scholarly journals Formation of Metal Colloids in Inverse Micelles and Microemulsions

1989 ◽  
Vol 177 ◽  
Author(s):  
Jess P. Wilcoxon ◽  
Rod L. Williamson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Growth Kinetics ◽  
Colloidal Suspensions ◽  
X Ray ◽  
Inverse Micelles ◽  
Transmission Electron ◽  
Inverse Micelle

ABSTRACTGold colloidal suspensions are produced from both inverse micelle solutions and microemulsions through both chemical and photolytic reduction of the appropriate salt. A variety of surfactant/solvent combinations yield varying results with respect to metalloid growth kinetics and stability as revealed through dynamic light scattering, small-angle x-ray and neutron scattering, and transmission electron microscopy.

scholarly journals Coprecipitation Method of Synthesis, Characterization, and Cytotoxicity of Pr3+:LaF3 (CPr = 3, 7, 12, 20, 30%) Nanoparticles

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Maksim S. Pudovkin ◽  
Pavel V. Zelenikhin ◽  
Victoria Shtyreva ◽  
Oleg A. Morozov ◽  
Darya A. Koryakovtseva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
High Resolution ◽  
Dynamic Light Scattering ◽  
Hydrodynamic Radius ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

The Pr3+:LaF3 (CPr = 3, 7, 12, 20, 30%) nanoparticles were characterized by means of high-resolution transmission electron microscopy, X-ray diffraction, optical spectroscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, and MTT assay. It was revealed that the average diameter of all the NPs is around 14–18 nm. The hydrodynamic radius of the Pr3+:LaF3 (CPr = 7%) nanoparticles strongly depends on the medium. It was revealed that hydrodynamic radii of the Pr3+:LaF3 (CPr = 7%) nanoparticles in water, DMEM, and RPMI-1640 biological mediums were 18 ± 5, 41 ± 6, and 186 ± 8 nm, respectively. The Pr3+:LaF3 (CPr = 7%) nanoparticles were nontoxic at micromolar concentrations toward COLO-320 cell line. The lifetime curves were fitted biexponentially, and for the Pr3+:LaF3 (CPr = 7%) NPs, the luminescence lifetimes of Pr3+ ions were 480 ± 2 and 53 ± 5 nanosec.

scholarly journals Effect of Different Variables on the Size Distribution of Barium Chromate Nanoparticles

2016 ◽  
Vol 11 (3) ◽  
pp. 32
Author(s):  
Mehdi Simiari ◽  
Mehrdad Manteghian ◽  
Malihe Ghashamshmi-Iraj.
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Sodium Citrate ◽  
Optimum Concentration ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Barium Chromate

In this study, the synthesis of BaCrO4 nanoparticles is performed by the reaction between Ba(NO3)2 and (NH4)2CrO4 in the presence of surfactant. Different analyses such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), Dynamic light scattering (DLS), and Energy Dispersive X-ray analysis (EDAX) are carried out to identify the features of nanoparticles. The tests are conducted in different concentrations of reactants and surfactants, and at the end, the results are compared. Optimum concentration is also measured and reported to achieve smaller nanoparticles. The results indicate that, in the synthesis of BaCrO4 nanoparticles, the best performance belongs to Sodium Citrate.

Polyethyleneimine Modified Biocompatible Poly(N-isopropylacrylamide)-Based Nanogels for Drug Delivery

2008 ◽  
Vol 8 (5) ◽  
pp. 2377-2384 ◽  
Author(s):  
Chang-Yun Quan ◽  
Hua Wei ◽  
Yun-Xia Sun ◽  
Si-Xue Cheng ◽  
Kun Shen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Transmission Electron ◽  
Potential Applications ◽  
Different Temperatures ◽  
The Mean ◽  
Stimuli Sensitive

A series of biocompatible and stimuli-sensitive poly(N-isopropylacrylamide-co-propyl acrylic acid) (P(NIPAAm-co-PAAc)) nanogels were synthesized by emulsion polymerization. In addition, polyethyleneimine (PEI) was further grafted to modify the PNIPAAm-based nanogels. The P(NIPAAm-co-PAAc)-g-PEI nanogels exhibited good thermosensitivity as well as pH sensitivity. Transmission electron microscopy (TEM) showed that the P(NIPAAm-co-PAAc)-g-PEI and P(NIPAAm-co-PAAc) nanogels displayed well dispersed spherical morphology. The mean sizes of the nanogels measured by dynamic light scattering (DLS) were from 100 nm to 500 nm at different temperatures. The cytotoxicity study indicated P(NIPAAm-co-PAAc) nanogels exhibited a better biocompatibility than both PNIPAAm nanogel and P(NIPAAm-co-PAAc)-g-PEI nanogel although all the three kinds of nanogels did not exhibit apparent cytotoxicity. The drug-loaded nanogels, especially the PEI-grafted nanogels, showed temperature-trigged controlled release behaviors, indicating the potential applications as an intelligent drug delivery system.

scholarly journals Estudio comparativo de la síntesis de nanopartículas de magnetita monodispersas

2018 ◽  
pp. 5-11
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Decomposition ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aqueous Suspension ◽  
The Body ◽  
Synthesis Route ◽  
Transmission Electron ◽  
Co Precipitation

Estudio comparativo de la síntesis de nanopartículas de magnetita monodispersas J.J. Atoche Medrano, J. A. Huamani Coaquira Universidad de Brasília, Campus Universitário Darcy Ribeiro, Brasília - CEP 70910-900 DOI: https://doi.org/10.33017/RevECIPeru2015.0001/ Resumen Actualmente el tipo de nanopartículas magnéticas más estudiados son los de estructura cúbica, espinela inversa, porque estos materiales presentan características de gran interés y sus posibles aplicaciones ya que facilitan la construcción de sistemas más complejos. Debemos considerar que debido a la presencia de metales de transición en la superficie de las nanopartículas es que se dan las condiciones para poder funcionalizarlas con otras moléculas a través de grupos funcionales complejos obteniendo materiales con características polares o apolares, dependiendo del tipo de aplicación que se desee utilizar. Teniendo en consideración que cuando se trabaja con sistemas biológicos las nanopartículas son detectadas por el sistema retículo endotelial (SRE), que a través de los macrófagos son los encargados de eliminar algún cuerpo extraño inerte que pudiera estar en el organismo. De esta manera, existe una necesidad de funcionalizar las nanopartículas obtenidas antes de ser administradas en el organismo para evitar ser reconocidas por el SRE. Esta funcionalización es responsable por evitar la aglomeración de las mismas permitiendo que ellas permanezcan en suspensión estable (coloides magnéticos) que pueden ser conducidos a través de campos magnéticos externos. En este trabajo, nosotros mostramos detalladamente los resultados obtenido en la mejora de la ruta de síntesis de un sistema de nano partículas en forma de ferrofluido de magnetita (Fe3O4) utilizando el método de descomposición térmica y comparamos nuestros resultados respecto a otra ruta de síntesis para sistema nano particulados llamado método de co-precipitación química. Para poder medir el tamaño, así como conocer las propiedades morfológicas y estructurales de las nanopartículas se procedió a la caracterización de nanopartículas obtenidas por los métodos de descomposición térmica y co-precipitación química a través de microscopia electrónica de transmisión (MET). Se encontró una distribución de tamaños con un promedio de 8 nm y polidispersión de 0.14. Estos resultados fueron corroborados por los resultados obtenidos mediante análisis de patrones de difracción de rayos X. La estabilidad del ferrofluido obtenido fue medida usando la técnica conocida como DLS (Dynamic Light Scattering), donde fue encontrado un valor de 42.8 mV, que está dentro del valor esperado para un sistema estable, considerando que para un sistema nanopartículado el valor de Zetasiser arriba de 30 mV representa una estabilidad de la suspensión acuosa. Al final de las medidas de caracterización se realizó la medida del valor del potencial de hidrógeno (pH) mediante un pH-metro, para estudiar la biocompatibilidad que presenta nuestra muestra de ferrofluido ya que nuestro interés es que este ferrofluido pueda ser usado como vehículo para direccionar principios activos o fármacos sobre una región específica en el organismo. Así después de realizada la medición fue encontrado un valor del pH de 7.23 lo que evidencia un sistema biocompatible para posibles aplicaciones biológicas. Descriptores: Descomposición térmica, co-precipitación, ferrofluido, nanopartículas, microscopia electrónica de transmisión. Abstract Currently the most studied type of magnetic nanoparticles are of cubic structure, inverse spinel, because these materials have very interesting features and possible applications since they facilitate building more complex systems. We must consider that due to the presence of transition metal on the surface of nanoparticles is that the conditions for funcionalizarlas with other molecules through complex functional groups obtaining materials with polar or apolar characteristics, depending on the type of implementation that want to use. Considering that when working with biological systems nanoparticles are detected by the reticuloendothelial system (RES). This functionalization is responsible for preventing agglomeration there of allowing them to remain in stable suspension (magnetic colloids) that can be driven by external magnetic fields. In this work, we show in detail the results obtained in improving the synthesis route system in the form of nanoparticles ferrofluid magnetite (Fe3O4) using the method of thermal decomposition and compare our results with respect to another synthesis route to nano particulate system method called chemical coprecipitation. To measure the size as well as knowing the morphological and structural properties of nanoparticles proceeded to the characterization of nanoparticles obtained by the methods of thermal decomposition and chemical co-precipitation through transmission electron microscopy (TEM). Size distribution averaging 8 nm and polydispersity of 0.14 was found. These results were corroborated by the results obtained by analyzing patterns of X-ray diffraction. The stability of the ferrofluid obtained was measured using the technique known as DLS (Dynamic Light Scattering), where it was found a value of 42.8 mV, which is within the expected value for a stable system, whereas for a nanoparticle system Zetasiser value above 30 mV represents a stability of the aqueous suspensión. At the end of characterization measures the extent of the value of the potential of hydrogen (pH) was performed using a pH meter, to study our sample having biocompatibility ferrofluid as our interest is that the ferrofluid could be used as vehicle for active ingredients or drugs addressing to a specific region in the body. And after completion of the measurement it was found a pH of 7.23 which shows a biocompatible system to possible biological applications. Keywords: Thermal decomposition, co-precipitation, ferrofluid, nanoparticles, transmission electron microscopy.

Fabrication of Nanocolorants Using Miniemulsion Solvent Evaporation Technique

2013 ◽  
Vol 785-786 ◽  
pp. 471-474
Author(s):  
Xiao Zhao ◽  
Shan Xu ◽  
Gao Zhan Xie
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Photoelectron Spectroscopy ◽  
Solvent Evaporation ◽  
Dye Molecules ◽  
X Ray ◽  
Transmission Electron ◽  
Evaporation Technique ◽  
Formulation Variables

The combined miniemulsion and solvent evaporation (MESE) method was employed to fabricate hydrophobic dye/polymer composite colorants in the present work. Using dynamic light scattering tests, the effect of the formulation variables on the size and size distribution of the prepared nanoparticles was examined. Transmission electron microscopy, UVvisible spectrophotometry, X-ray photoelectron spectroscopy, and elemental analysis results indicate that dye molecules or aggregates were successfully encapsulated in the poly (methyl methacrylate) matrix using the MESE method and the resulting composite colorant could be dispersed in water.

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