scholarly journals Polyfluorene-Based Multicolor Fluorescent Nanoparticles Activated by Temperature for Bioimaging and Drug Delivery

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1485 ◽  
Author(s):  
Marta Rubio-Camacho ◽  
Yolanda Alacid ◽  
Ricardo Mallavia ◽  
María José Martínez-Tomé ◽  
C. Reyes Mateo
Keyword(s):  
Mammalian Cells ◽  
Photophysical Properties ◽  
Drug Carriers ◽  
Fluorescent Nanoparticles ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Hydrophilic Drug ◽  
Thermosensitive Liposomes ◽  
Size And Morphology ◽  
The Stability

Multifunctional nanoparticles have been attracting growing attention in recent years because of their capability to integrate materials with different features in one entity, which leads them to be considered as the next generation of nanomedicine. In this work, we have taken advantage of the interesting properties of conjugated polyelectrolytes to develop multicolor fluorescent nanoparticles with integrating imaging and therapeutic functionalities. With this end, thermosensitive liposomes were coated with three recently synthesized polyfluorenes: copoly-((9,9-bis(6′-N,N,N-trimethylammonium)hexyl)-2,7-(fluorene)-alt-1,4-(phenylene)) bromide (HTMA-PFP), copoly-((9,9-bis(6′-N,N,N-trimethylammonium)hexyl)-2,7-(fluorene)-alt-4,7-(2- (phenyl)benzo(d) (1,2,3) triazole)) bromide (HTMA-PFBT) and copoly-((9,9-bis(6′-N,N,N- trimethylammonium)hexyl)-2,7-(fluorene)-alt-1,4-(naphtho(2,3c)-1,2,5-thiadiazole)) bromide (HTMA-PFNT), in order to obtain blue, green and red fluorescent drug carriers, respectively. The stability, size and morphology of the nanoparticles, as well as their thermotropic behavior and photophysical properties, have been characterized by Dynamic Light Scattering (DLS), Zeta Potential, transmission electron microscope (TEM) analysis and fluorescence spectroscopy. In addition, the suitability of the nanostructures to carry and release their contents when triggered by hyperthermia has been explored by using carboxyfluorescein as a hydrophilic drug model. Finally, preliminary experiments with mammalian cells demonstrate the capability of the nanoparticles to mark and visualize cells with different colors, evidencing their potential use for imaging and therapeutic applications.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

Effect of Magnesium Coating Prior to Lithium Loading over SBA-15 for Stabilization of its Mesostructure

2014 ◽  
Vol 917 ◽  
pp. 3-9
Author(s):  
Muhammad Ayoub ◽  
Ahmad Zuhairi Abdullah
Keyword(s):  
Pore Size ◽  
Pore Volume ◽  
Mesoporous Material ◽  
Mesoporous Structure ◽  
Electron Microscopic ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
The Stability ◽  
Basic Strength

Mesoporous material SBA-15 was synthesized using P123 and TEMOS as the templates. Lithium in the form of LiOH was loaded over a previously prepared SBA-15. The basic strength of the prepared samples of SBA-15 was found to increase but the mesoporous structure was severely destroyed. The mesoporous structure of the prepared SBA-15 was retained after coating it with 30 wt. % magnesium prior to LiOH loading. The stability of mesoporous structure was strongly influenced by the extent of magnesium coating. It was also noted that this structure was also affected by LiOH loading and significantly destroyed structure when magnesium coating value exceeded 20 %. These samples were thoroughly characterized for their surface area, pore volume, pore size, basic strength, SAXRD patterns and transmission electron microscopic (TEM) analysis.

scholarly journals Efficient Photocatalytic and EMI Shielding Properties of CdO/ La2O3 Nanocomposites

2021 ◽  
Author(s):  
Senthil S ◽  
SRINIVASAN S ◽  
THANGEESWARI T ◽  
MADHU B J ◽  
SILAMBARASAN M
Keyword(s):  
Electron Microscope ◽  
Lanthanum Oxide ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Violet Emission ◽  
Green Emission Peak ◽  
Transmission Electron ◽  
Cdo Nanoparticles ◽  
Size And Morphology

Abstract The pure CdO and CdO/La 2 O 3 , and CdO/La 2 O 3 /PVP nanocomposites were synthesized by microwave irradiation method. The prepared samples are analyzed by X-Ray diffraction (XRD), Fourier Transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM), Transmission electron microscope (TEM), UV visible spectrometer, Photoluminescence (PL), and Vibrating sample magnetometer (VSM). XRD and FTIR studies confirmed the formation of binary metallic nanocomposites. SEM and TEM analysis authenticate that the addition of lanthanum oxide and PVP influences the size and morphology of CdO nanoparticles the bandgap value can be tuned by the addition of La 2 O 3 and PVP. Photoluminescence spectra show the violet emission in the region between 432 nm to 460 nm and the green emission peak at 529 nm for all three synthesized samples. CIE color coordinates for CdO and CdO/La 2 O 3 , and CdO/La 2 O 3 /PVP nanocomposites were also estimated from emission spectrum. The VSM results confirmed that the nanocomposites possess the weak ferromagnetic properties due to the inclusion of La 2 O 3 and PVP. The dielectric constant, electrical conductivity and dielectric loss values at room temperature have been analyzed for CdO and CdO/La 2 O 3 , and CdO/La 2 O 3 /PVP nanocomposites. Among the three synthesized samples, the CdO/La 2 O 3 /PVP nanocomposite attain high electromagnetic shielding efficiency. Furthermore, the rare earth element lanthanum oxide and PVP enhances the efficiency of photocatalytic degradation of MB dye.

scholarly journals Green synthesis and stabilization of earthworm-like gold nanostructure and quasi-spherical shape using Caesalpinia sappan Linn. extract

2018 ◽  
Vol 7 (5) ◽  
pp. 424-432 ◽  
Author(s):  
Widsanusan Chartarrayawadee ◽  
Chee O. Too ◽  
Sukunya Ross ◽  
Gareth M. Ross ◽  
Kanlaya Jumpatong ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Green Synthesis ◽  
Spherical Shape ◽  
Colloidal Solutions ◽  
Tem Analysis ◽  
Caesalpinia Sappan ◽  
Synthesis Of Nanoparticles ◽  
Stabilizing Agents ◽  
Transmission Electron ◽  
The Stability

AbstractGreen synthesis of nanoparticles (NPs) has received much attention due to biocompatibility and being facile and eco-friendly.Caesalpinia sappanLinn. (CS) is a plant found in Southeast Asia and is commonly known as sappan wood. In this research, we are the first to successfully use CS extract as reducing and stabilizing agents for the green synthesis of gold NPs (AuNPs). Colloidal solutions of AuNPs after reduction show natural red-wine and dark purple color depending on the size of AuNPs, without the interference of the orange/reddish-orange color from the CS extract. The concentration of CS was investigated for the formation and stabilization of AuNPs in colloidal solution (i.e. morphology, size and zeta potential). It was found that the optimized concentration of the reducing agent for the green synthesis of AuNPs was in the range of 0.004–0.04 wt% of CS. As the concentration of CS was increased, the sizes of AuNPs decreased due to the adsorption and stabilizing effect of CS. Transmission electron microscopy (TEM) analysis showed differences in size and shape of the NPs with earthworm and quasi-spherical characteristics. The zeta potential of AuNPs synthesized in the presence of CS was approximately in the range of −10 mV to −20 mV, indicating the stability of AuNPs synthesized by CS.

scholarly journals Evaluation of effects of selenium nanoparticles on Bacillus subtilis

2019 ◽  
Vol 10 (4) ◽  
pp. 544-552
Author(s):  
N. O. Tymoshok ◽  
M. S. Kharchuk ◽  
V. G. Kaplunenko ◽  
V. S. Bityutskyy ◽  
S. I. Tsekhmistrenko ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Morphological Characteristics ◽  
Visible Spectrum ◽  
Drug Carriers ◽  
Biologically Active ◽  
Selenium Nanoparticles ◽  
Tem Analysis ◽  
Transmission Electron ◽  
Before And After ◽  
Active Substances

The present study was performed to characterize of selenium nanoparticles (Nano-Se) which were synthesized by pulsed laser ablation in liquids to obtain the aqueous selenium citrate solution. The study was conducted using bacteriological and electronic-microscopic methods. Transmission electron microscopy (TEM) and spectroscopy analyses demonstrated that nano-selenium particles obtained by the method of selenium ablation had the size of 4–8 nm. UV-Visible Spectrum colloidal solution Nano-Se exhibited absorption maxima at 210 nm. To clarify some effects of the action of Nano-Se on Bacillus subtilis, we investigated the interaction of Nano-Se with B. subtilis IMV B-7392 before and after incubation with Nano-Se, examining TEM images. It has been shown that exposure to B. subtilis IMV B-7392 in the presence of Nano-Se is accompanied by the rapid uptake of Nano-Se by bacterial culture. TEM analysis found that the electron-dense Nano-Se particles were located in the intracellular spaces of B. subtilis IMV B-7392. That does not lead to changes in cultural and morphological characteristics of B. subtilis IMV B-7392. Using TEM, it has been shown that penetration of nanoparticles in the internal compartments is accompanied with transient porosity of the cell membrane of B. subtilis IMV B-7392 without rupturing it. The effective concentration of Nano-Se 0.2 × 10–3 mg/mL was found to increase the yield of biologically active substances of B. subtilis. In order to create probiotic nano-selenium containing products, the nutrient medium of B. subtilis IMV B-7392 was enriched with Nano-Se at 0.2 × 10–3 mg/mL. It was found that particles Nano-Se are non-toxic to the culture and did not exhibit bactericidal or bacteriostatic effects. The experimentally demonstrated ability of B. subtilis to absorb selenium nanoparticles has opened up the possibility of using Nano-Se as suitable drug carriers.

scholarly journals Green Synthesis, Characterization, Enzyme Inhibition, Antimicrobial Potential, and Cytotoxic Activity of Plant Mediated Silver Nanoparticle Using Ricinus communis Leaf and Root Extracts

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 206
Author(s):  
Anadil Gul ◽  
Fozia ◽  
Asmat Shaheen ◽  
Ijaz Ahmad ◽  
Baharullah Khattak ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Ricinus Communis ◽  
Cost Effective ◽  
Synthesis Process ◽  
Ag Nps ◽  
Tem Analysis ◽  
Root Extracts ◽  
Transmission Electron ◽  
Mean Size ◽  
The Stability

The need of non-toxic synthesis protocols for nanoparticles arises developing interest in biogenic approaches. The present project was focused on cost effective, environment congenial synthesis of Ag nanoparticles and their biological applications. Leaf and root extracts of Ricinus communis were used as a reducing and stabilizing agent in synthesis process. A Proposed mechanism in published literature suggested that Indole-3-acetic acid, l-valine, triethyl citrate, and quercetin-3-0-p-d-glucopyranoside phytoconstituents of Ricinus communis act as reducing and capping agents. The synthesized Ag NPs were characterized with a help X-ray diffractometer, Transmission electron microscopy, UV-Vis spectrophotometry and Fourier Transform Infrared Spectroscopy (FTIR). The XRD results inveterate the synthesis of pure nano size crystalline silver particles. The FTIR data revealed the possible functional groups of biomolecules involved in bio reduction and capping for efficient stabilization of silver nanoparticles. TEM analysis confirmed the almost spherical morphology of synthesized particles with mean size 29 and 38 nm for R-Ag-NPs (root) and L-Ag-NPs (leaf), respectively. The stability of synthesized nanoparticles was examined against heat and pH. It was observed that synthesized nanoparticles were stable up to 100 °C temperature and also showed stability in neutral, basic and slightly acidic medium (pH 05–06) for several months while below pH 5 were unstable. The synthesized silver nanoparticles had promising inhibition efficiency in multiple applications, including as bactericidal/fungicidal agents and Urease/Xanthine oxidase enzymes inhibitors. The cytotoxicity of synthesized nanoparticles shows that the concentration under 20 μg/mL were biologically compatible.

Transmission Electron Microscopy of an Aluminum-Silver-Stainless Steel Solid State Bond

1985 ◽  
Vol 43 ◽  
pp. 172-173
Author(s):  
M. J. Carr ◽  
J. F. Shewbridge ◽  
T. O. Wilford
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Solid State ◽  
Specimen Preparation ◽  
Dimensional Control ◽  
Tem Analysis ◽  
Metal Parts ◽  
Dissimilar Metal ◽  
Transmission Electron ◽  
Short Time

Strong solid state bonds are routinely produced between physical vapor deposited (PVD) silver coatings deposited on sputter cleaned surfaces of two dissimilar metal parts. The low temperature (200°C) and short time (10 min) used in the bonding cycle are advantageous from the standpoint of productivity and dimensional control. These conditions unfortunately produce no microstructural changes at or near the interface that are detectable by optical, SEM, or microprobe examination. Microstructural problems arising at these interfaces could therefore easily go undetected by these techniques. TEM analysis has not been previously applied to this problem because of the difficulty in specimen preparation. The purpose of this paper is to describe our technique for preparing specimens from solid state bonds and to present our initial observations of the microstructural details of such bonds.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

TEM Sample Preparation Tricks for Advanced DRAMs

2015 ◽  
Author(s):  
Ching Shan Sung ◽  
Hsiu Ting Lee ◽  
Jian Shing Luo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Characterization Of Materials

Abstract Transmission electron microscopy (TEM) plays an important role in the structural analysis and characterization of materials for process evaluation and failure analysis in the integrated circuit (IC) industry as device shrinkage continues. It is well known that a high quality TEM sample is one of the keys which enables to facilitate successful TEM analysis. This paper demonstrates a few examples to show the tricks on positioning, protection deposition, sample dicing, and focused ion beam milling of the TEM sample preparation for advanced DRAMs. The micro-structures of the devices and samples architectures were observed by using cross sectional transmission electron microscopy, scanning electron microscopy, and optical microscopy. Following these tricks can help readers to prepare TEM samples with higher quality and efficiency.

Utilizing Nanoprobing and Circuit Diagnostics to Identify Key Failure Mechanism of Otherwise Nonvisible Defects in 20 nm Logic Devices

2014 ◽  
Author(s):  
M.K. Dawood ◽  
C. Chen ◽  
P.K. Tan ◽  
S. James ◽  
P.S. Limin ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Contact Layer ◽  
Fault Isolation ◽  
Tem Analysis ◽  
Logic Devices ◽  
Technology Advancement ◽  
Transmission Electron ◽  
Voltage Contrast ◽  
Almost All ◽  
20 Nm

Abstract In this work, we present two case studies on the utilization of advanced nanoprobing on 20nm logic devices at contact layer to identify the root cause of scan logic failures. In both cases, conventional failure analysis followed by inspection of passive voltage contrast (PVC) failed to identify any abnormality in the devices. Technology advancement makes identifying failure mechanisms increasingly more challenging using conventional methods of physical failure analysis (PFA). Almost all PFA cases for 20nm technology node devices and beyond require Transmission Electron Microscopy (TEM) analysis. Before TEM analysis can be performed, fault isolation is required to correctly determine the precise failing location. Isolated transistor probing was performed on the suspected logic NMOS and PMOS transistors to identify the failing transistors for TEM analysis. In this paper, nanoprobing was used to isolate the failing transistor of a logic cell. Nanoprobing revealed anomalies between the drain and bulk junction which was found to be due to contact gouging of different severities.

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