Author: MIGUEL ANGEL CAMACHO LOPEZ

Preparation of zinc peroxide nanoparticles by laser ablation of solid in liquids

HECTOR EMMANUEL PALMA PALMA MARILU CAMACHO LOPEZ MIGUEL ANGEL CAMACHO LOPEZ ALFREDO RAFAEL VILCHIS NESTOR (2015)

In the last decade, there has been interest on the synthesis and characterization of Zinc peroxide (ZnO2) due to its potential applications as biocide, bactericide, inorganic oxidant and so on. ZnO2 can be obtained as a powder with a cubic structure and has been utilized as a precursor to obtain Zinc oxide (ZnO). ZnO2 can be considered as an oxygen reservoir since when it is heated at relatively low temperatures oxygen is released. Various approaches have been utilized to synthetize ZnO2 powders like sol-gel, organometallic precursors, hydrothermal, Laser Ablation of Solids in Liquids (LASL), and so on. While the hydrothermal route is one of the most utilized methods to obtain ZnO2, the LASL technique has only been utilized by the Gondal´s group to synthesize zinc peroxide nanoparticles. Escobedo et al. have been reported a study of the vibrational properties of ZnO2 NPs synthesized by the hydrothermal method. Additionally, they present results of XRD, TEM and by thermal analysis determine the decomposition temperature of their ZnO2 NPs. Recently, the Escobedo-Morales’s group has reported a green method to prepare ZnO nanostructures employing as starting material ZnO2 (prepared by hydrothermal method)

Article

Física, Astronomía y Matemáticas CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

A facile method to prepare hexagonal molybdenum trioxide microrods

CARLOS INGRAM VARGAS CONSUELOS MIGUEL ANGEL CAMACHO LOPEZ (2014)

We report the successfully preparation of straight and well faceted hexagonal - MoO 3 rods by a simple method consisting o f a thermal treatment at low temperature applied to molybdenum diluited in a mixture of HCl and HNO 3. We have obtained sub-micrometer hexagonal rods several microns long with defect free walls. Electron scanning microscopy (SEM) and microRaman spectroscopy w ere used to characterize the obtained rods. ur results demonstrate the feasibility of synthesizing h-MoO 3 in a very simple way.

Article

Física, Astronomía y Matemáticas Hexagonal-MoO3 MicroRaman spectroscopy Microrods CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Armazones Celulares por la Técnica de Electrohilado

PABLO CAJERO VAZQUEZ MIGUEL ANGEL MELENDEZ LIRA MIGUEL ANGEL CAMACHO LOPEZ Marco Antonio Castillo Rubí Fernando Ricardo González Díaz (2010)

Se presenta una breve descripción de la técnica electrohilado, alcance, aplicaciones actuales y una propuesta para el desarrollo de equipos que son relativamente sencillos de implementar, en instituciones educativas o centros de investigación. Recientemente la técnica llamada electrohilado es propuesta para el desarrollo armazones celulares, dispositivos que proporcionan a las células el apoyo necesario para su proliferación y el mantenimiento de sus funciones diferenciadas y las señales biológicas requeridas para la conservación de la expresión génica específica, además, definen la arquitectura del tejido. La técnica de electrospinning consiste en que una solución polimérica es forzada a través de una boquilla mediante un campo eléctrico en donde el polímero forma fibras que rápidamente se adelgazan a diámetros más pequeños del orden de nm y um, esta técnica de electrohilado tiene sus orígenes en los Estados Unidos en la década de los 30's con otra serie de patentes procuradas por Formahls, haciéndose popular hasta la década de los 90's, donde tiene su mayor auge con fines cercanos a la industria textil, está técnica es propuesta para su uso en Salud particularmente en la ingeniería de tejidos, reparación de tejidos y, liberación de drogas. Nuestra propuesta es construir un equipo que incorpora a la técnica de electrospinning: dispositivo para un rango de movimiento de 360º (2rrad) a lo largo del eje del chorro, dispositivo para mezclar dos o tres polímeros, dispositivo para variar la distancia entre lo positivo electrodo y el electrodo negativo y también una caja que protege al usuario.

Article

Química Electrohilado Fibras Celulares Armazones BIOLOGÍA Y QUÍMICA

Preparation of quantum dots hydrogel nanocomposites with improved cytotoxicity

ABRAHAM GONZALEZ RUIZ MIGUEL ANGEL CAMACHO LOPEZ MIRIAM VERONICA FLORES MERINO (2017)

Nanocomposites are materials with unique properties and a wide range of applications. The combination of different nanostructures with traditional materials gives a variety of possibilities that should be analyzed. Especially, functional fluorescent semiconductor quantum dots (QDs) embedded in polymeric matrices have shown promising fluorescence and biocompatibility properties. These hybrid materials can be used in medical applications such as biodiagnostic and bioimaging. In this study, two hydrogels, one of polyethylene glycol diacrylate (PEGDA) and other of polyacrylamide (PAAm), were prepared with quantum dots of CdTe (4 nm of diameter) and characterized. The aim of this research was to analyze the optical properties of the nanocomposites and their cell viability. QDs nanocomposites were fabricated by a free radical polymerization process. The optical studies showed that the nanocomposites have well defined properties of fluorescence. To study the biocompatibility of the nanocomposites, metastatic B16f10 cell line were used and MTT assay was performed. The nanocomposites had a significant improved cell viability compared with QDs solutions.

Article

quantum dots hydrogels cytotoxixity BIOLOGÍA Y QUÍMICA

Characterization of nanostructured SnO2 films deposited by reactive DC-magnetron sputtering

MIGUEL ANGEL CAMACHO LOPEZ JOSE ROMAN GALEANA CAMACHO ALEJANDRO ESPARZA GARCIA CELIA ANGELINA SANCHEZ PEREZ Christian Julien (2013)

Nanostructured tin oxide thin films were deposited on silicon and glass slides substrates by reactive DC-Magnetron sputtering using a tin target in a mixture of argon and oxygen gases. The substrate temperature was varied in the range from 53 to 243 oC, keeping the other deposition parameters constant. The tin oxide films were characterized by: Scanning Electron Microscopy, Energy Dispersive Spectrometry, X Ray Diffraction, microRaman spectroscopy and UV-VIS spectroscopy. It was found that the substrate temperature has an effect mainly on the structural, morphological and optical properties of the thin films. At 53 and 90 oC the tetragonal crystalline phase was obtained while a mixture of crystalline phases (o-SnO2 and t-SnO2) was obtained at 148, 185 and 243 oC.

Article

Física, Astronomía y Matemáticas DC-magnetron sputtering tin oxide raman spectroscopy CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Biogenic Silver Nanoparticles as Sensors of Cu2+ and Pb2+ in Aqueous Solutions

LUISA ELENA SILVA DE HOYOS Víctor Sánchez Mendieta ALFREDO RAFAEL VILCHIS NESTOR MIGUEL ANGEL CAMACHO LOPEZ (2017)

Biogenic Silver Nanoparticles as Sensors of Cu2+ and Pb2+ in Aqueous Solutions

Silver nanoparticles (Ag-NPs) were bio-synthesized using Camellia sinensis (green tea) aqueous extract. Nanoparticles prepared with 10-3 M AgNO3 solution, using 3mL of green tea extract and at 60˚C, have spherical shape with a mean diameter of 7nm. The formation of the nanoparticles was confirmed by UV-Vis spectrophotometry through studies of the surface plasmon resonance (SPR). The morphology, size and crystalline structure of the Ag-NPs were determined using high definition transmission electron microscopy (TEM). Moreover, these green synthesized Ag-NPs were found to exhibit good sensing properties towards Cu2+ and Pb2+ ions in aqueous solutions. This metal ions-sensing ability of the biogenic Ag-NPs was monitored by UV-Vis spectrophotometry (SPR analyses) and fluorescence spectroscopy.

Article

Biogenic-silver Nanoparticles Camellia Sinensis Nanoparticles Ion-sensing Surface Plasmon BIOLOGÍA Y QUÍMICA

Quantification of phase content in TiO2 thin films by Raman spectroscopy

Victor Hugo Castrejón Sánchez Edgar Enrique Camps Carvajal MIGUEL ANGEL CAMACHO LOPEZ (2014)

Recently, it has been reported that TiO2 with mixture of phases (anatase/rutile) exhibit higher photocatalytic activity than TiO2 with pure anatase phase. Therefore, the production and correct quantification of the ratio of phases becomes an important task. In this work, anatase TiO2 thin films were obtained by the DC reactive magnetron sputtering technique. TiO2 with mixture of phases (anatase/rutile) were prepared by thermal annealing of the as-deposited thin films. The value of the anatase/rutile ratio in the titanium dioxide thin films was estimated using Raman spectroscopy. Additionally, it is reported the dependence of the bandgap of the TiO2 thin films as a function of the anatase/rutile ratio. The band gap of the TiO2 thin films was determined from diffuse reflectance measurements.

Article

Física, Astronomía y Matemáticas Anatase-rutile TiO2 Raman spectroscopy Reactive sputtering CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Laser ablated carbon nanodots for light emission

MIGUEL ANGEL CAMACHO LOPEZ Delfino Reyes Contreras MIGUEL MAYORGA ROJAS Duncan Weathers GREG SALAMO Zhiming Wang Biswarup Neogi (2016)

The synthesis of fluorescent carbon dots-like nanostructures (CNDs) obtained through the laser ablation of a carbon solid target in liquid environment is reported. The ablation process was induced in acetone with laser pulses of 1064, 532, and 355 nm under different irradiation times. Close-spherical amorphous CNDs with sizes between 5 and 20 nm, whose abundance strongly depends on the ablation parameters were investigated using electron microscopy and was confirmed using absorption and emission spectroscopies. The π- π* electronic transition at 3. 76 eV dominates the absorption for all the CNDs species synthesized under different irradiation conditions. The light emission is most efficient due to excitation at 3.54 eV with the photoluminescence intensity centered at 3. 23 eV. The light emission from the CNDs is most efficient due to ablation at 355 nm. The emission wavelength of the CNDs can be tuned from the near-UV to the green wavelength region by controlling the ablation time and modifying the ablation and excitation laser wavelength.

Article

laser ablation carbon nanodots photoluminescence BIOLOGÍA Y QUÍMICA

Síntesis de puntos cuánticos de CdTe mediante la técnica de ablación láser de sólidos en líquidos

Marco Antonio Camacho López MIGUEL ANGEL CAMACHO LOPEZ Delfino Reyes Contreras MIGUEL MAYORGA ROJAS LUIS ENRIQUE DIAZ SANCHEZ Adela Reyes Contreras ALMA MIREYA ARRIETA CASTAÑEDA ALFREDO RAFAEL VILCHIS NESTOR SANTIAGO CAMACHO LOPEZ (2014)

En este trabajo se presentan resultados sobre la caracterización de puntos cuánticos (PCs) en un medio líquido (acetona) obtenidos por ablación láser a partir de un blanco de Teluro de Cadmio (CdTe). La ablación de CdTe se llevó a cabo mediante un láser de Nd-YAG con pulsos láser de 30 picosegundos. Con el propósito de variar la concentración en la solución de PCs, se realizaron experimentos a diferentes tiempos de irradiación. Las soluciones coloidales de CdTe fueron caracterizadas por espectroscopía UV-Vis y de fotoluminiscencia. El tamaño y forma de los puntos cuánticos generados se determinaron por microscopía electrónica de transmisión (TEM, HRTEM), de donde se confirmó la obtención de nanoestructuras con geometría esférica con una distribución de tamaños entre 4 y 200 nm, centrado en 6 nm. El espectro de fotoluminiscencia de los puntos cuánticos en solución mostró una banda de emisión centrada en 488 nm cuando se excita con luz ultravioleta de 369 nm. Palabras c

Article

Física, Astronomía y Matemáticas Puntos cuánticos Teluro de cadmio Fotoluminiscencia In CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA

Study of the Optical Properties of Functionalized Gold Nanoparticles in Different Tissues and Their Correlation with the Temperature Increase

ANDRES CARRILLO CAZARES NALLELY PATRICIA JIMENEZ MANCILLA MYRNA ALEJANDRA LUNA GUTIERREZ KEILA ISAAC OLIVE MIGUEL ANGEL CAMACHO LOPEZ (2017)

Mie theory explains the interaction of light with a gold nanoparticle (AuNP) through the absorption (𝐶abs), scattering (𝐶sca), and extinction (𝐶ext) cross sections. These parameters have been calculated in the case of AuNPs dispersed in homogeneous media, but not for specific tissues. The aim of this research was to theoretically obtain the optical cross sections (𝐶abs, 𝐶sca, and 𝐶ext) of functionalized AuNPs in liver and colon tissues through Mie theory and correlate them with the temperature increase observed experimentally in tissues containing AuNPs under plasmonic photothermal irradiation using a Nd-YAG laser (𝜆 = 532 nm). Calculations showed that 𝐶abs represents 98.96 ± 0.03% of 𝐶ext at 532 nm. The 𝐶ext value for a functionalized AuNP in water was 365.66 nm2 (94% of the theoretical maximum value at 522.5 nm), 404.24 nm2 in colon (98% of the theoretical maximum value at 525 nm), and 442.39nm2 in liver (96% of the theoretical maximum value at 525 nm). Therefore, nanoparticles irradiated at 532nm are very close to their resonance value.These results correlated with the experimental irradiation of functionalized AuNPs in different tissues, where the average temperature increase showed the pattern liver > colon > water. The temperature increase observed (Δ𝑇 up to 13∘C) is sufficient to produce cellular death.

CATEDRAS-CONACYT-ININ-337

CONACYT-SEP-CB-2014-01-242443).

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gold nanoparticles AuNP-RGD thermotherapy absorption coefficients biological tissue MEDICINA Y CIENCIAS DE LA SALUD