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Colloidal gold
About: Colloidal gold is a research topic. Over the lifetime, 25158 publications have been published within this topic receiving 904430 citations.
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TL;DR: An electrochemical immunosensor for ultrasensitive detection of acrylamide (AA) in water and food samples exhibited a sensitive response to AA with a detection limit of 45.9% and working range of 187 ± 12.7 ng kg-1, indicating its potential application in AA monitoring.
21 citations
TL;DR: Results suggests that ACM-TNGs could be useful for the RF assisted cancer cells ablation with minimal toxicity compared with MnO2 nanorods.
Abstract: Gold nanoparticles (Au-NPs) based chitin-MnO2 ternary composite nanogels (ACM-TNGs) were prepared by the regeneration of chitin along with MnO2 nanorods (5–20 nm) and the incorporation of 10 nm sized Au-NPs to make “ACM-TNGs”. They were characterized with FT-IR, TG, and UV spectroscopy. The SEM showed spindle shaped 200 nm sized chitin–MnO2 nanogels (chitin–MnO2 NGs), whereas ACM-TNGs had spindle sizes of 220 nm. The ACM-TNGs were compatible up to 1 mg mL−1 and showed uptake into L929, HDF, MG63, T47D and A375 cell lines without affecting the cellular morphology. ACM-TNGs showed conductivity, and heating under a radio frequency (RF) source at 100 W for 2 min. They also showed the ability to kill breast cancer cells under RF radiation at 100 W for 2 min, when compared with the chitin–MnO2 NGs. The RF assisted ablation of breast cancer cells was confirmed by a live/dead assay. These results suggests that ACM-TNGs could be useful for the RF assisted cancer cells ablation with minimal toxicity compared with MnO2 nanorods.
21 citations
TL;DR: The method was successfully applied to the determination of Cd(II) in spiked lake water by the standard addition mode, and the detection limit is 4.5 pM.
Abstract: A colorimetric approach is presented for the determinaton of cadmium(II) using unmodified gold nanoparticles (AuNPs) as a colorimetric probe. The assay is based on AuNP aggregation that is induced by the complexes formed between Cd(II) and glutathione (GSH) in a concentrated solution of NaCl. Unmodified AuNPs are known to aggregate in high-salt medium, but GSH can prevent aggregation. In the presence of Cd(II), it will bind GSH, and this will cause the AuNPs to aggregate as indicated by yellow and red dots under dark-field microscopy observation and the formation of a blue coloration. By monitoring the intensity change of AuNPs (as a ratio of absorbances at 600 and 520 nm), Cd(II) can be quantified with a linear response in the 17 pM to 16.7 nM concentration range and a detection limit of 4.3 pM. The method was successfully applied to the determination of Cd(II) in spiked lake water by the standard addition mode, and the detection limit is 4.5 pM.
21 citations
TL;DR: The results show clearly that the production of gold nanoparticles from cell-free extracts require shorter times than the production from the biomass, and the implications of the results are also discussed for the processing ofgold nanoparticles and gold prodigiosin nanoparticles for localized cancer treatment.
Abstract: This paper presents the biosynthesis of gold nanoparticles and gold/prodigiosin nanoparticles from the bacterium, Serratia marcescens. The intra- and extra-cellular synthesis of gold nanoparticles is shown to occur over a range of pH and incubation times in cell-free extracts and biomass of Serratia marcescens that were reacted with 2.5 mM tetrachloroauric acid (HAuCl4). The formation of gold nanoparticles was recognized initially via color changes from yellow auro-chloride to shades of red or purple in gold nanoparticle solutions. UV–visible spectroscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and dynamic light scattering were also used to characterize gold nanoparticles produced within a range of pH conditions. The results show clearly that the production of gold nanoparticles from cell-free extracts require shorter times than the production of gold nanoparticles from the biomass. The implications of the results are also discussed for the processing of gold nanoparticles and gold prodigiosin nanoparticles for localized cancer treatment.
21 citations
TL;DR: It is shown that microscopic droplets can be brought into contact with one another with a monolayer of nanoparticles between them, resulting in a junction where electron transport is limited by the Coulomb blockade effect.
Abstract: We describe the spontaneous assembly of ligand-stabilized gold nanoparticles on the surfaces of gallium droplets in suspension. By subsequent deposition of these coated droplets onto substrates with patterned electrodes, we form devices that have controlled architecture on the nanometer scale, which allows control of electron transport. In particular, we show that microscopic droplets can be brought into contact with one another with a monolayer of nanoparticles between them, resulting in a junction where electron transport is limited by the Coulomb blockade effect. We characterize the gallium surfaces by optical and electron microscopy and measurement of the interfacial tension. We measure the current-voltage characteristics of devices consisting of one or more Ga droplets and nanoparticle layers in series. The results agree well with the conventional theory of the Coulomb blockade and show how this approach could be used to form hierarchically structured electronic devices.
21 citations