KG wurde von der RA Welch Foundation Zuschuss P-1760 unterstützt, TCU Andrews Institut für Mathematik und Pädagogik der Naturwissenschaften (KG), TCU Forschung und Kreativität Aktivität Grant (KG) und TCU SERC Grant (bis JHS).

1. Synthese von Biotin-Fc-cystein (1) <ol><li> Festphasenverfahren zur Herstellung von harzgebundenen 1. <ol><li> Zeigen Biotin beladene Harz (250 mg, 0,145 mmol) in eine Fritten Spritze und quellen des Harzes durch die Aufstellung Dimethylformamid (5 ml) und Schütteln der Spritze auf einen Laborschüttler für 20 min. Vertreiben die Lösung und wiederholen Dimethylformamid Schwellungen noch einmal. </li><li> Entfernen Sie die Fmoc-Schutzgruppe durch Zugabe von 6.4 ml 20% Piperidin in Dimethylformamid mit der Spritze, gefolgt von 10-15 Minuten schütteln. Wiederholen Sie den Entschützungsverfahren mit etwa 4-6 ml Piperidin. Methanol (1: 1), 3x Methanol: Dichlormethan (1: 1) mit einer Sequenz von 3x Dimethylformamid, 3x Dimethylformamid Waschen des Harzes, 3x Dichlormethan, ~ 5 ml. Machen einen Ninhydrintest (+) auf eine kleine Proben (~ 10) der Kügelchen eine erfolgreiche Entfernung der Schutzgruppe durch die Anwesenheit von blau nach Erhitzen zu bestätigen. </li><li> Mix eine Lösung, die 1&#39;-Fmoc-amino-ferrocen-1-carbonsäure(203,3 mg, 0,4350 mmol), 1-Hydroxybenzotriazolhydrat (58,8 mg, 0,413 mmol), Diisopropylcarbodiimid (0,0673 ml, 0,435 mmol), Diisopropylethylamin (0,0757 ml, 0,435 mmol) und eine 4: 1 Mischung von Dichlormethan und Dimethylformamid. Zeichnen Sie diese in den Fritten Spritze und schütteln auf einem Laborschüttler 6 Stunden. Dann vertreiben die Lösung aus der Spritze und wasche wie früher beschrieben. </li><li> Führen Sie den Ninhydrintest (-), wie oben beschrieben, um die Kopplung zu bestätigen. Der Ninhydrin-Test immer noch nützlich für die Bestätigung Kopplungs trotz der orange Farbe der Kügelchen von der Befestigung der Eisen enthaltende Einheit abgeleitet ist. </li><li> Dann Entfernen der Fmoc-Gruppe, die durch die Zugabe von 20% igem Piperidin in Dimethylformamid und wie oben beschrieben gewaschen. Der Ninhydrin-Test (+) verwendet werden, um Fmoc Entfernen zu bestätigen. </li><li> Wird eine Lösung aus Fmoc-Cys (Trt) -OH zusammen (254,8 mg, 0,4350 mmol), 1-Hydroxybenzotriazolhydrat (58,8 mg, 0,4125 mmol), Diisopropylcarbodiimid (0,0673 ml, 0,4350mmol), Diisopropylethylamin (0,0757 ml, 0,4350 mmol) und eine 4: 1-Mischung von Dichlormethan und Dimethylformamid. Fügen Sie diese Cysteinkopplung Cocktail die Fritte Spritze und schütteln für 6 Stunden. Waschen unter Verwendung des zuvor beschriebenen Protokolls. </li><li> Bestätigen Koppeln mit der Ninhydrin-Test (-), gefolgt von der Entfernung der Fmoc-Komponente mit 20% Piperidin und Waschen. Den freien terminalen Amins mit dem Ninhydrintest (+). </li></ol></li><li> Die Spaltung von 1 von dem Harz. <ol><li> Machen Sie eine Lösung von TFA (9,45 ml), Wasser (0,25 ml), 1,2-Ethandithiol (0,25 ml) und Triisopropyl Silan (0,1 ml), ist es an der Spritze hinzufügen und leicht schütteln 4 Stunden. </li><li> Sammle den erhaltenen rotbraune Lösung in ein Eppendorf-Röhrchen und verdampfe das TFA langsam unter Verwendung eines Luftstroms. </li><li> Hinzufügen kaltem Diethylether (~ 15 ml) zu dem Eppendorf-Röhrchen zur Ausfällung 1, die leichtem Rühren bildet. Trennen Sie das Produkt durch Zentrifugation (1 g, 5 min). THenne Wiederholungszyklen Diethylether Waschungen (~ 60 ml Gesamtvolumen) und Zentrifuge 1 als rot / braunen Feststoff zu erhalten. </li></ol></li></ol> 2. Charakterisierung und Analyse von 1 <ol><li> Zu bestätigen, dass die Identität der Verbindung und in Figur 2 unter Verwendung von 1 H (16 Abtastungen) und 13 C-NMR (512 Abtastungen) in deuteriertem Methanol (300 ul) und ESI-MS-Analyse gezeigt Zusammensetzung übereinstimmt. Erwarten Sie die folgenden Ergebnisse: 1 H-NMR-Spektrum (CD 3 OD) δ / ppm: 1,407 bis 1,684 (m, 6H), 2,245 (t, 2H), 2,665-3,150 (m, 12H), 4,015 (t, 1H), 4.104 (d, 2H ), 4,274 (q, 1H), 4.426 (d, 2H), 4.479 (q, 1H), 4,595 (t, 1H) und 13 C-NMR-Spektrum (CD 3 OD) δ / ppm: 24,644 (CH 2), 25,472 (CH 2), 28,051 (CH 2), 28.300 (CH2), 35,474 (CH 2), 38.698 (CH2), 39,241 (CH 2), 39,717 (CH 2), 55,340 / 55,538 (Cp-Ring), 60,286 (CH), 61,964 (CH), 62,521 / 62,821 (Cp-Ring), 66,038 / 66,170 (Cp-Ring), 69,153 / 69,328 (Cp-Ring), 71,468 / 71,593 (Cp-Ring), 76,466 (CH), 171,770 (C = O), 175,361 (C = O). ESI-MS (m / z): Gefunden: 639,00 [1 + Na] +, Theoretische: 639,1 [1 + Na] + und HR-MS (m / z): Gefunden: 617,2049 [1 + H] +, Theoretisch: 617.1622 [1 + H] +. </li><li> Eine HPLC, Elementaranalyse, die Zusammensetzung der isolierten 1 bestätigen. Durchführung HPLC Chromatogramme unter Verwendung einer C8-Umkehrphasensäule mit 100% MeOH bei einer Fließgeschwindigkeit von 0,5 ml / min. Hinweis: HPLC-Retentionszeiten waren: 3,198-4,674 min. </li></ol> 3. Immobilisierung von 1 auf einer Goldoberfläche <ol><li> Cut Polymer besicherten Gold-Folien in Quadrate von ~ 0,25 in 2. </li><li> Füllen eines 50 ml Becherglas mit DI-Wasser-Lösung von 1 (~ 1 mm). </li><li> Fügen Sie den Gold Folie, um das Becherglas geben und mit einem Uhrglas. Alleow die Glasobjektträger zu O / N bei RT inkubieren ohne Bewegung. </li><li> Entfernen Sie die Gold Folie aus der Lösung und lassen Sie es an der Luft trocknen. </li><li> Erhalten rasterelektronenmikroskopische Aufnahmen mit einem Rasterelektronenmikroskop (oder Äquivalent) an immobilisiertes Beobachten 1. </li></ol>

The authors have nothing to disclose.

Die Synthese von asymmetrischen Ferrocenderivate ist eine Herausforderung in Lösung. Beispielsweise versucht 1 herzustellen, in Lösung in Folge geringen Ausbeuten an dem gewünschten Produkt (weniger als 20%). Ebenso Reaktionen unter Verwendung 1&#39;-amino-Ferrocencarbonsäure (sans Fmoc) und Harz gebundenen Biotins in unlöslichen Produkt konsistent mit dem polymerisierten Produkt durch Baristic et al. und minimale Produkt. 47 Dies wird weiter durch Ferrocen kompliziert ...

Biosensoren sind kleine Vorrichtungen, die biomolekulare Erkennungstechnologie zu verwenden, wie die Plattform für die selektive Analyse und sind für ihre Spezifität, Geschwindigkeit und kostengünstige verwendet. Elektrochemische Biosensoren zum Nachweis von Biomolekülen sind an der Spitze dieses Feldes aufgrund ihrer Einfachheit, Wirtschaftlichkeit und hohe Empfindlichkeit. 1,3 Die allgemeine Anatomie dieser Sensoren ist eine Elektrode mit einem Erkennungsmolekül ausgestattet spezifisch für die biologischen Marker von Interesse . Bindung des Biomarkers durch die Erkennungsmolekül führt zu einer lokalen Änderung des Potentials oder Stroms, der durch eine einfache Messung erfasst werden können. Um die Erkennungsgruppe stammen aus Enzymen reichen, 4-8 Antikörper, 9-12 ganze Zellen, 13-16 Rezeptoren 17-20 21-23 Peptide und DNA 24 und sind weitgehend auf größere, biologische Moleküle konzentriert. 25-28 Forschung Bemühungen in diesem Bereich haben sich hauptsächlich auf Immun whe konzentriertRe ein Immunglobulin mit einem Redox-aktiven Kern immobilisiert (zB Ferrocen) und verwendet, um einen Antikörper von Interesse zu detektieren. Diese Studien wurden von klinischen Anwendungen aufgrund der schlechten Präzision und Zeitaufwand von den Komplikationen, die sich aus der Nutzung von Antigen / Antikörper stammen ausgeschlossen. 1,3 Wachsende Aufmerksamkeit auf den Nachweis von kleinen Molekülen (weniger als 1 kg / mol) der biomedizinischen Schwerpunkt , Ernährung und Umwelt Interesse neben der nationalen Sicherheit. 29 Die bekanntesten Beispiele für Biosensoren sind Selbsttest Zuckermessgeräte, die Siebdruck Enzymelektroden zu einer Taschenformat amperometrischen Meter gekoppelt haben. Diese Systeme verwenden typischerweise einen coulometrischen Methode, wo die Gesamtmenge an Ladung von der Glucoseoxidationsreaktion erzeugt wird, über einen Zeitraum gemessen. Marktfähige Geräte sind tragbar, robust und in der Hand gehalten, um den Einsatz leicht für die breite Bevölkerung zu machen. Redox-Tags wie Ferrocen sind necessary, um die elektrochemische Detektion von Biomarkern oder kleinen Molekülen in Lösung zu bieten, da die meisten Biomarker sind nicht eigenelektrochemisch aktiv. 30-38 Ferrocen eine metallorganische Molekül, das einen Goldstandard für Elektrochemie, die es eine ausgezeichnete Wahl für die Integration in elektrochemischen Biosensoren macht. Ferrocen-basierte Redox-aktive Spezies wurden bereits große Aufmerksamkeit auf der Grundlage der Ferrocen Kern haben erhielt aufgrund ihrer geringen Größe, gute Stabilität, bequem synthetischen Zugang, einfache chemische Modifikation, relativen Lipophilie und Einfachheit der Redox-Tuning. 3,30-42 Kleine Moleküle intensiv als Detektoren von Metallionen und kleine Moleküle verwendet. 32-38,43 Systeme Targeting größeren Spezies wie Biomoleküle die Anbringung von großen Antikörper oder Immunoglobuline, Ferrocen-Derivate, die auf einer elektrochemischen Oberflächen eingebettet wurden verwendet. 1,3,39 44 In jedem Fall ist das Potential und Strom intensiviertty der Fe-III / Fe II Redoxpaar wurde auf molekulare Kopplung verändert wird, wodurch eine neue spektroskopische Griff, das die Anwesenheit des Analyten Molekül. Diese Änderung ergibt sich aus der umfangreichen Überlappung zwischen dem pi-Systems der Cyclopentadienylringe und den Eisen d-Orbitale auftritt. Wenn das pi-Systems geändert wird, dh, derivatisiert oder umgesetzt wird, dann wird die Bahn-Wechselwirkung wird wiederum Veränderung. Dies wird die Fe Kern beeinflussen und kann als eine Verschiebung des Potentials des Fe-III / Fe II Paar beobachten. 40,45,46 Diese Eigenschaften machen ein solches System attraktiv zur Verwendung als ein Quantifizierungsmittel in einer elektrochemischen Immunoassay oder Biosensor. Um spezifisch für Biosensor Kapazitäten Ferrocen Systeme erzeugen ist es optimal, ein Cp-Ring mit dem Bio-Rezeptor spezifisch für ein Zielmolekül zu modifizieren und nutzen die anderen Cp Ring als Molekular Haltegurt an die elektrochemische Auslese oder elektrode (Abbildung 1). Synthese dieser asymmetrischen Ferrocenderivate wird durch Nebenreaktionen und die Bildung von auf intermolekulare Vernetzung gebildet dimere und polymere Spezies in Frage. 47 ist jedoch Kopplungschemie Herstellung einer Amidbindung der direkteste Weg zu einfachen Derivaten des Ferrocens mit biologischen Komponenten, wie beispiels bereitzustellen Peptide und deren Metaboliten. Daher können Festphasenverfahren zuerst in den 1950er Jahren von Merrifield für die Peptidsynthese entwickelt, um metallorganische Verbindungen Ferrocen verwendet werden. Durch die Verwendung des orthogonal substituiert 1&#39;-Fmoc-amino-ferrocen-1-carbonsäure-Molekül, ein System, das ein Ferrocen-Rezeptoreinheit (Biotin), elektroAuslese (Ferrocen) und Immobilisieren-Linker-Komponente (Cystein) enthalten kann, hat gebaut und hier detailliert beschrieben. Die Synthese dieser Bio-Konjugat wird ebenso diskutiert wie Beweise für die Immobilisierung auf einer Goldoberfläche. Diese Arbeit Vertrets der ersten Präsentation eines Systems von Biotin, Ferrocen und einer Aminosäure zur Immobilisierung auf einer Goldoberfläche besteht.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Biotin Novatag Resin</td>
			<td>NovaBiochem</td>
			<td>8550510001</td>
			<td></td>
		</tr>
		<tr>
			<td>TORVIQ 10ML LUER LOCK FRITTED SYRINGE</td>
			<td>Fisher</td>
			<td>NC9299151</td>
			<td></td>
		</tr>
		<tr>
			<td>piperdine</td>
			<td>Acros</td>
			<td>P/3520/PB05</td>
			<td></td>
		</tr>
		<tr>
			<td>ninhydrin test</td>
			<td>Sigma-Aldrich</td>
			<td>60017-1ea</td>
			<td></td>
		</tr>
		<tr>
			<td>1&#8217;-Fmoc-amino-ferrocene-1-carboxylic acid</td>
			<td>Omm Scientific</td>
			<td>Special Order</td>
			<td></td>
		</tr>
		<tr>
			<td>1-&#8203;Hydroxybenzotriazole hydrate</td>
			<td>Sigma-Aldrich</td>
			<td>157260-25G</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N&#8242;-Diisopropylcarbodiimide</td>
			<td>Sigma-Aldrich</td>
			<td>D125407-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-&#8203;Diisopropylethylamine</td>
			<td>Sigma-Aldrich</td>
			<td>496219-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Fmoc-Cys(Trt)-OH</td>
			<td>Novabiochem</td>
			<td>8520080025</td>
			<td></td>
		</tr>
		<tr>
			<td>trifluoroacetic acid</td>
			<td>Sigma-Aldrich</td>
			<td>T5408</td>
			<td></td>
		</tr>
		<tr>
			<td>1,2-ethanedithiol</td>
			<td>Sigma-Aldrich</td>
			<td>2930</td>
			<td></td>
		</tr>
		<tr>
			<td>triisopropyl silane</td>
			<td>Sigma-Aldrich</td>
			<td>233781</td>
			<td></td>
		</tr>
		<tr>
			<td>Eppendorf tubes (20 mL)</td>
			<td>any source</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>methanol</td>
			<td>any source</td>
			<td></td>
			<td>dry with molecular sieves prior to use &#38; store in 100 mL media bottle for easy usage.</td>
		</tr>
		<tr>
			<td>dichloromethane</td>
			<td>any source</td>
			<td></td>
			<td>dry with molecular sieves prior to use &#38; store in 100 mL media bottle for easy usage.</td>
		</tr>
		<tr>
			<td>dimethylformamide</td>
			<td>any source</td>
			<td></td>
			<td>dry with molecular sieves prior to use &#38; store in 100 mL media bottle for easy usage.</td>
		</tr>
		<tr>
			<td>centrifuge</td>
			<td>any source</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

synthetic methodology for asymmetric ferrocene derived bio-conjugate systems via solid phase resin-based methodology

Früherkennung ist ein Schlüssel zur erfolgreichen Behandlung der meisten Krankheiten, und ist vor allem dann wichtig für die Diagnose und Behandlung von vielen Arten von Krebs. Die am häufigsten verwendeten Techniken sind bildgebende Verfahren wie Kernspintomographie (MRT), Positronen-Emissions-Topographie (PET) und Computertomographie (CT) und sind optimal für das Verständnis der physikalischen Struktur der Krankheit, kann aber nur einmal alle vier durchgeführt werden 6 Wochen durch die Verwendung von bildgebenden Mittel und die Gesamtkosten. Vor diesem Hintergrund ist die Entwicklung der &quot;Point of Care&quot; Techniken wie Biosensoren, die das Stadium der Erkrankung und / oder Wirksamkeit der Behandlung in der Praxis des Arztes zu bewerten und tun dies in einer angemessenen Zeitspanne, würde Behandlungsprotokolle zu revolutionieren. 1 Wie ein Mittel, um zu erforschen Ferrocen Biosensoren zum Nachweis von biologisch relevanten Molekülen 2 wurden Methoden entwickelt, um Ferrocen-Biotin hierin beschriebenen Bio-Konjugaten. Dieser Bericht wird auf einer Biotin-Ferrocen-Cystein-System, das auf einer Goldoberfläche immobilisiert werden können, konzentrieren.

Das Harz-gebundenen Form von 1 ist in 2 gezeigt. Die kovalente Bindung des Ferrocen-Komponente führt zu einem orangen Farbton mit den Harzperlen, die persistent mit kontinuierlichen Waschen und indikativ für einen immobilisierten eisenhaltigen Komplex ist, um die Eisenaufnahme im Gegensatz durch die PEG-Komponente des Harzkügelchens. Die harzfreien Form 1 ist in der Farbe der Harzkügelchen identisch. Nach der Entfernung der Verbindung aus den Harzperlen, die Reinhei...

Watch this Scientific Journal Video about Synthetic Methodology for Asymmetric Ferrocene Derived Bio-conjugate Systems via Solid Phase Resin-based Methodology at JoVE.com

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

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

Synthesemethoden für Asymmetric Ferrocen abgeleitete Bio-Konjugat-Systemen über Festphasen-Resin-basierte Methodik

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

synthetic-methodology-for-asymmetric-ferrocene-derived-bio-conjugate

Research

JoVE Journal

Chemistry

9.6K Aufrufe.  Texas Christian University. The synthesis of asymmetric species of ferrocene is challenging using solution techniques. This report focuses on the methods carried out to produce a ferrocene-biotin bioconjugate using facile and clean reactions accomplished via solid-phase synthesis. Incorporation of a thiolate moiety is shown to impart the ability for immobilization on gold surfaces.

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

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40&#160;&#176;C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure.
The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)1-4. For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather accurate and reproducible measurements in a timely fashion.

High-pressure Sapphire Cell for Phase Equilibria Measurements of CO2/Organic/Water Systems

The high pressure sapphire cell apparatus is a unique tool to study, without sampling, phase behavior under a wide range of pressures. Using a cathetometer, very precise volume measurements can be recorded to measure liquid expansion and phase composition. Thus, this synthetic method enables the study of (1) phase equilibria of multi-component mixtures and (2) the partition behavior of catalyst or model compounds as a function of pressure.

Hochdruck-Sapphire-Zelle für Phasengleichgewichte Messungen der CO<sub&gt; 2</sub&gt; / Bio-/ Wasser-Systeme

The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. ...

Forschung

Chemie

Stabilizing Hepatocellular Phenotype Using Optimized Synthetic Surfaces

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

This article will focus on developing polymer coated surfaces for long-term, stable culture of stem cell derived human hepatocytes.

Stabilisierung Leberzell Phänotyp mit optimierten Surfaces

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

X-ray Powder Diffraction in Conservation Science: Towards Routine Crystal Structure Determination of Corrosion Products on Heritage Art Objects

The crystal structure determination and refinement process of corrosion products on historic art objects using laboratory high-resolution X-ray powder diffraction (XRPD) is presented in detail via two case studies.
The first material under investigation was sodium copper formate hydroxide oxide hydrate, Cu4Na4O(HCOO)8(OH)2&#8729;4H2O (sample 1) which forms on soda glass/copper alloy composite historic objects (e.g., enamels) in museum collections, exposed to formaldehyde and formic acid emitted from wooden storage cabinets, adhesives, etc. This degradation phenomenon has recently been characterized as &#34;glass induced metal corrosion&#34;.
For the second case study, thecotrichite, Ca3(CH3COO)3Cl(NO3)2&#8729;6H2O (sample 2), was chosen, which is an efflorescent salt forming needlelike crystallites on tiles and limestone objects which are stored in wooden cabinets and display cases. In this case, the wood acts as source for acetic acid which reacts with soluble chloride and nitrate salts from the artifact or its environment.
The knowledge of the geometrical structure helps conservation science to better understand production and decay reactions and to allow for full quantitative analysis in the frequent case of mixtures.

Modern high resolution X-ray powder diffraction (XRPD) in the laboratory is used as an efficient tool to determine crystal structures of long-known corrosion products on historic objects.

X-ray Powder Diffraction in Conservation Science: Auf dem Weg Routine Kristallstrukturbestimmung von Korrosionsprodukten auf Heritage Kunstobjekte

The crystal structure determination and refinement process of corrosion products on historic art objects using laboratory high-resolution X-ray powder ...

Measurement of Particle Size Distribution in Turbid Solutions by Dynamic Light Scattering Microscopy

A protocol for measuring polydispersity of concentrated polymer solutions using dynamic light scattering is described. Dynamic light scattering is a technique used to measure the size distribution of polymer solutions or colloidal particles. Although this technique is widely used for the assessment of polymer solutions, it is difficult to measure the particle size in concentrated solutions due to the multiple scattering effect or strong light absorption. Therefore, the concentrated solutions should be diluted before measurement. Implementation of the confocal optical component in a dynamic light scattering microscope1 helps to overcome this barrier. Using such a microscopic system, both transparent and turbid systems can be analyzed under the same experimental setup without a dilution. As a representative example, a size distribution measurement of a temperature-responsive polymer solution was performed. The sizes of the polymer chains in an aqueous solution were several tens of nanometers at a temperature below the lower critical solution temperature (LCST). In contrast, the sizes increased to more than 1.0 &#181;m when above the LCST. This result is consistent with the observation that the solution turned turbid above the LCST.

A protocol for the direct measurement of particle size distribution in concentrated solutions using dynamic light scattering microscopy is presented.

Die Messung der Partikelgrößenverteilung in trüber Lösungen durch Dynamic Light Scattering Mikroskopie

A protocol for measuring polydispersity of concentrated polymer solutions using dynamic light scattering is described. Dynamic light scattering is a ...

Integration of Miniaturized Solid Phase Extraction and LC-MS/MS Detection of 3-Nitrotyrosine in Human Urine for Clinical Applications

Free 3-nitrotyrosine (3-NT) has been extensively used as a possible biomarker for oxidative stress. Increased levels of 3-NT have been reported in a wide variety of pathological conditions. However, existing methods lack the sufficient sensitivity and/or specificity necessary to measure the low endogenous level of 3-NT reliably and are too cumbersome for clinical applications. Hence, analytical improvement is urgently needed to accurately quantify the levels of 3-NT and verify the role of 3-NT in pathological conditions. This protocol presents the development of a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) detection combined with a miniaturized solid phase extraction (SPE) for the rapid and accurate measurement of 3-NT in human urine as a non-invasive biomarker for oxidative stress. SPE using a 96-well plate markedly simplified the process by combining sample cleanup and analyte enrichment without tedious derivatization and evaporation steps, reducing solvent consumption, waste disposal, risk of contamination and overall processing time. The employment of 25 mM ammonium acetate (NH4OAc) at pH 9 as the SPE elution solution substantially enhanced the selectivity. Mass spectrometry signal response was improved through adjustment of the multiple reaction monitoring (MRM) transitions. Use of 0.01% HCOOH as additive on a pentafluorophenyl (PFP) column (150 mm x 2.1 mm, 3 &#181;m) improved signal response another 2.5-fold and shortened the overall run time to 7 min. A lower limit of quantitation (LLOQ) of 10 pg/mL (0.044 nM) was achieved, representing a significant sensitivity improvement over the reported assays. This simplified, rapid, selective and sensitive method allows two plates of urine samples (n = 192) to be processed in a 24 h time-period. Considering the markedly improved analytical performance, and non-invasive and inexpensive urine sampling, the proposed assay is beneficial for pre-clinical and clinical studies.

A selective and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method coupled with an efficient solid phase extraction on a mixed-mode cation-exchange (MCX) 96-well microplate was developed for the measurement of free 3-nitrotyrosine (3-NT) in human urine with high throughput, which is suitable for clinical applications.

Integration von miniaturisierter Festphasenextraktion und LC-MS / MS-Nachweis von 3-Nitrotyrosin im menschlichen Urin für klinische Anwendungen

Free 3-nitrotyrosine (3-NT) has been extensively used as a possible biomarker for oxidative stress. Increased levels of 3-NT have been reported in a wide ...

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the average content of fluorinated drugs in their formulated drug product forms: tablets or capsules. This method is specific to fluorinated drugs because it detects only the content of fluorine, avoiding interference from the excipients that lack fluorine. The advantages of measuring the active content of fluorinated drugs using low-field 19F TD-NMR versus high-field 19F solid-state (SS) NMR are the simplicity of the method; the low cost; and the non-destructive nature of the technique, with all samples recoverable in intact forms (e.g., powders, tablets, and capsules), making this technique affordable for any laboratory.
We have tested the method with three fluorinated drug products available on the market - cinacalcet, lansoprazole, and ciprofloxacin - with doses ranging from 15 to 500 mg. The results of the analyses, measured by low-field 19F TD-NMR, supported the reported label claims for the average drug content.
Based on the simplicity and reproducibility of the analysis, we envision this methodology being implemented in any laboratory, including manufacturing plants, as a process analytical technology (PAT) tool in the pharmaceutical industry.

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

A simple and non-destructive technique that measures the average content of drug substances in formulated drug products containing fluorine using low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) is presented here. The technique can be applied to the development and manufacturing of drugs in the pharmaceutical industry.

Anwendung und Methodik der zerstörungsfreien 19F Zeitbereich NMR-Technik den Inhalt in Fluor-haltige Arzneimittel zu messen

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the ...

Phase Behavior of Charged Vesicles Under Symmetric and Asymmetric Solution Conditions Monitored with Fluorescence Microscopy

Phase-separated giant unilamellar vesicles (GUVs) exhibiting coexisting liquid-ordered and liquid-disordered domains are a common biophysical tool to investigate the lipid raft hypothesis. Numerous studies, however, neglect the impact of physiological solution conditions. On that account, the current work presents the effect of high-salinity buffer and trans-membrane solution asymmetry on liquid-liquid phase separation in charged GUVs grown from dioleylphosphatidylglycerol, egg sphingomyelin, and cholesterol. The effects were studied under isothermal and varying temperature conditions.
We describe equipment and experimental strategies applicable for monitoring the stability of coexisting liquid domains in charged vesicles under symmetric and asymmetric high-salinity solution conditions. This includes an approach to prepare charged multicomponent GUVs in high-salinity buffer at high temperatures. The protocol entails the option to perform a partial exchange of the external solution by a simple dilution step while minimizing the vesicle dilution. An alternative approach is presented utilizing a microfluidic device that allows for a complete external solution exchange. The solution effects on phase separation were also studied under varying temperatures. To this end, we present the basic design and utility of an in-house built temperature control chamber. Furthermore, we reflect on the assessment of the GUV phase state, pitfalls associated with it and how to circumvent them.

Experiments on phase separated giant unilamellar vesicles (GUVs) frequently neglect physiological solution conditions. This work presents approaches to study the effect of high-salinity buffer on liquid-liquid phase separation in charged multicomponent GUVs as a function of trans-membrane solution asymmetry and temperature.

Phasenverhalten von geladenen Vesikeln unter symmetrischen und asymmetrischen Lösungsbedingungen überwacht mit Fluoreszenz-Mikroskopie

Phase-separated giant unilamellar vesicles (GUVs) exhibiting coexisting liquid-ordered and liquid-disordered domains are a common biophysical tool to ...

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2'-O-thiophenylmethyl Modification and Characterization via Circular Dichroism

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular methodology for applications in various fields and for different research purposes. The procedure described herein focuses on the synthesis, purification, and characterization of dodecamers of RNA 5&#39;-[CUA CGG AAU CAU]-3&#39; containing zero, one, or two modifications located at the C2&#39;-O-position. The probes are based on 2-thiophenylmethyl groups, incorporated into RNA nucleotides via standard organic synthesis and introduced into the corresponding oligonucleotides via their respective phosphoramidites. This report makes use of phosphoramidite chemistry via the four canonical nucleobases (Uridine (U), Cytosine (C), Guanosine (G), Adenosine (A)), as well as 2-thiophenylmethyl functionalized nucleotides modified at the 2&#39;-O-position; however, the methodology is amenable for a large variety of modifications that have been developed over the years. The oligonucleotides were synthesized on a controlled-pore glass (CPG) support followed by cleavage from the resin and deprotection under standard conditions, i.e., a mixture of ammonia and methylamine (AMA) followed by hydrogen fluoride/triethylamine/N-methylpyrrolidinone. The corresponding oligonucleotides were purified via polyacrylamide electrophoresis (20% denaturing) followed by elution, desalting, and isolation via reversed-phase chromatography (Sep-pak, C18-column). Quantification and structural parameters were assessed via ultraviolet-visible (UV-vis) and circular dichroism (CD) photometric analysis, respectively. This report aims to serve as a resource and guide for beginner and expert researchers interested in embarking in this field. It is expected to serve as a work-in-progress as new technologies and methodologies are developed. The description of the methodologies and techniques within this document correspond to a DNA/RNA synthesizer (refurbished and purchased in 2013) that uses phosphoramidite chemistry.

Protocol for the Solid-phase Synthesis of Oligomers of RNA Containing a 2&#039;-O-thiophenylmethyl Modification and Characterization via Circular Dichroism

This article provides a detailed procedure on the solid-phase synthesis, purification, and characterization of dodecamers of RNA modified at the C2&#39;-O-position. UV-vis and circular dichroism photometric analyses are used to quantify and characterize structural aspects, i.e., single-strands or double-strands.

Protokoll für die Festphasensynthese von Oligomeren der RNA mit einem 2&#39;-<em&gt; O</em&gt; -thiophenylmethyl-Modifikation und Charakterisierung über Kreisdichroismus

Solid-phase synthesis has been used to obtain canonical and modified polymers of nucleic acids, specifically of DNA or RNA, which has made it a popular ...

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

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

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

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

Charakterisierung von synthetischen Polymeren Matrix Assisted Laser Desorption Ionisation Zeit der Massenspektrometrie Flug (MALDI-TOF)

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

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

A convenient synthetic route for spirocyclic heterocycles is well sought after due to the molecule&#39;s potential use in biological systems. By means of solid-phase synthesis, regenerating Michael (REM) linker strategies, and 1,3-dipolar cycloaddition, a library of structurally similar heterocycles, both with and without a spirocyclic center, can be constructed. The main advantages of the solid-support synthesis are as follows: first, each reaction step can be driven to completion using a large excess of reagents resulting in high yields; next, the use of commercially available starting materials and reagents keep the costs low; finally, the reaction steps are easy to purify via simple filtration. The REM linker strategy is attractive because of its recyclability and traceless nature. Once a reaction scheme is completed, the linker can be reused multiple times. In a typical solid-phase synthesis, the product contains either a part of or the whole linker, which can prove undesirable. The REM linker is &#34;traceless&#34; and the point of attachment between the product and the polymer is indistinguishable. The high diastereoselectivity of the intramolecular 1,3-dipolar cycloaddition is well documented. Limited by the insolubility of the solid support, the reaction progression can only be monitored by a change in the functional groups (if any) via infrared (IR) spectroscopy. Thus, the structural identification of intermediates cannot be characterized by conventional nuclear magnetic resonance (NMR) spectroscopy. Other limitations to this method stem from the compatibilities of the polymer/linker to the desired chemical reaction scheme. Herein we report a protocol that allows for the convenient production of spirocyclic heterocycles that, with simple modifications, can be automated with high-throughput techniques.

Here we present a protocol to demonstrate an efficient method for the synthesis of spirocyclic heterocycles. The five-step process utilizes solid-phase synthesis and regenerating Michael linker strategies. Generally difficult to synthesize, we present a customizable method for the synthesis of spirocyclic molecules otherwise inaccessible to other modern approaches.

Festphasen-Synthese von [4,4] Spirocyclic Oximes

A convenient synthetic route for spirocyclic heterocycles is well sought after due to the molecule&#39;s potential use in biological systems. By means of ...