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A facile cuprous oxide nanoparticles functionalized electro-reduced graphene oxide modified glassy carbon electrode (denoted as Cu2O NPs-ERGO/GCE) was fabricated via a simple physical adsorption and electrochemical reduction approach. Cyclic voltammetry and second-order derivative linear scan voltammetry were used to investigate the electrocatalysis oxidation of vanillin on the Cu2O NPs-ERGO/GCE. The compound yielded a well-defined voltammetric response in 0.1 M H2SO4 at 0.916 V (vs. saturated calomel electrode (SCE)). A linear calibration graph was obtained in the concentration range of 0.1 μM to 10 μM and 10 μM to 100 μM, while the detection limit (S/N = 3) is 10 nM. In addition, the Cu2O NPs-ERGO/GCE presented well anti-interference ability, stability, and reproducibility. It was used to detect vanillin sensitively and rapidly in different commercial food products, and the results were in agreement with the values obtained by high performance liquid chromatography.

Cuprous oxide nanoparticles (Cu 2 O NPs) were dispersed into a graphene oxide (GO) solution to form a homogeneous Cu 2 O-GO dispersion. After this, the cuprous oxide nanoparticles were functionalized to electrochemically reduce the graphene oxide decorated glassy carbon electrode (Cu 2 O-ErGO/GCE). This was prepared by coating the Cu 2 O-GO dispersion onto the surface of the glassy carbon electrode (GCE), which was followed by a potentiostatic reduction process. An irreversible two-electron reaction of uric acid (UA) was observed at the voltammetric sensor. Moreover, the high concentrations of dopamine (DA) and ascorbic acid (AA) hardly affected the peak current of UA, which suggested that Cu 2 O-ErGO/GCE have excellent selectivity for UA. This is probably because the response peaks of the three compounds are well-separated from each other. The oxidation peak current was proportional to the concentration of UA in the ranges of 2.0 nM−0.6 µM and 0.6 µM−10 µM, respectively, with a low limit of detection (S/N = 3, 1.0 nM) after an accumulation time of 120 s. Cu 2 O-ErGO/GCE was utilized for the rapid detection of UA in human blood serum and urine samples with satisfactory results. when detecting UA with bare electrodes since they have similar oxidation peak potentials [10][11][12]. Nanocomposite-modified electrodes can improve the anti-interference performance and selectivity, which is a common method that is used to solve this problem. At present, many chemically modified electrodes have been proposed for the determination of UA [9,[13][14][15][16][17][18][19][20][21][22] although their selectivity is limited, especially due to the coexistence of DA and AA. Hence, developing a modified electrode with high sensitivity and selectivity to meet clinical demands is still challengeable and desirable.Catalysts 2018, 8, x FOR PEER REVIEW 2 of 15 potentials [10][11][12]. Nanocomposite-modified electrodes can improve the anti-interference performance and selectivity, which is a common method that is used to solve this problem. At present, many chemically modified electrodes have been proposed for the determination of UA [9,[13][14][15][16][17][18][19][20][21][22] although their selectivity is limited, especially due to the coexistence of DA and AA. Hence, developing a modified electrode with high sensitivity and selectivity to meet clinical demands is still challengeable and desirable. Scheme 1. The reaction mechanism of UA.In the past few years, transition metals and metal oxides have received increasing attention in many fields, such as sensors and electrocatalysis, due to their unique sensing performance and superior electrocatalytic activity [9,11,23,24]. Among these metal oxides, cuprous oxide (Cu2O) is a new type of p-type semiconductor with a narrow band gap, which can also be easily excited by visible light. Due to their outstanding advantages, such as non-toxic, low cost and stable photochemical properties, Cu2O nanoparticles have been extensively used in many fields, such as new energy, photocatalytic degradation, ...

A strategy for constructing novel DNA–anionic porphyrin supramolecular assemblies by “fixation” of CNTs and “inclusion” of CDs was reported.

Catalytic degradation of organic pollutants by nanomaterials is an effective way for environmental remediation. The Fenton reaction involving H2O2 oxidation catalysed by Fe3+ is an advisable way for wastewater degradation. Herein, Fe3O4/SiO2 core-shell nanoparticles were prepared as catalyst by coprecipitation and sol-gel methods, and this catalyst is used for degradation of fuchsin in wastewater by H2O2. The Fenton reaction between H2O2 and Fe3O4 is proposed to explain the catalytic performance. The coating of SiO2 on Fe3O4 nanoparticles could dramatically stabilize the Fe3O4 in aqueous solution and prevent their oxidation. More importantly, the magnetic property of Fe3O4 nanoparticles endows them with good recyclability. Thus, due to the outstanding catalytic results, almost 100% removal degradation was achieved within 5 min over a wide pH value range at room temperature, which is better than that without catalysts. Temperature is a positive factor for improving the degradation rate, but room temperature is selected as the best temperature for economic and energy savings reasons, because more than 98% of fuchsins can still be degraded at room temperature. Moreover, these Fe3O4/SiO2 core-shell nanoparticles exhibit excellent magnetic recyclability and stable properties after repeated utilization. Therefore, these as-presented Fe3O4/SiO2 core-shell nanoparticles with low-cost and high performance are expected to be applied in practical industry wastewater degradation.

In the present work, a novel electrochemical sensor was developed for the detection of trace cadmium with high sensitivity and selectivity in an easy and eco-friendly way. Firstly, a glassy carbon electrode (GCE) was modified with nontoxic sodium carboxymethyl cellulose (CMC) by a simple drop-casting method, which was applied to detect cadmium by differential pulse anodic stripping voltammetry (DPASV) in a solution containing both target cadmium and eco-friendly bismuth ions, based on a quick electro-codeposition of these two metal ions on the surface of the modified electrode (CMC-GCE). Investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Fourier transform infrared spectroscopy (FT-IR), both CMC (with good film-forming ability) and bismuth (with well-defined stripping signal) were found to be well complexed with target cadmium, leading to vital signal amplification for cadmium detection at a sub-nanomolar level. Under the optimal conditions, the proposed sensor exhibited a good linear stripping signal response to cadmium (Ⅱ) ion, in a concentration range of 0.001 μmol/L–1 μmol/L with a limit of detection of 0.75 nmol/L (S/N = 3). Meanwhile, the results demonstrate that this novel electrochemical sensor has excellent sensitivity and reproducibility, which can be used as a promising detection technique for testing natural samples such as tap water.

Human epidermal growth factor receptor (EGFR) has become a well-established target for the treatment of non-small cell lung cancer (NSCLC). However, a large number of in-frame deletion, insertion and duplication mutations in the EGFR tyrosine kinase (TK) domain have been observed to alter drug response to such a kinase target. Thus, a systematic investigation of the intermolecular interactions between the clinical small-molecule agents and various EGFR in-frame mutants would help to establish a complete picture of drug response to kinase mutations in lung cancer, and to design new EGFR inhibitors with high potency and selectivity to target drug-resistant mutants. Here, we describe a combined pipeline to explore the drug response of five representative EGFR inhibitors, including three FDA-approved agents (gefitinib, erlotinib and lapatinib) and two compounds under clinical development (AEE788 and TAK-285) to a number of clinically relevant EGFR in-frame mutations, aiming at a comprehensive understanding of molecular mechanism and biological implication underlying drug resistance and sensitivity to EGFR in-frame mutations. It was found that the insertion and duplication mutations in exon 20 can generally cause drug resistance to EGFR due to the reduced size of kinase's active pocket, while deletion mutations in exon 19 associate closely with increased inhibitor sensitivity to EGFR by establishing additional non-bonded interactions across complex interface, including hydrogen bonds, cation-π interactions and hydrophobic contacts.

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