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. Preparazione di singoli e multi-droga Micelle caricate da solvente Metodo Casting <ol><li> Pesare DTX 1 mg o EVR 1 mg o di entrambi i farmaci a 1 mg ciascuna per le micelle doppio farmaco (DDM). </li><li> Pesare 15 mg di PEG 2000 - b -PLA 1800 e PEG 4000 - b -PLA 2200 sia per individuali o DDM. </li><li> Sciogliere le droghe / farmaci e il polimero in 0,5 ml di acetonitrile e posto in un pallone a fondo tondo da 5 ml. </li><li> Forma un film polimerico farmaco distribuito sottile facendo evaporare il farmaco (s) soluzione acetonitrile -polymer sotto pressione ridotta utilizzando un evaporatore rotante. Impostare l&#39;evaporatore rotante a 100 rpm, la temperatura dell&#39;acqua di 40 vasca o C e una pressione di 260 mbar di vuoto per 5 minuti, seguito da una riduzione a 100 mbar per ulteriori 3 min. </li><li> Reidratare il film di droga-polimero con 0,5 ml di acqua deionizzata a 50 ° C e scuotere delicatamente il pallone per formare le micelle. </li><li> Filtrare il risultatoing soluzione micellare attraverso un filtro di nylon 0,2 micron per rimuovere qualsiasi farmaco o contaminanti un-dissolto in una provetta da centrifuga da 1,5 ml. </li></ol> 2. Valutazione di droga Caricamento e alla stabilità nel Micelle Utilizzando Reverse-fase ad alte prestazioni cromatografia liquida (RP-HPLC) <ol><li> Effettuare analisi RP-HPLC con una colonna C8 equilibriated a 40 ° C in una modalità isocratica con una fase mobile di acetonitrile / acqua (62/38) contenente 0,1% di acido fosforico e 1% di metanolo ad una portata di 1 ml / min e un volume di iniezione di 10 ml. </li><li> Diluire micelle preparati al momento (sezione 1) 1: 100 in fase mobile prima di analizzare da RP-HPLC per determinare caricamento iniziale della droga. Conservare diluiti individuali micelle e DDM a temperatura ambiente (25 ° C) per 48 ore e si preparano freschi 1: 100 campioni diluiti in fase mobile di rivalutare da RP-HPLC e determinare droga (s) stabilità in micelle oltre 24 ore. </li><li> Monitorare DTX e EVR picchi a 227 e 279 nm, rispettivamentecon tempi di ritenzione di 1,7 e 5,7 minuti rispettivamente. Eseguire tutte le misurazioni in triplice copia. Presentare i dati come media ± SD droga carico. </li></ol> 3. valutazione delle dimensioni delle particelle micelle da Dynamic Light Scattering (DLS) <ol><li> Diluire micelle preparate (come descritto nella sezione 1) in acqua deionizzata a rapporto 1:20 per ottenere una concentrazione finale di 1,5 mg di polimero / ml. </li><li> Misurare l&#39;intensità del laser He-Ne (633 nm) a 173 ° per determinare dispersione. Eseguire tutte le misurazioni a 25 ° C dopo un pre-equilibrazione per 2 minuti. </li><li> Eseguire tutte le misurazioni in triplice copia. Dati presente come dimensione media Z-media ± SD insieme con l&#39;indice di polidispersità (PDI) della distribuzione. </li></ol> 4. Valutazione in vitro Drug uscita da Micelle individuali e DDM <ol><li> Preparare i singoli micelle e DDM come descritto nella sezione 1. Caricare 2,5 ml di micelle in una cassetta da 3 ml con dialisiun peso molecolare di cut-off (MWCO) di 7000 g / mol. NOTA: Questo MWCO stato scelto per consentire al farmaco libero (s) insieme con le molecole di polimero non associate a diffondere liberamente dalla cassetta e quindi garantire condizioni sink. </li><li> Posizionare le cassette in 2,5 L di 10 mM pH 7,4 tampone fosfato (diluire soluzione madre 200 mm) e modificare il buffer ogni 3 ore per garantire condizioni di sink. Mantenere la temperatura del tampone a 37 ° C per tutta la durata dell&#39;esperimento. </li><li> A 0, 0,5, 1, 2, 3, 6, 9, 12, 24, e 48 ore, prelevare 150 microlitri della soluzione in cassette e sostituire con 150 ml di tampone fresco. </li><li> Analizzare i campioni utilizzando RP-HPLC previste nella sezione 2 per determinare la concentrazione del farmaco. Curve-fit dei dati di rilascio del farmaco (s) sulla base di un modello di diffusione semplice con un&#39;associazione esponenziale una fase utilizzando il software stastitical. </li><li> Calcolare il tempo necessario per raggiungere il 50% di rilascio di farmaci (t 1/2) edroga ach in singoli micelle o DDM in base alla curva raccordo. Eseguire tutte le misure in quaterna. </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...

Copolimeri a blocchi anfifilici con struttura ripetendo composta da domini idrofili e idrofobi possono spontaneamente auto-assemblano a formare tre assemblee macromolecolari tridimensionali conosciuti come micelle polimeriche. Queste strutture hanno un core idrofobico interno circondato da un guscio idrofilo. Il core idrofobico ha la capacità di incorporare farmaci idrofobici mediante intrappolamento fisico attraverso interazioni idrofobiche o mediante coniugazione chimica a catena polimerica. 1 Molti vantaggi esistono per utilizzare questi copolimeri a blocchi per formare micelle per il drug delivery. Questi includono l&#39;incorporazione di farmaci scarsamente solubili, migliorando farmacocinetica dei farmaci incorporati, e la biocompatibilità e / o biodegradabilità dei polimeri li rende un sostituto sicuro per solubilizzanti convenzionali. 2 Un altro vantaggio dell&#39;utilizzo di micelle polimeriche è la loro granulometria colloidale, tra 15- 150 nm 3, che li rende attraenti per paconsegna renteral. Pertanto, nel corso degli ultimi 20 anni micelle polimeriche sono emersi come sistemi di drug delivery vitali per farmaci scarsamente solubili in acqua soprattutto per la terapia del cancro. 3,4 Attualmente ci sono cinque formulazioni micellari polimerici per la terapia del cancro in fase di sperimentazione clinica. 4 Quattro delle micelle negli studi clinici sono copolimeri a base di PEG diblock mentre l&#39;ultimo è un copolimero a tre blocchi contenente polietilenossido. La dimensione di queste micelle variava da 20 nm a 85 nm. Il vantaggio di usare polimeri a base di PEG è la loro biocompatibilità e in funzione del secondo blocco può anche essere biodegradabili. Recentemente nuovi sistemi di somministrazione dei farmaci a base di acido -polylactic blocco polyethyleneglycol- (PEG-b -PLA) micelle polimeriche sono stati sviluppati per la consegna contemporanea di più farmaci antitumorali. Le micelle PEG-b- PLA sono sia biocompatibile e biodegradabile. Questi multi-farmaco micelle caricati hanno dimostrato comeinibizione ynergistic di diversi modelli di tumori in vitro e in vivo e in forma 2,5,6 nella corrente paradigma di utilizzare più farmaci in chemioterapia per prevenire la resistenza e ridurre la tossicità. Pertanto, non vi è un grande interesse per la preparazione e la caratterizzazione di questi sistemi di drug delivery micellari per l&#39;uso nel cancro e altre malattie. Nel lavoro di seguito abbiamo delineato un processo step-by-step per cui tali micelle possono essere preparati e caratterizzati prima di valutare negli stati di malattia d&#39;interesse. Ai fini di questo lavoro, docetaxel (DTX) e everolimus (EVR) sono stati scelti due agenti anti-tumorali scarsamente solubili. Sia DTX e EVR sono composti scarsamente solubili in acqua con solubilità in acqua intrinseche a 1,9 e 9,6 mg / ml. 7,8 Due PEG-polimeri b -PLA con diversi pesi molecolari sono stati utilizzati in questo protocollo, come i mattoni per la polimerico formulato micelle,questi polimeri sono PEG 2000 - b -PLA 1800 (3.800 Da) e PEG 4000 - b -PLA 2200 (6.200 Da). PEG micelle b -PLA possono quindi fornire una piattaforma unica come nanocarrier per DTX e EVR individualmente e in combinazione. Le richieste Reagenti / Materiali e attrezzature necessarie per preparare e caratterizzare queste micelle sono elencati nella tabella 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

Copolimeri a blocchi anfifilici come blocco polyethyleneglycol- acido -polylactic (PEG-b- PLA) possono auto-assemblarsi in micelle di sopra del loro concentrazione micellare critica che formano nuclei idrofobici circondati da gusci idrofili in ambienti acquosi. Il nucleo di queste micelle può essere utilizzato per caricare farmaci idrofobici, scarsamente idrosolubili come docetaxel (DTX) e everolimus (EVR). Caratterizzazione sistematica delle capacità della struttura micelle e droga di carico sono importanti prima in vitro e in vivo può essere effettuata. L&#39;obiettivo del protocollo qui descritto è quello di fornire le misure di caratterizzazione necessari per realizzare prodotti micellari standardizzati. DTX e EVR hanno solubilità intrinseca di 1,9 e 9,6 mg / ml Preparazione di queste micelle può essere realizzato per fusione solvente che aumenta la solubilità in acqua di DTX e EVR a 1,86 e 1,85 mg / ml, rispettivamente. Stabilità droga in micelle evalranea a temperatura ambiente per 48 ore indica che il 97% o più dei farmaci sono mantenuti in soluzione. Dimensioni micella è stata valutata utilizzando light scattering dinamico e indicato che la dimensione di queste micelle era inferiore a 50 nm e dipendeva dal peso molecolare del polimero. Rilascio del farmaco da parte delle micelle è stata valutata utilizzando la dialisi, in condizioni sink a pH 7,4 a 37 ° C oltre 48 ore. Curve risultati adatti indicano che il rilascio del farmaco è guidato da un processo di primo ordine che indica che è guidato diffusione.

DTX individuali o micelle EVR e DTX e EVR DDM in PEG b -PLA micelle sono formulati con successo in entrambi i PEG 4000 - b -PLA 2200 o PEG 2000 - b -PLA 1800 (Figura 1). DTX, EVR, e il DDM ha mostrato stabilità simile a PEG 4000 - b -PLA 2200 o PEG 2000 - b -PLA 1800 più di 48 ore (Figura 2). Caricamento farmacolog...

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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.

Preparazione e caratterizzazione di individuale e Multi-droga Loaded Fisicamente intrappolate polimerici Micelle

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

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Chemistry

11.2K Views.  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.

Video: 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-e-pool Sintesi e caratterizzazione di peptidi Terziario Ammide Biblioteca

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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Chimica

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.

Sintesi e caratterizzazione di funzionalizzato metallo-organici quadri

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.

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.

Preparazione e caratterizzazione di SDF-1α-Chitosan-Destrano solfato nanoparticelle

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.

Sintesi e caratterizzazione di supramolecolari colloidi

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

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.

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.

Anionico polimerizzazione di un copolimero Amphiphilic per la preparazione di copolimero a blocchi micelle stabilizzata da π-¸ Interazioni 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.

Sintesi di ciclici polimeri e caratterizzazione di loro moto diffusivo allo stato fuso alla molecola Piano unico

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.

Sintesi di Plant fenolo-derivati ​​polimerici Colorante per tintura diretto o Mordente a base di capelli

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.

Preparazione e<em&gt; In Vitro</em&gt; Caratterizzazione del dendrimero a base di agenti di contrasto per risonanza magnetica

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

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We present methods for depositing and passively manipulating C60 molecules on rippled graphene that advance the pursuit of realizing applications involving 1D C60/graphene hybrid structures. The techniques applied in this exposition are geared towards high vacuum systems with preparation areas capable of supporting molecular deposition as well as thermal annealing of the samples. We focus on C60 deposition at low pressure using a homemade Knudsen cell connected to a scanning tunneling microscopy (STM) system. The number of molecules deposited is regulated by controlling the temperature of the Knudsen cell and the deposition time. One-dimensional (1D) C60 chain structures with widths of two to three molecules can be prepared via tuning of the experimental conditions. The surface mobility of the C60 molecules increases with annealing temperature allowing them to move within the periodic potential of the rippled graphene. Using this mechanism, it is possible to control the transition of 1D C60 chain structures to a hexagonal close packed quasi-1D stripe structure.

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Here we present a protocol for the fabrication of C60/graphene hybrid nanostructures by physical thermal evaporation. Particularly, the proper manipulation of deposition and annealing conditions allow the control over the creation of 1D and quasi 1D C60 structures on rippled graphene.

Preparazione e caratterizzazione di nanostrutture ibride C60/Graphene

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We ...

Synthesis and Characterization of 1,2-Dithiolane Modified Self-Assembling Peptides

This report focuses on the synthesis of an N-terminus 1,2-dithiolane modified self-assembling peptide and the characterization of the resulting self-assembled supramolecular structures. The synthetic route takes advantage of solid-phase peptide synthesis with the on-resin coupling of the dithiolane precursor molecule, 3-(acetylthio)-2-(acetylthiomethyl)propanoic acid, and the microwave-assisted thioacetate deprotection of the peptide N-terminus before final cleavage from the resin to yield the 1,2-dithiolane modified peptide. After the high-performance liquid chromatography (HPLC) purification of the 1,2-dithiolane peptide, derived from the nucleating core of the A&#946; peptide associated with Alzheimer&#39;s disease, the peptide is shown to self-assemble into cross-&#946; amyloid fibers. Protocols to characterize the amyloid fibers by Fourier-transform infrared spectroscopy (FT-IR), circular dichroism spectroscopy (CD) and transmission electron microscopy (TEM) are presented. The methods of N-terminal modification with a 1,2-dithiolane moiety to well-characterized self-assembling peptides can now be explored as model systems to develop post-assembly modification strategies and explore dynamic covalent chemistry on supramolecular peptide nanofiber surfaces.

A protocol for the synthesis of a 1,2-dithiolane modified peptide and the characterization of the supramolecular structures resulting from the peptide self-assembly.