scholarly journals Green Method Synthesised Graphene-Silver Electrochemical Nanobiosensors for Ethambutol and Pyrazinamide

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 879
Author(s):  
Rachel Fanelwa AjayI ◽  
Siphokazi Tshoko ◽  
Yonela Mgwili ◽  
Siphamandla Nqunqa ◽  
Takalani Mulaudzi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Limit Of Detection ◽  
Low Cost ◽  
Ag Nps ◽  
Green Method ◽  
Tb Treatment ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
P450 2D6

A novel nanobiosensor was constructed with graphene oxide (GO) sheets coupled to pear extract-based green-synthesised silver nanoparticles (Ag-NPs) to which cytochrome P450-2D6 (CYP2D6) enzyme was attached. The biosensor was applied in the electrochemical detection of the tuberculosis (TB) treatment drugs, ethambutol (EMB) and pyrazinamide (PZA). The surface morphology of the green-synthesised nanocomposites was studied by performing High-Resolution Transmission Electron Microscopy (HR-TEM) and High-Resolution Scanning Electron Microscopy (HR-SEM). Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy were used for structural analysis, while Ultraviolet Visible (UV-Vis) Spectroscopy was used in the optical characterisation of the nanocomposite material. Electrochemical studies on glassy carbon electrode (GCE), which were done by Cyclic Voltammetry (CV), showed that the GO|Ag-NPs||GCE electrode was highly conductive, and thereby indicating its suitability as a platform for nanobiosensor development. The non-toxic and low-cost green GO|Ag-NPs|CYP2D6||GCE nanobiosensor was used to determine EMB and PZA. The very low limit of detection (LOD) values of the biosensor for EMB (0.2962 × 10−2 nM, S/N = 3) and PZA (0.897 × 10−2 nM, S/N = 3) demonstrate that the green nanobiosensor is more sensitive than other biosensors reported for EMB and PZA.

scholarly journals Three-Dimensional Printed Polylactic Acid (PLA) Surgical Retractors with Sonochemically Immobilized Silver Nanoparticles: The Next Generation of Low-Cost Antimicrobial Surgery Equipment

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 985 ◽  
Author(s):  
Lazaros Tzounis ◽  
Petros I. Bangeas ◽  
Aristomenis Exadaktylos ◽  
Markos Petousis ◽  
Nectarios Vidakis
Keyword(s):  
Electron Microscopy ◽  
3D Printing ◽  
Polylactic Acid ◽  
Low Cost ◽  
Three Dimensional ◽  
Film Deposition ◽  
Average Particle ◽  
Ag Nps ◽  
Fused Deposition ◽  
Vis Spectroscopy

A versatile method is reported for the manufacturing of antimicrobial (AM) surgery equipment utilising fused deposition modelling (FDM), three-dimensional (3D) printing and sonochemistry thin-film deposition technology. A surgical retractor was replicated from a commercial polylactic acid (PLA) thermoplastic filament, while a thin layer of silver (Ag) nanoparticles (NPs) was developed via a simple and scalable sonochemical deposition method. The PLA retractor covered with Ag NPs (PLA@Ag) exhibited vigorous AM properties examined by a reduction in Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Escherichia coli (E. coli) bacteria viability (%) experiments at 30, 60 and 120 min duration of contact (p < 0.05). Scanning electron microscopy (SEM) showed the surface morphology of bare PLA and PLA@Ag retractor, revealing a homogeneous and full surface coverage of Ag NPs. X-Ray diffraction (XRD) analysis indicated the crystallinity of Ag nanocoating. Ultraviolent-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM) highlighted the AgNP plasmonic optical responses and average particle size of 31.08 ± 6.68 nm. TEM images of the PLA@Ag crossection demonstrated the thickness of the deposited Ag nanolayer, as well as an observed tendency of AgNPs to penetrate though the outer surface of PLA. The combination of 3D printing and sonochemistry technology could open new avenues in the manufacturing of low-cost and on-demand antimicrobial surgery equipment.

scholarly journals An Electrochemical Immunosensor Based on SPA and rGO-PEI-Ag-Nf for the Detection of Arsanilic Acid

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 172
Author(s):  
Yanwei Wang ◽  
Dongdong Ma ◽  
Gaiping Zhang ◽  
Xuannian Wang ◽  
Jingming Zhou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Limit Of Detection ◽  
Electrochemical Immunosensor ◽  
Detection Range ◽  
Optimal Experiment ◽  
Arsanilic Acid ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Good Potential ◽  
The Stability

A sensitive electrochemical immunosensor was prepared for rapid detection of ASA based on arsanilic acid (ASA) monoclonal antibody with high affinity. In the preparation of nanomaterials, polyethyleneimine (PEI) improved the stability of the solution and acted as a reducing agent to generate reduced graphene oxide (rGO) with relatively strong conductivity, thereby promoting the transfer of electrons. The dual conductivity of rGO and silver nanoparticles (AgNPs) improved the sensitivity of the sensor. The synthesis of nanomaterials were confirmed by UV-Vis spectroscopy, X-ray diffraction, transmission electron microscopy and scanning electron microscopy. In the optimal experiment conditions, the sensor could achieve the detection range of 0.50–500 ng mL−1 and the limit of detection (LOD) of 0.38 ng mL−1 (S/N = 3). Moreover, the sensor exhibited excellent specificity and acceptable stability, suggesting that the proposed sensor possessed a good potential in ASA detection. Thus, the as-prepared biosensor may be a potential way for detecting other antibiotics in meat and animal-derived foods.

Direct Hydrothermal Processing of Long Titanate Nanofibers from Natural Rutile

2006 ◽  
Vol 317-318 ◽  
pp. 243-246 ◽  
Author(s):  
Yoshikazu Suzuki ◽  
Sorapong Pavasupree ◽  
Susumu Yoshikawa ◽  
Ryoji Kawahata
Keyword(s):  
Electron Microscopy ◽  
Low Cost ◽  
High Yield ◽  
Hydrothermal Processing ◽  
Reaction Step ◽  
X Ray ◽  
Sodium Hydrogen ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Natural Rutile

Via the direct hydrothermal processing using natural rutile as a starting material, long titanate nanofibers (typically 10-500 μm in length and 20-50 nm in diameter) have been successfully synthesized in high yield Transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), electron diffraction, and UV-Vis spectroscopy demonstrated that the as-synthesized nanofibers presumably consisted of sodium hydrogen trititanate ((Na,H)2Ti3O7, e.g., Na0.4H1.6Ti3O7) including some hexatitanate-type defects ((Na,H)2Ti6O13). The direct hydrothermal treatment for natural rutile will be a promising low-cost processing for 1-D nanomaterials, which can act not only as the reaction step but also as the purification.

scholarly journals BIOSYNTHESIS AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM MANGROVE BARK – RHIZOPHORA MUCRONATA EXTRACT

2020 ◽  
pp. 91-94
Author(s):  
AJI JOVITHA AT ◽  
DEIVASIGAMANI B
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silver Nanoparticles ◽  
High Resolution ◽  
Room Temperature ◽  
Energy Dispersive ◽  
Rhizophora Mucronata ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy

Objective: The present study attempted to synthesize AgNPs from mangrove bark Rhizophora mucronata and analyze characteristics. The synthesized AgNPs analyzed with UV–vis spectroscopy, high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) for confirming the nanoparticles. Methods: The dried R. mucronata bark was powdered and kept in at 55°C for 15 min in a water bath and cooled at room temperature to get the extract. The R. mucronata bark extract was treated with silver nitrate and kept overnight in the dark environment which will turn the solution to dark brown color. The silver nanoparticles were characterized using UV–visible absorption at room temperature. Further characterization was also done with X-ray diffraction, high-resolution transmission electron microscope measurements, and DLS analysis. Results: The synthesized AgNPs were analyzed with various analytical methods that revealed the abundant presence of silver nanoparticles. The UV–vis spectroscopy analysis exposed the surface plasmon resonance peak of 422 nm. High-resolution transmission electron microscopy (HRTEM) analysis indicated the size ranging from 10 nm to 200 nm in diameter and a spherical shaped poly dispersal of the particles. The energy-dispersive X-ray (EDX) and DLS also confirmed the presence of silver atoms. Conclusion: Silver nanoparticles of Rhizophora mucronata bark revealed a well-defined structure and may be used in antimicrobial function in further researches.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

High Resolution Transmission Electron Microscopy of an automobile catalytic converter

1990 ◽  
Vol 48 (4) ◽  
pp. 242-243
Author(s):  
Jan-Olle Malm ◽  
Jan-Olov Bovin
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Catalytic Converter ◽  
Active Material ◽  
Image Intensifier ◽  
High Resolution Electron Microscopy ◽  
Detailed Knowledge ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Atomic Surface

Understanding of catalytic processes requires detailed knowledge of the catalyst. As heterogeneous catalysis is a surface phenomena the understanding of the atomic surface structure of both the active material and the support material is of utmost importance. This work is a high resolution electron microscopy (HREM) study of different phases found in a used automobile catalytic converter.The high resolution micrographs were obtained with a JEM-4000EX working with a structural resolution better than 0.17 nm and equipped with a Gatan 622 TV-camera with an image intensifier. Some work (e.g. EDS-analysis and diffraction) was done with a JEM-2000FX equipped with a Link AN10000 EDX spectrometer. The catalytic converter in this study has been used under normal driving conditions for several years and has also been poisoned by using leaded fuel. To prepare the sample, parts of the monolith were crushed, dispersed in methanol and a drop of the dispersion was placed on the holey carbon grid.

Thrombus formation on artificial surfaces: Correlative microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 840-841
Author(s):  
Quintin J. Lai ◽  
Stuart L. Cooper ◽  
Ralph M. Albrecht
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Low Voltage ◽  
Thrombus Formation ◽  
Blood Platelets ◽  
Polymer Surfaces ◽  
Flow Conditions ◽  
Transmission Electron ◽  
Adhesion Of Platelets ◽  
Microscopic Techniques

Thrombus formation and embolization are significant problems for blood-contacting biomedical devices. Two major components of thrombi are blood platelets and the plasma protein, fibrinogen. Previous studies have examined interactions of platelets with polymer surfaces, fibrinogen with platelets, and platelets in suspension with spreading platelets attached to surfaces. Correlative microscopic techniques permit light microscopic observations of labeled living platelets, under static or flow conditions, followed by the observation of identical platelets by electron microscopy. Videoenhanced, differential interference contrast (DIC) light microscopy permits high-resolution, real-time imaging of live platelets and their interactions with surfaces. Interference reflection microscopy (IRM) provides information on the focal adhesion of platelets on surfaces. High voltage, transmission electron microscopy (HVEM) allows observation of platelet cytoskeletal structure of whole mount preparations. Low-voltage, high resolution, scanning electron microscopy allows observation of fine surface detail of platelets. Colloidal gold-labeled fibrinogen, used to identify the Gp Ilb/IIIa membrane receptor for fibrinogen, can be detected in all the above microscopies.

Automatic Registering and Stitching of TEM/STEM Image Mosaics

2013 ◽  
Author(s):  
Chung-Ching Lin ◽  
Franco Stellari ◽  
Lynne Gignac ◽  
Peilin Song ◽  
John Bruley
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Vlsi Circuit ◽  
Significant Progress ◽  
Research Areas ◽  
Automated Method ◽  
Transmission Electron ◽  
Stem Image ◽  
High Resolution Images ◽  
Global Optimal

Abstract Transmission Electron Microscopy (TEM) and scanning TEM (STEM) is widely used to acquire ultra high resolution images in different research areas. For some applications, a single TEM/STEM image does not provide enough information for analysis. One example in VLSI circuit failure analysis is the tracking of long interconnection. The capability of creating a large map of high resolution images may enable significant progress in some tasks. However, stitching TEM/STEM images in semiconductor applications is difficult and existing tools are unable to provide usable stitching results for analysis. In this paper, a novel fully automated method for stitching TEM/STEM image mosaics is proposed. The proposed method allows one to reach a global optimal configuration of each image tile so that both missing and false-positive correspondences can be tolerated. The experiment results presented in this paper show that the proposed method is robust and performs well in very challenging situations.

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