This study was supported by the grant from AACP New Pharmacy Faculty Research Award Program, Medical Research Foundation of Oregon New Investigator Grant, Oregon State University-Startup fund, and Pacific University, School of Pharmacy Start-up fund.

1. Preparação de individuais e multi-drogas Micelles carregado pelo método de fundição de solvente <ol><li> Pesar DTX 1 mg ou 1 mg EVR ou ambas as drogas em 1 mg cada, para as micelas dupla droga (DDM). </li><li> Pesar 15 mg de PEG 2000 - b -PLA 1800 ou PEG 4000 - b -PLA 2200 para qualquer indivíduo ou DDM. </li><li> Dissolve-se os medicamentos e / ou drogas e do polímero em 0,5 ml de acetonitrilo e colocar num frasco de fundo redondo de 5 ml. </li><li> Formar uma película fina de polímero de droga distribuída por evaporação do (s) fármaco -polymer solução de acetonitrilo sob pressão reduzida utilizando um evaporador rotativo. Definir o evaporador rotativo a 100 rpm, a temperatura do banho de água de 40 ° C e uma pressão de vácuo de 260 mbar durante 5 minutos, seguido de uma redução para 100 mbar durante mais 3 min. </li><li> Re-hidratar o filme de fármaco e polímero, com 0,5 ml de água desionizada a 50 ° C e agitar suavemente o frasco para formar as micelas. </li><li> Filtrar o resultadoing solução micelar através de um filtro de nylon de 0,2 um para remover qualquer droga ou contaminantes dissolvidos-un para um tubo de centrífuga de 1,5 ml. </li></ol> 2. Avaliação da droga carregamento e da estabilidade em micelas de fase reversa usando Cromatografia Líquida de Alta Eficiência (HPLC) de <ol><li> Realizar a análise por RP-HPLC com uma coluna C8 equilibriated a 40 ° C num modo isocrático com uma fase móvel de acetonitrilo / água (62/38) contendo ácido fosfórico a 0,1% e 1% de metanol a um caudal de 1 ml / min e um volume de injecção de 10 ul. </li><li> Diluir micelas recém-preparados (Ponto 1) 1: 100 em fase móvel antes de analisar por RP-HPLC para determinar a carga de medicamento inicial. Loja não diluídas micelas individuais e DDM à temperatura ambiente (25 ° C) durante 48 horas e preparar frescos 1: 100 amostras diluídas em fase móvel para re-avaliar por RP-HPLC e determinar medicamento (s) em micelas estabilidade ao longo de 24 horas. </li><li> Monitorar DTX e IVE picos a 227 e 279 nm, respectivamentecom tempos de retenção de 1,7 e 5,7 min, respectivamente. Executar todas as medições em triplicado. Apresentam dados como a carga média ± SD de drogas. </li></ol> 3. Avaliação das micelas de tamanho de partículas por espalhamento dinâmico de luz (DLS) <ol><li> Diluir micelas preparadas de fresco (como descrito na secção 1) em água desionizada a uma razão de 1:20 para dar uma concentração final de polímero de 1,5 mg / ml. </li><li> Medir a intensidade do laser He-Ne (633 nm) a 173 ° para determinar espalhamento. Executar todas as medições a 25 ° C após um pré-equilibração durante 2 min. </li><li> Executar todas as medições em triplicado. Dados apresentam-se como a dimensão média de Z-média ± DP, juntamente com o índice de polidispersibilidade (PDI) da distribuição. </li></ol> 4. Avaliação da In Vitro Drogas lançamento de micelas individuais e DDM <ol><li> Prepare micelas individuais e DDM, conforme descrito na secção 1. Carga de 2,5 ml das micelas numa cassete de diálise com 3 mlum peso molecular de corte (MWCO) de 7000 g / mol. NOTA: Este MWCO foi escolhido para permitir que o fármaco livre (s), juntamente com as moléculas do polímero não associados a difundir livremente para fora da cassete e, assim, assegurar as condições de imersão. </li><li> Coloque as cassetes em 2,5 L de pH 7,4 mM de tampão de fosfato 10 (preparado por diluição de solução stock de 200 mM) e mudar o tampão de cada 3 horas para garantir as condições de imersão. Manter a temperatura do tampão a 37 ° C durante toda a duração da experiência. </li><li> Aos 0, 0,5, 1, 2, 3, 6, 9, 12, 24, e 48 h, retirar 150 ul da solução nas cassetes e substituir com 150 ul de tampão fresco. </li><li> Analisar as amostras usando RP-HPLC, tal como estabelecido na secção 2 para determinar a concentração do fármaco. Curve-se ajustar os dados de liberação da droga (s) com base em um modelo de difusão simples, com uma fase de uma associação exponencial usando software stastitical. </li><li> Calcular o tempo necessário para alcançar 50% de libertação do fármaco (t 1/2) de eACH droga em micelas individuais ou DDM com base no ajuste de curva. Executar todas as medições em quádruplo. </li></ol>

<ol>
	<li>Yokoyama, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymeric+micelles+as+a+new+drug+carrier+system+and+their+required+considerations+for+clinical+trials.">Polymeric micelles as a new drug carrier system and their required considerations for clinical trials.</a> Expert Opin Drug Deliv. 7, 145-158 (2010).</li><li>Shin, H. C., Alani, A. W., Rao, D. A., Rockich, N. C., Kwon, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-drug+loaded+polymeric+micelles+for+simultaneous+delivery+of+poorly+soluble+anticancer+drugs.">Multi-drug loaded polymeric micelles for simultaneous delivery of poorly soluble anticancer drugs.</a> J Control Release. 140, 294-300 (2009).</li><li>Adams, M. L., Lavasanifar, A., Kwon, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amphiphilic+block+copolymers+for+drug+delivery.">Amphiphilic block copolymers for drug delivery.</a> J Pharm Sci. 92, 1343-1355 (2003).</li><li>Oerlemans, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymeric+micelles+in+anticancer+therapy:+targeting,+imaging+and+triggered+release.">Polymeric micelles in anticancer therapy: targeting, imaging and triggered release.</a> Pharm Res. 27, 2569-2589 (2010).</li><li>Shin, H. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+3-in-1+polymeric+micelle+nanocontainer+for+poorly+water-soluble+drugs.">A 3-in-1 polymeric micelle nanocontainer for poorly water-soluble drugs.</a> Mol Pharm. 8, 1257-1265 (2011).</li><li>Hasenstein, J. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antitumor+activity+of+Triolimus:+a+novel+multidrug-loaded+micelle+containing+Paclitaxel+Rapamycin,+and+17-AAG.">Antitumor activity of Triolimus: a novel multidrug-loaded micelle containing Paclitaxel Rapamycin, and 17-AAG.</a> Mol Cancer Ther. 11, 2233-2242 (2012).</li><li>Mazzaferro, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bivalent+sequential+binding+of+docetaxel+to+methyl-beta-cyclodextrin.">Bivalent sequential binding of docetaxel to methyl-beta-cyclodextrin.</a> Int J Pharm. 416, 171-180 (2011).</li><li>Iwase, Y., Maitani, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preparation+and+in+vivo+evaluation+of+liposomal+everolimus+for+lung+carcinoma+and+thyroid+carcinoma.">Preparation and in vivo evaluation of liposomal everolimus for lung carcinoma and thyroid carcinoma.</a> Biol Pharm Bull. 35, 975-979 (2012).</li><li>Mishra, G. P., Doddapaneni, B. S., Nguyen, D., Alani, A. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antiangiogenic+effect+of+docetaxel+and+everolimus+as+individual+and+dual-drug-loaded+micellar+nanocarriers.">Antiangiogenic effect of docetaxel and everolimus as individual and dual-drug-loaded micellar nanocarriers.</a> Pharm Res. 31, 660-669 (2014).</li><li>Xu, W., Ling, P., Zhang, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymeric+micelles,+a+promising+drug+delivery+system+to+enhance+bioavailability+of+poorly+water-soluble+drugs.">Polymeric micelles, a promising drug delivery system to enhance bioavailability of poorly water-soluble drugs.</a> J Drug Deliv. 2013, 340315 (2013).</li><li>Lavasanifar, A., Samuel, J., Kwon, G. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Poly(ethylene+oxide)-block-poly(L-amino+acid)+micelles+for+drug+delivery.">Poly(ethylene oxide)-block-poly(L-amino acid) micelles for drug delivery.</a> Adv Drug Deliv Rev. 54, 169-190 (2002).</li></ol>

The authors have nothing to disclose.

The use of polymeric micelles for drug delivery continues to expand due to their versatility and ability to deliver hydrophobic drugs for various disease states. Therefore, the techniques needed to prepare and characterize these formulations prior to use in cell culture or animals is a critical first step to determine the best pairing between the drug and the polymer. PEG-b-PLA are excellent amphiphilic block copolymers for drug delivery purposes. However, the block length of the hydrophilic and hydrophobic s...

Copolímeros em bloco anfifílicos com estrutura de repetição compostas de domínios hidrofílicos e hidrofóbicos pode auto-montar espontaneamente para formar três montagens macromoleculares tridimensionais conhecidas como micelas poliméricas. Estas estruturas têm um núcleo hidrófobo interior rodeado por uma camada hidrófila. O núcleo hidrofóbico tem a capacidade para incorporar drogas hidrofóbicas, quer por armadilha física através de interacções hidrofóbicas ou por conjugação química sobre a espinha dorsal do polímero. 1 Muitas vantagens existem para a utilização desses copolímeros em bloco, para formar micelas para entrega da droga. Estes incluem incorporação de fármacos fracamente solúveis, melhorar a farmacocinética dos fármacos incorporados, e a biocompatibilidade e / ou a biodegradabilidade dos polímeros torna uma alternativa segura para solubilizadores convencionais. 2 Outra vantagem do uso de micelas poliméricas é o seu tamanho de partícula coloidal, entre 15- 150 nm 3, tornando-os atraentes para paentrega renteral. Por conseguinte, ao longo dos últimos 20 anos, surgiram micelas poliméricas como sistemas de distribuição de drogas viáveis ​​para fármacos pouco solúveis em água, especialmente para a terapia do cancro 3,4. Actualmente existem cinco formulações micelares poliméricos para a terapia do cancro em fase de ensaios clínicos. 4 Quatro das micelas em ensaios clínicos são os copolímeros dibloco baseados em PEG enquanto que a última é um copolímero de tribloco de óxido de polietileno contendo. O tamanho destas micelas variou de 20 nm a 85 nm. A vantagem da utilização de polímeros à base de PEG é a sua biocompatibilidade e, dependendo do segundo bloco também pode ser biodegradável. Recentemente, os sistemas de administração de fármacos à base nova no bloco polyethyleneglycol- ácido -polylactic (PEG-b--PLA) micelas poliméricas têm sido desenvolvidos para a entrega simultânea de vários fármacos anti-cancerígenos. As micelas de PEG-PLA B- são ambos biocompatível e biodegradável. Estes fármacos múltiplos micelas carregadas têm mostrado comoynergistic inibição de diferentes cancros em modelos in vitro e in vivo 2,5,6 e inserem-se no paradigma actual de utilização de vários fármacos em quimioterapia para prevenir a resistência e diminuir a toxicidade. Portanto, há uma grande quantidade de interesse em preparar e caracterizar esses sistemas de entrega de drogas micelares para uso no cancro e outros estados de doença. No trabalho abaixo nós esboçamos um processo passo-a-passo pelo qual tais micelas podem ser preparados e caracterizados antes de avaliá-los em estados de doença de interesse. Para os fins deste trabalho dois agentes anti-cancro fracamente solúveis, docetaxel (DTX) e everolimus (EVR) ter sido escolhido. Ambos DTX e EVR são compostos pouco solúveis em água com solubilidades intrínsecas de água em 1,9 e 9,6 ng / ml, respectivamente. 7,8 Duas PEG polímeros b -PLA com diferentes pesos moleculares foram utilizados neste protocolo como os blocos de construção para a polimérica formulados micelas,estes polímeros são PEG 2000 - b -PLA 1800 (3800 Da) e PEG 4000 - b -PLA 2200 (6200 Da). PEG micelas b -PLA pode, portanto, fornecer uma plataforma única como um nanocarrier para DTX e EVR individualmente e em combinação. Os reagentes necessários / Materiais e equipamentos necessários para preparar e caracterizar estas micelas estão listadas na Tabela 1.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>PEG2000-b-PLA1800</td>
			<td>Advanced Polymer Materials, Inc</td>
			<td>6-01- PLA/2000</td>
			<td>PLA MW can be specified on ordering</td>
		</tr>
		<tr>
			<td>PEG4000-b-PLA2200</td>
			<td>Advanced Polymer Materials, Inc</td>
			<td>6-01- PLA/4000</td>
			<td>PLA MW can be specified on ordering</td>
		</tr>
		<tr>
			<td>Docetaxel</td>
			<td>LC Laboratories</td>
			<td>D-1000</td>
			<td>100 mg</td>
		</tr>
		<tr>
			<td>Everolimus</td>
			<td>LC Laboratories</td>
			<td>E-4040</td>
			<td>100 mg</td>
		</tr>
		<tr>
			<td>Acetonitrile</td>
			<td>EMD/VWR</td>
			<td>EM-AX0145-1</td>
			<td>HPLC grade; 4 L</td>
		</tr>
		<tr>
			<td>Round bottom flask&#160;</td>
			<td>Glassco/VWR</td>
			<td>89426-496</td>
			<td>5 mL</td>
		</tr>
		<tr>
			<td>RV 10 Control Rotary Evaporators</td>
			<td>IKA Works</td>
			<td>8025001</td>
			<td>Rotoevaporator</td>
		</tr>
		<tr>
			<td>Shimadzhu HPLC with DAD detector</td>
			<td>Shimadzhu</td>
			<td></td>
			<td>RP-HPLC</td>
		</tr>
		<tr>
			<td>Slide-a-lyzer dialysis casette MWCO 7000</td>
			<td>Thermo Scientific, Inc</td>
			<td>66370</td>
			<td>3 mL</td>
		</tr>
		<tr>
			<td>Phosphate buffer pH 7.4 200 mM</td>
			<td>VWR</td>
			<td>100190-870</td>
			<td>500 mL</td>
		</tr>
		<tr>
			<td>Malvern NanoZS</td>
			<td>Malvern Instruments, UK</td>
			<td></td>
			<td>DLS</td>
		</tr>
		<tr>
			<td>Nylon filter</td>
			<td>Acrodisc/VWR</td>
			<td>28143-242</td>
			<td>13 mm; 0.2&#181;M</td>
		</tr>
		<tr>
			<td>Phosphoric acid, NF</td>
			<td>Spectrum Chemical/VWR</td>
			<td>700000-626</td>
			<td>100 mL</td>
		</tr>
		<tr>
			<td>GraphPad Prism</td>
			<td><a href="http://www.graphpad.com/">www.graphpad.com</a></td>
			<td></td>
			<td>Analysis software</td>
		</tr>
		<tr>
			<td>Zorbax SB-C8 Rapid Resolution cartridge&#160;</td>
			<td>Agilent Technologies</td>
			<td>866953-906</td>
			<td>4.6 &#215;75mm, 3.5 micron</td>
		</tr>
	</tbody>
</table>

preparation and characterization of individual and multi-drug loaded physically entrapped polymeric micelles

Copolímeros em bloco anfifílicos como bloco polyethyleneglycol- ácido -polylactic (PEG- b- PLA) pode auto-montar em micelas acima da concentração micelar crítica formando núcleos hidrofóbicos cercadas por escudos hidrofílicos em ambientes aquosos. O núcleo destas micelas pode ser utilizado para carregar medicamentos hidrofóbicos, fracamente solúveis em água, como o docetaxel (DTX) e everolimus (EVR). Caracterização sistemática da estrutura de micelas e carregamento de drogas capacidades são importantes antes in vitro e estudos in vivo podem ser conduzidos. O objectivo do protocolo aqui descrito é o de proporcionar os passos de caracterização necessárias para obter produtos normalizados micelares. DTX e IVE têm solubilidades intrínsecas de 1,9 e 9,6 ug / ml, respectivamente, de preparação dessas micelas pode ser conseguido através de evaporação de solvente, que aumenta a solubilidade aquosa da DTX e IVE a 1,86 e 1,85 mg / ml, respectivamente. Estabilidade do fármaco em micelas evalmicas situadas à temperatura ambiente durante 48 hr indica que 97% ou mais dos fármacos são retidos na solução. Tamanho das micelas foi avaliado usando dispersão dinâmica de luz e indicou que o tamanho dessas micelas era inferior a 50 nm e dependente do peso molecular do polímero. A libertação do fármaco a partir das micelas foi avaliada por meio de diálise em condições de imersão a pH 7,4 a 37 ° C durante 48 h. Resultados indicam que o ajustamento da curva de libertação do fármaco é accionado por um processo de primeira ordem indicando que ele está orientado difusão.

DTX individual ou micelas EVR e DTX e IVE DDM em micelas de PEG-b--PLA são formuladas com sucesso, quer em PEG 4000 - b -PLA 2200 ou PEG 2000 - b -PLA 1800 (Figura 1). DTX, RVP e o DDM mostraram estabilidade semelhante em PEG 4000 - b -PLA 2200 ou PEG 2000 - 1800 b -PLA mais de 48 h (Figura 2). Carga de droga inicial de EVR em...

Watch this Scientific Journal Video about Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles at JoVE.com

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

Preparação e caracterização de Individual e Multi-carregadas com droga Fisicamente Entrapped poliméricos Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

preparation-characterization-individual-multi-drug-loaded-physically

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11.2K visualizações.  Pacific University. The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

Vídeo: Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

Split-and-piscina Síntese e Caracterização de Peptídeos Terciário Amide Biblioteca

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

Química

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Síntese e caracterização de funcionalizados metal-organic frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1&#945; (Stromal cell-derived factor-1&#945;), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1&#945;-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1&#945; is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form.

Preparation and Characterization of SDF-1&amp;#945;-Chitosan-Dextran Sulfate Nanoparticles

The objective of this protocol is to incorporate SDF-1&#945;, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1&#945; from the nanoparticles.

Preparação e Caracterização de SDF-1α-Quitosana As nanopartículas de sulfato de dextrano

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Síntese e Caracterização de Supramoleculares Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Low-energy Cathodoluminescence for (Oxy)Nitride Phosphors

Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and flexibility of their emission properties can be achieved by controlling their composition and dopants. However, a lot of work is still required to improve their properties and to reduce the production cost. A possible approach is to correlate the luminescence properties of the Sialon particles with their local structural and chemical environment in order to optimize their growth parameters and find novel phosphors. For such a purpose, the low-voltage cathodoluminescence (CL) microscopy is a powerful technique. The use of electron as an excitation source allows detecting most of the luminescence centers, revealing their luminescence distribution spatially and in depth, directly comparing CL results with the other electron-based techniques, and investigating the stability of their luminescence properties under stress. Such advantages for phosphors characterization will be highlighted through examples of investigation on several Sialon phosphors by low-energy CL.

Low-energy Cathodoluminescence for OxyNitride Phosphors

An excellent chemical and luminescence stabilities of (oxy)nitride phosphors present it as an promising alternative to currently used sulfide and oxide phosphors. In this paper, we present the way to investigate its local luminescence properties using low-energy cathodoluminescence (CL).

Catodoluminescência baixa energia para (oxi) Phosphors nitreto

Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Síntese Facile de micelas Worm-like por luz visível Mediated Dispersão Polimerização Usando Photoredox Catalisador

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &#960;-&#960; Stacking Interactions

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI &#60; 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy. The potential of the copolymer for use in drug delivery applications was evaluated in a preliminary manner including in vitro biocompatibility, loading and release of the hydrophobic anti-cancer drug doxorubicin (DOX). A stable micelle formulation of DOX was prepared with drug loading levels up to 14% (wt%), drug loading efficiencies &#62; 60% (w/w) and sustained release of drug over 4 days under physiologically relevant conditions (acidic and neutral pH, presence of albumin). The high drug loading level and sustained release is attributed to stabilizing &#960;-&#960; interactions between DOX and the core-forming block of the micelles.

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &amp;#960;-&amp;#960; Stacking Interactions

The key steps of living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE) are described. The resulting block copolymer micelles (BCMs) were loaded with doxorubicin 14% (wt%) and sustained release of drug over 4 days under physiologically relevant conditions was obtained.

Aniônico polimerização de um copolímero anfifílicas para Preparação de copolímero em bloco As micelas estabilizada por interacções de empilhamento π-¸

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl ...

Synthesis of Cyclic Polymers and Characterization of Their Diffusive Motion in the Melt State at the Single Molecule Level

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single molecule level. An electrostatic self-assembly and covalent fixation (ESA-CF) process is used for the synthesis of the cyclic poly(tetrahydrofuran) (poly(THF)). The diffusive motion of individual cyclic polymer chains in a melt state is visualized using single molecule fluorescence imaging by incorporating a fluorophore unit in the cyclic chains. The diffusive motion of the chains is quantitatively characterized by means of a combination of mean-squared displacement (MSD) analysis and a cumulative distribution function (CDF) analysis. The cyclic polymer exhibits multiple-mode diffusion which is distinct from its linear counterpart. The results demonstrate that the diffusional heterogeneity of polymers that is often hidden behind ensemble averaging can be revealed by the efficient synthesis of the cyclic polymers using the ESA-CF process and the quantitative analysis of the diffusive motion at the single molecule level using the MSD and CDF analyses.

A protocol for the synthesis and characterization of diffusive motion of cyclic polymers at the single molecule level is presented.

Síntese de polímeros cíclicos e Caracterização do seu movimento difusivo no estado fundido na molécula de nível único

We demonstrate a method for the synthesis of cyclic polymers and a protocol for characterizing their diffusive motion in a melt state at the single ...

Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing

Effective hair dyeing through in situ incubation of keratin hair with the products of fungal laccase-catalyzed polymerization of plant phenols has been previously demonstrated. However, the dyeing process takes a long time to complete compared to commercial hair-dyeing products. To overcome this bottleneck, pre-synthesized polymeric products of the oxidative reaction of Trametes versicolor laccase on catechin and catechol, either with or without mordant agents (e.g., FeSO4), were here employed to achieve permanent keratin hair dyeing in various colors and shades. The laccase action in acidic sodium acetate buffer led to a deep black coloration after coupling reactions between the plant phenols. The colored dye products were then desalted and concentrated with ultrafiltration. The dyes, with or without mordant agents, caused a significant increase in &#916;E values (i.e., color difference value) in gray human hair within 2.5 hours. In addition, different keratin colors and shades were induced depending upon the mordanting and pH changes. The dyed hair also exhibited a strong resistance to detergent treatments, indicating that our methods can give rise to permanent hair dyeing.&#160;Overall, our work has provided novel insight into developing eco-friendly hair-dyeing methods as alternatives to commercial toxic diamine-based dyes.

Here, we present a protocol to use pre-synthesized polymeric products derived from fungal laccase-catalyzed polymerization of plant phenols, either with or without mordant agents (e.g., FeSO4), to induce detergent-resistant keratin hair dyeing within 2.5 hours.

Síntese de Corantes poliméricos fábrica de fenol-derivados para coloração capilar direta ou Mordant-base

Effective hair dyeing through in situ incubation of keratin hair with the products of fungal laccase-catalyzed polymerization of plant phenols has been ...

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

preparação e<em&gt; In Vitro</em&gt; Caracterização de agentes de contraste à base de dendrímeros para Ressonância Magnética

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...