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. Préparation de l&#39;individu et multi-drogue micelles chargées par la méthode de coulée de solvant <ol><li> Peser DTX 1 mg ou 1 mg EVR ou les deux médicaments à 1 mg chacune pour les micelles double de drogue (DDM). </li><li> Peser 15 mg de PEG 2000 - b -PLA 1800 ou PEG 4000 - b -PLA 2200 soit individuelle ou DDM. </li><li> Dissoudre les drogues / médicaments et le polymère dans 0,5 ml d&#39;acétonitrile et placer dans un 5 ml flacon à fond rond. </li><li> Former un film de polymère mince de médicament distribué en évaporant le (s) solution d&#39;acétonitrile -polymère de médicament sous pression réduite en utilisant un évaporateur rotatif. Réglez l&#39;évaporateur rotatif à 100 tours par minute, la température du bain d&#39;eau de 40 ° C et une pression de vide de 260 mbars pendant 5 min, suivie par une réduction de 100 mbar pendant 3 min plus. </li><li> Réhydrater le film médicament-polymère avec 0,5 ml d&#39;eau déminéralisée à 50 ° C et agiter doucement le flacon pour former les micelles. </li><li> Filtrer le résultating solution micellaire à travers un filtre en nylon de 0,2 um pour éliminer les contaminants ou tout médicament non dissous dans un tube de centrifugeuse de 1,5 ml. </li></ol> 2. Évaluation des médicaments en cours de chargement et de la stabilité dans les micelles Utilisation phase inverse Chromatographie Liquide Haute Performance (CLHP-PI) <ol><li> Effectuer l&#39;analyse RP-HPLC avec une colonne C8 equilibriated à 40 ° C dans un mode isocratique avec une phase mobile d&#39;acétonitrile / eau (62/38) contenant 0,1% d&#39;acide phosphorique et 1% de methanol à un débit de 1 ml / min et un volume d&#39;injection de 10 ul. </li><li> Diluer micelles fraîchement préparés (section 1) 1: 100 dans la phase mobile avant d&#39;analyser par RP-HPLC pour déterminer le chargement initial de la drogue. Magasin non dilués micelles individuelles et DDM à la température ambiante (25 ° C) pendant 48 heures et préparent fraîches 1: 100 échantillons dilués dans la phase mobile de réévaluer par RP-HPLC et de déterminer la drogue (s) de la stabilité dans les micelles plus de 24 h. </li><li> Surveiller DTX et EVR pics à 227 et 279 nm, respectivementavec des temps de rétention de 1,7 min et 5,7 respectivement. Effectuer toutes les mesures en triple exemplaire. Les données actuelles en moyenne ± SD charge médicamenteuse. </li></ol> 3. Évaluation des micelles la taille des particules par diffusion dynamique de lumière (DLS) <ol><li> Diluer micelles fraîchement préparés (comme décrit dans la section 1) dans de l&#39;eau déminéralisée à un ratio de 1:20 pour donner une concentration de polymère finale de 1,5 mg / ml. </li><li> Mesurer l&#39;intensité du laser He-Ne (633 nm) à 173 ° pour déterminer la dispersion. Effectuer toutes les mesures à 25 ° C après pré-équilibrage pendant 2 min. </li><li> Effectuer toutes les mesures en triple exemplaire. Les données actuelles que la taille moyenne du Z-moyenne ± écart avec l&#39;indice de polydispersité (PDI) de la distribution. </li></ol> 4. L&#39;évaluation de médicament in vitro de presse de micelles individuelles et DDM <ol><li> Préparer micelles individuelles et DDM comme décrit dans la section 1. Chargez 2,5 ml de micelles dans une cassette 3 ml de dialyseun poids moléculaire de coupure (MWCO) de 7000 g / mol. NOTE: Ce MWCO a été choisie pour permettre le médicament libre (s) en même temps que les molécules de polymère non associés à diffuser librement hors de la cassette et donc assurer des conditions de puits. </li><li> Placez les cassettes dans 2,5 L de 10 mM pH 7,4 tampon phosphate (préparé en diluant la solution mère de 200 mM) et de changer le tampon toutes les 3 heures pour assurer des conditions de puits. Maintenir la température du tampon à 37 ° C pendant toute la durée de l&#39;expérience. </li><li> A 0, 0,5, 1, 2, 3, 6, 9, 12, 24 et 48 h, retirer de 150 ul de la solution dans les cassettes et le remplacer avec 150 pi de tampon frais. </li><li> Analyser les échantillons en utilisant RP-HPLC comme établie à l&#39;article 2 pour déterminer la concentration du médicament. Ajustement de courbe les drogue (s) de données de rejets fondées sur un modèle simple de diffusion avec une association exponentielle à une phase en utilisant un logiciel stastitical. </li><li> Calculer le temps nécessaire pour atteindre 50% de la libération du médicament (t 1/2) ehaque drogue dans les micelles individuelles ou DDM basé sur l&#39;ajustement de la courbe. Effectuer toutes les mesures en quadruplet. </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...

Copolymères séquencés amphiphiles avec structure en répétant composées de domaines hydrophiles et hydrophobes peuvent spontanément auto-assembler pour former trois ensembles macromoléculaires dimensions connues comme les micelles polymériques. Ces structures ont un noyau hydrophobe interne entouré par une enveloppe hydrophile. Le noyau hydrophobe a la capacité d&#39;incorporer des médicaments hydrophobes soit par piégeage physique ou par des interactions hydrophobes par conjugaison chimique à l&#39;ossature du polymère. 1 De nombreux avantages exister à l&#39;utilisation de ces copolymères à blocs pour former des micelles pour l&#39;administration de médicaments. Ceux-ci comprennent l&#39;incorporation de médicaments peu solubles, ce qui améliore la pharmacocinétique des médicaments incorporés, et la biocompatibilité et / ou de la biodégradabilité des polymères en fait une solution de rechange sans danger à des solubilisants classiques. 2 Un autre avantage de l&#39;utilisation des micelles polymères est leur taille de particule colloïdale, entre 15- 3 150 nm, ce qui les rend attrayants pour parenteral livraison. Par conséquent, au cours des 20 dernières années micelles polymères ont émergé comme les systèmes de délivrance de médicaments viables pour les médicaments solubles dans l&#39;eau en particulier pour le traitement du cancer 3,4. Actuellement, il existe cinq formulations micellaires polymères pour la thérapie du cancer subissant des essais cliniques. 4 Quatre des micelles dans les essais cliniques sont copolymères diblocs à base de PEG tandis que le dernier est un copolymère triséquencé d&#39;oxyde de polyéthylène contenant. La taille de ces micelles varie de 20 nm à 85 nm. L&#39;avantage d&#39;utiliser des polymères à base de PEG est leur biocompatibilité et en fonction de la deuxième séquence peut aussi être biodégradable. Récemment de nouveaux systèmes de délivrance de médicaments basés sur le bloc polyethyleneglycol- acide -polylactic (PEG b -PLA) micelles polymères ont été développés pour la livraison simultanée de plusieurs médicaments anticancéreux. Les micelles PEG-b- PLA sont à la fois biocompatible et biodégradable. Ces multi-drogues micelles chargées ont montré queynergistic inhibition de différents modèles de cancers in vitro et in vivo et 2,5,6 ajustement dans le paradigme actuel de l&#39;utilisation de plusieurs médicaments dans la chimiothérapie pour prévenir la résistance et abaisser la toxicité. Par conséquent, il ya un grand intérêt dans la préparation et la caractérisation de ces systèmes de délivrance de médicaments micellaires pour une utilisation dans le cancer et d&#39;autres états pathologiques. Dans le travail ci-dessous, nous avons défini un processus étape par étape par laquelle ces micelles peuvent être préparés et caractérisés avant de les évaluer dans des états pathologiques d&#39;intérêt. Aux fins de ce travail deux agents anti-cancéreux mal-solubles, le docétaxel (DTX) et l&#39;évérolimus (EVR) ont été choisis. Les deux DTX et EVR sont des composés peu solubles dans l&#39;eau avec solubilité dans l&#39;eau intrinsèques à 1,9 et 9,6 pg / ml respectivement. 7,8 Deux PEG-b -PLA polymères avec des poids moléculaires différents ont été utilisés dans ce protocole que les blocs de construction pour le polymère formulée à des micelles,ces polymères sont PEG 2000 - b -PLA 1800 (3800 Da) et le PEG 4000 - b -PLA 2200 (6200 Da). PEG-b de micelles -PLA peuvent donc fournir une plate-forme unique en tant que nanocarrier pour DTX et EVR individuellement et en combinaison. Les réactifs / Matériels et équipements requis nécessaires pour préparer et caractériser ces micelles sont énumérés dans le tableau 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

Copolymères séquencés amphiphiles comme bloc polyethyleneglycol- acide -polylactic (PEG b- PLA) peuvent auto-assembler dans des micelles-dessus de leur concentration micellaire critique formant noyaux hydrophobes entourés par des obus hydrophiles dans des environnements aqueux. Le noyau de ces micelles peut être utilisé pour charger, des médicaments peu solubles hydrophobes comme le docétaxel (DTX) et l&#39;évérolimus (EVR). Caractérisation systématique de la capacité de la structure micellaire et la charge de médicament est importante avant in vitro et in vivo peut être réalisée. Le but du protocole décrit ci-après est de fournir les étapes de caractérisation nécessaires à la réalisation des produits micellaires normalisés. DTX EVR et ont des solubilités intrinsèques de 1,9 et 9,6 pg / ml respectivement préparation de ces micelles peut être réalisé par coulée au solvant qui augmente la solubilité aqueuse de DTX et EVR à 1,86 et 1,85 mg / ml, respectivement. La stabilité des médicaments dans les micelles evald&#39;atténuations à la température ambiante pendant 48 heures indique que 97% ou plus des médicaments sont conservées en solution. La taille des micelles a été évaluée en utilisant la diffusion dynamique de la lumière et a indiqué que la taille de ces micelles est inférieure à 50 nm et dépend de la masse moléculaire du polymère. La libération du médicament à partir des micelles a été évaluée en utilisant la dialyse dans des conditions d&#39;évier à pH 7,4 à 37 o C pendant 48 h. Courbe résultats de l&#39;ajustement indiquent que la libération du médicament est entraîné par un premier processus de commande indiquant qu&#39;il est entraînée diffusion.

DTX individu ou micelles EVR et DTX et EVR DDM dans PEG-b -PLA micelles sont formulés avec succès dans les deux PEG 4000 - b -PLA 2 200 ou PEG 2000 - b -PLA 1800 (Figure 1). DTX, EVR, et le DDM ont montré une stabilité similaire dans PEG 4000 - b -PLA 2200 ou PEG 2000 - b -PLA 1 800 plus de 48 heures (Figure 2). ...

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.

Préparation et caractérisation de la personne et de multi-drogue Loaded Physiquement piégé micelles polymériques

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 vues.  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.

Vidéo: 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-et-piscine Synthèse et caractérisation de peptides tertiaire Amide Bibliothèque

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

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Chimie

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.

Cadres de synthèse et la caractérisation de fonctionnalisé métal-organique

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.

Préparation et caractérisation des SDF-1α-chitosane-Sulfate de Dextran nanoparticules

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.

Synthèse et caractérisation de supramoléculaires 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).

Cathodoluminescence basse énergie pour (Oxy) luminophores de Nitrure

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.

Synthèse Facile de micelles Worm-like par lumière visible Mediated Dispersion Polymérisation En utilisant photoredox Catalyst

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.

Anionique Polymérisation d&#39;un copolymère amphiphile pour la préparation du copolymère bloc micelles Stabilisé par π-tc Interactions Stacking

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.

Synthèse des polymères cycliques et caractérisation de leur mouvement Diffusive dans l&#39;État Melt à la molécule unique 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 ...

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.

Synthèse des colorants polymères végétaux Phénol dérivés pour Direct ou Mordant-base Teinture de cheveux

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.

Préparation et<em&gt; In vitro</em&gt; Caractérisation des agents de contraste à base de dendrimères pour imagerie par résonance magnétique

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