Preparation of Graphene Composite and Its Application in the Detection of Tumor Markers

2020 ◽  
Vol 12 (9) ◽  
pp. 1312-1322
Author(s):  
Beiguang Zhang ◽  
Jialin Wang ◽  
Li Ping ◽  
Yanfa Zhong ◽  
Fangzhi Li
Keyword(s):  
Quantum Yield ◽  
Tumor Markers ◽  
Photoelectron Spectroscopy ◽  
Graphene Quantum Dots ◽  
Ras Oncogene ◽  
Graphene Composite ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Optical Stability ◽  
Low Toxicity

Pancreatic cancer is a malignant tumor with high mutation rate of K-ras oncogene. Therefore, a material capable of detecting the expression of K-ras oncogene was prepared, and it was expected to realize the early diagnosis and treatment of cancer. Graphene quantum dots (GQDs), as a new carbon nanomaterial, has good optical stability and low toxicity biocompatibility. However, pure GQDs has the defect of low quantum yield, which limits its application in ultra-sensitive detection. To enhance quantum yield of GQDs, nitrogen atoms were introduced into GQDs to obtain nitrogen-doped GQDs (N-GQDs). Compared with the unalloyed GQDs, the electrochemical luminescence (ECL) efficiency of the doped N-GQDs was improved greatly. Through the analysis of its ECL mechanism, the deoxyribonucleic acid (DNA) was adopted as the connecting medium to adjust the distance between the GQDs and Aurum nanoparticles (AuNPs). Based on the energy transfer between GQDs and AuNPs, the change of ECL signal of GQDs was controlled. On the basis of this theory, N-GQDs@AuNPsssDNA composite was constructed, its morphology and chemical composition were characterized by various means, and its ECL properties were analyzed. Ultraviolet visible (UV-Vis) absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) results showed that the graphene composite N-GQDs@AuNPs was successfully prepared. UV-Vis spectroscopy showed that the probe DNA was connected to AuNPs, which indicated that the production of N-GQDs@AuNPs-ssDNA was successfully realized. N-GQDs/AUNPs-ssDNA and target K-ras DNA were incubated at 37 C for 1 h to achieve DNA doublestranded hybridization. The results showed that the graphene composites prepared in this study could be used to quantitatively determine the target K-ras tumor markers.

scholarly journals Microwave-assisted preparation of ZnS and ZnSe nanocrystals with different morphologies for photodegradation process of organic dyes

2019 ◽  
Author(s):  
Katarzyna Matras-Postolek ◽  
A. Zaba ◽  
S. Sovinska ◽  
D. Bogdal
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Organic Dyes ◽  
Zinc Sulphide ◽  
Conventional Heating ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Zinc sulphide (ZnS) and zinc selenide (ZnSe) and manganese-doped and un-doped with different morphologies from 1D do 3D microflowers were successfully fabricated in only a few minutes by solvothermal reactions under microwave irradiation. In order to compare the effect of microwave heating on the properties of obtained  nanocrystals, additionally the synthesis under conventional heating was conducted additionally in similar conditions. The obtained nanocrystals were systematically characterized in terms of structural and optical properties using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DR UV-Vis), Fourier-transform infrared spectroscopy (FT-IR), photoluminescence spectroscopy (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area analysis. The photocatalytic activity of ZnSe, ZnS, ZnS:Mn and ZnSe:Mn nanocrystals with different morphologies was evaluated by the degradation of methyl orange (MO) and Rhodamine 6G (R6G), respectively. The results show that Mn doped NCs samples had higher coefficient of degradation of organic dyes under ultraviolet irradiation (UV).

scholarly journals A Comparison Study of Functional Groups (Amine vs. Thiol) for Immobilizing AuNPs on Zeolite Surface

Nanomaterials ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 1034 ◽  
Author(s):  
Xi Rao ◽  
Michaël Tatoulian ◽  
Cédric Guyon ◽  
Stephanie Ognier ◽  
Chenglin Chu ◽  
...  
Keyword(s):  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Gold Surface ◽  
Thiol Group ◽  
Wet Chemistry ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Group 3 ◽  
Diffuse Reflectance Infrared

Immobilization of gold nanoparticles (AuNPs) on the surface of zeolite has received a great interest due to Au@zeolite’s unique characteristics and high performance for catalysis. In this work we studied the grafting of two different functional molecules; one having an amine group (3-aminopropyl)triethoxysilane (APTES) and the second having a thiol group (3-mercaptopropyl)trimethoxysilane (MPTES) on the surface of zeolite using the same wet chemistry method. The modified zeolite surfaces were characterized using zeta potential measurements; diffuse reflectance infrared fourier transform (DRIFT) and X-ray photoelectron spectroscopy (XPS). The results confirmed a successful deposition of both functional groups at the topmost surface of the zeolite. Furthermore; transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy and XPS results clearly evidenced that APTES provided a better AuNPs immobilization than MPTES as a result of; (1) less active functions obtained after MPTES deposition, and (2) the better attaching ability of thiol to the gold surface.

One-Pot Hydrothermal Synthesis of Sulfur-Doped SnO2 Nanoparticles and their Enhanced Photocatalytic Properties

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650035 ◽  
Author(s):  
Lin Ma ◽  
Limei Xu ◽  
Xuyao Xu ◽  
Xiaoping Zhou ◽  
Lingling Zhang
Keyword(s):  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Sno2 Nanoparticles ◽  
Light Response ◽  
One Pot ◽  
X Ray ◽  
Transmission Electron ◽  
Light Region ◽  
Vis Spectroscopy

Sulfur-doped SnO2 nanoparticles with ultrafine sizes have been successfully prepared by a one-pot hydrothermal method. The obtained samples are characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy (HRTEM), thermogravimetric (TG), analyzer UV-Vis spectroscopy, photoluminescence (PL) and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the doping level of sulfur element as well as the bandgaps of SnO2 can be controlled to a certain extent by varying the amount of L-cysteine (L-cys). When evaluated as photocatalysts in the degradation of rhodamine B (RhB) and reduction of Cr(VI) under visible light region, the resultant sulfur-doped SnO2 nanoparticles demonstrate obviously enhanced photocatalytic activities due to the markedly improved visible light response and effective separation of the photo-generated electron–hole pairs.

scholarly journals Efficient Method for the Concentration Determination of Fmoc Groups Incorporated in the Core-Shell Materials by Fmoc–Glycine

Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3983
Author(s):  
Elżbieta Szczepańska ◽  
Beata Grobelna ◽  
Jacek Ryl ◽  
Amanda Kulpa ◽  
Tadeusz Ossowski ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Core Shell ◽  
Amino Groups ◽  
The Core ◽  
Transmission Electron ◽  
Model Sample ◽  
Vis Spectroscopy ◽  
Fmoc Group ◽  
Synthesis Procedure

In this paper, we described the synthesis procedure of TiO2@SiO2 core-shell modified with 3-(aminopropyl)trimethoxysilane (APTMS). The chemical attachment of Fmoc–glycine (Fmoc–Gly–OH) at the surface of the core-shell structure was performed to determine the amount of active amino groups on the basis of the amount of Fmoc group calculation. We characterized nanostructures using various methods: transmission electron microscope (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) to confirm the modification effectiveness. The ultraviolet-visible spectroscopy (UV-vis) measurement was adopted for the quantitative determination of amino groups present on the TiO2@SiO2 core-shell surface by determination of Fmoc substitution. The nanomaterials were functionalized by Fmoc–Gly–OH and then the fluorenylmethyloxycarbonyl (Fmoc) group was cleaved using 20% (v/v) solution of piperidine in DMF. This reaction led to the formation of a dibenzofulvene–piperidine adduct enabling the estimation of free Fmoc groups by measurement the maximum absorption at 289 and 301 nm using UV-vis spectroscopy. The calculations of Fmoc loading on core-shell materials was performed using different molar absorption coefficient: 5800 and 6089 dm3 × mol−1 × cm−1 for λ = 289 nm and both 7800 and 8021 dm3 × mol−1 × cm−1 for λ = 301 nm. The obtained results indicate that amount of Fmoc groups present on TiO2@SiO2–(CH2)3–NH2 was calculated at 6 to 9 µmol/g. Furthermore, all measurements were compared with Fmoc–Gly–OH used as the model sample.

scholarly journals Gold Nanoparticle-Graphene Oxide Nanocomposites That Enhance the Device Performance of Polymer Solar Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Ming-Kai Chuang ◽  
Fang-Chung Chen ◽  
Chain-Shu Hsu
Keyword(s):  
Graphene Oxide ◽  
Gold Nanoparticle ◽  
Photoelectron Spectroscopy ◽  
Polymer Solar Cells ◽  
Environmentally Friendly ◽  
Metal Nanoparticle ◽  
Graphene Oxides ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Vis Spectroscopy

Metal nanoparticle-decorated graphene oxides are promising materials for use in various optoelectronic applications because of their unique plasmonic properties. In this paper, a simple, environmentally friendly method for the synthesis of gold nanoparticle-decorated graphene oxide that can be used to improve the efficiency of organic photovoltaic devices (OPVs) is reported. Here, the amino acid glycine is employed as an environmentally friendly reducing reagent for the reduction of gold ions in the graphene oxide solutions. Transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, UV-Vis spectroscopy, and Raman spectroscopy are used to characterize the material properties of the resulting nanomaterials. Furthermore, these nanocomposites are employed as the anode buffer layer in OPVs to trigger surface plasmonic resonance, which improved the efficiency of the OPVs. The results indicate that such nanomaterials appear to have great potential for application in OPVs.

Synthesis and characterization of thermosensitive and polarity-sensitive fluorescent PNIPAM-coated gold nanoparticles

e-Polymers ◽  
2017 ◽  
Vol 17 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Chunhua Luo ◽  
Meijuan Qian ◽  
Qiujing Dong
Keyword(s):  
Photoelectron Spectroscopy ◽  
Au Nanoparticles ◽  
Synthesis And Characterization ◽  
Strong Fluorescence ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Grafting Through ◽  
Polarity Sensitive

AbstractThermosensitive PNIPAM-coated Au nanoparticles (AuNPs@P(NIPAM-co-MADMAC)) were synthesized by the radical “grafting through” copolymerization of 4-methacryloyloxy-4′-dimethylaminochalcone (MADMAC), MAEL-capped AuNPs and N-isopropylacrylamide (NIPAM) using azobisisobutyronitrile (AIBN) as the initiator. AuNPs@P(NIPAM-co-MADMAC) were characterized by transmission electron microscopy (TEM), ultraviolet-visible (UV-Vis) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), 1H nuclear magnetic resonance (NMR), and Fourier transform infrared (FTIR) spectroscopy. AuNPs@P(NIPAM-co-MADMAC) exhibited thermo-sensitivity from poly(NIPAM-co-MADMAC) chains and sensitive fluorescence from the MADMAC group. AuNPs@P(NIPAM-co-MADMAC) showed weak fluorescence after the temperature increased from 25°C to 45°C, or after β-cyclodextrin (β-CD) was added. Furthermore, it exhibited strong fluorescence when the solvent was changed to ethanol or chloroform.

scholarly journals Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4068
Author(s):  
Jakub Wawrzyniak ◽  
Jakub Karczewski ◽  
Jacek Ryl ◽  
Katarzyna Grochowska ◽  
Katarzyna Siuzdak
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nickel Nanoparticles ◽  
Size Control ◽  
Metallic Nickel ◽  
X Ray ◽  
Oxygen Generation ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Order Of Magnitude ◽  
Current Densities

Nowadays, more than ever, environmental awareness is being taken into account when it comes to the design of novel materials. Herein, the pathway to the creation of a colloid of spherical, almost purely metallic nickel nanoparticles (NPs) through pulsed laser ablation in ethanol is presented. A complex description of the colloid is provided through UV-vis spectroscopy and dynamic light scattering analysis, ensuring insight into laser-induced nanoparticle homogenization and size-control of the NPs. The transmission electron spectroscopy revealed spherical nanoparticles with a narrow size distribution, whereas the energy-dispersive X-ray spectroscopy accompanied by the X-ray photoelectron spectroscopy revealed their metallic nature. Furthermore, an example of the application of the colloidal nanoparticles is presented, where a quick, five-min ultrasound modification results in over an order of magnitude higher current densities in the titania-based electrode for the oxygen evolution reaction.

scholarly journals Au@Ag Core@Shell Nanoparticles Synthesized with Rumex hymenosepalus as Antimicrobial Agent

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Jesús Mauro Adolfo Villalobos-Noriega ◽  
Ericka Rodríguez-León ◽  
César Rodríguez-Beas ◽  
Eduardo Larios-Rodríguez ◽  
Maribel Plascencia-Jatomea ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Bimetallic Nanoparticles ◽  
Lag Phase ◽  
Core Shell ◽  
Root Extract ◽  
Dependent Manner ◽  
X Ray ◽  
Transmission Electron ◽  
Gold Silver ◽  
Vis Spectroscopy

AbstractIn this work, we used a sequential method of synthesis for gold–silver bimetallic nanoparticles with core@shell structure (Au@AgNPs). Rumex hymenosepalus root extract (Rh), which presents high content in catechins and stilbenes, was used as reductor agent in nanoparticles synthesis. Size distribution obtained by Transmission Electron Microscopy (TEM) gives a mean diameter of 36 ± 11 nm for Au@AgNPs, 24 ± 4 nm for gold nanoparticles (AuNPs), and 13 ± 3 nm for silver nanoparticles (AgNPs). The geometrical shapes of NPs were principally quasi-spherical. The thickness of the silver shell over AuNPs is around 6 nm and covered by active biomolecules onto the surface. Nanoparticles characterization included high angle annular dark field images (HAADF) recorded with a scanning transmission electron microscope (STEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD), UV–Vis Spectroscopy, Zeta Potential, and Dynamic Light Scattering (DLS). Fourier Transform Infrared Spectrometer (FTIR), and X-ray Photoelectron Spectroscopy (XPS) show that nanoparticles are stabilized by extract molecules. A growth kinetics study was performed using the Gompertz model for microorganisms exposed to nanomaterials. The results indicate that AgNPs and Au@AgNPs affect the lag phase and growth rate of Escherichia coli and Candida albicans in a dose-dependent manner, with a better response for Au@AgNPs

In-Situ Preparation of Binary-Phase Silver Nanoparticles at a High Ag+ Concentration

2006 ◽  
Vol 6 (3) ◽  
pp. 777-782 ◽  
Author(s):  
Md. Habib Ullah ◽  
Il Kim ◽  
Chang-Sik Ha
Keyword(s):  
Silver Nanoparticles ◽  
Size Distribution ◽  
Photoelectron Spectroscopy ◽  
Metal Salt ◽  
Water Soluble ◽  
The Other ◽  
X Ray ◽  
In Situ Preparation ◽  
Transmission Electron ◽  
Vis Spectroscopy

Stable and monodisperse silver nanoparticles (NPs) have been synthesized using high metal salt concentration (up to 0.735 M) through a simple but novel technique. It is based on one-step procedure that uses glycerol for reducing Ag+ in the presence of o-phenylenediamine (o-PDA) resulting the nanoparticles are in two forms (one water-soluble, the other a precipitated). The water-soluble phase contains NPs that have a bimodal size distribution (2–3 and 5–6 nm); the other comprises precipitated NPs, having a unimodal size distribution (2–3 nm). The water-soluble NPs are covalently bonded to the aromatic amine molecules to form isolated units, while the precipitated nanoparticles are embedded in the networks formed by cross-linking between COOH groups of hydroxypyruvic acid (oxidized form of glycerol) and NH2 groups of o-PDA molecules. We used transmission electron microscopy (TEM), UV–Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) to characterize the silver products obtained.

scholarly journals Synthesis, Characterization and Photocatalytic Performance of Calcined ZnCr-Layered Double Hydroxides

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3051
Author(s):  
Somia Djelloul Bencherif ◽  
Juan Jesús Gallardo ◽  
Iván Carrillo-Berdugo ◽  
Abdellah Bahmani ◽  
Javier Navas
Keyword(s):  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Textural Properties ◽  
Operational Parameters ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Crystal Violet Dye ◽  
Double Hydroxide ◽  
Double Hydroxides

The development of new materials for performing photocatalytic processes to remove contaminants is an interesting and important research line due to the ever-increasing number of contaminants on our planet. In this sense, we developed a layered double hydroxide material based on Zn and Cr, which was transformed into the corresponding oxide by heat treatment at 500 °C. Both materials were widely characterized for their elemental composition, and structural, morphological, optical and textural properties using several experimental techniques such as x-ray diffraction, x-ray photoelectron spectroscopy, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, UV-vis spectroscopy and physisorption techniques. In addition, the photocatalytic activity of both materials was analysed. The calcined one showed interesting photocatalytic activity in photodegradation tests using crystal violet dye. The operational parameters for the photocatalytic process using the calcined material were optimised, considering the pH, the initial concentration of the dye, the catalyst load, and the regeneration of the catalyst. The catalyst showed good photocatalytic activity, reaching a degradation of 100% in the optimised conditions and showing good performance after five photodegradation cycles.

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