This research was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada, the Canada Research Chairs Program, and Simon Fraser University. This work made use of 4D LABS shared facilities supported by the Canada Foundation for Innovation (CFI), British Columbia Knowledge Development Fund (BCKDF) and Simon Fraser University.

1. Sintesi della NaYF 4 / Yb 3+ / Er 3+ Upconverting nanoparticelle (UCNP) <ol><li> Sistemare il dispositivo come seguito: <ol><li> Posizionare un 250 ml di riscaldamento mantello su una piastra di agitazione regolare e collegare il mantello sulla coppia termico. </li><li> Posizionare un pallone a fondo arrotondato da 250 ml dotato di ancoretta magnetica sul mantello di riscaldamento con la corretta chiusura. </li><li> Collegare un adattatore di aria al collo sinistra del pallone a fondo tondo e collegare l&#39;adattatore aria alla linea Schlenk con tubi di plastica. </li><li> Collegare un adattatore di vetro a destra collo del pallone a fondo tondo e fissare un adattatore termometro sull&#39;adattatore vetro. Inserire la sonda di temperatura nel pallone attraverso l&#39;adattatore termometro e collegarlo alla termocoppia. </li><li> Collegare un capo di distillazione al collo centro del pallone a fondo tondo. Posizionare un tappo sulla parte superiore della testa di distillazione. Collegare la testa ad un condensatore, seguito da un distillat vuotoAdattatore di ioni e un round pallone a fondo da 50 ml. Collegare l&#39;adattatore di distillazione sotto vuoto di un gorgogliatore attraverso tubo di plastica. </li></ol></li><li> Pesare 1,17 g (3,9 mmoli) di acetato di ittrio, 0,439 g di acetato di itterbio e 0,0727 g (0,1 mmoli) di acetato di Erbio e metterli nella reazione pallone a fondo tondo. </li><li> Aggiungere 30 ml di acido oleico e 75 ml di ottadecene alla beuta mediante un cilindro graduato. </li><li> Risciacquare lato della reazione pallone a fondo tondo con 5 ml di metanolo per assicurarsi che nessun acido oleico e ottadecene è bloccato ai lati del pallone di reazione. </li><li> Collegare il pallone di reazione di una doppia linea collettore Schlenk e girate la valvola corrispondente per mantenere il pallone di reazione collegato alla linea di azoto. </li><li> Accendere termocoppia, impostare la temperatura a 80 ° C, e gradualmente riscaldare il sistema a questa temperatura. A 80 ° C e dopo tutte le materie prime sono dissolti, togliere la camicia di riscaldamento e permettere la reazione diraffreddare a 30 ° C. </li><li> Quando la temperatura raggiunge i 30 ° C, togliere la testa di distillazione, commutare l&#39;adattatore aria dal collo sinistra al collo centrale e chiudere il collo sinistro con un tappo. Lentamente introdurre vuoto per pallone di reazione ruotando la valvola sulla linea schlenk dalla linea di azoto alla linea del vuoto. Tutti i componenti a basso punto di ebollizione sarà tirato fuori dalla reazione a questo punto. </li><li> Quando la soluzione ferma gorgogliare, alza la temperatura a 115 ° C in una velocità di 5 ° C / min. </li><li> Una volta che la temperatura raggiunge 115 ° C, mantenere questa temperatura per 15 minuti, quindi rimuovere la camicia di riscaldamento e raffreddare la reazione a 50 ° C. In seguito, passare rapidamente il set-up torna alla forma originale riattaccare la testa di distillazione al collo di mezzo e l&#39;adattatore aria sulla testa di sinistra. </li><li> Pesare 0,74 g (12,5 mmol) di NaOH e 0,50 g (20,0 mmol) di NH 4 F durante il processo di raffreddamento, e dissolverliin 50 ml di metanolo per sonicazione. </li><li> Dopo sonicazione, versare la soluzione nella reazione rotonda pallone a fondo e risciacquare le pareti del pallone con 5 ml di MeOH. </li><li> La soluzione viene lasciata sotto agitazione a 50 ° C per 30 min. </li><li> Aumentare la temperatura a 75 ° C per distillare il metanolo. </li><li> Durante la distillazione, svuotare il pallone di raccolta quando necessario. Dopo la distillazione viene terminato, riscaldare la reazione a 300 ° C sotto protezione di azoto più velocemente possibile. </li><li> Una volta che la temperatura raggiunge 300 ° C, mantenere questa temperatura per 1 ora. Se necessario, coprire il setup con un foglio di alluminio per aiutare a mantenere la temperatura. Togliere quindi fonte di calore e lasciare la reazione raffreddare a temperatura ambiente. </li><li> Una volta raffreddata a temperatura ambiente, la soluzione dividere equamente in tre tubi centrifugazione (50 ml tubi, circa 35 ml di soluzione per ciascuna provetta) e rabboccare il tubo 50 ml scala utilizzando etanolo anidro. Centrifuga tutto tegli provette a 3.400 xg per 15 min. Dopo centrifugazione, i UCNPs dovrebbero essere osservati sul lato dei tubi come un precipitato bianco. </li><li> Scartare il surnatante e redisperse il pellet UCNPs in esani (7,5 ml di esani per ogni tubo), quindi riempire il tubo con etanolo alla scala 50 ml. Provette da centrifuga di nuovo a 3.400 xg per 15 min. </li><li> Una volta che la centrifugazione è completa, scartare il surnatante e redisperse le UCNPs solido in 30 ml di CHCl3 per ulteriore uso. </li></ol> 2. Nanoassemblies Assemblaggio di acqua dispersibili organici contenenti Dye Molecole e Upconverting Nanoparticelle <ol><li> Sciogliere 25 mg (0,0147 mmol) di poli (alt stirene anidride -maleic) (PSMA) in 3 ml di CHCl 3 in una fiala di scintillazione dotato di ancoretta magnetica. Questa quantità è una quantità ottimizzata dopo prove multiple. </li><li> Aggiungere 250 microlitri (47 mg / ml) del upconverting nanoparticelle soluzione cloroformica azioni al Scintillation fiala. </li><li> Chiudere la fiala e posizionarlo sulla piastra di agitazione magnetica, e agitare la soluzione a temperatura ambiente per 2 ore. </li><li> Pesare 160 mg (0,0773 mmoli) di polietere ammina 2070, e sciogliere in 1 ml di CHCl3. Quindi aggiungere questa soluzione nella fiala di scintillazione in una porzione con una pipetta. La soluzione diventerà pallido giallo che indica la reazione di polietere ammina 2070 con i gruppi di anidride sul PSMA. </li><li> Continuare ad agitare la soluzione per una notte a temperatura ambiente. </li><li> Misurare la quantità appropriata di molecole di colorante organiche poi dispensare nel flaconcino scintillazione in una porzione, mescolare la soluzione risultante per 1 ora. <ol><li> Per il campione TPP-NP (nanoassembly contenente guscio di polimero, tetrafenil porfirina e nanoparticelle Upconverting), aggiungere direttamente 1 mg di tetrafenil porfirina al flaconcino scintillazione. Per il campione di DAE-UCNP (nanoassembly contenente guscio di polimero, le molecole diarylethene e upconverting nanoparticelles), la quantità di ciascuno molecole diarylethene è 2 × 10 -7 mol. Aggiungere le due molecole diarylethene nella soluzione di reazione. I volumi dei due molecole diarylethene sono: DAE-1o (1,8 mM), 111 microlitri e DAE-2o (1.6 mM), 125 microlitri. </li></ol></li><li> Rimuovere il CHCl3 solvente a pressione ridotta utilizzando un evaporatore rotante, quindi aggiungere 3 ml di NaOH acquosa 0,001 M (pH ≈ 11) al flaconcino scintillazione, seguito da sonicazione il flaconcino fino a formare una sospensione lattiginosa. </li><li> Posizionare la fiala posteriore sull&#39;evaporatore rotante, e rimuovere con attenzione il restante CHCl3 fino sospensione è trasformata in una soluzione limpida. </li><li> Trasferire la soluzione dal flaconcino scintillazione ai tubi centrifugazione due 1,5 ml coniche, quindi centrifugare la soluzione a 20.600 xg per 25 min. </li><li> Eliminare il supernatante, quindi aggiungere un totale di 3 ml di H 2 O deionizzata nei due tubi (1,5 ml per provetta), sonicare i tubi redisperse pelletnel deionizzata H 2 O. </li><li> Centrifugare i due tubi di nuovo a 20.600 xg per 25 min. </li><li> Eliminare il surnatante, quindi aggiungere un totale di 3 ml di H 2 O deionizzata nei due tubi (1,5 ml per provetta). Sonicare i tubi redisperse i pellet nel deionizzata H 2 O. </li><li> Filtrare il campione nanoparticelle dispersione acquosa attraverso un filtro a siringa da 0,2 micron per ottenere il campione finale per ulteriori test. </li></ol>

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The authors have nothing to disclose.

Le nanoparticelle sintetizzate secondo questo protocollo hanno una distribuzione dimensionale da 20 a 25 nm centrata a circa il 22,5 nm. 26,27 Possono essere classificati come particelle sferiche con una struttura reticolare 4 ospitante α-NaYF. Ci sono due passaggi critici di questo protocollo. Nella sintesi UCNP, è essenziale per mantenere la temperatura di riscaldamento ed il tempo il più preciso possibile per assicurare una stretta distribuzione della dimensione delle particelle. Simultanea a...

Oggi c&#39;è ancora un urgente bisogno di sviluppare nuovi tipi di agenti bio-imaging. Molti sonde fluorescenti nuovi sono stati ben documentati. 1-6 Tuttavia, i miglioramenti sostanziali nella risoluzione dell&#39;immagine rimane una sfida. 7 Un metodo pratico è di modulare direttamente le sonde a fluorescenza tra una &#39;luce&#39; stato emissivi ed uno stato bonificato &#39;dark&#39;. 8-12 Questo particolare metodo è stato applicato a sviluppare tecnologie quali l&#39;esaurimento emissione stimolata (STED) microscopia a 13 e stocastico microscopia ottica ricostruzione (STORM). 14 Un altro approccio per modulare fluorescenza è accoppiare cromofori fotorisposta insieme con sonde fluorescenti. 15,16 Toggling cromoforo fotosensibile tra due isomeri in cui solo uno degli isomeri può agire come un efficiente trasferimento di energia-accettore, permette il controllo sulla quenching della fluorescenza da the sonda attraverso trasferimento Förster Resonance Energy (FRET) e altri meccanismi. Il risultato è la creazione di uno stato emissiva ed uno stato temprato che può essere alternato da esposizione del cromoforo fotosensibile a diverse lunghezze d&#39;onda della luce. Cromofori diarylethene fotoresponsivi possono essere commutati tra reversibilmente un isomero anello aperto incolore e un anello chiuso isomero colorato su irradiazione con UV e luce visibile. 17-19 La stabilità termica dei due isomeri e gli spettri di assorbimento sintonizzabile dell&#39;anello chiuso isomero make diarileteni molto buoni candidati come FRET controllabile accettori. nanoparticelle 20-23 Lanthanide drogato NaYF 4 Upconverting sono utili per bio-immagini. 24 Queste nanoparticelle assorbono la luce nel vicino infrarosso ed emettono luce in diverse regioni dello spettro visibile. Esempi di modulazione fluorescenza unendo cromofori diarylethene fotorisposta e nanoparticelle sono state preprecedentemente riportato dal nostro gruppo. 25-27 Tuttavia, i sistemi descritti in ciascun esempio necessaria una modifica sintetico aggiuntivo per collegare i diarileteni alla superficie delle nanoparticelle, che complica lo sviluppo di sistemi più diversi. Qui si dimostra un semplice &#39;plug-and-play&#39; il metodo per preparare molecole di colorante organico idrodisperdibili e nanoparticelle Upconverting fotorisposta utilizzando una strategia di self-assembly. La scelta dei polimeri; poli (stirene-alt anidride -maleic) e polietere ammina 2070 forniscono sia un ambiente idrofobico e idrofilo. Le sezioni idrofoba del polimero aiuto tenere i normalmente insolubili in acqua molecole organiche e nanoparticelle Upconverting insieme, considerando che la regione idrofila del polimero è fondamentale per mantenere la solubilità in acqua. Per prima dimostrare sintesi delle nanoparticelle Upconverting dal metodo nucleazione termico. Poi, proveremo how le molecole organiche e nanoparticelle Upconverting sono incapsulati all&#39;interno delle regioni idrofobiche del guscio polimero e rimangono stabili in ambiente acquoso semplicemente co-agitazione una soluzione di nanoparticelle Upconverting, polimero e molecole diverse colorante organico, seguita da una comoda procedura di work-up. Dimostriamo anche come modulare emissione di fluorescenza delle assemblee con irradiazione di luce esterna. Anticipiamo il campo di applicazione di questo metodo &#39;plug-and-play&#39; per rendere nanoassemblies idrodisperdibili continuerà ad espandersi.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>yttrium acetate</td>
			<td>sigma</td>
			<td>326046</td>
			<td>Yttrium(III) acetate hydrate</td>
		</tr>
		<tr>
			<td>ytterbium acetate</td>
			<td>sigma</td>
			<td>544973</td>
			<td>&#160;Ytterbium(III) acetate hydrate&#160;</td>
		</tr>
		<tr>
			<td>erbium acetate</td>
			<td>sigma</td>
			<td>325570</td>
			<td>Erbium(III) acetate hydrate</td>
		</tr>
		<tr>
			<td>oleic acid</td>
			<td>sigma</td>
			<td>75096</td>
			<td>analytical standard</td>
		</tr>
		<tr>
			<td>octadecene</td>
			<td>sigma</td>
			<td>O806&#160;</td>
			<td>Technical grade&#160;</td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td></td>
			<td>S5881&#160;</td>
			<td>reagent grade</td>
		</tr>
		<tr>
			<td>NH4F</td>
			<td></td>
			<td>216011</td>
			<td>ACS reagent</td>
		</tr>
		<tr>
			<td>poly(styrene-alt-maleic anhydride)</td>
			<td>sigma</td>
			<td>4422699</td>
			<td>Average Mn= 1700</td>
		</tr>
		<tr>
			<td>JeffAmine 2070</td>
			<td>Huntsman</td>
			<td>M-2070</td>
			<td></td>
		</tr>
		<tr>
			<td>Varian Carry 300</td>
			<td>Agilent</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>JDSU NIR laser</td>
			<td>JSDU</td>
			<td>L4-9897510-100M</td>
			<td>980 nm diode laser</td>
		</tr>
	</tbody>
</table>

a 'plug and play' method to create water-dispersible nanoassemblies containing an amphiphilic polymer, organic dyes and upconverting nanoparticles

In this protocol, we first describe a procedure to synthesize lanthanide doped upconverting nanoparticles (UCNPs). We then demonstrate how to generate amphiphilic polymers in situ, and describe a protocol to encapsulate the prepared UCNPs and different organic dye molecules (porphyrins and diarylethenes) using polymer shells to form stable water-dispersible nanoassemblies. The nanoassembly samples containing both the UCNPs and the diarylethene organic dyes have interesting photochemical and photophysical properties. Upon 365 nm UV irradiation, the diarylethene group undergoes a visual color change. When the samples are irradiated with visible light of another specific wavelength, the color fades and the samples return to the initial colorless state. The samples also emit visible light from the UCNPs upon irradiation with 980 nm near-infrared light. The emission intensity of the samples can be tuned through alternate irradiation with UV and visible light. Modulation of fluorescence can be performed for many cycles without observable degradation of the samples. This versatile encapsulation procedure allows for the transfer of hydrophobic molecules and nanoparticles from an organic solvent to an aqueous medium. The polymer helps to maintain a lipid-like microenvironment for the organic molecules to aid in preservation of their photochemical behavior in water. Thus this method is ideal to prepare water-dispersible photoresponsive systems. The use of near-infrared light to activate upconverting nanoparticles allows for lower energy light to be used to activate photoreactions instead of more harmful ultraviolet light.

Spettri di assorbimento e spettri di fotoluminescenza sono stati raccolti per il campione DAE-UCNP. Gli spettri di assorbimento sono utilizzati per confrontare la sovrapposizione spettrale tra i cromofori diarylethene chiusi e le nanoparticelle Upconverting. Le fotografie dei campioni (sia TPP-UCNP e DAE-UCNP) sono stati inclusi anche per dimostrare il successo incapsulamento di molecole di colorante organico e nanoparticelle Upconverting, che si trovano all&#39;interno dei gusci di polimeri anfifilici in fase acquosa. ...

Watch this Scientific Journal Video about A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles at JoVE.com

A &#039;Plug and Play&#039; Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

Organic dye molecules and oleic acid coated upconverting nanoparticles are not water-soluble. This protocol describes a &#8216;plug and play&#8217; method that enables the transfer of organic dye molecules and upconverting particles from their initial hydrophobic solvent to water.

Un metodo &#39;Plug and Play&#39; per creare Nanoassemblies acqua dispersibile contenenti un polimero Amphiphilic, coloranti organici e Upconverting nanoparticelle

In this protocol, we first describe a procedure to synthesize lanthanide doped upconverting nanoparticles (UCNPs). We then demonstrate how to generate ...

a-plug-play-method-to-create-water-dispersible-nanoassemblies

Research

JoVE Journal

Chemistry

A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

9.8K Views.  Simon Fraser University. Organic dye molecules and oleic acid coated upconverting nanoparticles are not water-soluble. This protocol describes a ‘plug and play’ method that enables the transfer of organic dye molecules and upconverting particles from their initial hydrophobic solvent to water. 

Video: A 'Plug and Play' Method to Create Water-dispersible Nanoassemblies Containing an Amphiphilic Polymer, Organic Dyes and Upconverting Nanoparticles

Analysis of Volatile and Oxidation Sensitive Compounds Using a Cold Inlet System and Electron Impact Mass Spectrometry

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The analysis of volatile and oxidation sensitive compounds by mass spectrometry is not easily achieved, as all state-of-the-art mass spectrometric methods require at least one sample preparation step, e.g., dissolution and dilution of the analyte (electrospray ionization), co-crystallization of the analyte with a matrix compound (matrix-assisted laser desorption/ionization), or transfer of the prepared samples into the ionization source of the mass spectrometer, to be conducted under atmospheric conditions. Here, the use of a sample inlet system is described which enables the analysis of volatile metal organyls, silanes, and phosphanes using a sector field mass spectrometer equipped with an electron impact ionization source. All sample preparation steps and the sample introduction into the ion source of the mass spectrometer take place either under air-free conditions or under vacuum, enabling the analysis of compounds highly susceptible to oxidation. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes, which have to be handled using inert conditions, such as the Schlenk technique. The principle of operation is presented in this video.

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The presented technique is especially of interest for inorganic chemists, working with metal organyls, silanes, or phosphanes which have to be handled using inert conditions, such as the Schlenk technique.

Analisi di composti volatili sensibili e ossidazione utilizzando un sistema di aspirazione a freddo e impatto elettronico Spettrometria di Massa

This video presents a protocol for the mass spectrometrical analysis of volatile and oxidation sensitive compounds using electron impact ionization. The ...

Ricerca

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 ...

A Simple Method for the Size Controlled Synthesis of Stable Oligomeric Clusters of Gold Nanoparticles under Ambient Conditions

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like oligomeric clusters of these yellow nanoparticles of narrow size distribution are synthesized under ambient conditions via two methods. The delay-time method controls the number of subunits in the oligoclusters by varying the time between the addition of HAuCl4 to alkaline solution and the subsequent addition of reducing agent, NaSCN. The yellow oligoclusters produced range in size from ~3 to ~25 nm. This size range can be further extended by an add-on method utilizing hydroxylated gold chloride (Na+[Au(OH4-x)Clx]-) to auto-catalytically increase the number of subunits in the as-synthesized oligocluster nanoparticles, providing a total range of 3 nm to 70 nm. The crude oligocluster preparations display narrow size distributions and do not require further fractionation for most purposes. The oligoclusters formed can be concentrated &#62;300 fold without aggregation and the crude reaction mixtures remain stable for weeks without further processing. Because these oligomeric clusters can be concentrated before derivatization they allow expensive derivatizing agents to be used economically. In addition, we present two models by which predictions of particle size can be made with great accuracy.

We describe a simple method for producing highly stable oligomeric clusters of gold nanoparticles via the reduction of chloroauric acid (HAuCl4) with sodium thiocyanate (NaSCN). The oligoclusters have a narrow size distribution and can be produced with a wide range of sizes and surface coats.

Un metodo semplice per la dimensione sintesi controllata di stabili oligomeriche Grappoli di oro nanoparticelle in condizioni ambientali

Reducing dilute aqueous HAuCl4 with sodium thiocyanate (NaSCN) under alkaline conditions produces 2 to 3 nm diameter nanoparticles. Stable grape-like ...

An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions

A comprehensive understanding of signaling pathways requires detailed knowledge regarding ligand-receptor interaction. This article describes two fast and reliable point-by-point protocols of enzyme-linked immunosorbent assays (ELISAs) for the investigation of ligand-receptor interactions: the direct ligand-receptor interaction assay (LRA) and the competition LRA. As a case study, the ELISA based analysis of the interaction between different lambda interferons (IFNLs) and the alpha subunit of their receptor (IL28RA) is presented: the direct LRA is used for the determination of dissociation constants (KD values) between receptor and IFN ligands, and the competition LRA for the determination of the inhibitory capacity of an oligopeptide, which was designed to compete with the IFNLs at their receptor binding site. Analytical steps to estimate KD and half maximal inhibitory concentration (IC50) values are described. Finally, the discussion highlights advantages and disadvantages of the presented method and how the results enable a better molecular understanding of ligand-receptor interactions.

The presented protocols describe two enzyme-linked immunosorbent assay (ELISA) based techniques for the rapid investigation of ligand-receptor interactions: The first assay allows the determination of dissociation constant between ligand and receptor. The second assay enables a rapid screening of blocking peptides for ligand-receptor interactions.

Un ELISA Based rilegatura e metodo concorrenza di determinare con rapidità interazioni ligando-recettore

A comprehensive understanding of signaling pathways requires detailed knowledge regarding ligand-receptor interaction. This article describes two fast and ...

The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ethylene-propylene rubber, grafted with maleic anhydride, is thermo-reversibly cross-linked in two steps. The pending anhydride moieties are first modified with furfurylamine to graft furan groups to the rubber backbone. These pendant furan groups are then cross-linked with a bis-maleimide via a Diels-Alder coupling reaction. Both reactions can be performed under a broad range of experimental conditions and can easily be applied on a large scale. The material properties of the resulting Diels-Alder cross-linked rubbers are similar to a peroxide-cured ethylene/propylene/diene rubber (EPDM) reference. The cross-links break at elevated temperatures (&#62; 150 &#176;C) via the retro-Diels-Alder reaction and can be reformed by thermal annealing at lower temperatures (50-70 &#176;C). Reversibility of the system was proven with infrared spectroscopy, solubility tests and mechanical properties. Recyclability of the material was also shown in a practical way, i.e., by cutting a cross-linked sample into small parts and compression molding them into new samples displaying comparable mechanical properties, which is not possible for conventionally cross-linked rubbers.

A simple two-step approach involving rubber modification and cross-linking yields fully reworkable, elastic rubber products.

La preparazione e la proprietà di Thermo-reversibile reticolato Chimica Gomma Via Diels-Alder

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ...

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient radiolabeling of DBCO-group-functionalized gold nanoparticles using a copper-free click reaction. Radioiodination of the stannylated precursor (2) was carried out by using [125I]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified 125I-labeled azide (1) was obtained with high radiochemical yield (75 &plusmn; 10%, n = 8) and excellent radiochemical purity (&gt;99%). For the synthesis of radiolabeled 13-nm-sized gold nanoparticles, the DBCO-functionalized gold nanoparticles (3) were prepared by using a thiolated polyethylene glycol polymer. A copper-free click reaction between 1 and 3 gave the 125I-labeled gold nanoparticles (4) with more than 95% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method using a strain-promoted copper-free click reaction will be useful for the efficient and convenient radiolabeling of DBCO-group-containing nanomaterials.

An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group

A detailed procedure for the synthesis of a 125I-labeled azide and the radiolabeling of dibenzocyclooctyne (DBCO)-group-conjugated, 13-nm-sized gold nanoparticles using a copper-free click reaction is described.

Un protocollo ottimizzato per la radiomarcatura efficiente di oro nanoparticelle utilizzando un<sup&gt; 125</sup&gt; Azide gruppo I-etichettati protesico

Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient ...

Grafting Multiwalled Carbon Nanotubes with Polystyrene to Enable Self-Assembly and Anisotropic Patchiness

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a free-radical polymerization strategy to enable the modulation of the nanotube surface properties and produce supramolecular self-assembly of the nanostructures. First, a selective hydroxylation of the pristine nanotubes through a biphasic catalytically mediated oxidation reaction creates superficially distributed reactive sites at the sidewalls. The latter reactive sites are subsequently modified with methacrylic moieties using a silylated methacrylic precursor to create polymerizable sites. Those polymerizable groups can address further polymerization of styrene to produce a hybrid nanomaterial containing PS chains grafted to the nanotube sidewalls. The polymer-graft content, amount of silylated methacrylic moieties introduced and hydroxylation modification of the nanotubes are identified and quantified by Thermogravimetric Analysis (TGA). The presence of reactive functional groups hydroxyl and silylated methacrylate are confirmed by Fourier Transform Infrared Spectroscopy (FT-IR). Polystyrene-grafted carbon nanotube solutions in tetrahydrofuran (THF) provide wall-to-wall collinearly self-assembled nanotubes when cast samples are analyzed by transmission electron microscopy (TEM). Those self-assemblies are not obtained when suitable blanks are similarly cast from analogous solutions containing non-grafted counterparts. Therefore, this method enables the modification of the nanotube anisotropic patchiness at the sidewalls which results into spontaneous auto-organization at the nanoscale.

A procedure for the synthesis of polystyrene-grafted multiwalled carbon nanotubes using successive chemical modification steps to selectively introduce the polymer chains to the sidewalls and their self-assembly via anisotropic patchiness is presented.

L'innesto Multiwalled Carbon Nanotubes con polistirolo per abilitare l'auto-assemblaggio e discromie anisotropo

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a ...

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables the acquisition of photoluminescence spectra covering the time regime from nanoseconds up to 0.1 s. This enables us to follow the changes in the intensity (decay) and emission of the spectra over time. Using this method, it is possible to study diverse photophysical phenomena, such as the emission of phosphorescence, and the contributions of prompt and delayed fluorescence in molecules showing thermally activated delayed fluorescence (TADF). Remarkably, all spectra and decays are obtained in a single experiment. This can be done for solids (thin film, powder, crystal) and liquid samples, where the only limitations are the spectral sensitivity of the camera and the excitation wavelength (532 nm, 355 nm, 337 nm, and 266 nm). This technique is, thus, very important when investigating the excited state dynamics in organic emitters for their application in organic light-emitting diodes and other areas where triplet harvesting is of paramount importance. Since triplet states are strongly quenched by oxygen, emitters with efficient TADF luminescence, or those showing room temperature phosphorescence (RTP), must be correctly prepared in order to remove any dissolved oxygen from solutions and films. Otherwise, no long-lived emission will be observed. The method of degassing solid samples as presented in this work is basic and simple, but the degassing of liquid samples creates additional difficulties and is particularly interesting. A method of minimizing solvent loss and changing the sample concentration, while still enabling to remove oxygen in a very efficient and a repeatable manner, is presented in this work.

Here, we present a method of the spectroscopic characterization of organic molecules by means of time-resolved photoluminescence spectroscopy on the nanosecond-to-millisecond timescale in oxygen-free conditions. Methods to efficiently remove oxygen from the samples and, thus, limit luminescence quenching are also described.

Tempo-risolta caratterizzazione fotofisica di tripletto-raccoglitrici composti organici a un utilizzo di ambiente privo di ossigeno un iCCD telecamera

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables ...

Raman and IR Spectroelectrochemical Methods as Tools to Analyze Conjugated Organic Compounds

In the presented work, two spectroelectrochemical techniques are discussed as tools for the analysis of the structural changes occurring in the molecule on the vibrational level of energy. Raman and IR spectroelectrochemistry can be used for advanced characterization of the structural changes in the organic electroactive compounds. Here, the step-by-step analysis by means of Raman and IR spectroelectrochemistry is shown. Raman and IR spectroelectrochemical techniques provide complementary information about structural changes occurring during an electrochemical process, i.e. allows for the investigation of redox processes and their products. The examples of IR and Raman spectroelectrochemical analysis are presented, in which the products of the redox reactions, both in solution and solid state, are identified.

A protocol of step-by-step Raman and IR spectroelectrochemical analysis is presented.

Raman e IR Spettroelettrochimica metodi come strumenti per analizzare composti organici coniugati

In the presented work, two spectroelectrochemical techniques are discussed as tools for the analysis of the structural changes occurring in the molecule ...

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, allowing for the synthesis of isotactic poly(&#945;-hydroxy acids) with expected molecular weights (&#62;140 kDa) and narrow molecular weight distributions (Mw/Mn &#60; 1.1). This ring-opening polymerization is mediated by Ni and Zn complexes in the presence of an alcohol initiator and a photoredox Ir catalyst, irradiated by a blue LED (400 - 500 nm). The polymerization is performed at a low temperature (-15 &#176;C) to avoid undesired side reactions. The complete monomer consumption can be achieved within 4 - 8 hours, providing a polymer close to the expected molecular weight with narrow molecular weight distribution. The resulted number-average molecular weight shows a linear correlation with the degree of polymerization up to 1000. The homodecoupling 1H NMR study confirms that the obtained polymer is isotactic without epimerization. This polymerization reported herein offers a strategy for achieving rapid, controlled O-carboxyanhydrides polymerization to prepare stereoregular poly(&#945;-hydroxy acids) and its copolymers bearing various functional side-chain groups.

Controlled Photoredox Ring-Opening Polymerization of O-Carboxyanhydrides Mediated by Ni/Zn Complexes

A protocol for the controlled photoredox ring-opening polymerization of O-carboxyanhydrides mediated by Ni/Zn complexes is presented.

Controllata di polimerizzazione per apertura di anello Photoredox di O- Carboxyanhydrides mediata da complessi di Ni/Zn

Here, we describe an effective protocol that combines photoredox Ni/Ir catalysis with the use of a Zn-alkoxide for efficient ring-opening polymerization, ...