Some important modern techniques like UV-VIS spectroscopy, diffraction light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), Selected area electron diffraction (SAED) and electron diffraction X-ray (EDX) were involved for the characterization of synthesized AuNPs. Chemical reduction and Size-controlled growth of spherical AuNPs were followed for this particular synthesis of AuNPs.

scholarly journals Synthesis and Characterization Gold Nanoparticles Using Extracts of Sarang Semut (Myrmecodia pendans) For Sensing of Glucose

2019 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Andi Suciati ◽  
Abdul Wahid Wahab ◽  
Paulina Taba
Keyword(s):  
Gold Nanoparticles ◽  
Glucose Sensor ◽  
Color Change ◽  
Low Cost ◽  
Xrd Analysis ◽  
Measurement Range ◽  
Sem Analysis ◽  
Chloroauric Acid ◽  
Particle Size Analyzer ◽  
Visible Spectra

Abstract. Gold nanoparticles have been synthesized with simple and relatively safe method by using kaemferol and quercetin containing aqueous extract of Myrmecodia pendans (sarang semut plant). Under this method, it was able to obtain AuNPs and measured the size. The formation of the nanoparticles were identified by the color change (yellow to red) occurred in the chloroauric acid solution after additional aquoeos extract of sarang semut plant. The UV-Visible spectra and particle size analyzer indicated the successful formation of AuNPs with wavelength of 521.5 nm which was stable for 4 days, evidenced by the presence of particles with a size 53.2 nm. XRD analysis showed the difractogram peak of gold nanopartcle. The result of SEM analysis indicated gold nanopartcle surface with spherical and rod-like shapes. Glucose sensor utilized gold nanopartcle as catalyst with measurement range 2–5 mM and regresision 0,868, detection limit of sensor was in concentration 2-5 mM  was 7,5 mM with sensitivity 0,736 A.mM-1.mm-2. Glucose concentration obtained in blood serum was 78,48mg/dL. Gold nanoparticles is promising to detect blood sugar with simply, securely, low cost without using enzyme and harmful material.

scholarly journals The Effect of PEI and PVP-Stabilized Gold Nanoparticles on Equine Platelets Activation: Potential Application in Equine Regenerative Medicine

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Mateusz Hecold ◽  
Roma Buczkowska ◽  
Aleksandra Mucha ◽  
Jakub Grzesiak ◽  
Olga Rac-Rumijowska ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Growth Factors ◽  
Growth Factor ◽  
Regenerative Medicine ◽  
Chemical Reduction ◽  
Interleukin 1 ◽  
Mrna Level ◽  
Bone Morphogenetic Protein 2 ◽  
Chloroauric Acid ◽  
Vis Spectroscopy

The aim of this work was to assess the effect of different stabilizing agents, for example, polyethylenimine (PEI) and polyvinylpyrrolidone (PVP), on gold nanoparticles (AuNPs) and their influence on equine platelet activation and release of particular growth factors. The gold nanoparticles were produced by chemical reduction of chloroauric acid. UV-Vis spectroscopy confirmed the presence of gold nanoparticles in investigated solutions. The AuNPs were incubated with whole blood at various concentrations. The morphology of platelets in PRP prepared from the blood incubated with AuNPs was characterized by scanning transmission electron microscopy, whereas the concentrations of growth factors and cytokines were evaluated by ELISA assays. The most promising results were obtained with equine platelets incubated with 5% AuNPs stabilized by PEI, which lead to secretion of bone morphogenetic protein 2 (BMP-2), vascular endothelial growth factor (VEGF), and fibroblast growth factor 1 (FGF-1) and simultaneously cause decrease in concentration of interleukin-1 alpha (IL-1α). The qRT-PCR confirmed ELISA test results. The incubation with 5% AuNPs stabilized by PEI leads to upregulation of BMP-2 and VEGF transcripts of mRNA level and to downregulating expression of interleukin-6 (IL-6). Obtained data shed a promising light on gold nanoparticle application for future regenerative medicine application.

Sign in / Sign up

Export Citation Format

Share Document