Les auteurs tiennent à remercier le Dr Jumpei Morimoto et le Dr Todd Doran pour une aide précieuse. Ce travail a été soutenu par un contrat du NHLBI (NO1-HV-00242).

<ol>
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Les auteurs déclarent qu&#39;ils n&#39;ont aucun intérêt financier concurrents.

Peptides amides tertiaires (APE) sont une superfamille d&#39;oligomères peptidomimétiques. Outre les peptides bien étudiés, peptoids et les peptides N-méthylés, une grande partie des composés de cette famille reste peu étudié, majorly raison d&#39;un manque de méthode de synthèse pour accéder générales peptides N-alkylés. Ici, nous décrivons une méthode efficace pour synthétiser PTA avec des blocs de construction chiraux dérivés d&#39;acides aminés. Auparavant, nous avons signalé à utiliser un nou...

Sont des composés peptidomimétiques qui imitent la structure des peptides naturels. Ils sont conçus pour conserver l&#39;activité biologique, tout en surmontant certains des problèmes associés aux peptides naturels, y compris la perméabilité cellulaire et la stabilité contre la protéolyse 1-3. En raison de la nature oligomère de ces composés, de grandes bibliothèques de synthèse peuvent être facilement accessibles par des voies de synthèse de sous-monomères ou monomères 4-7. Une des classes les plus étudiées de peptidomimétiques est peptoids. Les peptoïdes sont des oligomères de glycines N-alkylés qui peuvent être facilement synthétisés en utilisant une stratégie de sous-monomère 8, 9. Beaucoup de ligands de protéines utiles ont été identifiés avec succès de criblage de grandes banques de peptoïdes synthétique contre des cibles de protéines 1, 10-14. Néanmoins, &quot;hits&quot; identifiés dans les bibliothèques peptoïdes archives rarement très haute affinité vers des cibles protéiques 1,10-14,22. Une major différence entre les peptoïdes et les peptides naturels est que la plupart des peptoïdes n&#39;ont généralement pas la capacité de former une structure secondaire en raison de l&#39;absence de centres chiraux et des contraintes conformationnelles. Pour résoudre ce problème, plusieurs stratégies ont été développées au cours de la dernière décennie, en grande partie en se concentrant sur ​​la modification des chaînes latérales contenues sur les principaux atomes d&#39;azote de la chaîne 15-22. Récemment, nous avons développé une nouvelle voie de synthèse d&#39;introduire des chaînes naturelles latérales d&#39;acides aminés sur un squelette peptoïde pour créer peptides amides tertiaires 23. Peptides amides tertiaires (APE) sont une famille de peptidomimétiques qui incluent, mais ne sont pas limités à des peptides (R 2 = H), les peptoïdes (R 1 = H) et les peptides N-méthylés super (R 1 ≠ H, R 2 = Me) . (Voir Figure 1) Notre voie de synthèse emploie des acides aminés naturels comme source de chiralité et des chaînes latérales sur le45; carbone, et les amines primaires disponibles dans le commerce pour fournir les N-substitutions. Par conséquent, un espace chimique plus grande que celle des peptides simples, des peptoïdes ou des peptides N-méthylés peuvent être explorées. Spectres de dichroïsme circulaire ont montré que les molécules d&#39;ATP sont très structurés en solution. Caractérisation de l&#39;un des complexes protéiques PTA-montre bien que les contraintes de conformation de PTA sont nécessaires pour la liaison. Récemment, nous avons également découvert que certaines des molécules d&#39;ATP possèdent une meilleure perméabilité cellulaire que leurs homologues de peptoïdes et de peptides. Nous croyons que ces bibliothèques de PTA peuvent être une bonne source de ligands de haute affinité pour les protéines cibles. Dans cet article, nous allons discuter de la synthèse d&#39;un échantillon d&#39;une bille un composé (OBOC) bibliothèque de PTA dans les détails avec quelques meilleures conditions pour le couplage et le clivage de ces composés.

<table border="0" cellpadding="0" cellspacing="0" width="889">
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		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">3-Methoxypropylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">M25007</td>
			<td>CAS:5332-73-0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">2-Methoxyethylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">143693</td>
			<td>CAS:109-85-3</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">N-(3-Aminopropyl)-2-pyrrolidinone</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">136565&#160;</td>
			<td>CAS:7663-77-6&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">N,N&#39;-Diisopropylcarbodiimide (DIC)</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">115211000</td>
			<td>CAS:693-13-0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">N,N-Diisopropylethylamine (DIPEA)</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">D125806</td>
			<td>CAS:7087-68-5</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;">NaNO2</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">424340010</td>
			<td>CAS:7631-99-4</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">NAOD 40% solution in water</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">200058-506</td>
			<td>CAS:7732-18-5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Piperidine</td>
			<td style="width:169px;">ALFA AESAR</td>
			<td style="width:160px;">A12442-AE</td>
			<td>CAS:110-89-4</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Piperonylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">P49503&#160;</td>
			<td>CAS:2620-50-0</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Propylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">240958</td>
			<td>CAS:107-10-8</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Trifluoroacetic acid</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">299537</td>
			<td>CAS:76-05-1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">&#945;-Cyano-4-hydroxycinnamic acid&#160;</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">39468</td>
			<td>CAS:28166-41-8&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">&#945;-ketoglutarate</td>
			<td style="width:169px;">ALFA AESAR</td>
			<td style="width:160px;">AAA10256-22</td>
			<td style="width:311px;">CAS:328-50-7</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Tentagel Resin with RINK linker</td>
			<td style="width:169px;">Rapp-Polymere</td>
			<td style="width:160px;">S30023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Alanine transaminase</td>
			<td style="width:169px;">Roche</td>
			<td style="width:160px;">10105589001</td>
			<td>AKA: Glutamate-Pyruvate Transaminase (GPT)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:249px;">Incubator</td>
			<td style="width:169px;">New Brunswick Scientific</td>
			<td style="width:160px;">Innova44</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">NMR</td>
			<td style="width:169px;">Bruker</td>
			<td style="width:160px;">400MHz</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">MALDI mass spectrometer</td>
			<td style="width:169px;">Applied Biosystems&#160;</td>
			<td style="width:160px;">4800 MALDI-TOF/TOF</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Lyophilizer</td>
			<td style="width:169px;">SP Scientific</td>
			<td style="width:160px;">VirTis benchtop K</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Syringe reactor</td>
			<td style="width:169px;">INTAVIS&#160;</td>
			<td style="width:160px;">Reaction Column</td>
			<td>3ml, 5ml, 10ml, 20ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Vacuum manifold&#160;</td>
			<td style="width:169px;">Promega</td>
			<td style="width:160px;">A7231</td>
			<td>Vac-Man</td>
		</tr>
	</tbody>
</table>

split-and-pool synthesis and characterization of peptide tertiary amide library

Peptidomimetics sont d&#39;excellentes sources de ligands protéiques. La nature oligomères de ces composés nous permet d&#39;accéder à de grandes bibliothèques de synthèse sur phase solide en utilisant la chimie combinatoire. Une des classes les plus étudiés de peptidomimétiques est peptoids. Les peptoïdes sont faciles à synthétiser et ont été montrés pour être résistant à la protéolyse et de la cellule-perméable. Au cours de la dernière décennie, de nombreux ligands de protéines utiles ont été identifiés par criblage de banques de peptoïdes. Cependant, la plupart des ligands identifiés dans les bibliothèques peptoïdes ne s&#39;affichent pas une affinité élevée, à de rares exceptions. Cela peut être dû, en partie, à l&#39;absence de centres chiraux et des contraintes conformationnelles des molécules peptoïdes. Récemment, nous avons décrit une nouvelle voie de synthèse pour accéder peptides amides tertiaires (APE). PTA sont une superfamille de peptidomimétiques qui incluent, mais ne sont pas limités à des peptides, des peptoïdes et les peptides N-méthylés. Avec des chaînes latérales sur les deux α-carbone et des atomes d&#39;azote principaux de la chaîne,la conformation de ces molécules sont grandement limitée par encombrement stérique et 1,3 allylique souche. (Figure 1) Notre étude suggère que ces molécules d&#39;ATP sont très structurés en solution et peuvent être utilisés pour identifier des ligands protéiques. Nous croyons que ces molécules peuvent être une source future de ligands protéiques de haute affinité. Ici, nous décrivons la méthode de synthèse combinant la puissance de deux split-et-piscine et stratégies sous-monomères pour synthétiser un échantillon d&#39;un cordon d&#39;un composé (OBOC) bibliothèque de PTA.

Ici, nous montrons trois spectres MALDI représentatifs d&#39;un trimère de PTA de liaison. Comme le montre la figure 6A, lorsqu&#39;il est clivé à température ambiante en utilisant 50% de solution de TFA / DCM, une dégradation significative est observée. Sur la figure 6A, un sommet 593 et 484 correspondent au segment de liaison et le trimère de PTA, respectivement, montrent que la molécule entière a été synthétisé avec succès le bourrelet mais dégradée lors du clivage. ...

Watch this Scientific Journal Video about Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library at JoVE.com

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptides amides tertiaires (APE) sont une superfamille de peptidomimétiques qui incluent, mais ne sont pas limités à des peptides, des peptoïdes et les peptides N-méthylés. Nous décrivons ici une méthode synthétique qui combine à la fois divisée et-piscine et stratégies sous-monomères pour synthétiser un une bille bibliothèque d&#39;un composé de PTA.

Split-et-piscine Synthèse et caractérisation de peptides tertiaire Amide Bibliothèque

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

split-pool-synthesis-characterization-peptide-tertiary-amide

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Carboxylic Acid Derivatives

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18.0K vues.  The Scripps Research Institute.  Peptides amides tertiaires (APE) sont une superfamille de peptidomimétiques qui incluent, mais ne sont pas limités à des peptides, des peptoïdes et les peptides N-méthylés. Nous décrivons ici une méthode synthétique qui combine à la fois divisée et-piscine et stratégies sous-monomères pour synthétiser un une bille bibliothèque d'un composé de PTA. 

Vidéo: Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization

The traditional strategy for the introduction of chemical functionalities is the use of solid-phase synthesis by appending suitably modified phosphoramidite precursors to the nascent chain. However, the conditions used during the synthesis and the restriction to rather short sequences hamper the applicability of this methodology. On the other hand, modified nucleoside triphosphates are activated building blocks that have been employed for the mild introduction of numerous functional groups into nucleic acids, a strategy that paves the way for the use of modified nucleic acids in a wide-ranging palette of practical applications such as functional tagging and generation of ribozymes and DNAzymes. One of the major challenges resides in the intricacy of the methodology leading to the isolation and characterization of these nucleoside analogues.
	
	In this video article, we present a detailed protocol for the synthesis of these modified analogues using phosphorous(III)-based reagents. In addition, the procedure for their biochemical characterization is divulged, with a special emphasis on primer extension reactions and TdT tailing polymerization. This detailed protocol will be of use for the crafting of modified dNTPs and their further use in chemical biology.

The protocol described herein aims to explain and abridge the numerous obstacles in the way of the intricate route leading to modified nucleoside triphosphates. Consequently, this protocol facilitates both the synthesis of these activated building-blocks and their availability for practical applications.

Nucléosidiques Triphosphates - de la synthèse à caractérisation biochimique

The  traditional strategy for the introduction of chemical functionalities is the  use of solid-phase synthesis by appending suitably modified ...

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Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is 1H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

This protocol describes the use of amide coupling reactions of isonicotinic acid and diaminoalkanes to form bridging ligands suitable for use in the synthesis of multinuclear platinum complexes, which combine aspects of the anticancer drugs BBR3464 and picoplatin.

Amide Réaction de couplage pour la synthèse de ligands à base de bispyridine et leur complexation Platinum comme dinucléaires agents anticancéreux

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Cadres de synthèse et la caractérisation de fonctionnalisé métal-organique

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the hydroxylmethylene phosphine precursor with ammonia in methanol under a nitrogen atmosphere. The N-triphosPh ligand precipitates from the solution after approximately 1 hr of reflux and can be isolated analytically pure via simple cannula filtration procedure under nitrogen. Reaction of the N-triphosPh ligand with [Ru3(CO)12] under reflux affords a deep red solution that show evolution of CO gas on ligand complexation. Orange crystals of the complex [Ru(CO)2{N(CH2PPh2)3}-&#954;3P] (2) were isolated on cooling to RT. The 31P{1H} NMR spectrum showed a characteristic single peak at lower frequency compared to the free ligand. Reaction of a toluene solution of complex 2 with oxygen resulted in the instantaneous precipitation of the carbonate complex [Ru(CO3)(CO){N(CH2PPh2)3}-&#954;3P] (3) as an air stable orange solid. Subsequent hydrogenation of 3 under 15 bar of hydrogen in a high-pressure reactor gave the dihydride complex [RuH2(CO){N(CH2PPh2)3}-&#954;3P] (4), which was fully characterized by X-ray crystallography and NMR spectroscopy. Complexes 3 and 4 are potentially useful catalyst precursors for a range of hydrogenation reactions, including biomass-derived products such as levulinic acid (LA). Complex 4 was found to cleanly react with LA in the presence of the proton source additive NH4PF6 to give [Ru(CO){N(CH2PPh2)3}-&#954;3P{CH3CO(CH2)2CO2H}-&#954;2O](PF6) (6).

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Ruthenium phosphine complexes are widely used for homogeneous catalytic reactions such as hydrogenations. The synthesis of a series of novel tridentate ruthenium complexes bearing the N-triphos ligand N(CH2PPh2)3 is reported. Additionally, the stoichiometric reaction of a dihydride Ru&#8211;N-triphos complex with levulinic acid is described.

La synthèse, la caractérisation et la réactivité d&#39;une série de ruthénium<em&gt; N</em&gt; -triphos<sup&gt; Ph</sup&gt; Complexes

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Synthèse, caractérisation et fonctionnalisation des hybrides Au / CdS et Au / ZnS de base / Shell Nanoparticules

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency.
Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position.
We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites&#39; viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a systematic screen for the most biological active conformation. This method provides a general, fast, and facile way to synthesize cyclic peptides.

A simple and general method for the synthesis of cyclic peptides using microwave irradiation is outlined. This procedure enables the synthesis of backbone cyclic peptides with a collection of different conformations while retaining the side chains and the pharmacophoric moieties., and therefore, allows to screen for the bioactive conformation.

Développement d&#39;un Backbone peptide cyclique Bibliothèque en tant que potentiel Antiparasitaires Therapeutics Utilisation irradiation micro-ondes

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Synthèse et caractérisation de supramoléculaires Colloids

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

Synthesis and Characterization of Fe-doped Aluminosilicate Nanotubes with Enhanced Electron Conductive Properties

The goal of the protocol is to synthesize Fe-doped aluminosilicate nanotubes of the imogolite type with the formula (OH)3Al2-xFexO3SiOH. Doping with Fe aims at lowering the band gap of imogolite, an insulator with the chemical formula (OH)3Al2O3SiOH, and at modifying its adsorption properties towards azo-dyes, an important class of organic pollutants of both wastewater and groundwater.
Fe-doped nanotubes are obtained in two ways: by direct synthesis, where FeCl3 is added to an aqueous mixture of the Si and Al precursors, and by post-synthesis loading, where preformed nanotubes are put in contact with a FeCl3&#8226;6H2O aqueous solution. In both synthesis methods, isomorphic substitution of Al3+ by Fe3+ occurs, preserving the nanotube structure. Isomorphic substitution is indeed limited to a mass fraction of ~1.0% Fe, since at a higher Fe content (i.e., a mass fraction of 1.4% Fe), Fe2O3 clusters form, especially when the loading procedure is adopted. The physicochemical properties of the materials are studied by means of X-ray powder diffraction (XRD), N2 sorption isotherms at -196 &#176;C, high resolution transmission electron microscopy (HRTEM), diffuse reflectance (DR) UV-Vis spectroscopy, and &#950;-potential measurements. The most relevant result is the possibility to replace Al3+ ions (located on the outer surface of the nanotubes) by post-synthesis loading on preformed imogolite without perturbing the delicate hydrolysis equilibria occurring during nanotube formation. During the loading procedure, an anionic exchange occurs, where Al3+ ions on the outer surface of the nanotubes are replaced by Fe3+ ions. In Fe-doped aluminosilicate nanotubes, isomorphic substitution of Al3+ by Fe3+ is found to affect the band gap of doped imogolite. Nonetheless, Fe3+ sites on the outer surface of nanotubes are able to coordinate organic moieties, like the azo-dye Acid Orange 7, through a ligand-displacement mechanism occurring in an aqueous solution.

Here, we present a protocol to synthesize and characterize Fe-doped aluminosilicate nanotubes. The materials are obtained by either sol-gel synthesis upon addition of FeCl3&#8226;6H2O to the mixture containing the Si and Al precursors or by post-synthesis ionic exchange of preformed aluminosilicate nanotubes.

Synthèse et caractérisation de Fe dopé Aluminosilicate Nanotubes aux propriétés conductrices améliorées Electron

The goal of the protocol is to synthesize Fe-doped aluminosilicate nanotubes of the imogolite type with the formula (OH)3Al2-xFexO3SiOH. Doping with Fe ...

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles (PPAs) and Related Biomaterials

Polyamine-based Peptide Amphiphiles (PPAs) are a new class of self-assembling amphiphilic biomaterials-related to the peptide amphiphiles (PAs). Traditional PAs possess charged amino acids as solubilizing groups (lysine, arginine), which are directly connected to a lipid segment or can contain a linker region made of neutral amino acids. Tuning the peptide sequence of PAs can yield diverse morphologies. Similarly, PPAs possess a hydrophobic segment and neutral amino acids, but also contain polyamine molecules as water solubilizing (hydrophilic) groups. As is the case with PAs, PPAs can also self-assemble into diverse morphologies, including small rods, twisted nano-ribbons, and fused nano-sheets, when dissolved in water. However, the presence of both primary and secondary amines on a single polyamine molecule poses a significant challenge when synthesizing PPAs. In this paper, we show a simple protocol, based on literature precedents, to achieve a facile synthesis of PPAs using solid phase peptide synthesis (SPPS). This protocol can be extended to the synthesis of PAs and other similar systems. We also illustrate the steps that are needed for cleavage from the resin, identification, and purification.

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles PPAs and Related Biomaterials

The synthesis of polyamine-based peptide amphiphiles (PPAs) is a significant challenge due to the presence of multiple amine nitrogens, which requires judicious use of protecting groups to mask these reactive functionalities. In this paper, we describe a facile method for the preparation of these new class of self-assembling molecules.

Protocole facile pour la synthèse d’auto-assemblage axée sur les polyamines peptides Amphiphiles (AAE) et des biomatériaux

Polyamine-based Peptide Amphiphiles (PPAs) are a new class of self-assembling amphiphilic biomaterials-related to the peptide amphiphiles (PAs). ...

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

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

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