Esta pesquisa foi apoiada pela National Science Foundation Parcerias para Pesquisa e Educação em Materiais (PREM) Grant No. DMR-0934218. Ele também foi apoiado por Número Award 2G12RR013646-11 do Centro Nacional de Pesquisa de Recursos. O conteúdo é da exclusiva responsabilidade dos autores e não representam necessariamente a posição oficial do Centro Nacional de Pesquisa de Recursos ou do National Institutes of Health.

1. Prata preparação de sementes <ol><li> Prepare uma solução estoque de nitrato de prata (AgNO 3), tendo uma massa arbitrária e misturando-o com 10 mL de água deionizada (DI). Calcular molaridade da solução. Manter a solução em um lugar escuro para isolá-lo da luz. </li><li> Adicionar 14,7 mg de citrato de sódio tribásico (Na 3 C 6 H 5 O 7) a 10 mL de água DI para fazer uma solução 5 mM. Agitar o frasco até o pó estar dissolvido. </li><li> Adicionar 15,1 mg de borohidreto de sódio (NaBH 4) para outro frasco com 10 mL de água DI para fazer uma solução 40 mM. Feche o frasco imediatamente. Agite suavemente a solução com a mão e colocá-lo num copo com gelo. Colocar o copo na geladeira e iniciar um temporizador (t1 = 0). A solução recém-feita será utilizado em 15 min que é tempo suficiente para esfriá-la. </li><li> A partir da solução estoque de nitrato de prata, 1.1), preparar 10 mL de 0,25 mM. Coloque um ímã mexendo no frasco e stmexendo art. </li><li> Adicionar 0,25 mL da solução de citrato de sódio tribásico 1.2) a 1.4). </li><li> Em t 1 = 15 min remover a solução de borohidreto de sódio, 1,3), do frigorífico. Usando uma pipeta, recolher 0,4 mL desta solução e adicioná-la a 1,5). Nota: Adicione a solução em um único golpe rápido. A cor vai virar para amarelo. Agitar a solução por 5 min. </li><li> Em t 1 = 20 min mexendo parar, retire o ímã do frasco e manter o frasco em um lugar escuro. Não feche o frasco. </li><li> Manter a solução no escuro à temperatura ambiente por pelo menos 2 horas antes de usar. De preferência, utilizar as sementes dentro de uma semana de preparação. </li></ol> 2. Preparação da solução de crescimento <ol><li> Prepare 80 mM de ácido ascórbico (C 6 H 8 O 6) pela adição de 140 mg a 10 mL de água DI. </li><li> Prepare 10 mL de uma solução concentrada de cloreto de ouro (HAuCl 4). Calcule a molaridade da solução. Manter a solution isolado da luz. </li><li> Prepare 20 ml de 50 mM de brometo de cetiltrimetilamônio (CTAB - C 19 H 42 BRN) pela adição de 364 mg a um frasco com 20 mL de água DI. Coloque imediatamente um ímã mexendo no frasco e começar a mexer em um prato quente a 30 ° C. Depois de pó CTAB esteja completamente dissolvido ea solução torna-se transparente por sua vez desligar o aquecedor da placa, mas continue a mexer até a etapa 2.7). </li><li> Adicionar solução de 1.1) para a solução 2.3) para obter uma molaridade final de 4.9x10 mM -2. Iniciar um temporizador (t 2 = 0). </li><li> Em t 2 = 1 min adicione a solução de 2.2) para 2.4) para obter uma molaridade final de 0,25 mM. </li><li> Em t 2 = 2 min adicione 0,1 mL de 2,1) para 2,5). A solução ficará incolor. </li><li> Em t 2 = 2 min 20 seg adicionar 0,05 mL de 1,8) (sementes de prata) para 2,6). Agitar a suspensão durante 15 min. A suspensão, inicialmente, ficar azul e depois marrom. </li><li> Em t 2 = 17 min mexendo parar, retire o magnet e manter a suspensão à temperatura ambiente por 24 horas. </li></ol> 3. Separar nanostars ouro de CTAB de imagem, a caracterização ou experimentação Nota: CTAB pode cristalizar em temperatura ambiente. Para dissolver o calor cristais o ouro coloidal a 30 ° C ou mergulhe o frasco em água quente água da torneira até que os cristais se dissolvem. <ol><li> Sonicate a suspensão por 2 min. </li><li> Centrifugar a suspensão por 5 min a 730 rcf. Nanostars irá acumular na parede do tubo. </li><li> Remover o máximo da suspensão com uma pipeta tomando cuidado para não remover o nanostars. </li><li> Adicione a água DI para o tubo e sonicate por 2 min. </li><li> Centrifugar a suspensão por 3 min a 460 rcf. A suspensão contém menos CTAB, portanto, menor a força centrífuga é necessário para separar o nanostars. </li><li> Repita os passos 3.3) e 3.4). </li><li> Adicione a água DI para a suspensão e centrifugar por 3 min a 380 rcf. </li><li> REPEA<html> t passos 3.3) e 3.4). O nanostars estão prontos para imagens, espectroscopia, ou experimentação. </li></ol> 4. Resultados representativos: A Figura 1 mostra eletrônica de transmissão microscópio (TEM) imagens das sementes de prata fotografada usando um JEOL 2010-F TEM. As sementes têm uma forma esférica e um tamanho médio de 15 nm. Nanostars ouro são gravadas usando um Hitachi S-5500 em microscópio eletrônico de varredura (SEM) mode. A Figura 2 mostra ampliações cada vez maior da nanostars sintetizado com o nosso método. Partículas em forma de estrela são aproximadamente 70% de todas as partículas do colóide. Não formou estrelas aparecem como cachos amorfa de decahedra e rombóides (não mostrado). A Figura 3 mostra várias nanostars único ouro. O tamanho dos intervalos nanostars de 200 nm e 300 nm eo número de dicas variam de 7 a 10. Se o ouro nanopartículas sintetizadas por este método são deixados em CTAB eles mantêm a sua forma, pelo menos, um mês após a síntese. e_content &quot;&gt; Nós medimos o espectro de absorção das sementes de prata e nanostars usando um Cary-14 Olis espectrofotômetro. O pico de absorção das sementes foi de 400 nm, enquanto que o pico de absorção do nanostars foi entre 800 nm e 850 nm (Figura 4 ). <img src="/files/ftp_upload/3570/3570fig1.jpg" alt="Figura 1" /> Figura 1. Eletrônica de transmissão de imagens de microscópio de sementes de prata. <img src="/files/ftp_upload/3570/3570fig2.jpg" alt="Figura 2" /> Figura 2. Scanning imagens de microscopia eletrônica de nanostars ouro. <img src="/files/ftp_upload/3570/3570fig3.jpg" alt="Figura 3" /> Figura 3. Scanning imagens de microscopia eletrônica de nanostars único ouro. <img src="/files/ftp_upload/3570/3570fig4.jpg" alt="Figura 6" /> Figura 4. Espectros de absorção normalizada de sementes de prata (linha pontilhada) e ouronanostars (linha contínua).

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Não há conflitos de interesse declarados.

Neste trabalho apresentamos um método para sintetizar nanostars ouro utilizando sementes de prata. Descobrimos que as sementes de prata resultou em um rendimento de 70% da produção nanostars. O nanostars ter um pico de absorção do infravermelho próximo, o que corresponde à sua superfície modo de ressonância plasmon, centrado entre 800 nm e 850 nm 7, 23. Estas propriedades propriedades permitem nanostars nosso ouro para ser de uso para aplicações biomédicas 24-26, tais como foto-térmica...

<table border="1"><tbody><tr><td> Nome do reagente </td><td> Companhia </td><td> Número de catálogo </td><td> Pureza </td></tr><tr><td> Citrato de sódio desidratar tribásico </td><td> Sigma </td><td> S4641 </td><td> 99,0% </td></tr><tr><td> Nitrato de prata </td><td> Aldrich </td><td> 204390 </td><td> 99,9999% </td></tr><tr><td> Borohidreto de sódio </td><td> Aldrich </td><td> 213462 </td><td> 99% </td></tr><tr><td> L-ácido ascórbico </td><td> Sigma-Aldrich </td><td> 255564 </td><td> 99% + </td></tr><tr><td> Trihidrato de cloreto de ouro </td><td> Aldrich </td><td> 520918 </td><td> 99,9% + </td></tr><tr><td> Brometo de hexadeciltrimetilamônio (CTAB) </td><td> Sigma </td><td> H6269 </td><td></td></tr></tbody></table><table border="1"><tbody><tr><td> Nome de equipamentos </td><td> Companhia </strong&gt; </td><td> Comentários </td></tr><tr><td> JEOL 2010-F </td><td> JEOL </td><td> Microscopia eletrônica de transmissão </td></tr><tr><td> Hitachi S-5500 </td><td> Hitachi </td><td> Usado em modo de digitalização microscópio eletrônico </td></tr><tr><td> Olis Cary-14 espectrofotômetro </td><td> Olis </td><td> Espectrofotômetro </td></tr></tbody></table>

gold nanostar synthesis with a silver seed mediated growth method

As propriedades físicas, químicas e óticas de nano-escala colóides dependem de seu tamanho, material, composição e forma 1-5. Há um grande interesse no uso de nano-colóides para a foto-ablação térmica, distribuição de medicamentos e muitas outras aplicações biomédicas 6. O ouro é usado particularmente por causa de sua baixa toxicidade 7-9. Uma propriedade de metal nano-colóides é que eles podem ter uma superfície de forte ressonância de plasma de 10. O pico da superfície modo de ressonância de plasma depende da estrutura e composição do metal nano-colóides. Desde que o plasma de superfície modo de ressonância é estimulado com a luz que há uma necessidade de ter a absorção de pico no infravermelho próximo, onde transmissividade tecido biológico é máxima 11, 12. Nós apresentamos um método para sintetizar ouro coloidal em forma de estrela, também conhecido como nanopartículas em forma de estrela ou 13-15 nanostars 16. Este método baseia-se comoOLUÇÃO contendo sementes de prata que são usadas como agente de nucleação para o crescimento anisotrópico de colóides de ouro 17-22. Microscopia eletrônica de varredura de análise (SEM) da resultante de ouro coloidal mostrou que 70% das nanoestruturas foram nanostars. Os outros 30% das partículas foram aglomerados amorfa de decahedra e rombóides. O pico de absorção da nanostars foi detectada a ser no infravermelho próximo (840 nm). Assim, o nosso método produz nanostars ouro adequado para aplicações biomédicas, especialmente para a foto-ablação 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

Sintetizamos nanostars em forma de estrela de ouro usando um método de crescimento de sementes de prata mediada. O diâmetro do nanostars varia de 200 a 300 nm eo número de dicas variam de 7 a 10. As nanopartículas têm uma ampla ressonância de plasmons de superfície de modo centrado no infravermelho próximo.

Síntese Nanostar ouro com um método de crescimento de sementes de Prata Mediated

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 visualizações.  The University of Texas at San Antonio. Sintetizamos nanostars em forma de estrela de ouro usando um método de crescimento de sementes de prata mediada. O diâmetro do nanostars varia de 200 a 300 nm eo número de dicas variam de 7 a 10. As nanopartículas têm uma ampla ressonância de plasmons de superfície de modo centrado no infravermelho próximo.

Vídeo: 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.

Axon Crescimento Stretch: O Mecanotransdução do Crescimento Neuronal

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

Bioengenharia

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).

Síntese, Assembléia e Caracterização de monocamada Protected Films nanopartículas de ouro para Eletroquímica monocamada Protein

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.

Observando e quantificando compactação de gel de fibrina mediada por fibroblasto

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.

Síntese de uma proteína artificial intein mediada 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.

Formação de biomembrana Microarrays com um método de montagem baseada em Rodo

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.

Síntese de nanofibras baseado em queratina de Engenharia 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.

Síntese de nanopartículas de ouro lipossomas Integrated Photo-reactivos e medição das suas microbolhas cavitação em cima do pulso laser de excitação

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.

Síntese de hidrogeles com propriedades anti-deposição como membranas de purificação de água

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.

Síntese de funcionalizados 10 nm polímero-revestida com partículas de ouro para o direcionamento do endotélio e entrega da droga

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.

Síntese de nanotubos de carbono de paredes Multi modificados com nanopartículas de prata e avaliação das suas actividades antibacterianas e propriedades 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 ...