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. Herstellung von Einzel- und Multi-Drogen-Loaded Mizellen durch Lösungsmittelgießen Methode <ol><li> Abwiegen DTX 1 mg oder EVR 1 mg oder beide Medikamente bei 1 mg jeweils für die Dual-Drogen Mizellen (DDM). </li><li> Man wiegt 15 mg PEG 2000 - b -PLA 1800 oder PEG 4000 - b -PLA 2200 für individuelle oder DDM. </li><li> Lösen die Arzneimittel / Drogen und das Polymer in 0,5 ml Acetonitril und in eine 5 ml-Rundkolben. </li><li> Bilden eine dünne Arzneimittelpolymerschicht verteilt durch Verdampfen des Arzneimittel (s) -Polymer Acetonitril-Lösung unter vermindertem Druck unter Verwendung eines Rotationsverdampfers. Den Drehverdampfer auf 100 Upm, die Wasserbadtemperatur von 40 ° C und einem Unterdruck von 260 mbar für 5 min, gefolgt von einer Reduktion auf 100 mbar für weitere 3 min. </li><li> Rehydrieren die Wirkstoff-Polymer-Film mit 0,5 ml deionisiertem Wasser bei 50 ° C und die Flasche schütteln, um die Mizellen zu bilden. </li><li> Filtern Sie die Ergebnisseing micellare Lösung durch ein 0,2 um Nylon-Filter, um jede nicht gelösten Arzneimittels oder Verunreinigungen in einem 1,5 ml Zentrifugenröhrchen zu entfernen. </li></ol> 2. Bewertung der Wirkstoffbeladung und Stabilität in Mizellen mit Reverse-Phase-Hochleistungsflüssigchromatographie (RP-HPLC) <ol><li> Zuführen RP-HPLC-Analyse mit einer C8-Säule bei 40ºC mit einer mobilen Phase aus Acetonitril / Wasser (62/38), das 0,1% Phosphorsäure und 1% Methanol bei einer Fließgeschwindigkeit von 1 ml / min equilibriert in einem isokratischen Modus und einem Injektionsvolumen von 10 ul. </li><li> Verdünnen Sie frisch zubereitete Mizellen (Abschnitt 1) ​​1: 100 in der mobilen Phase vor der Analyse durch RP-HPLC, um anfängliche Wirkstoffbeladung zu bestimmen. Shop unverwässerte einzelnen Mizellen und DDM bei Raumtemperatur (25 ° C) für 48 Stunden und bereiten frische 1: 100 verdünnten Proben in der mobilen Phase neu zu bewerten durch RP-HPLC und Drug (s) Stabilität in Mizellen bestimmen, über 24 Stunden. </li><li> Überwachen DTX und EVR Peaks bei 227 und 279 nm bzw.mit Retentionszeiten von 1,7 und 5,7 min auf. Führen Sie alle Messungen in dreifacher Ausfertigung. Vorliegenden Daten als Mittelwert ± SD Wirkstoffbeladung. </li></ol> 3. Bewertung der Mizellen Partikelgröße mittels dynamischer Lichtstreuung (DLS) <ol><li> Verdünnter frisch hergestellten Mizellen in entionisiertem Wasser in einem Verhältnis von 1:20 (wie in Abschnitt 1 beschrieben), um eine endgültige Polymerkonzentration von 1,5 mg / ml zu ergeben. </li><li> Messen der Intensität des He-Ne-Laser (633 nm) bei 173 ° bis Streuung zu bestimmen. Führen Sie alle Messungen bei 25 ° C folgende pre-Äquilibrierung für 2 min. </li><li> Führen Sie alle Messungen in dreifacher Ausfertigung. Vorhandenen Daten als Mittelwert Z-durchschnittliche Größe ± SA zusammen mit der Polydispersitätsindex (PDI) der Verteilung. </li></ol> 4. Bewertung der In-vitro-Wirkstofffreisetzung aus Einzel Mizellen und DDM <ol><li> Bereiten einzelnen Mizellen und DDM, wie in Abschnitt 1. Legen Sie 2,5 ml der Mizellen in einen 3 ml Dialysekassette mit beschriebenein Molekulargewicht-Cut-off (MWCO) von 7.000 g / mol. ANMERKUNG: Diese MWCO wurde gewählt, um das freie Arzneimittel (n) zusammen mit den nicht-assoziierten Polymermoleküle zu ermöglichen, sich frei aus der Kassette diffundieren und dadurch sicherzustellen Sinkbedingungen. </li><li> Legen Sie die Kassetten in 2,5 l 10 mM pH 7,4 Phosphatpuffer (durch Verdünnen Lager 200 mM Lösung hergestellt), und ändern Sie den Puffer alle 3 Stunden, um Sink-Bedingungen zu gewährleisten. Aufrechterhaltung der Temperatur des Puffers bei 37 ° C während der gesamten Dauer des Experiments. </li><li> Bei 0, 0,5, 1, 2, 3, 6, 9, 12, 24 und 48 Stunden, zurückzutreten 150 ul der Lösung in den Kassetten und ersetzen mit 150 ul frischem Puffer. </li><li> Analysieren Sie die Proben unter Verwendung von RP-HPLC, wie in Kapitel 2 festgelegt, um die Arzneimittelkonzentration zu bestimmen. Kurvenanpassung die Drug (s) Release-Daten auf der Basis einer einfachen Diffusionsmodell mit einer Phase exponentiellen Verband mit stastitical Software. </li><li> Berechnet die benötigte Zeit, bis 50% Wirkstofffreisetzung erreicht (t 1/2) each Medikament in einzelnen Mizellen oder DDM basierend auf der Kurvenanpassung. Führen Sie alle Messungen in Vierergruppe. </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...

Amphiphilen Blockcopolymeren mit sich wiederholenden Struktur aus hydrophilen und hydrophoben Domänen spontan selbstorganisieren, um dreidimensionale makromolekularen Anordnungen als polymere Mizellen zu bilden. Diese Strukturen haben eine innere hydrophobe Kern, der von einer hydrophilen Schale umgeben ist. Der hydrophobe Kern hat die Fähigkeit, hydrophobe Arzneimittel entweder durch physikalischen Einschluß durch hydrophobe Wechselwirkungen oder durch chemische Konjugation an das Polymergerüst einzubauen. 1 Viele Vorteile bestehen bei der Verwendung dieser Blockcopolymere Micellen zur Arzneimittelabgabe zu bilden. Diese umfassen den Einbau von schlecht löslichen Arzneimitteln, die Verbesserung der pharmakokinetischen Eigenschaften der eingearbeiteten Arzneimittel und die Biokompatibilität und / oder die biologische Abbaubarkeit der Polymeren macht sie eine sichere Alternative zu herkömmlichen Lösungsvermittlern. 2 Ein weiterer Vorteil der Verwendung von polymeren Mizellen ist ihre kolloidale Teilchengröße zwischen 15- 150 nm 3, so dass sie für pa attraktivrenteral Lieferung. Deshalb in den letzten 20 Jahren polymere Mizellen wurden als lebensfähig Drug Delivery-Systemen für schlecht wasserlösliche Arzneimittel vor allem für die Krebstherapie 3,4 entstand. Derzeit gibt es fünf polymere mizellaren Formulierungen für die Krebstherapie in der klinischen Erprobung. 4 Vier der Mizellen in klinischen Studien sind auf PEG-Basis Diblockcopolymere während das letzte ein Triblockcopolymer Polyethylenoxid enthält. Die Größe dieser Micellen variiert von 20 nm bis 85 nm. Der Vorteil der Verwendung von PEG basierenden Polymere ist ihre Biokompatibilität und abhängig vom zweiten Block kann auch biologisch abbaubar sein. Kürzlich neuen Drug Delivery-Systemen auf Basis von Polyethylenglykol- Block -Polymilchsäure (PEG-b -PLA) polymere Mizellen sind für die gleichzeitige Bereitstellung von mehreren Krebsmedikamente entwickelt. Die PEG-b- PLA Mizellen sind sowohl biokompatibel und biologisch abbaubar. Diese Mehr Arzneimittel beladene Mizellen wie gezeigtynergistic Hemmung von verschiedenen Krebsmodellen in vitro und in vivo 2,5,6 und passen in die aktuelle Paradigma unter Verwendung mehrerer Chemotherapeutika, um Widerstand zu verhindern und Absenken Toxizität. Daher gibt es ein großes Interesse in der Herstellung und Charakterisierung dieser mizellaren Arzneistoffabgabesysteme zur Verwendung bei Krebs und anderen Krankheitszuständen. In der Arbeit unten haben wir einen Schritt-für-Schritt-Verfahren, mit denen solche Mizellen können hergestellt und charakterisiert, bevor sie in die Bewertung von Krankheitszuständen von Interesse werden skizziert. Für den Zweck dieser Arbeit zwei schlecht löslichen Antikrebsmitteln, Docetaxel (DTX) und Everolimus (EVR) wurden ausgewählt. Sowohl DTX und EVR sind schlecht wasserlösliche Verbindungen mit intrinsischen Wasserlöslichkeit bei 1,9 und 9,6 &amp; mgr; g / ml. 7,8 zwei PEG-b -PLA Polymeren mit unterschiedlichen Molekulargewichten wurden in diesem Protokoll als Bausteine ​​für die formulierten polymeren verwendet Micellendiese Polymere PEG 2000 - b -PLA 1800 (3800 Da) und PEG 4000 - b -PLA 2200 (6200 Da). PEG-b -PLA Mizellen kann deshalb eine einzigartige Plattform als Nanotransporter für DTX und EVR einzeln und in Kombination. Die benötigten Reagenzien / Erforderliche Materialien und Geräte für die Vorbereitung und charakterisieren diese Mizellen sind in Tabelle 1 aufgeführt.

<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

Amphiphile Blockcopolymere wie Polyethylenglykol- Block -Polymilchsäure (PEG-b-PLA) können durch Selbstorganisation Micellen oberhalb ihrer kritischen Mizellenkonzentration bilden hydrophobe Kerne durch hydrophile Schale in wässrigen Umgebungen umgeben. Der Kern dieser Mizellen können genutzt werden, um hydrophobe, schlecht wasserlöslichen Medikamenten wie Docetaxel (DTX) und Everolimus (EVR) zu laden. Systematische Charakterisierung der Mizellen-Struktur und Wirkstoffbeladung Fähigkeiten sind wichtig, vor der in vitro und in vivo-Studien durchgeführt werden. Das Ziel des hierin beschriebenen Protokolls ist es, die notwendigen Schritte zur Charakterisierung standardisierten micellare Produkte erzielen. DTX EVR intrinsische Löslichkeiten von 1,9 und 9,6 ug / ml Die Herstellung dieser Mizellen kann durch Lösungsmittelgießen, welche die Wasserlöslichkeit des DTX EVR bis 1,86 und 1,85 mg / ml erhöht erreicht werden. Arzneimittelstabilität in Mizellen evalüber 48 Stunden bei Raumtemperatur ausgewertet zeigt an, dass 97% oder mehr der Arzneimittel in Lösung gehalten wird. Mizellengröße wurde unter Verwendung der dynamischen Lichtstreuung bewertet und zeigte, daß die Größe dieser Micellen unter 50 nm und hing von dem Molekulargewicht des Polymers. Wirkstofffreisetzung aus den Micellen wurde mittels Dialyse unter Sink-Bedingungen bei pH 7,4 bei 37 ° C über 48 Stunden beurteilt. Kurvenanpassung Ergebnisse zeigen, dass Wirkstofffreisetzung ist von einem Prozess erster Ordnung anzeigt, dass sie die Diffusion angetrieben.

Einzelne DTX oder EVR Mizellen und DTX und EVR DDM in PEG-b -PLA Mizellen erfolgreich entweder in PEG 4000 formuliert - b -PLA 2200 oder PEG 2000 - b -PLA 1800 (Abbildung 1). DTX EVR und DDM zeigten ähnliche Stabilität in PEG 4000 - b -PLA 2200 oder PEG 2000 - b -PLA 1800 über 48 Stunden (Abbildung 2). Anfänglich...

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.

Herstellung und Charakterisierung von Einzel-und Multi-Wirkstoff beladen Körperlich Eingeschlossene Polymermicellen

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 Aufrufe.  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.

Serie: 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-Pool-Synthese und Charakterisierung von Peptid-Amid-Tertiär-Bibliothek

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

Forschung

Chemie

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.

Synthese und Charakterisierung von funktionalisierten Metall-organische Gerüste

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.

Herstellung und Charakterisierung von SDF-1α-Chitosan-Nanopartikel Dextransulfat

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.

Synthese und Charakterisierung von supramolekularen Kolloid-

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).

Niederenergetische Kathodolumineszenz für (Oxy) Nitride Phosphore

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.

Einfache Synthese von wurmartigen Mizellen durch sichtbares Licht Mediated Dispersion Polymerisation mit Photoredox Katalysator

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.

Die anionische Polymerisation eines amphiphilen Copolymer zur Herstellung von Blockcopolymermicellen Stabilisiert durch π-π-Stapelwechselwirkungen

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.

Synthese cyclischer Polymere und Charakterisierung ihrer Diffusionsbewegung im geschmolzenen Zustand auf der Einzelmolekülebene

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.

Synthese von Pflanzen Phenol abgeleitete Polymere Farbstoffe für die direkte oder Beize-basierte Haarfärbung

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.

Vorbereitung und<em&gt; In Vitro</em&gt; Charakterisierung der für Magnetresonanz-Kontrastmittel Dendrimer-basierten

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