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9 papers found.
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Shape-dependent cytotoxicity and cellular uptake of gold nanoparticles synthesized using green tea extract

In the present report, three different shapes of chitosan-capped gold nanoparticles (nanospheres, nanostars, and nanorods) were synthesized to investigate the effects of shape on cytotoxicity and cellular uptake in cancer cells. Green tea extract was utilized as a reducing agent to reduce gold salts to gold nanospheres. Gold nanostars were prepared using an as-prepared nanosphere...

Asymmetric dumbbell-shaped silver nanoparticles and spherical gold nanoparticles green-synthesized by mangosteen (Garcinia mangostana) pericarp waste extracts

Asymmetric dumbbell-shaped silver nanoparticles and spherical gold nanoparticles green-synthesized by mangosteen (Garcinia mangostana) pericarp waste extracts Ji Su Park, Eun-Young Ahn, Youmie Park ... Ji su Park eun-Young ahn Youmie Park Mangosteen (Garcinia mangostana) pericarp waste extract was used to synthesize gold and silver nanoparticles by a green strategy. The extract was both a reducing

Green Synthesis and Catalytic Activity of Gold Nanoparticles Synthesized by Artemisia capillaris Water Extract

Gold nanoparticles were synthesized using a water extract of Artemisia capillaris (AC-AuNPs) under different extract concentrations, and their catalytic activity was evaluated in a 4-nitrophenol reduction reaction in the presence of sodium borohydride. The AC-AuNPs showed violet or wine colors with characteristic surface plasmon resonance bands at 534~543 nm that were dependent...

Catalytic reduction of 4-nitrophenol with gold nanoparticles synthesized by caffeic acid

In this study, various concentrations of caffeic acid (CA) were used to synthesize gold nanoparticles (CA-AuNPs) in order to evaluate their catalytic activity in the 4-nitrophenol reduction reaction. To facilitate catalytic activity, caffeic acid was removed by centrifugation after synthesizing CA-AuNPs. The catalytic activity of CA-AuNPs was compared with that of centrifuged CA...

Cold welding of gold nanoparticles on mica substrate: Self-adjustment and enhanced diffusion

From the images of HR-TEM, FE-SEM, and AFM, the cold welding of gold nanoparticles (AuNPs) on a mica substrate is observed. The cold-welded gold nanoparticles of 25 nm diameters are found on the mica substrate in AFM measurement whereas the size of cold welding is limited to 10 nm for nanowires and 2~3 nm for nanofilms. Contrary to the nanowires requiring pressure, the AuNPs are...

Concentration Effect of Reducing Agents on Green Synthesis of Gold Nanoparticles: Size, Morphology, and Growth Mechanism

Under various concentration conditions of reducing agents during the green synthesis of gold nanoparticles (AuNPs), we obtain the various geometry (morphology and size) of AuNPs that play a crucial role in their catalytic properties. Through both theoretical and experimental approaches, we studied the relationship between the concentration of reducing agent (caffeic acid) and the...

Catechin-capped gold nanoparticles: green synthesis, characterization, and catalytic activity toward 4-nitrophenol reduction

An eco-friendly approach is described for the green synthesis of gold nanoparticles using catechin as a reducing and capping agent. The reaction occurred at room temperature within 1 h without the use of any external energy and an excellent yield (99%) was obtained, as determined by inductively coupled plasma mass spectrometry. Various shapes of gold nanoparticles with an...

Earthworm extracts utilized in the green synthesis of gold nanoparticles capable of reinforcing the anticoagulant activities of heparin

Gold nanoparticles were obtained using a green synthesis approach with aqueous earthworm extracts without any additional reducing or capping agents. The gold nanoparticles were characterized using UV-visible spectrophotometry, high-resolution transmission electron microscopy, atomic force microscopy, field emission scanning electron microscopy, X-ray diffraction, Fourier...

Determination of the structure of oligosaccharides prepared from acharan sulfate

The fine structure of acharan sulfate, a recently discovered glycosaminoglycan isolated from Achatina fulica, was examined. This glycosaminoglycan has a major disaccharide repeating unit of →4)-α-D-G1cNpAc(1→4)-α-L-IdoAp2S(1→ (where G1cNpAc is N-acetylglucosamine, IdoAp is iduronic acid, and S is sulfate) making it structurally related to both heparin and heparan sulfate. Using...