DCH, MB e FK foram apoiados por uma Siga EPSRC no Fundo. BL-V e DS foram todos suportados pela MRC studentships doutoramento. KC foi apoiado pelo financiamento da Plataforma Medicina Regenerativa Reino Unido.

1. Síntese de PHNGAD (Poli [1,6-hexanodiol / neopentilglicol / di (etileno-glicol) de ácido adípico--alt] diol) <img alt="Esquema 1" fo:content-width="5in" src="/files/ftp_upload/51723/51723scheme1.jpg" width="500" /> Esquema 1: Síntese de PHNAGD Representação esquemática da síntese de PHNAGD.. PHNAGD foi preparado pela reacção de 1,6-Hexanodiol, dietilenoglicol, neoppentyl glicol e ácido adípico. PHNAGD, Poli [1,6-hexanodiol / neopentilglicol / di (etileno-glicol) de ácido adípico--alt] diol. <ol><li> Aplicar um tratamento de calor para os monómeros de 1,6-hexanodiol, di (etileno-glicol) e neopentil glicol a 40 ° C durante 48 horas num forno de vácuo para remover qualquer água residual. Deixa-se a frio até a temperatura ambiente sob vácuo. </li><li> Adicionar 22 mmoles de cada monómero e ácido adípico (55 mmol) a um balão de fundo redondo de duas tubuladuras equipado com uma barra de agitação e ligado a um aparelho de Dean-Stark. </li><li> Coloque todo o conjunto sob vácuo e aquecer lentamente a ABLssware a 40 ° C durante 6 horas, a fim de evitar qualquer possibilidade de absorção de humidade, durante a adição do produto químico para o balão. </li><li> Adicionar através de uma seringa, gota a gota, 0,0055 mole do catalisador de titânio (IV), butóxido de potássio. </li><li> Agita-se a mistura de reacção a 180 ° C, sob uma atmosfera de N 2 durante 24 h, e recolher a água residual na armadilha de Dean-Stark. Permitir que o produto a arrefecer até à temperatura ambiente. </li></ol> 2 Síntese de PU134 <img alt="Esquema 2" fo:content-width="5in" src="/files/ftp_upload/51723/51723scheme2.jpg" width="500" /> Esquema 2: Síntese de PU134 Representação esquemática da síntese de poliuretano PU134 134 foi preparado através da reacção de 1,0 equivalentes de um PHNGAD com 2,0 equiv de um 4,4 &#39;-metilenobis (fenil-isocianato), seguido pela adição de 1,0. equiv de um extensor de cadeia de 1,4-butanodiol. <ol><li> Misturar um equivalente do poliol PHNGAD (Mn ~ 1800 Da, 3,2 mmol) com dois equivalentes de 4&#39;4-metilenobis (fenil isocianato) (6,4 mmol) em N, N-dimetilformamida (12 ml). </li><li> Agita-se a mistura de reacção a 70 ° C, sob uma atmosfera de N 2. </li><li> Adicionar através de uma seringa, gota a gota, o catalisador de titânio (IV), butóxido de potássio (0,8% em peso). </li><li> Após 1 hora, adicionar um equivalente do extensor de cadeia de 1,4-butanodiol (3,2 mmol). Aumentar a temperatura a 90 ° C e agita-se durante 24 horas sob uma atmosfera de N 2. </li><li> Após a reacção, recolher o poliuretano por precipitação por adição de éter dietílico (hexano ou água pode também ser usado), gota a gota para a solução reaccional até a precipitação ocorre. </li><li> Centrifuga-se a solução a 5300 xg durante 5 min. </li><li> Decantar o sobrenadante e secar a 40 ° C num forno de vácuo até que o solvente se evapora. Nota: A fim de garantir que o produto final da reacção possuem os parâmetros de correcção relativos à distribuição do peso molecular, o grou funcionalps do polímero, e as temperaturas de fusão e de transição vítrea, de várias técnicas e métodos de análise pode ser utilizado, tais como a cromatografia de permeação em gel ou espectrometria de FITR. </li></ol> 3 Preparação de Soluções PU134 <ol><li> Pesar 200 mg de PU134 em uma garrafa de vidro. </li><li> Diluir PU134 para uma concentração final de 2% de uma série de solventes: clorofórmio, uma combinação de clorofórmio e de tolueno na proporção 1: 1, tetra-hidrofurano, e uma combinação de tetra-hidrofurano e diclorometano na proporção 1: 1. Nota: A escolha do solvente direita varia dependendo do polímero a ser usado. Diferentes solventes possuem diferentes pontos de ebulição, que podem afectar a solubilização do polímero. </li><li> Agitar a suspensão vigorosamente durante 20 min à temperatura ambiente usando um agitador a uma velocidade de 200 mot / min, até a solução se tornar homogénea e é observado nenhum precipitado. </li></ol> 4 Revestimento de Vidro Slides com PU134 <ol><li> Coloque uma rouDN 15 mm 2 lamela no aplicador de rotação. </li><li> Aplicar 50 ul da solução a cada PU134 usando uma pipeta. Ajustar o volume da solução em conformidade PU134 para o tamanho lamela necessário manter o volume à superfície relação proporcional. </li><li> Gire cada lamela de 7 seg a 23 x g. </li><li> Ar lamela seco à temperatura ambiente durante pelo menos 24 horas antes da esterilização. </li></ol> 5. Irradiação de Coverslip <ol><li> Gamma-irradiar polímero lamela revestida através da aplicação de uma dose de 10 Grays utilizando um irradiador de laboratório durante 12 min. </li><li> UV irradiar polímero revestido lamela usando a 30 W, lâmpada UV por 16 min cada lado. </li><li> Coloque a lamela revestida com polímero em uma placa de cultura de tecido apropriado de acordo com o tamanho do diapositivo. </li></ol> 6. Microscopia Eletrônica de Varredura <ol><li> Ouro revestimento por pulverização catódica lamela polímero para 200 segundos em uma atmosfera de 5 x 10 -1 milibares de pressão. </li><li> Capture a micrographs da lamela polímero revestido usando um microscópio eletrônico de varredura em uma tensão de aceleração de 20 kV em modo de imagem de elétrons secundários. </li></ol> 7. Observações Microscopia de Força Atômica <ol><li> Digitalizar uma área de 20 x 20 um de a superfície do polímero. </li><li> Configurar uma taxa de varredura de 1,32 Hz a 1,60 Hz. </li><li> Configure uma resolução de 512 x 512 pixels na região digitalizada. </li><li> Calcular a raiz quadrada da média (RMS ou QR) do revestimento usando a média dos desvios de altura retirados do plano médio de dados de imagem, expressa como: <img fo:content-width="1in" src="/files/ftp_upload/51723/51723eq1.jpg" width="123" /> Quando Zi é o valor actual Z, e N é o número de pontos dentro da área dada. </li><li> 7.5 Calcule o desvio ou média rugosidade da superfície (Ra) da imagem, usando, <img fo:content-width="1.5in" src="/files/ftp_upload/51723/51723eq2.jpg" width="154" /> Quando Z (x) é a função que descreve tele superfície perfil analisados ​​em termos de altura (Z) e posições (x) da amostra ao longo do comprimento de avaliação de &quot;L&quot;. Ra representa o valor médio da superfície em relação ao plano central. </li></ol> 8 Cultura e diferenciação celular <ol><li> Cultura e diferenciar o humano linha de células-tronco embrionárias (hESC) H9, conforme descrito no Hay 17. </li><li> Separar as células utilizando um reagente de dissociação e replate los para PU134 lâminas revestidas no Dia 9 do processo de diferenciação, na presença de um meio isento de soro como descrito no Szkolnicka 18,19. Nota: O uso de uma célula de dissociação enzimática é preferido ao descolamento celular física. </li></ol> 9. citocromo P450 Ensaio Funcional <ol><li> Medir a actividade do CYP3A seguindo as instruções do fabricante. </li><li> Incubar hESC hepatócitos derivados no dia 13 ou no dia 19, e meios de comunicação, sem células - como controle negativo, com o substr apropriadocomeu durante 5 horas a 37 ° C. </li><li> Colete sobrenadantes de células e meios de comunicação, realizar o ensaio de acordo com as instruções do fabricante. </li><li> Medir o nível de actividade de CYP e normalizada em relação à área de superfície (2 cm). </li></ol> 10. Imunocoloração <ol><li> Lavar células estaminais embrionárias humanas hepatócitos derivados com PBS, durante 1 min, repetir duas vezes. </li><li> Adicionar gelo frio 100% de metanol para fixar as células, em lugar de -20 ° C durante 10 min. </li><li> Lavar as células com PBS durante 5 minutos e repetir duas vezes. </li><li> Incubar as células com PBS / T (0,1% de tween) / 10% de BSA durante 1 hora à temperatura ambiente. </li><li> Aspirar a solução de PBST e adicionar o anticorpo primário adequado diluídos em PBS / T (0,1% de tween) / BSA a 1%, incubar a 4 ° C com agitação suave S / N. </li><li> Lavar as células com PBS / T (0,1% de tween) / BSA a 1% durante 5 minutos e repetir três vezes. </li><li> Diluir o anticorpo apropriado em PBS / T (0,1% de tween) / BSA a 1%, adicionar às células e incuba-se no escuro à temperatura ambiente durante 1 hora com agitação suave. </li><li> Lavar as células com PBS durante 5 minutos e repetir três vezes. </li><li> Adicionar MOWIOL 488 (contendo DAPI 1: 1000) a cada poço, adicione uma lamela suavemente para reduzir o número de bolhas de ar. Loja células fixas, a 4 ° C no escuro. Observe a coloração utilizando um microscópio com filtro apropriado e lâmpada fluorescente. Os anticorpos primários e secundários optimizados estão listadas na Tabela 1. </li></ol>

<ol>
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O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=UV+and+gamma+irradiation+effects+on+surface+properties+of+polyurethane+derivate+from+castor+oil.">UV and gamma irradiation effects on surface properties of polyurethane derivate from castor oil.</a> Pol&#237;meros. 23 (3), 305-311 (2013).</li><li>Rosu, L., Cascaval, C. N., Ciobanu, C., Rosu, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+UV+radiation+on+the+semi-interpenetrating+polymer+networks+based+on+polyurethane+and+epoxy+maleate+of+bisphenol+A.">Effect of UV radiation on the semi-interpenetrating polymer networks based on polyurethane and epoxy maleate of bisphenol A.</a> Journal of Photochemistry and Photobilogy A: Chemistry. 169 (2), 177-185 (2005).</li><li>Yang, X. F., Tallman, D. E., Bierwagen, G. P., Croll, S. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blistering+and+degradation+of+polyurethane+coatings+under+different+accelerated+weathering+tests.">Blistering and degradation of polyurethane coatings under different accelerated weathering tests.</a> Polymer Degradation and Stability. 77 (1), 103-109 (2002).</li></ol>

DCH é CSO, Diretor, fundador e acionista da FibromEd Products Ltd. MB e JPI são acionistas fundadores em FibromEd Products Ltd.

Muitos dos actuais métodos utilizados para gerar células estaminais a partir de hepatócitos de confiar em matrizes indefinidas de origem animal. Estes substratos podem ser caros e altamente variável, afetando a função celular e estabilidade, o que representa uma barreira significativa à aplicação. Por isso, foi realizada uma triagem dos materiais sintéticos que apoiam a cultura de células-tronco derivadas de hepatócitos. Foram identificadas, um poliuretano simples (PU134), formada por polimerização de PHNG...

Os materiais biológicos têm sido amplamente utilizados para a manutenção e diferenciação de células estaminais pluripotentes 1. Enquanto permitindo, estes substratos biológicos, muitas vezes contêm uma infinidade de componentes indefinidos. Matrigel é um substrato comumente usado para a cultura e diferenciação de células-tronco. Infelizmente, a sua composição variável influencia a função de células e fenótipo. Apesar de uma variedade de matrizes biológicas alternativas, mais definidos foram utilizados 2-7, a sua origem animal ou pobre escalabilidade os torna candidatos inadequados para o fabrico industrial. Portanto, a identificação de alternativas sintéticas, com composição definida e desempenho de confiança, são objetivos-chave na investigação sobre células estaminais. Numa tentativa de ultrapassar as limitações dos substratos de cultura celular indefinido, a colaboração entre interdisciplinar da química e da biologia identificaram materiais sintéticos com a capacidade para suportar o fenótipo da célula. Synthsubstratos etic são escaláveis, de baixo custo, e podem ser fabricados em estruturas 3D complexas, imitando o ambiente in vivo. Devido a estas propriedades de substratos sintéticos têm sido amplamente utilizados para suportar e conduzir a diferenciação de muitos tipos de células 8-10. Ensaios avançadas e de alto rendimento têm facilitado a rápida triagem de materiais sintéticos, a partir de grandes bibliotecas, e entregues novos materiais com propriedades flexíveis com larga aplicação em pesquisa e desenvolvimento 11-13 biomédica. Utilizando alto rendimento, tecnologia de rastreio de polímero de micro-arranjo, que rapidamente identificado um poliuretano simples (PU134), adequado para a manutenção de células estaminais derivadas de hepatócitos humanos. Este polímero verificou-se ser superior a substratos derivados de animais no que diz respeito à função e diferenciação de hepatócitos 14-16. Temos posteriormente otimizado o processo de condições de revestimento, topografia e esterilização para acessar efeitossobre o desempenho do polímero de estabilização da função de hepatócitos e tempo de vida. Isto tem implicações significativas no que diz respeito à compreensão de fundamentos da biologia dos hepatócitos para modelagem baseada em células e aplicações de medicina regenerativa. A tecnologia aqui descrita representa um exemplo de como a superfície de um polímero sintético pode ser optimizado para preservar fenótipo celular. Acreditamos que a combinação desta tecnologia com um protocolo de diferenciação de hepatócitos sem soro eficiente tem o potencial de proporcionar uma produção escalável de hepatócitos para uso em modelagem in vitro e medicina regenerativa.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Synthesis, preparation, coating and characterization of polymer PU134 coated coverslips</td>
		</tr>
		<tr>
			<td>Shaker</td>
			<td>Edmun B&#252;hler</td>
			<td>KS-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Irradiator</td>
			<td>CIS Biointernational</td>
			<td>IBL 637&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Spin coater</td>
			<td>Specialty Coating System</td>
			<td>&#160;P-6708</td>
			<td></td>
		</tr>
		<tr>
			<td>Scanning Electron Microscope&#160;</td>
			<td>Philips</td>
			<td>XL30CPSEM</td>
			<td></td>
		</tr>
		<tr>
			<td>Atomic Force Microscope</td>
			<td>DimensionV Nanoscope, VEECO</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>p4-GLO CYP3A4</td>
			<td>Promega</td>
			<td>V8902</td>
			<td></td>
		</tr>
		<tr>
			<td>UV bulb</td>
			<td>ESCO</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>NanoScope analysis software</td>
			<td>VEECO</td>
			<td></td>
			<td>version 1.20</td>
		</tr>
		<tr>
			<td>Fluorescence microscope</td>
			<td>Olympus</td>
			<td>TH45200</td>
			<td>Use Volocity 4 Software</td>
		</tr>
		<tr>
			<td>Tissue culture plates</td>
			<td>Corning, UK&#160;</td>
			<td>3527</td>
			<td></td>
		</tr>
		<tr>
			<td>glass slides</td>
			<td>Scientific Laboratory Supplies</td>
			<td>MIC3308</td>
			<td></td>
		</tr>
		<tr>
			<td>Diethylene glycol</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>93171</td>
			<td></td>
		</tr>
		<tr>
			<td>&#160;1,6-hexanediol</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>240117</td>
			<td></td>
		</tr>
		<tr>
			<td>Neopentyl glycol</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>408255</td>
			<td></td>
		</tr>
		<tr>
			<td>Adipic acid</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>9582</td>
			<td></td>
		</tr>
		<tr>
			<td>anhydrous N,N-Dimethylformamide</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>227056</td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl ether</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>676845</td>
			<td></td>
		</tr>
		<tr>
			<td>titanium (IV) butoxide&#160;</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>244112</td>
			<td></td>
		</tr>
		<tr>
			<td>1,4-butanediol&#160;</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>493732</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum oven</td>
			<td>Thermoscientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4,4&#8217;-Methylenebis(phenyl isocyanate)</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>101688</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetrahydrofurane</td>
			<td>Sigma&#8211;Aldrich</td>
			<td>401757</td>
			<td></td>
		</tr>
		<tr>
			<td>Sputter coater</td>
			<td>Bal-Tec SCD 050</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Inmunostaining</td>
		</tr>
		<tr>
			<td>Phosphate buffer saline (-MgCl2, -CaCl2)</td>
			<td>Gibco</td>
			<td>10010031</td>
			<td>&#160;Store at room temperature</td>
		</tr>
		<tr>
			<td>PBST, PBS made up with 0.1% TWEEN 20&#160;</td>
			<td>&#160; Scientific Laboratory Supplies Ltd</td>
			<td>EC607&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>&#160; Scientific Laboratory Supplies Ltd</td>
			<td>CHE5010</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>Sigma-Aldrich, UK</td>
			<td>A7906</td>
			<td></td>
		</tr>
		<tr>
			<td>MOWIOL 488 DAPI</td>
			<td>Calbiochem</td>
			<td>475904</td>
			<td>Made up in Tris HCL and glycerol as per manufacturers instructions</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Cell culture and Functional assay</td>
		</tr>
		<tr>
			<td>CYP3A activity pGLO kit</td>
			<td>Promega</td>
			<td>V8902</td>
			<td></td>
		</tr>
		<tr>
			<td>Hepatozyme</td>
			<td>Gibco</td>
			<td>17705021</td>
			<td></td>
		</tr>
		<tr>
			<td>TryLE express</td>
			<td>Life Technologies</td>
			<td><a href="http://www.lifetechnologies.com/order/catalog/product/12604013">12604013</a></td>
			<td></td>
		</tr>
	</tbody>
</table>

stabilizing hepatocellular phenotype using optimized synthetic surfaces

Currently, one of the major limitations in cell biology is maintaining differentiated cell phenotype. Biological matrices are commonly used for culturing and maintaining primary and pluripotent stem cell derived hepatocytes. While biological matrices are useful, they permit short term culture of hepatocytes, limiting their widespread application. We have attempted to overcome the limitations using a synthetic polymer coating. Polymers represent one of the broadest classes of biomaterials and possess a wide range of mechanical, physical and chemical properties, which can be fine-tuned for purpose. Importantly, such materials can be scaled to quality assured standards and display batch-to-batch consistency. This is essential if cells are to be expanded for high through-put screening in the pharmaceutical testing industry or for cellular based therapy. Polyurethanes (PUs) are one group of materials that have shown promise in cell culture. Our recent progress in optimizing a polyurethane coated surface, for long-term culture of human hepatocytes displaying stable phenotype, is presented and discussed.

Solvente de polímero influencia a topografia da superfície de polímero revestido Poliuretano 134 foi solubilizado em clorofórmio, quer isoladamente ou em combinação com tolueno ou tetra-hidrofurano ou diclorometano, e as lâminas de vidro de spin-revestidos com as diferentes formulações. A microscopia electrónica de varrimento (SEM) e de microscopia de força atómica (AFM), foram utilizados para caracterizar as propriedades físicas dos revestimentos de polímeros ...

Watch this Scientific Journal Video about Stabilizing Hepatocellular Phenotype Using Optimized Synthetic Surfaces at JoVE.com

Stabilizing Hepatocellular Phenotype Using Optimized Synthetic Surfaces

Este artigo irá focar no desenvolvimento de superfícies de polímeros revestido de longo prazo, estável cultura de células-tronco derivadas de hepatócitos humanos.

Estabilização hepatocelular Fenótipo Usando superfícies sintéticas otimizados

Currently, one of the major limitations in cell biology is maintaining differentiated cell phenotype. Biological matrices are commonly used for culturing ...

stabilizing-hepatocellular-phenotype-using-optimized-synthetic

Research

JoVE Journal

Chemistry

10.2K visualizações.  University of Edinburgh.  Este artigo irá focar no desenvolvimento de superfícies de polímeros revestido de longo prazo, estável cultura de células-tronco derivadas de hepatócitos humanos. 

Vídeo: Stabilizing Hepatocellular Phenotype Using Optimized Synthetic Surfaces

Covalent Binding of BMP-2 on Surfaces Using a Self-assembled Monolayer Approach

Bone morphogenetic protein 2 (BMP-2) is a growth factor embedded in the extracellular matrix of bone tissue. BMP-2 acts as trigger of mesenchymal cell differentiation into osteoblasts, thus stimulating healing and de novo bone formation. The clinical use of recombinant human BMP-2 (rhBMP-2) in conjunction with scaffolds has raised recent controversies, based on the mode of presentation and the amount to be delivered. The protocol presented here provides a simple and efficient way to deliver BMP-2 for in vitro studies on cells. We describe how to form a self-assembled monolayer consisting of a heterobifunctional linker, and show the subsequent binding step to obtain covalent immobilization of rhBMP-2. With this approach it is possible to achieve a sustained presentation of BMP-2 while maintaining the biological activity of the protein. In fact, the surface immobilization of BMP-2 allows targeted investigations by preventing unspecific adsorption, while reducing the amount of growth factor and, most notably, hindering uncontrolled release from the surface. Both short- and long-term signaling events triggered by BMP-2 are taking place when cells are exposed to surfaces presenting covalently immobilized rhBMP-2, making this approach suitable for in vitro studies on cell responses to BMP-2 stimulation.

We describe a method for accomplishing efficient immobilization of BMP-2 on surfaces. Our approach is based on the formation of a self-assembled monolayer to achieve the covalent binding of BMP-2 via its free amine residues. This method is a useful tool to study signaling at the cell membrane.

A ligação covalente de BMP-2 em superfícies com uma monocamada auto-montada Abordagem

Bone morphogenetic protein 2 (BMP-2) is a growth factor embedded in the extracellular matrix of bone tissue. BMP-2 acts as trigger of mesenchymal cell ...

Química

Towards Biomimicking Wood: Fabricated Free-standing Films of Nanocellulose, Lignin, and a Synthetic Polycation

Woody materials are comprised of plant cell walls that contain a layered secondary cell wall composed of structural polymers of polysaccharides and lignin. Layer-by-layer (LbL) assembly process which relies on the assembly of oppositely charged molecules from aqueous solutions was used to build a freestanding composite film of isolated wood polymers of lignin and oxidized nanofibril cellulose (NFC). To facilitate the assembly of these negatively charged polymers, a positively charged polyelectrolyte, poly(diallyldimethylammomium chloride) (PDDA), was used as a linking layer to create this simplified model cell wall. The layered adsorption process was studied quantitatively using quartz crystal microbalance with dissipation monitoring (QCM-D) and ellipsometry. The results showed that layer mass/thickness per adsorbed layer increased as a function of total number of layers. The surface coverage of the adsorbed layers was studied with atomic force microscopy (AFM). Complete coverage of the surface with lignin in all the deposition cycles was found for the system, however, surface coverage by NFC increased with the number of layers. The adsorption process was carried out for 250 cycles (500 bilayers) on a cellulose acetate (CA) substrate. Transparent free-standing LBL assembled nanocomposite films were obtained when the CA substrate was later dissolved in acetone. Scanning electron microscopy (SEM) of the fractured cross-sections showed a lamellar structure, and the thickness per adsorption cycle (PDDA-Lignin-PDDA-NC) was estimated to be 17 nm for two different lignin types used in the study. The data indicates a film with highly controlled architecture where nanocellulose and lignin are spatially deposited on the nanoscale (a polymer-polymer nanocomposites), similar to what is observed in the native cell wall.

The objective of this research was to form synthetic plant cell wall tissue using layer-by-layer assembly of nanocellulose fibrils and isolated lignin assembled from dilute aqueous suspensions.&#160; Surface measurement techniques of quartz crystal microbalance and atomic force microscopy were used to monitor the formation of the polymer-polymer nanocomposite material.

Rumo Biomimicking Madeira: Fabricados free-standing Filmes de nanocellulose, lignina, e uma policátion sintético

Woody materials are comprised of plant cell walls that contain a layered secondary cell wall composed of structural polymers of polysaccharides and ...

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy)3]2+ (bpy = bipyridine), onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces.

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of novel materials. Coupled with analysis by in situ secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS), soft landing provides unprecedented insights into the interactions of well-defined species with surfaces.

In situ SIMS e IR Espectroscopia de Superfícies bem definidos preparados pela Soft Landing de Íons Mass-selecionados

Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using ...

Synthetic Methodology for Asymmetric Ferrocene Derived Bio-conjugate Systems via Solid Phase Resin-based Methodology

Early detection is a key to successful treatment of most diseases, and is particularly imperative for the diagnosis and treatment of many types of cancer. The most common techniques utilized are imaging modalities such as Magnetic Resonance Imaging (MRI), Positron Emission Topography (PET), and Computed Topography (CT) and are optimal for understanding the physical structure of the disease but can only be performed once every four to six weeks due to the use of imaging agents and overall cost. With this in mind, the development of &#8220;point of care&#8221; techniques, such as biosensors, which evaluate the stage of disease and/or efficacy of treatment in the clinician&#8217;s office and do so in a timely manner, would revolutionize treatment protocols.1 As a means to exploring ferrocene based biosensors for the detection of biologically relevant molecules2, methods were developed to produce ferrocene-biotin bio-conjugates described herein. This report will focus on a biotin-ferrocene-cysteine system that can be immobilized on a gold surface.

The synthesis of asymmetric species of ferrocene is challenging using solution techniques. This report focuses on the methods carried out to produce a ferrocene-biotin bioconjugate using facile and clean reactions accomplished via solid-phase synthesis. Incorporation of a thiolate moiety is shown to impart the ability for immobilization on gold surfaces.

Metodologia sintética para Asymmetric Ferroceno Derivados Sistemas Bio-conjugadas via Metodologia base de resina em Fase Sólida

Early detection is a key to successful treatment of most diseases, and is particularly imperative for the diagnosis and treatment of many types of cancer. ...

Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues

Protein alignments are commonly used to evaluate the similarity of protein residues, and the derived consensus sequence used for identifying functional units (e.g., domains). Traditional consensus-building models fail to account for interpositional dependencies &#8211; functionally required covariation of residues that tend to appear simultaneously throughout evolution and across the phylogentic tree. These relationships can reveal important clues about the processes of protein folding, thermostability, and the formation of functional sites, which in turn can be used to inform the engineering of synthetic proteins. Unfortunately, these relationships essentially form sub-motifs which cannot be predicted by simple &#8220;majority rule&#8221; or even HMM-based consensus models, and the result can be a biologically invalid &#8220;consensus&#8221; which is not only never seen in nature but is less viable than any extant protein. We have developed a visual analytics tool, StickWRLD, which creates an interactive 3D representation of a protein alignment and clearly displays covarying residues. The user has the ability to pan and zoom, as well as dynamically change the statistical threshold underlying the identification of covariants. StickWRLD has previously been successfully used to identify functionally-required covarying residues in proteins such as Adenylate Kinase and in DNA sequences such as endonuclease target sites.

Synthetic protein sequences based on consensus motifs typically ignore co-evolving residues, that imply interpositional dependencies (IPDs). IPDs can be essential to activity, and designs that disregard them may result in suboptimal results. This protocol uses StickWRLD to identify IPDs and help inform rational protein design, resulting in more efficient results.

Otimização de proteínas sintéticas: Identificação de interposição Dependências Indicating Estruturalmente e / ou resíduos funcionalmente ligadas

Protein alignments are commonly used to evaluate the similarity of protein residues, and the derived consensus sequence used for identifying functional ...

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient radiolabeling of DBCO-group-functionalized gold nanoparticles using a copper-free click reaction. Radioiodination of the stannylated precursor (2) was carried out by using [125I]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified 125I-labeled azide (1) was obtained with high radiochemical yield (75 &plusmn; 10%, n = 8) and excellent radiochemical purity (&gt;99%). For the synthesis of radiolabeled 13-nm-sized gold nanoparticles, the DBCO-functionalized gold nanoparticles (3) were prepared by using a thiolated polyethylene glycol polymer. A copper-free click reaction between 1 and 3 gave the 125I-labeled gold nanoparticles (4) with more than 95% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method using a strain-promoted copper-free click reaction will be useful for the efficient and convenient radiolabeling of DBCO-group-containing nanomaterials.

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

A detailed procedure for the synthesis of a 125I-labeled azide and the radiolabeling of dibenzocyclooctyne (DBCO)-group-conjugated, 13-nm-sized gold nanoparticles using a copper-free click reaction is described.

Um protocolo otimizado para a radiomarcação eficiente de nanopartículas de ouro usando um<sup&gt; 125</sup&gt; Marcado com Eu Azida grupo prostético

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient ...

Color Spot Test As a Presumptive Tool for the Rapid Detection of Synthetic Cathinones

Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and other border protection agencies globally. Color testing is a presumptive identification technique indicating the presence or absence of a particular drug class using rapid and uncomplicated chemical methods. Owing to their relatively recent emergence, a color test for the specific identification of synthetic cathinones is not currently available. In this study, we introduce a protocol for the presumptive identification of synthetic cathinones, employing three aqueous reagent solutions: copper(II) nitrate, 2,9-dimethyl-1,10-phenanthroline (neocuproine) and sodium acetate. Small pin-head sized amounts (approximately 0.1-0.2 mg) of the suspected drugs are added to the wells of a porcelain spot plate, and each reagent is then added dropwise sequentially before heating on a hotplate. A color change from very light blue to yellow-orange after 10 min indicates the likely presence of synthetic cathinones. The highly stable and specific test reagent has the potential for use in the presumptive screening of unknown samples for synthetic cathinones in a forensic laboratory. However, the nuisance of an added heating step for the color change result limits the test to laboratory application and decreases the likelihood of an easy translation to field testing.

Here we present a simple, inexpensive, and selective chemical spot test protocol for the detection of synthetic cathinones, a class of new psychoactive substances. The protocol is suitable for use in various areas of law enforcement that encounter illicit material.

Cor de teste local como uma ferramenta presuntiva para a detecção rápida de Cathinones sintético

Synthetic cathinones are a large class of new psychoactive substances (NPS) that are increasingly prevalent in drug seizures made by law enforcement and ...

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight (MALDI-TOF) Mass Spectrometry

There are many techniques that can be employed in the characterization of synthetic homopolymers, but few provide as useful of information for end group analysis as matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). This tutorial demonstrates methods for optimization of the sample preparation, spectral acquisition, and data analysis of synthetic polymers using MALDI-TOF MS. Critical parameters during sample preparation include the selection of the matrix, identification of an appropriate cationization salt, and tuning the relative proportions of the matrix, cation, and analyte. The acquisition parameters, such as mode (linear or reflector), polarization (positive or negative), acceleration voltage, and delay time, are also important. Given some knowledge of the chemistry involved to synthesize the polymer and optimizing both the data acquisition parameters and the sample preparation conditions, spectra should be obtained with sufficient resolution and mass accuracy to enable the unambiguous determination of the end groups of most homopolymers (masses below 10,000) in addition to the repeat unit mass and the overall molecular weight distribution. Though demonstrated on a limited set of polymers, these general techniques are applicable to a much wider range of synthetic polymers for determining mass distributions, though end group determination is only possible for homopolymers with narrow dispersity.

Characterization of Synthetic Polymers via Matrix Assisted Laser Desorption Ionization Time of Flight MALDI-TOF Mass Spectrometry

A protocol for the matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) characterization of synthetic polymers is described including the optimization of sample preparation, spectral acquisition, and data analysis.

Caracterização de Polímeros Sintéticos via Espectrometria de Massa por Ionização a Laser com Matriz Assistida por Tempo de Voo (MALDI-TOF)

There are many techniques that can be employed in the characterization of synthetic homopolymers, but few provide as useful of information for end group ...

Light-driven Molecular Motors on Surfaces for Single Molecular Imaging

The design and synthesis of a synthetic system that aims for the direct visualization of a synthetic rotary motor at the single molecule level on surfaces are demonstrated. This work requires careful design, considerable synthetic effort, and proper analysis. The rotary motion of the molecular motor in solution is shown by 1H NMR and UV-vis absorption spectroscopy techniques. In addition, the method to graft the motor onto an amine-coated quartz is described. This method helps to gain more insight into molecular machines.

The manuscript describes how to synthesize and graft a molecular motor on surfaces for single molecular imaging.

Motores moleculares orientado a luz em superfícies para única imagem Molecular

The design and synthesis of a synthetic system that aims for the direct visualization of a synthetic rotary motor at the single molecule level on surfaces ...

A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of materials is highly related to its photocatalytic performance, it is necessary to standardize the synthetic methods in order to obtain the most functional architectures and, thus, the highest photocatalytic efficiency. Here, we report a reliable route to obtain BiOI microspheres via the solvothermal process, using Bi(NO3)3 and potassium iodide (KI) as precursors, and ethylene glycol as a template. The synthesis is standardized in a 150 mL autoclave, at 126 &#176;C for 18 h. This results in 2-3 &#181;m-sized mesoporous microspheres, with a relevant specific surface area (61.3 m2/g). Shortening the reaction times in the synthesis results in amorphous structures, while higher temperatures lead to a slight increase in the porosity of the microspheres, with no effect in the photocatalytic performance. The materials are photo-active under UV-A/visible light irradiation for the degradation of the antibiotic ciprofloxacin in water. This method has demonstrated to be effective in interlaboratory tests, obtaining similar BiOI microspheres in Mexican and Chilean research groups.

This article describes a synthetic method to obtain bismuth oxyiodide microspheres, which are highly functional to perform the photocatalytic removal of organic pollutants, such as ciprofloxacin, in water under UV-A/visible light irradiation.

Um método sintético Facile para obter Oxyiodide de bismuto microesferas altamente funcional para os processos de Photocatalytic de depuração de água

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of ...