Esta investigación fue apoyada por las asociaciones para la Fundación Nacional de Ciencias para la Investigación y Educación en Materiales (PREM) Donación No. DMR-0934218. Que también fue apoyada por número de premios 2G12RR013646-11 del Centro Nacional para Recursos de Investigación. El contenido es responsabilidad exclusiva de sus autores y no representa necesariamente la postura oficial del Centro Nacional para Recursos de Investigación o de los Institutos Nacionales de Salud.

1. Plata preparación de las semillas <ol><li> Prepare una solución madre de nitrato de plata (AgNO 3) mediante la adopción de una masa arbitraria y la mezcla con 10 ml de agua desionizada (DI). Calcular molaridad de la solución. Mantener la solución en un lugar oscuro para aislarlo de la luz. </li><li> Añadir 14,7 mg de citrato de sodio tribásico (Na 3 C 6 H 5 O 7) a 10 mL de agua desionizada para obtener una solución 5 mM. Agitar el vial hasta que el polvo se disuelve. </li><li> Añadir 15,1 mg de borohidruro de sodio (NaBH 4) a otro vial con 10 ml de agua desionizada para obtener una solución 40 mM. Cerrar el frasco inmediatamente. Agite suavemente la solución a mano, y colocarla en un vaso con hielo. Coloque el recipiente en el refrigerador y comenzar un contador de tiempo (t1 = 0). La solución recién hecha se utilizará en 15 minutos que es tiempo suficiente para que se enfríe. </li><li> De la solución madre de nitrato de plata, 1,1), preparar 10 ml a 0,25 mM. Coloque un imán de agitación en el vial y strevolviendo de arte. </li><li> Añadir 0,25 ml de la solución de citrato de sodio tribásico 1,2) a 1,4). </li><li> En el instante t 1 = 15 min se retira la solución de borohidruro de sodio, 1,3), de la nevera. Con una pipeta tomar 0,4 ml de esta solución y agregarla a 1,5). Nota: Añadir la solución de un golpe único y rápido. El color se convertirá en amarillo. Agitar la solución durante 5 minutos. </li><li> En el instante t 1 = 20 min agitando detener, eliminar el imán del vial y mantener el frasco en un lugar oscuro. No cierre el frasco. </li><li> Mantener la solución en la oscuridad a temperatura ambiente durante al menos 2 horas antes de usar. Es preferible utilizar las semillas dentro de una semana de preparación. </li></ol> 2. El crecimiento de preparación de la solución <ol><li> Prepare 80 mM de ácido ascórbico (C 6 H 8 O 6) mediante la adición de 140 mg a 10 mL de agua desionizada. </li><li> Prepare 10 ml de una solución concentrada de cloruro de oro (HAuCl 4). Calcular la molaridad de la solución. Mantenga la solucin aislada de la luz. </li><li> Prepare 20 ml de 50 mM de bromuro (CTAB - C 19 H 42 BRN) mediante la adición de 364 mg a un vial con 20 ml de agua desionizada. Inmediatamente coloque un imán de agitación en el vial y empezar a agitar en un plato caliente a 30 ° C. Después de polvo CTAB se disuelva por completo y la solución se vuelve transparente a su vez el calentador de la placa, pero seguir revolviendo hasta el paso 2.7). </li><li> Añadir la solución 1,1) a la solución de 2.3) para obtener una molaridad final de 4.9x10 mm -2. Iniciar un temporizador (t 2 = 0). </li><li> En t 2 = 1 min agregar la solución de 2,2) a 2,4) para obtener una molaridad final de 0,25 mM. </li><li> En t 2 = 2 min, añadir 0,1 ml de 2,1) a 2,5). La solución se volverá de color. </li><li> En t 2 = 2 min 20 seg añadir 0,05 ml de 1,8) (semillas de plata) a 2,6). Agitar la suspensión durante 15 minutos. La suspensión inicial se vuelve azul y marrón entonces. </li><li> En t 2 = 17 min agitando detener, eliminar el mAgNet y mantener la suspensión a temperatura ambiente durante 24 horas. </li></ol> 3. Separar el oro de nanoestrellas CTAB para la imagen, la caracterización o la experimentación Nota: CTAB puede cristalizar a temperatura ambiente. Para disolver los cristales de calor hasta el coloide de oro a 30 ° C o sumergir el frasco en caliente el agua del grifo hasta que los cristales se disuelven. <ol><li> Sonicar la suspensión durante 2 minutos. </li><li> Centrifugar la suspensión durante 5 minutos a 730 RCF. Nanoestrellas se acumulan en la pared del tubo. </li><li> Eliminar la mayor cantidad de la suspensión con una pipeta con cuidado de no quitar el nanoestrellas. </li><li> Añadir agua desionizada al tubo y sonicar durante 2 min. </li><li> Centrifugar la suspensión durante 3 minutos a 460 RCF. La suspensión contiene menos CTAB, la fuerza centrífuga es menor por lo tanto, es necesario separar el nanoestrellas. </li><li> Repita los pasos 3.3) y 3.4). </li><li> Añadir agua desionizada a la suspensión y centrifugar durante 3 minutos a 380 RCF. </li><li> REPITE<html> t pasos 3.3) y 3.4). El nanoestrellas están listos para imágenes, la espectroscopia o la experimentación. </li></ol> 4. Los resultados representativos: La figura 1 muestra el microscopio electrónico de transmisión (TEM) imágenes de las semillas de plata imágenes utilizando un JEOL 2010-F TEM. Las semillas tienen una forma esférica y un tamaño medio de 15 nm. Nanoestrellas oro son imágenes utilizando un Hitachi S-5500 en el microscopio electrónico de barrido (SEM) de modo. La Figura 2 muestra el aumento de los aumentos nanoestrellas sintetizado con nuestro método. Partículas en forma de estrella son aproximadamente el 70% de todas las partículas en el coloide. No formaron las estrellas aparecen como grupos amorfos de decahedra y romboides (no mostrado). La Figura 3 muestra varias nanoestrellas oro individual. El tamaño de los rangos de nanoestrellas de 200 nm a 300 nm y el número de consejos varían de 7 a 10. Si las nanopartículas de oro sintetizadas por este método se dejan en CTAB que conservan su forma por lo menos un mes después de la síntesis. e_content &quot;&gt; Se midieron los espectros de absorción de las semillas de plata y nanoestrellas utilizando un Cary-14 Olis espectrofotómetro. El pico de absorción de las semillas fue de 400 nm, mientras que el pico de absorción de la nanoestrellas fue de entre 800 nm y 850 nm (Figura 4 ). <img src="/files/ftp_upload/3570/3570fig1.jpg" alt="Figura 1" /> Figura 1. Transmisión de imágenes de microscopio electrónico de las semillas de plata. <img src="/files/ftp_upload/3570/3570fig2.jpg" alt="Figura 2" /> Figura 2. Digitalización de imágenes de microscopio electrónico de nanoestrellas oro. <img src="/files/ftp_upload/3570/3570fig3.jpg" alt="Figura 3" /> Figura 3. Digitalización de imágenes de microscopio electrónico de nanoestrellas oro individual. <img src="/files/ftp_upload/3570/3570fig4.jpg" alt="Figura 6" /> Figura 4. Espectros de absorción normalizado de las semillas de plata (línea discontinua) y el oronanoestrellas (línea continua).

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No hay conflictos de interés declarado.

En este trabajo hemos presentado un método para sintetizar nanoestrellas oro con semillas de plata. Se encontró que las semillas de plata resultó en un rendimiento del 70% de la producción de nanoestrellas. El nanoestrellas tienen un pico cerca de absorción de infrarrojos, lo que corresponde a su modo de resonancia de plasmones superficiales, centrada entre 800 nm y 850 nm 7, 23. Estas propiedades permiten a nuestros nanoestrellas propiedades de oro para ser de utilidad para aplicaciones biomédicas <sup...

<table border="1"><tbody><tr><td> Nombre del reactivo </td><td> Empresa </td><td> Número de catálogo </td><td> Pureza </td></tr><tr><td> Citrato de sodio tribásico deshidratar </td><td> Sigma </td><td> S4641 </td><td> 99,0% </td></tr><tr><td> Nitrato de plata </td><td> Aldrich </td><td> 204390 </td><td> 99,9999% </td></tr><tr><td> Borohidruro de sodio </td><td> Aldrich </td><td> 213462 </td><td> 99% </td></tr><tr><td> Ácido L-ascórbico </td><td> Sigma-Aldrich </td><td> 255564 </td><td> 99 +% </td></tr><tr><td> Trihidrato de cloruro de oro </td><td> Aldrich </td><td> 520918 </td><td> 99,9% + </td></tr><tr><td> Hexadeciltrimetilamonio (CTAB) </td><td> Sigma </td><td> H6269 </td><td></td></tr></tbody></table><table border="1"><tbody><tr><td> Nombre del equipo </td><td> Empresa </stRong&gt; </td><td> Comentarios </td></tr><tr><td> JEOL 2010-F </td><td> JEOL </td><td> Microscopio electrónico de transmisión </td></tr><tr><td> Hitachi S-5500 </td><td> Hitachi </td><td> Se utiliza en modo de escaneo microscopio electrónico </td></tr><tr><td> Olis Cary-14 espectrofotómetro </td><td> Olis </td><td> Espectrofotómetro </td></tr></tbody></table>

gold nanostar synthesis with a silver seed mediated growth method

Las propiedades físicas, químicas y ópticas de nano-escala de los coloides dependen de su composición material, tamaño y forma 5.1. Hay un gran interés en el uso de nano-coloides para la foto-ablación térmica, la administración de fármacos y muchas otras aplicaciones biomédicas 6. El oro se utiliza en particular debido a su baja toxicidad 7-9. Una propiedad de metal nano-coloides es que pueden tener una superficie fuerte resonancia de plasmones de 10. El pico del modo de resonancia de plasmones superficiales depende de la estructura y composición del metal de nano-partículas coloidales. Dado que el modo de resonancia de plasmones de superficie se estimula con la luz es necesario para que el pico de absorción en el infrarrojo cercano, donde la transmisividad tejido biológico es máxima 11, 12. Se presenta un método para sintetizar en forma de estrella de oro coloidal, también conocido como nanopartículas en forma de estrella o 13-15 nanoestrellas 16. Este método se basa en quelución que contiene las semillas de plata que se utiliza como agente de nucleación para el crecimiento anisotrópico de los coloides de oro 17-22. Microscopía electrónica de barrido (SEM), análisis del oro coloidal resultante mostró que el 70% de las nanoestructuras se nanoestrellas. El otro 30% de las partículas eran grupos amorfos de decahedra y romboides. El pico de absorción de la nanoestrellas se detectó que en el infrarrojo cercano (840 nm). Por lo tanto, nuestro método produce nanoestrellas oro adecuado para aplicaciones biomédicas, en particular para la foto-ablación térmica.

Watch this Scientific Journal Video about Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method at JoVE.com

Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method

Hemos sintetizado nanoestrellas en forma de estrella de oro con una mediada de plata de semillas método de crecimiento. El diámetro de la nanoestrellas oscila entre 200 y 300 nm y el número de consejos varían de 7 a 10. Las nanopartículas tienen una superficie amplia de plasmones modo de resonancia centrada en el infrarrojo cercano.

Síntesis de oro Nanostar con un método de la Simiente de Plata crecimiento mediada por

The physical, chemical and optical properties of nano-scale colloids depend on their material composition, size and shape 1-5. There is a great interest ...

gold-nanostar-synthesis-with-a-silver-seed-mediated-growth-method

Research

JoVE Journal

Bioengineering

24.9K vistas.  The University of Texas at San Antonio. Hemos sintetizado nanoestrellas en forma de estrella de oro con una mediada de plata de semillas método de crecimiento. El diámetro de la nanoestrellas oscila entre 200 y 300 nm y el número de consejos varían de 7 a 10. Las nanopartículas tienen una superficie amplia de plasmones modo de resonancia centrada en el infrarrojo cercano.

Video: Gold Nanostar Synthesis with a Silver Seed Mediated Growth Method

Axon Stretch Growth: The Mechanotransduction of Neuronal Growth

During pre-synaptic embryonic development, neuronal processes traverse short distances to reach their targets via growth cone. Over time, neuronal somata are separated from their axon terminals due to skeletal growth of the enlarging organism (Weiss 1941; Gray, Hukkanen et al. 1992). This mechanotransduction induces a secondary mode of neuronal growth capable of accommodating continual elongation of the axon (Bray 1984; Heidemann and Buxbaum 1994; Heidemann, Lamoureux et al. 1995; Pfister, Iwata et al. 2004).
Axon Stretch Growth (ASG) is conceivably a central factor in the maturation of short embryonic processes into the long nerves and white matter tracts characteristic of the adult nervous system. To study ASG in vitro, we engineered bioreactors to apply tension to the short axonal processes of neuronal cultures (Loverde, Ozoka et al. 2011). Here, we detail the methods we use to prepare bioreactors and conduct ASG. First, within each stretching lane of the bioreactor, neurons are plated upon a micro-manipulated towing substrate. Next, neurons regenerate their axonal processes, via growth cone extension, onto a stationary substrate. Finally, stretch growth is performed by towing the plated cell bodies away from the axon terminals adhered to the stationary substrate; recapitulating skeletal growth after growth cone extension.
Previous work has shown that ASG of embryonic rat dorsal root ganglia neurons are capable of unprecedented growth rates up to 10mm/day, reaching lengths of up to 10cm; while concurrently resulting in increased axonal diameters (Smith, Wolf et al. 2001; Pfister, Iwata et al. 2004; Pfister, Bonislawski et al. 2006; Pfister, Iwata et al. 2006; Smith 2009). This is in dramatic contrast to regenerative growth cone extension (in absence of mechanical stimuli) where growth rates average 1mm/day with successful regeneration limited to lengths of less than 3cm (Fu and Gordon 1997; Pfister, Gordon et al. 2011). Accordingly, further study of ASG may help to reveal dysregulated growth mechanisms that limit regeneration in the absence of mechanical stimuli.

A unique tissue engineering method was developed to elongate numerous nerve fibers in culture by recapitulating axon stretch growth; a form of nervous system growth whereby nerves elongate in conjunction with growth of the enlarging body.

El crecimiento del axón Tramo: El Mecanotransducción de crecimiento neuronal

During pre-synaptic embryonic development, neuronal processes traverse short distances to reach their targets via growth cone. Over time, neuronal somata ...

Investigación

Bioingeniería

Synthesis, Assembly, and Characterization of Monolayer Protected Gold Nanoparticle Films for Protein Monolayer Electrochemistry

Colloidal gold nanoparticles protected with alkanethiolate ligands called monolayer protected gold clusters (MPCs) are synthesized and subsequently incorporated into film assemblies that serve as adsorption platforms for protein monolayer electrochemistry (PME). PME is utilized as the model system for studying electrochemical properties of redox proteins by confining them to an adsorption platform at a modified electrode, which also serves as a redox partner for electron transfer (ET) reactions. Studies have shown that gold nanoparticle film assemblies of this nature provide for a more homogeneous protein adsorption environment and promote ET without distance dependence compared to the more traditional systems modified with alkanethiol self-assembled monolayers (SAM).1-3 In this paper, MPCs functionalized with hexanethiolate ligands are synthesized using a modified Brust reaction4 and characterized with ultraviolet visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and proton (1H) nuclear magnetic resonance (NMR). MPC films are assembled on SAM modified gold electrode interfaces by using a "dip cycle" method of alternating MPC layers and dithiol linking molecules. Film growth at gold electrode is tracked electrochemically by measuring changes to the double layer charging current of the system. Analogous films assembled on silane modified glass slides allow for optical monitoring of film growth and cross-sectional TEM analysis provides an estimated film thickness. During film assembly, manipulation of the MPC ligand protection as well as the interparticle linkage mechanism allow for networked films, that are readily adaptable, to interface with redox protein having different adsorption mechanism. For example, Pseudomonas aeruginosa azurin (AZ) can be adsorbed hydrophobically to dithiol-linked films of hexanethiolate MPCs and cytochrome c (cyt c) can be immobilized electrostatically at a carboxylic acid modified MPC interfacial layer. In this report, we focus on the film protocol for the AZ system exclusively. Investigations involving the adsorption of proteins on MPC modified synthetic platforms could further the understanding of interactions between biomolecules and man-made materials, and consequently aid the development of biosensor schemes, ET modeling systems, and synthetic biocompatible materials.5-8

Alkanethiolate stabilized gold colloids known as monolayer protected clusters (MPCs) are synthesized, characterized, and assembled into thin films as an adsorption interface for protein monolayer electrochemistry of simple redox protein like Pseudomonas aeruginosa azurin (AZ) and cytochrome c (cyt c).

Síntesis, de la Asamblea, y caracterización de una sola capa de nanopartículas de oro protegidas Films de Electroquímica de proteínas monocapa

Colloidal gold nanoparticles protected with alkanethiolate ligands called monolayer protected gold clusters (MPCs) are synthesized and subsequently ...

Observing and Quantifying Fibroblast-mediated Fibrin Gel Compaction

Cells embedded in collagen and fibrin gels attach and exert traction forces on the fibers of the gel. These forces can lead to local and global reorganization and realignment of the gel microstructure. This process proceeds in a complex manner that is dependent in part on the interplay between the location of the cells, the geometry of the gel, and the mechanical constraints on the gel. To better understand how these variables produce global fiber alignment patterns, we use time-lapse differential interference contrast (DIC) microscopy coupled with an environmentally controlled bioreactor to observe the compaction process between geometrically spaced explants (clusters of fibroblasts). The images are then analyzed with a custom image processing algorithm to obtain maps of the strain. The information obtained from this technique can be used to probe the mechanobiology of various cell-matrix interactions, which has important implications for understanding processes in wound healing, disease development, and tissue engineering applications.

Time-lapse microscopy and image processing techniques were used to observe and analyze fibroblast-mediated gel compaction and fibrin fiber realignment in an environmentally controlled bioreactor over a 48 hr&#160;period.

Observación Y Cuantificación De Fibroblastos Mediada Por Fibrina Gel Compactamiento

Cells embedded in collagen and fibrin gels attach and exert traction forces on the fibers of the gel. These forces can lead to local and global ...

Synthesis of an Intein-mediated Artificial Protein Hydrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of this hydrogel are two protein block-copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. A highly hydrophilic random coil is inserted into one of the block-copolymers for water retention. Mixing of the two protein block copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit with crosslinkers at either end that rapidly self-assembles into a hydrogel. This hydrogel is very stable under both acidic and basic conditions, at temperatures up to 50 &#176;C, and in organic solvents. The hydrogel rapidly reforms after shear-induced rupture. Incorporation of a &#34;docking station peptide&#34; into the hydrogel building block enables convenient incorporation of &#34;docking protein&#34;-tagged target proteins. The hydrogel is compatible with tissue culture growth media, supports the diffusion of 20 kDa molecules, and enables the immobilization of bioactive globular proteins. The application of the intein-mediated protein hydrogel as an organic-solvent-compatible biocatalyst was demonstrated by encapsulating the horseradish peroxidase enzyme and corroborating its activity.

We present the synthesis of a split-intein-mediated protein hydrogel. The building blocks of this hydrogel are two protein copolymers each containing a subunit of a trimeric protein that serves as a crosslinker and one half of a split intein. Mixing of the two protein copolymers triggers an intein trans-splicing reaction, yielding a polypeptide unit that self-assembles into a hydrogel. This hydrogel is highly pH- and temperature-stable, compatible with organic solvents, and easily incorporates functional globular proteins.

Síntesis de una proteína artificial mediada Intein hidrogel

We present the synthesis of a highly stable protein hydrogel mediated by a split-intein-catalyzed protein trans-splicing reaction. The building blocks of ...

Formation of Biomembrane Microarrays with a Squeegee-based Assembly Method

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are heterogeneous mixtures of many types of lipids, contain membrane-bound proteins and are decorated with carbohydrates. In some experiments, it is desirable to decouple the biophysical or biochemical properties of the lipid bilayer from those of the natural membrane. Such cases call for the use of model systems such as giant vesicles, liposomes or supported lipid bilayers (SLBs). Arrays of SLBs are particularly attractive for sensing applications and mimicking cell-cell interactions. Here we describe a new method for forming SLB arrays. Submicron-diameter SiO2 beads are first coated with lipid bilayers to form spherical SLBs (SSLBs). The beads are then deposited into an array of micro-fabricated submicron-diameter microwells. The preparation technique uses a "squeegee" to clean the substrate surface, while leaving behind SSLBs that have settled into microwells. This method requires no chemical modification of the microwell substrate, nor any particular targeting ligands on the SSLB. Microwells are occupied by single beads because the well diameter is tuned to be just larger than the bead diameter. Typically, more 75% of the wells are occupied, while the rest remain empty. In buffer SSLB arrays display long-term stability of greater than one week. Multiple types of SSLBs can be placed in a single array by serial deposition, and the arrays can be used for sensing, which we demonstrate by characterizing the interaction of cholera toxin with ganglioside GM1. We also show that phospholipid vesicles without the bead supports and biomembranes from cellular sources can be arrayed with the same method and cell-specific membrane lipids can be identified.

Supported lipid bilayers and natural membrane particles are convenient systems that can approximate the properties of cell membranes and be incorporated in a variety of analytical strategies. Here we demonstrate a method for preparing microarrays composed of supported lipid bilayer-coated SiO2 beads, phospholipid vesicles or natural membrane particles.

Formación de biomembrana Microarrays con un método basado en la Asamblea Rasero

Lipid bilayer membranes form the plasma membranes of cells and define the boundaries of subcellular organelles. In nature, these membranes are ...

Synthesis of Keratin-based Nanofiber for Biomedical Engineering

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of these porous nanofibers is of great interest due to their unique physiochemical properties. Here we elaborate on the fabrication of keratin containing poly (&#949;-caprolactone) (PCL) nanofibers (i.e., PCL/keratin composite fiber). Water soluble keratin was first extracted from human hair and mixed with PCL in different ratios. The blended solution of PCL/keratin was transformed into nanofibrous membranes using a laboratory designed electrospinning set up. Fiber morphology and mechanical properties of the obtained nanofiber were observed and measured using scanning electron microscopy and tensile tester. Furthermore, degradability and chemical properties of the nanofiber were studied by FTIR. SEM images showed uniform surface morphology for PCL/keratin fibers of different compositions. These PCL/keratin fibers also showed excellent mechanical properties such as Young&#39;s modulus and failure point. Fibroblast cells were able to attach and proliferate thus proving good cell viability. Based on the characteristics discussed above, we can strongly argue that the blended nanofibers of natural and synthetic polymers can represent an excellent development of composite materials that can be used for different biomedical applications.

Electrospun nanofibers have a high surface area to weight ratio, excellent mechanical integrity, and support cell growth and proliferation. These nanofibers have a wide range of biomedical applications. Here we fabricate keratin/ PCL nanofibers, using the electrospinning technique, and characterize the fibers for possible applications in tissue engineering.

Síntesis de nanofibras a base de Queratina de Ingeniería Biomédica

Electrospinning, due to its versatility and potential for applications in various fields, is being frequently used to fabricate nanofibers. Production of ...

Synthesis of Gold Nanoparticle Integrated Photo-responsive Liposomes and Measurement of Their Microbubble Cavitation upon Pulse Laser Excitation

Photo-responsive nanoparticles (NPs) have received considerable attention because of their potential in providing spatial, temporal, and dosage control over the drug release. However, most of the relevant technologies are still in the development process and are unprocurable by clinics. Here, we describe a facile fabrication of these photo-responsive NPs with commercially available gold NPs and thermo-responsive liposomes. Calcein is used as a model drug to evaluate the encapsulation efficiency and the release kinetic profile upon heat/light stimulation. Finally, we show that this photo-triggered release is due to the membrane disruption caused by microbubble cavitation, which can be measured with hydrophone.

This protocol describes a simple preparation method for gold nanoparticle integrated photo-responsive liposomes with the commercially available materials. It also shows how to measure the microbubble cavitation process of the synthesized liposomes upon the treatment of pulsed laser.

Síntesis de nanopartículas de oro liposomas Integrado fotosensible y la medición de su microburbujas cavitación al pulso láser de excitación

Photo-responsive nanoparticles (NPs) have received considerable attention because of their potential in providing spatial, temporal, and dosage control ...

Synthesis of Hydrogels with Antifouling Properties As Membranes for Water Purification

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and thus achieving stable water permeability through membranes over time. Here, we report a facile method to prepare hydrogels based on zwitterions for membrane applications. Freestanding films can be prepared from sulfobetaine methacrylate (SBMA) with a crosslinker of poly(ethylene glycol) diacrylate (PEGDA) via photopolymerization. The hydrogels can also be prepared by impregnation into hydrophobic porous supports to enhance the mechanical strength. These films can be characterized by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) to determine the degree of conversion of the (meth)acrylate groups, using goniometers for hydrophilicity and differential scanning calorimetry (DSC) for polymer chain dynamics. We also report protocols to determine the water permeability in dead-end filtration systems and the effect of foulants (bovine serum albumin, BSA) on membrane performance.

This paper reports practical methods to prepare hydrogels in freestanding films and impregnated membranes and to characterize their physical properties, including water transport properties.

Síntesis de hidrogeles con propiedades antiincrustantes como membranas de purificación de agua

Hydrogels have been widely utilized to enhance the surface hydrophilicity of membranes for water purification, increasing the antifouling properties and ...

Synthesis of Functionalized 10-nm Polymer-coated Gold Particles for Endothelium Targeting and Drug Delivery

Gold nanoparticles (AuNPs) have been used extensively in medical research due to their size, biocompatibility, and modifiable surface. Specific targeting and drug delivery are some of the applications of these AuNPs, but endothelial extracellular matrices&#39; defensive properties hamper particle uptake. To address this issue, we describe a synthesis method for ultrasmall gold nanoparticles to improve vascular delivery, with customizable functional groups and polymer lengths for further adjustments. The protocol yields 2.5 nm AuNPs that are capped with tetrakis(hydroxymethyl)phosphonium chloride (THPC). The replacement of THPC with hetero-functional polyethylene glycol (PEG) on the surface of the AuNP increases the hydrodynamic radius to 10.5 nm while providing various functional groups on the surface. The last part of the protocol includes an optional addition of a fluorophore to allow the AuNPs to be visualized under fluorescence to track nanoparticle uptake. Dialysis and lyophilization were used to purify and isolate the AuNPs. These fluorescent nanoparticles can be visualized in both in vitro and in vivo experiments due to the biocompatible PEG coating and fluorescent probes. Additionally, the size range of these nanoparticles render them an ideal candidate for probing the glycocalyx without disrupting normal vasculature function, which may lead to improved delivery and therapeutics.

We describe a method of synthesizing biocompatible 10-nm gold nanoparticles, functionalized by coating poly-ethylene glycol onto the surface. These particles can be used in vitro and in vivo for delivering therapeutics to nanoscale cellular and extracellular spaces that are difficult to access with conventional nanoparticle sizes.

Síntesis de funcionalizados 10 nm recubierto de polímero partículas de oro para apuntar el endotelio y el suministro de medicamentos

Gold nanoparticles (AuNPs) have been used extensively in medical research due to their size, biocompatibility, and modifiable surface. Specific targeting ...

Synthesis of Multi-walled Carbon Nanotubes Modified with Silver Nanoparticles and Evaluation of Their Antibacterial Activities and Cytotoxic Properties

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver MWCNTs were prepared by the reductive deposition of silver from an aqueous solution of AgNO3 on the oxidized MWCNTs. Given the unique color of the CNTs, it was not possible to apply them to the minimum inhibitory concentration or mitochondrial toxicity assays to evaluate the toxicity and antibacterial properties, since they would interfere with the assays. The inhibition zone and minimum bactericidal concentration for the Ag-MWCNTs were measured and Live/Dead and Trypan Blue assays were used to measure the toxicity and antibacterial properties without interfering with the color of the CNTs.

In this study, antimicrobial nanomaterials were synthesized by acidic oxidation of multiwalled carbon nanotubes and subsequent reductive deposition of silver nanoparticles. Antimicrobial activity and cytotoxicity tests were performed with the as-prepared nanomaterials.

Síntesis de nanotubos de carbono multipared modificados con nanopartículas de plata y la evaluación de sus actividades antibacterianas y propiedades citotóxicas

In this study, multi-walled carbon nanotubes (MWCNTs) were treated with an aqueous sulfuric acid solution to form an oxygen-based functional group. Silver ...