A Novel Amperometric Immunosensor for Detection of Alpha-Fetoprotein Based on Magnetic and Electroactive Nanoprobes

2011 ◽  
Vol 345 ◽  
pp. 411-416
Author(s):  
Ling Hua Meng ◽  
Yu Ting Cao ◽  
Fu Tao Hu ◽  
Tian Hua Li ◽  
Ning Gan
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Alpha Fetoprotein ◽  
Serum Samples ◽  
Electron Mediator ◽  
Experimental Conditions ◽  
Au Nps ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes ◽  
First Time

A novel three-dimensional, magnetic and electroactive nanoprobes were constructed for the first time. Using hemin (TPP) as electron mediator, mutli-walled carbon nanotubes with carboxyl groups (MCNTs) as supporter, a novel (MCNTs-TPP-Fe3O4)magnetic nanocomposites were first prepared. Then using alpha-fetoprotein (AFP) as model system, gold nanoparticles (Au NPs) as immobilizing matrix, the AFP/anti-AFP/Au NPs/ MCNTs-TPP-Fe3O4nanoprobes were prepared and then dropped on the surface of screen-printed working electrode (SPCE) to construct a new amperometric immunosensors for detecting biomakers. The microstructure of different nanoparticles were observed by transmission electron microscopy (TEM) andX-ray fluorescence spectrometery (XRFS). Under optimal experimental conditions, the logarithm of response signal was proportional to the logarithm of AFP concentration from 0.1 to 200 ng/mL, with a correlation coefficient of 0.998. The detection limit was 0.04 ng/mL at a signal-to-noise ratio of 3. The proposed method offered a platform for fast, sensitive and simultaneous determination for serum samples.

A comparative study on the cold type and thermal type field emission guns used in the same electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 58-59
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Signal To Noise Ratio ◽  
Electron Source ◽  
Resolving Power ◽  
Optical Source ◽  
Experimental Conditions ◽  
High Brightness ◽  
Illumination System ◽  
Transmission Electron

On accout of its high brightness, small optical source size, and minimal energy spread, the field emission gun (FEG) has the advantage that it provides the conventional transmission electron microscope (TEM) with a highly coherent illumination system and directly improves the resolving power and signal-to-noise ratio of the scanning electron microscope (SEM). The FEG is generally classified into two types; the cold field emission (C-FEG) and thermal field emission gun (T-FEG). The former, in which a field emitter is used at the room temperature, was successfully developed as an electron source for the SEM. The latter, in which the emitter is heated to the temperature range of 1000-1800°K, was also proved to be very suited as an electron source for the TEM, as well as for the SEM. Some characteristics of the two types of the FEG have been studied and reported by many authors. However, the results of the respective types have been obtained separately under different experimental conditions.

Image Restoration of One-Dimensional HgTe Crystals Formed within Single Walled Carbon Nanotubes

2006 ◽  
Vol 514-516 ◽  
pp. 1131-1134
Author(s):  
Jeremy Sloan ◽  
Robin Carter ◽  
Angus I. Kirkland ◽  
Rüdiger R. Meyer ◽  
Alexis Vlandas ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Three Dimensional ◽  
Single Walled Carbon Nanotubes ◽  
One Dimensional ◽  
Single Walled Carbon ◽  
Semiconductor Crystals ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes ◽  
Separate Crystal

Restored high resolution transmission electron microscopy (HRTEM) images have been recorded from 1D semiconductor crystals formed within narrow diameter (ca. 1.4 nm) single walled carbon nanotubes (SWNTs). Two unique projections were obtained from separate crystal fragments encapsulated within separate nanotubes that has facilitated the reconstruction of the three dimensional arrangement of atoms within the two encapsulated fragments.

scholarly journals Preparation of Nano-Sized Mesoporous Silica and Its Application in Immobilization of β-galactosidase from Aspergillus Oryzae

2017 ◽  
Vol 9 (1) ◽  
pp. 65
Author(s):  
Jiao Yang ◽  
Zhenzhen Liu ◽  
Huan Ge ◽  
Sufang Sun
Keyword(s):  
Mesoporous Silica ◽  
Aspergillus Oryzae ◽  
Nitrogen Adsorption ◽  
Ammonium Bromide ◽  
Experimental Conditions ◽  
Transmission Electron ◽  
Alkaline Conditions ◽  
Activity Yield ◽  
Cetyl Trimethyl Ammonium ◽  
First Time

In alkaline conditions, monodisperse nano-sized mesoporous silica was synthesized using cetyl trimethyl ammonium bromide (CTAB) as template and tetraethoxysilane (TEOS) silica as source in ethanol / water cosolvent conditions. Using method of nitrogen adsorption, specific surface area of the dried monodisperse nano-sized mesoporous silica was about 1591 m2/g and the pore size was about 3.8 nm. The field-emission scanning electron microscope (SEM) micrographs showed that the silica particles obtained were spherical with an approximate diameter of 160 nm and of good dispersion. Transmission electron microscopy (TEM) revealed that the carrier had an excellent cellular structure with disordered multi-channels and smooth surface. The nano-sized mesoporous silica above was employed to immobilize β-galactosidase from aspergillus oryzae for the first time. At the experimental conditions in section 2.4, the enzyme activity and the activity yield were 535.11 U/g dry carrier and 79.63%, respectively. Kinetic data of the immobilized enzyme such as optimum temperature, pH, and thermal and pH stability among other valuable results were also determined.

A study of the submicron indent-induced plastic deformation

1999 ◽  
Vol 14 (6) ◽  
pp. 2251-2258 ◽  
Author(s):  
C. F. Robertson ◽  
M. C. Fivel
Keyword(s):  
Plastic Deformation ◽  
Three Dimensional ◽  
Dislocation Nucleation ◽  
Dislocation Dynamics ◽  
Dynamics Simulation ◽  
Nanoindentation Test ◽  
Experimental Conditions ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Transmission Electron

A new method has been developed to achieve a better understanding of submicron indent-induced plastic deformation. This method combines numerical modeling and various experimental data and techniques. Three-dimensional discrete dislocation dynamics simulation and the finite element method (FEM) were used to model the experimental conditions associated with nanoindentation testing in fcc crystals. Transmission electron microscopy (TEM) observations of the indent-induced plastic volume and analysis of the experimental loading curve help in defining a complete set of dislocation nucleation rules, including the shape of the nucleated loops and the corresponding macroscopic loading. A validation of the model is performed through direct comparisons between a simulation and experiments for a nanoindentation test on a [001] copper single crystal up to 50 nm deep.

Synthesis and characterization of 3D Cu0.45Mn0.55O2 nanoflowers with novel photoluminescence and magnetic properties

2014 ◽  
Vol 28 (09) ◽  
pp. 1450071
Author(s):  
Arbab Mohammad Toufiq ◽  
Fengping Wang ◽  
Qurat-ul-ain Javed ◽  
Quanshui Li ◽  
Yan Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Three Dimensional ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Growth Method ◽  
First Time

In this paper, three-dimensional (3D) Cu 0.45 Mn 0.55 O 2 nanoflowers self-assembled by interconnecting dense stacked single-crystalline nanoplates have been prepared using the template-free hydrothermal growth method. The morphology, phase structure and composition of the as-prepared nanomaterial were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDX). FESEM and TEM analyses show that the size of 3D Cu 0.45 Mn 0.55 O 2 nanoflowers is in the range of 1–1.5 μm and the thickness of interconnected nanoplates is about 40 nm on the average. The photoluminescence (PL) spectra of the as-prepared Cu 0.45 Mn 0.55 O 2 nanostructures at room temperature exhibits prominent emission bands located in red–violet spectral region. Moreover, magnetic investigations revealed the weak ferromagnetic behavior of the as-prepared Cu 0.45 Mn 0.55 O 2 nanoflowers and reported for the first time using vibrating sample magnetometer (VSM).

scholarly journals Cu-Doped ZnO Nanoparticles for Non-Enzymatic Glucose Sensing

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 929
Author(s):  
Amira Mahmoud ◽  
Mosaab Echabaane ◽  
Karim Omri ◽  
Julien Boudon ◽  
Lucien Saviot ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Chemical Properties ◽  
Differential Pulse ◽  
Glucose Sensing ◽  
Serum Samples ◽  
Experimental Conditions ◽  
Active Electrode ◽  
Transmission Electron

Copper-doped zinc oxide nanoparticles (NPs) CuxZn1−xO (x = 0, 0.01, 0.02, 0.03, and 0.04) were synthesized via a sol-gel process and used as an active electrode material to fabricate a non-enzymatic electrochemical sensor for the detection of glucose. Their structure, composition, and chemical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) and Raman spectroscopies, and zeta potential measurements. The electrochemical characterization of the sensors was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Cu doping was shown to improve the electrocatalytic activity for the oxidation of glucose, which resulted from the accelerated electron transfer and greatly improved electrochemical conductivity. The experimental conditions for the detection of glucose were optimized: a linear dependence between the glucose concentration and current intensity was established in the range from 1 nM to 100 μM with a limit of detection of 0.7 nM. The proposed sensor exhibited high selectivity for glucose in the presence of various interfering species. The developed sensor was also successfully tested for the detection of glucose in human serum samples.

CARBON NANOTUBES/GRAPHENE THREE-DIMENSIONAL NETWORKS ARCHITECTURE LOADING WITH Ni AND ITS ADSORPTION PROPERTIES

NANO ◽  
2014 ◽  
Vol 09 (02) ◽  
pp. 1450019 ◽  
Author(s):  
BIN ZENG ◽  
YOUXIN LUO ◽  
QIYUAN LIU ◽  
WUJUN ZENG
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Three Dimensional ◽  
Ni Nanoparticles ◽  
X Ray Diffraction ◽  
High Adsorption ◽  
X Ray ◽  
Transmission Electron ◽  
3D Network ◽  
First Time

The composite of carbon nanotubes/graphene networks loaded- Ni (CNTs/GR- Ni ) were successfully synthesized by spray drying and post-calcinating method for the first time. The synthesized products were systematically studied by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The result showed the hybrid of CNTs and graphene composed the 3D network structure and Ni nanoparticles were attaching on their surface. Adsorption performance evidenced that the obtained nanocomposite possessed high adsorption efficiency and excellent separation property.

scholarly journals Transmission Electron Microscopy and Three-Dimensional Tomography of Peptide-Coated Single-Walled Carbon Nanotubes

2011 ◽  
Vol 17 (S2) ◽  
pp. 1008-1009
Author(s):  
P Bajaj ◽  
J Nguyen ◽  
C Gilpin ◽  
G Dieckmann ◽  
C Chiu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
Three Dimensional ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Three-Dimensional Porous Carbon Nanotube Papers as Current Collector and Buffer for SnO2 Anodes

NANO ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. 1750141 ◽  
Author(s):  
Xiaogang Sun ◽  
Zhiwen Qiu ◽  
Long Chen ◽  
Manyuan Cai ◽  
Jie Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Anode Materials ◽  
Composite Electrode ◽  
Three Dimensional ◽  
Current Collector ◽  
Discharge Process ◽  
Composite Anode ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

A novel three-dimensional porous conductive papers have been successfully synthesized via a simple physical route. Multi-walled carbon nanotubes (MWCNTs)@SnO2 composite anode materials are embedded in porous conductive papers. The peculiar structure can accommodate the huge volume expansion of MWCNTs@SnO2 composite anode materials during charge–discharge process. The framework formed by MWCNTs and cellulose can greatly improve the strength, stability and flexibility of the electrode. In addition, the structure successfully prevent the aggregation of SnO2 nanoparticles and collapse of MWCNTs@SnO2 composite electrode, leading to the improvement in electrochemical utilization and stable cyclability. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The electrochemical properties and application were evaluated by galvanostatic discharge–charge testing and cycling voltammetry. As a result, the MWCNTs@SnO2 composite electrode showed excellent rate performance. The discharge capacity remains about 680[Formula: see text]mAh g[Formula: see text] after 100 cycles at 200[Formula: see text]mA g[Formula: see text], and even around 300[Formula: see text]mAh g[Formula: see text] at 1000[Formula: see text]mA g[Formula: see text].

A Simple Approach for Immobilization of Fe-Core/Au-Shell Magnetic Nanoparticles on Multi-Walled Carbon Nanotubes via Cu(I) Huisgen Cycloaddition: Preparation and Characterization

2018 ◽  
Vol 279 ◽  
pp. 187-191 ◽  
Author(s):  
Duy Trinh Nguyen ◽  
Nguyen Phu Thuong Nhan ◽  
Tran Thien Hien ◽  
Nguyen Dai Hai ◽  
Dai Viet N. Vo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Quantum Interference ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Rapid Separation ◽  
Au Nps ◽  
Simple Strategy ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this report, we demonstrated a novel efficient a simple strategy route for the preparation of smart hybrid Fe-core/Au-shell magnetic onto multi-walled carbon nanotubes (CNT) sidewalls via Cu (I)-catalyzed 1, 3-dipolar cycloaddition (“click” coupling). The fabrication of gold-coated iron nanoparticles (Fe@AuNPs) is initially achieved by employing a two-step reverse micelle process. A new azide terminated ligand was first synthesized to change Fe@AuNPs by ligand exchange reaction. The Fe@Au NPs decorated MWNTs (MWNTs-Fe@Au) nanohybrids were synthesized by the reaction of an azide-containing Fe@Au NPs with alkyne-functionalized MWNTs via the Cu (I)-catalyzed 1,3-dipolar cycloaddition reaction. Energy dispersive X-ray (EDX) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and Transmission electron microscopy (HR-TEM) were used to study the changes in surface functionalities and demonstrate the successful immobilization of Fe@Au on CNT surface. In addition, the superconducting quantum interference device (SQUID) study revealed that the nanohybrids possess superparamagnetic character which is susceptible to rapid separation under an external magnetic field.

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