Direct simultaneous electrochemical determination of glutathione (GSH) and glutathione disulfide (GSSG) has been presented using a nanoscale copper hydroxide carbon ionic liquid composite electrode. To the best of our knowledge, this is the first report on the simultaneous determination of these two biologically important compounds based on their direct electrochemical oxidation. Incorporation of copper(II) hydroxide nanostructures in the composite electrode results in complexation of Cu(II) with the thiol group of GSH and leads to a significant decrease in GSH oxidation overpotential, while an anodic peak corresponding to the direct oxidation of GSSG as the product of GSH oxidation is observed at higher overvoltages. Low detection limits of 30 nM for GSH and 15 nM for GSSG were achieved based on a signal-to-noise ratio of 3. The proposed method is free from interference of cysteine, homocysteine, ascorbic acid (AA), and uric acid (UA). No electrode surface fouling was observed during successive scans. Stability, high sensitivity, and low detection limits made the proposed electrode applicable for the analysis of biological fluids.

An easy and cost effective route for mass production of graphene nanosheets (GNSs) is an essential requirement for design of different sensors, conductive composites and future nanoelectronic devices. Scalable and large area GNSs were synthesized by a thermal treatment of a graphite-ionic liquid crystal composite as a starting material. This composite was heated in a furnace with a flow of argon gas at 700 C for 1 h. Intercalation of ionic liquid crystals between graphite layers, their decomposition and evolution of gases assist in exfoliation of graphite and separation of layers. The proposed method extends the scope for production of high-quality, high-yield, unoxidized and defects free GNSs for a wide range of applications. The ability to produce bulk GNSs from a graphitic precursor with an easy and relatively low-cost approach can propel us to real-world applications of GNSs.

Ultra-thin and large gold nanosheets were easily synthesized by using a deep eutectic solvent as a reducing and directing agent with gum arabic as a stabilizer and shape-controlling agent through a seed-less protocol.

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(2015) A new X-ray contrast agent based on highly stable gum arabic-gold nanoparticles synthesised in deep eutectic solvent, Journal of Experimental Nanoscience, 10:12, 911-924, DOI: 10.1080/17458080.2014 To link to this article: https://doi.org/10.1080/17458080.2014.933493 This paper reports a novel method of fabricating gum arabic coated gold nanoparticles (GA-GNPs) synthesised in a deep eutectic solvent (DES) for use as a new X-ray contrast agent. GA-GNPs were prepared simply by mixing a solution of 0.01% DES, GA and tetra chloroauric (III) acid at room temperature. DES was prepared using choline chloride (ChCl), gallic acid and glycerol as the precursors. A complete characterisation study of GA-GNPs was undertaken using transmission electron microscopy, dynamic light scattering, X-ray diffraction analysis. In vitro study of the as-prepared GA-GNPs revealed the high potential of these nanoparticles as X-ray contrast agents. Compared with the common clinically available CT contrast agent, Visipaque, the synthesised GA-GNPs showed more than three fold X-ray attenuation coefficient. GA-GNPs were found to be remarkably stable in biological media. The development of such nontoxic, biocompatible nanostructures could be an advancement in diagnostic nanomedicine.

Investigation of non-covalent interaction of hydrophobic surfaces with the protein G (PrG) is necessary due to their frequent utilization in immunosensors and ELISA. It has been confirmed that surfaces, including carbonous-nanostructures (CNS) could orient proteins for a better activation. Herein, PrG interaction with single-walled carbon nanotube (SWCNT) and graphene (Gra) nanostructures was studied by employing experimental and MD simulation techniques. It is confirmed that the PrG could adequately interact with both SWCNT and Gra and therefore fine dispersion for them was achieved in the media. Results indicated that even though SWCNT was loaded with more content of PrG in comparison with the Gra, the adsorption of the PrG on Gra did not induce significant changes in the IgG tendency. Several orientations of the PrG were adopted in the presence of SWCNT or Gra; however, SWCNT could block the PrG-FcR. Moreover, it was confirmed that SWCNT reduced the α-helical structure content in the PrG. Reduction of α-helical structure of the PrG and improper orientation of the PrG-SWCNT could remarkably decrease the PrG tendency to the Fc of the IgG. Importantly, the Gra could appropriately orient the PrG by both exposing the PrG-FcR and also by blocking the fragment of the PrG that had tendency to interact with Fab in IgG.

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