Imaging thiol redox status in murine tumors in vivo with rapid-scan electron paramagnetic resonance

Thiol redox status is an important physiologic parameter that affects the success or failure of cancer treatment. Rapid scan electron paramagnetic resonance (RS EPR) is a novel technique that has shown higher signal-to-noise ratio than conventional continuous-wave EPR in in vitro studies. Here we used RS EPR to acquire rapid three-dimensional images of the thiol redox status of tumors and normal tissues in living mice. This work presents, for the first time, in vivo RS EPR images of the kinetics of the reaction of 2H,15N-substituted disulfide-linked dinitroxide (PxSSPx) spin probe with intracellular glutathione. The cleavage rate is proportional to the intracellular glutathione concentration. Feasibility was demonstrated in a FSa fibrosarcoma tumor model in C3H mice. Similar to other in vivo and cell model studies, decreasing intracellular glutathione concentration by treating mice with L-buthionine sulfoximine (BSO) markedly altered the kinetic images

The composition dependent structure and catalytic activity of nanostructured Cu–Ni bimetallic oxides

Nanostructured CuO–NiO bimetallic oxide was used as a catalyst for the effective conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP).</p

Correction: The composition dependent structure and catalytic activity of nanostructured Cu–Ni bimetallic oxides

Correction for ‘The composition dependent structure and catalytic activity of nanostructured Cu–Ni bimetallic oxides’ by S. Vivek et al., New J. Chem., 2020, 44, 9691–9698, https://doi.org/10.1039/D0NJ01753A.</jats:p

Gel electrophoresis using a selective radical for the separation of single-walled carbon nanotubes

We have applied agarose gel electrophoresis (AGE) to single-walled carbon nanotubes (SWNTs) that have been pre-reacted with metallic-selective ionic radicals and then re-suspended with sodium cholate (SC) surfactant to obtain highly purified (up to 98%) semiconducting single-walled carbon nanotubes (s-SWNTs). The proposed combination method exploits the preferential reactivity with the metallic nanotube of the radicals generated from an azo naphthalene compound (Direct Blue 71 (I)) to preferentially increase the surface charge, and therefore the electrophoretic mobilities, of the metallic nanotube population under the influence of the electric field in AGE. The excellent separation achieved was verified by UV-vis-NIR and Raman spectroscopy as well as by the performance of field effect transistors fabricated with semiconducting-enriched SWNTs. FETs fabricated with I-assisted AGE-separated semiconducting nanotubes exhibited mobilities of [similar]3.6 to 11.7 cm2 V−1 s−1 and on/off ratios from 10^2 to 10^6.ASTAR (Agency for Sci., Tech. and Research, S’pore)Published versio

Electroanalysis of Nickel Ions Released in Artificial Saliva From Three Orthodontic Arch Wires: Stainless Steel (SS), NiTi, and CuNiTi

Background: Nickel titanium wires are superior for first alignment because they have exceptional shape memory and super-elasticity. Increased concerns have been raised about the high rate of nickel (Ni) allergy and the growing usage of dental biomaterials that contain Ni. Aim: The aim of the study was to analyze and evaluate the rate of nickel release from different types of orthodontic arch wires. Materials and methods: A set of arch wires of nickel titanium (NiTi), SS and Cu-NiTi were immersed in artificial saliva for three days and analyzed after three days. The amount of Ni ions released from the sample were evaluated using electrochemical techniques such as Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and polarization (Tafel) plot. Results: The EIS and Tafel graph confirmed the s-NiTi, s-CuNiTi showed an excellent corrosion resistance than the s-SS. From all the above measurements, we can conclude that the saliva can affect the corrosion resistance property of the SS, NiTi, CuNiTi day by day. Conclusion: From this study it was concluded that the saliva can affect the corrosion resistance property of the SS, NiTi, CuNiTi day by day, and there was nickel ion release but at a very negligible rate

Reduced Graphene Oxide-Poly(3,4-ethylenedioxythiophene) Polystyrenesulfonate Based Dual-Selective Sensor for Iron in Different Oxidation States

A dual-selective sensor platform for detection of iron in ferrous (Fe²⁺) and ferric (Fe³⁺) oxidation states was developed. Upon dispersing reduced graphene oxide (rGO) sheets into poly­(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) polymer, we deposited a hybrid film of rGO-PEDOT:PSS onto a glassy carbon electrode (GCE) surface. Effective intercalation of rGO sheets in PEDOT:PSS film was observed by Raman spectroscopy, UV–vis-NIR spectroscopy, and scanning electron microscopy. The rGO-PEDOT:PSS/GCE sensor showed high electrocatalytic activity for Fe²⁺/Fe³⁺ redox reaction. Using amperometry with controlled applied potential, we demonstrated selective detection of both Fe²⁺ and Fe³⁺ with rGO-PEDOT:PSS/GCE. The sensor responded linearly to Fe²⁺ from 20–833 μM (at 0.6 V) and Fe³⁺ from 1–833 μM (at 0.4 V) in 0.5 M KCl + 0.05 M HCl. The presence of several common metal and organic interferents such as Cu²⁺, Co²⁺, Ag⁺, Pb²⁺, Cd²⁺, Zn²⁺, Mn²⁺, Ni²⁺, Hg²⁺, l-glycine, l-cysteine, l-tyrosine, glucose, KCN, guanine, uric acid, xanthan, salicylate, tartrazine, and naphthol yellow did not affect the selective detection of Fe²⁺ and Fe³⁺. In addition, detection of Fe²⁺ and Fe³⁺ ions in a red wine sample and iron supplement tablets were performed with satisfactory results. The sensor was also useful in determining oxidation kinetics of Fe²⁺ using hydrogen peroxide and measuring Fe³⁺ by differential pulse voltammetry. Thus, rGO/PEDOT:PSS hybrid film based electrode we developed can serve as a practical sensor for detecting iron in its different oxidation states in real samples for different applications