A sensitive electrochemical detection of metronidazole in synthetic serum and urine samples using low-cost screen-printed electrodes modified with reduced graphene oxide and C60 / 药物分析学报

Monitoring the concentration of antibiotics in body fluids is essential to optimizing the therapy and minimizing the risk of bacteria resistance,which can be made with electrochemical sensors tailored with appropriate materials.In this paper,we report on sensors made with screen-printed electrodes(SPE)coated with fullerene(C60),reduced graphene oxide(rGO)and Nafion(NF)(C60-rGO-NF/SPE)to determine the antibiotic metronidazole(MTZ).Under optimized conditions,the C60-rGO-NF/SPE sensor exhibited a linear response in square wave voltammetry for MTZ concentrations from 2.5×10-7 to 34×10-6 mol/L,with a detection limit of 2.1×10-7 mol/L.This sensor was also capable of detecting MTZ in serum and urine,with recovery between 94％and 100％,which are similar to those of the standard chromatographic method(HPLC-UV).Because the C60-rGO-NF/SPE sensor is amenable to mass pro-duction and allows for MTZ determination with simple principles of detection,it fulfills the requirements of therapeutic drug monitoring programs.

Synthesis and electrochemical properties of environmental free L-glutathione grafted graphene oxide/ZnO nanocomposite for highly selective piroxicam sensing / 药物分析学报

A simple and reliable strategy was proposed to engineer the glutathione grafted graphene oxide/ZnO nanocomposite(glutathione-GO/ZnO)as electrode material for the high-performance piroxicam sensor.The prepared glutathione-GO/ZnO nanocomposite was well characterized by X-ray diffraction(XRD),Fourier transform infrared spectrum(FTIR),X-ray photoelectron spectroscopy(XPS),field emission scanning electron microscopy(FE-SEM),cyclic voltammetry(CV),electrochemical impedance spectros-copy(EIS)and differential pulse voltammetry(DPV).The novel nanocomposite modified electrode showed the highest electrocatalytic activity towards piroxicam(oxidation potential is 0.52 V).Under controlled experimental parameters,the proposed sensor exhibited good linear responses to piroxicam concentrations ranging from 0.1 to 500 μM.The detection limit and sensitivity were calculated as 1.8 nM and 0.2 μA/μM·cm2,respectively.Moreover,it offered excellent selectivity,reproducibility,and long-term stability and can effectively ignore the interfering candidates commonly existing in the pharmaceutical tablets and human fluids even at a higher concentration.Finally,the reported sensor was successfully employed to the direct determination of piroxicam in practical samples.

Research progress in graphene derivatives promoting bone regeneration / 中华口腔医学杂志

Graphene derivatives are the new bioactive material with good physical and chemical properties and excellent biocompatibility. It has been found that graphene derivatives can improve the mechanical properties of biomaterials and promote the adhesion, proliferation and differentiation of osteoblast-related cells, so as to promote implant-bone bonding and repair of bone defects. This makes it a research hotpot in the field of bone tissue regeneration. In this paper, the mechanism of graphene derivatives promoting bone regeneration and their application in the oral field were reviewed, so as to provide theoretical basis for their application in basic and clinical research.

Detection of prostate specific antigen-based on dual signal amplified electrochemical immunoassay / 中国药科大学学报

@#A sandwiched electrochemical immunoassay based on the AuNPs@GSH-CdTe as a signal label, which formed by GSH-CdTe QDs and AuNPs, with dual signal amplified by reduced graphene oxide and AuNPs was proposed for the sensitive detection of prostate specific antigen(PSA). Through a sandwich immunoreaction, the target PSA and AuNPs@GSH-CdTe labeled Ab1 were captured to rGO/AuNPs-Ab2 surface. After the HNO3-dissolution step, square wave stripping voltammetry(SWSV)analysis of the captured CdTe QDs was used to quantify the concentration of PSA. In this system, AuNPs possessedlarge specific surface and good biocompatibility, which could effectively expand the amount of antigen and GSH-CdTe QDs loading and signals amplifying, while rGO played a synergistic amplification role due to its large specific surface. The proposed method showed good linearity ranging from 0. 5 to 200 ng/mL with the detection limits of 5. 0 pg/mL. It also showed excellent selectivity, good reproducibility, satisfactory stability. In addition, the method was successfully applied to the determination of real samples. The result was satisfactory and the recovery could fall in 98. 20%- 106. 2%, which represented a novel approach for versatile detection of tumor markers.

Molecularly Imprinted Polymer Electrochemical Sensor Based on Fe3O4/MnO2 Doped Graphene Composites for Determination of 17β-Estradiol in Aquatic Environment / 分析化学

In this paper, Fe3O4/MnO2doped graphene molecularly imprinted hybrid material ( Fe3O4/MnO2-MIP@ RGO ) was successfully synthesized via reversible addition fragmentation chain transfer ( RAFT ) molecularly imprinting technique by using methacrylic acid as functional monomer, divinylbenzene as cross-linker, Fe3O4/MnO2@ RGO as carrier, and 17β-estradiol ( 17β-E2 ) as template molecule. A novel molecularly imprinting electrochemical sensor by using Fe3O4/MnO2-MIP@ RGO modified electrode was constructed to specifically detect trace 17β-E2 in water. The experimental results showed that the Fe3O4/MnO2-MIP@ RGO electrochemical sensor exhibited rapid and linear current response to 17β-E2 in water samples with a linear range of 4 nmol/L to 0. 8 μmol/L ( R=0. 9852) , the detection limit was 47. 2 pmol/L (3σ) and the relative standard deviation (RSD) was from 2. 1% to 2. 5% . This study provides a simple and efficient, economical and reliable method for the monitoring of 17β-estradiol in the complex water environment.

Electrochemical Detection of Dopamine Based on MnO2 Nanowires/Reduced Graphene Oxide Composites Modified Glassy Carbon Electrode / 分析化学

MnO2nanowires-reduced graphene oxide composite (MnO2-RGO) was used to modify glassy carbon electrodes (GCE) and applied for the electrochemical determination of dopamine (DA). The microstructure of MnO2nanowires and MnO2-RGO nanocomposite material was characterized by scanning microscope and X-ray powder diffraction. Then the electrochemical reduction condition for preparing MnO2-RGO/GCE and experimental conditions for determining DA were optimized systematically. The electrochemical behavior of DA on the bare electrode and RGO or MnO2-RGO modified electrodes was also investigated in pH 3.5 phosphate buffer solution (PBS) by cyclic voltammetry. The results shows that the oxidation peaks of ascorbic acid (AA), dopamine (DA) and uric acid (UA) can be well separated and the peak to peak separations were 268 mV (AA-DA) and 128 mV (DA-UA), respectively. Moreover, the linear response ranges for the determination of DA were 0.06-1.0 μmol/L and 1.0-80 μmol/L with the detection limit of 1.0 nmol/L (S/N=3). The proposed method has been applied to the determination of dopamine in human blood serum sample with satisfactory results.

Facile Solvothermal Synthesis of Reduced Graphene Oxide-BiPO4 Nanocomposite with Enhanced Photocatalytic Activity / 分析化学

Reduced graphene oxide-BiPO4 ( RGO-BiPO4 ) nanocomposite was synthesized successfully via a one-pot solvothermal method using graphene oxide and bismuth nitrate as precursors and glycerin as solvent at 200℃ for 1 h. The morphology and structure of as-prepared nanocomposite were characterized by SEM, TEM, XRD, XPS, SERS and UV-Visible spectrum. The photocatalytic activity of the nanocomposite was evaluated by the photodegradation of Rhodamine B ( RhB) dye under UV irradiation and it was found that RGO-BiPO4 nanocomposite possessed higher photocatalytic activity than that of pure BiPO4 . RhB could be decomposed 87. 5% within 2 h. Under the same conditions, only 45. 7% of the RhB dye could be decomposed by BiPO4 . The enhancement of photocatalytic activity could be attributed to the effective charge separation due to the electron-accepting and transporting properties of graphene.

Study of Electrochemical Sensor for Nitrite Based on Composites of Zirconium Dioxide Nanoparticles/Reduced Graphene Oxide / 分析化学

A nitrite electrochemical sensor based on electrodeposition of zirconium dioxide nanoparticles on reduced graphene oxide modified electrode was successfully constructed for the detection of nitrite. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry and amperometric i-t curve. Under the optimal conditions, the amperometric i-t curve response of the electrode showed a linear relationship with nitrite concentration in the range of 3.0×10Symbolm_7-1.0×10Symbolm_6 mol/L and 1.0×10Symbolm_6-6.0×10Symbolm_6 mol/L, and the detection limit was 1.0×10Symbolm_7 mol/L (S/N=3). The fabricated sensor exhibited high sensitivity, good stability and high reproducibility. This sensor was applied for the detection of nitrite in sausage samples with favorable recoveries of 93.7％-110.4％ and relative standard deviation (RSD) of 1.6％-2.1％.

Comparative study of adsorptive role of carbonaceous materials in removal of UV-active impurities of paclitaxel extracts / 药物分析学报

Graphite oxide (GO) and reduced graphene oxide (rGO) nanosheets were synthesized with a low-cost manufacturing method. The morphology and structures of the synthesized samples were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier-transform infrared (FTIR) and Raman spectroscopy. The efficiencies of GO and rGO as novel candidate adsorbents in the pre-purification of paclitaxel were compared and contrasted with those of commercial graphite (Gt), graphene (G) and multi-wall carbon nanotube (MWCNT). According to UV–vis and HPLC analyses, rGO was evaluated as the best absorbent for the removal of impurities in pre-purification of paclitaxel from plant cell cultures. In contrast, the GO had the poorest proficiency for paclitaxel pre-purification in comparison with the other carbonaceous adsorbents. This is attributed to the existence of many localized defects in the π-structure of GO that is related to weakness ofπ–πstacking interactions between crude extract impurities and GO.

Toxicity of multi-walled carbon nanotubes, graphene oxide, and reduced graphene oxide to zebrafish embryos / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>This study was aimed to investigate the toxic effects of 3 nanomaterials, i.e. multi-walled carbon nanotubes (MWCNTs), graphene oxide (GO), and reduced graphene oxide (RGO), on zebrafish embryos.</p><p><b>METHODS</b>The 2-h post-fertilization (hpf) zebrafish embryos were exposed to MWCNTs, GO, and RGO at different concentrations (1, 5, 10, 50, 100 mg/L) for 96 h. Afterwards, the effects of the 3 nanomateria on spontaneous movement, heart rate, hatching rate, length of larvae, mortality, and malformations ls were evaluated.</p><p><b>RESULTS</b>Statistical analysis indicated that RGO significantly inhibited the hatching of zebrafish embryos. Furthermore, RGO and MWCNTs decreased the length of the hatched larvae at 96 hpf. No obvious morphological malformation or mortality was observed in the zebrafish embryos after exposure to the three nanomaterials.</p><p><b>CONCLUSION</b>MWCNTs, GO, and RGO were all toxic to zebrafish embryos to influence embryos hatching and larvae length. Although no obvious morphological malformation and mortality were observed in exposed zebrafish embryos, further studies on the toxicity of the three nanomaterials are still needed.</p>