Anti-Anisakis antibodies in colon cancer patients and their relationship with γδ T-cells.

Many pathogens are related to carcinogenesis. Chronic inflammation, as a result of persistent infection, leads to DNA damage, higher expression of oncogenes, decreased apoptosis and immunosuppression, which are some of the reasons for cancer induction. Among parasites, Schistosoma, Opistorchis and Clonorchis are recognised as infectious agents which contribute to cancer. A relationship between Anisakis and cancer was hypothesised because cellular responses to Anisakis products could result in inflammation and DNA damage. Previous research has shown a decrease in CD8+ γδ T-cells and an increase in αß and γδ T-cell apoptosis in colon cancer (CC) samples. Ninety-two CC patients and 60 healthy subjects were recruited. γδ and αß T-cells were analysed, and their apoptosis was evaluated. Anti-Anisakis antibodies were tested in sera from CC patients and controls. Anti-Anisakis IgG, IgM, IgA and IgE antibodies were significantly higher in CC patients. A significant increase in anti-Anisakis IgA levels was observed in patients with angiolymphatic invasion. The number of all γδ T-cells, as well as CD3+ CD4+ αß T-cells, was significantly lower in CC patients. The apoptosis of all T-cells was significantly increased in patients with CC. We observed a significantly higher percentage of anti-Anisakis IgE positive patients having a deficit of CD3+ γδ T-cells. Our results suggest a relationship between Anisakis and CC.

Self-assembly pathways in a triphenylalanine peptide capped with aromatic groups.

Peptide derivatives and, most specifically, their self-assembled supramolecular structures are being considered in the design of novel biofunctional materials. Although the self-assembly of triphenylalanine homopeptides has been found to be more versatile than that of homopeptides containing an even number of residues (i.e. diphenylalanine and tetraphenylalanine), only uncapped triphenylalanine (FFF) and a highly aromatic analog blocked at both the N- and C-termini with fluorenyl-containing groups (Fmoc-FFF-OFm), have been deeply studied before. In this work, we have examined the self-assembly of a triphenylalanine derivative bearing 9-fluorenylmethyloxycarbonyl and benzyl ester end-capping groups at the N- and C-termini, respectively (Fmoc-FFF-OBzl). The antiparallel arrangement clearly dominates in ß-sheets formed by Fmoc-FFF-OBzl, whereas the parallel and antiparallel dispositions are almost isoenergetic in Fmoc-FFF-OFm ß-sheets and the parallel one is slightly favored for FFF. The effects of both the peptide concentration and the medium on the self-assembly process have been examined considering Fmoc-FFF-OBzl solutions in a wide variety of solvent:co-solvent mixtures. In addition, Fmoc-FFF-OBzl supramolecular structures have been compared to those obtained for FFF and Fmoc-FFF-OFm under identical experimental conditions. The strength of π-π stacking interactions involving the end-capping groups plays a crucial role in the nucleation and growth of supramolecular structures, which determines the resulting morphology. Finally, the influence of a non-invasive external stimulus, ultrasounds, on the nucleation and growth of supramolecular structures has been examined. Overall, FFF-based peptides provide a wide range of supramolecular structures that can be of interest in the biotechnological field.

Stereoselective, Ruthenium-Photocatalyzed Synthesis of 1,2-Diaminotruxinic Bis-amino Acids from 4-Arylidene-5(4H)-oxazolones.

The irradiation of (Z)-2-phenyl-4-aryliden-5(4H)-oxazolones 1 in deoxygenated CH2Cl2 at 25 °C with blue light (465 nm) in the presence of [Ru(bpy)3](BF4)2 (5% mole ratio) as a triplet photocatalyst promotes the [2+2] photocycloaddition of the C═C bonds of the 4-arylidene moiety, thus allowing the completely regio- and stereoselective formation of cyclobutane-bis(oxazolone)s 2 as single stereoisomers. Cyclobutanes 2 have been unambiguously characterized as the µ-isomers and contain two E-oxazolones coupled in an anti-head-to-head form. The use of continuous-flow techniques in microreactors allows the synthesis of cyclobutanes 2 in only 60 min, compared with the 24-48 h required in batch mode. Ring opening of the oxazolone heterocycle in 2 with a base affords the corresponding 1,2-diaminotruxinic bis-amino esters 3, which are also obtained selectively as µ-isomers. The ruthenium complex behaves as a triplet photocatalyst, generating the reactive excited state of the oxazolone via an energy-transfer process. This reactive excited state has been characterized as a triplet diradical 3(E/Z)-1* by laser flash photolysis (transient absorption spectroscopy). This technique also shows that this excited state is the same when starting from either (Z)- or (E)-oxazolones. Density functional theory calculations show that the first step of the [2+2] cycloaddition between 3(E/Z)-1* and (Z)-1 is formation of the C(H)-C(H) bond and that (Z) to (E) isomerization takes place at the 1,4-diradical thus formed.

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF3.

The irradiation of (Z)-2-phenyl-4-aryliden-5(4H)-thiazolones 2 with blue light (465 nm) in CH2Cl2 solution promotes [2 + 2]-photocycloaddition of the exocyclic C═C bonds and the formation of the dispirocyclobutanes 3. This reaction takes place with high stereoselectivity, given that the ε-isomer (1,3 head-to-tail syn coupling) is formed in more than 90% yield in most of the cases. However, irradiation of 5(4H)-thiazolones 2 with blue light (456 nm) in dry MeOH in the presence of BF3·OEt2 leads to the monospirocyclobutanes 4 with full stereoselectivity, also affording the ε-isomer. A ring-opening reaction of only one of the thiazolone rings appears to have taken place in 4 upon methanolysis, leading to the corresponding ester and thioamide groups. The treatment of free 4-aryliden-5(4H)-thiazolones 2 with a base in alcohol (NaOR/ROH) also produces a ring-opening reaction of the heterocycle by methanolysis, although, under these reaction conditions, further intramolecular S-attack at the exocyclic C(H)═C bond and cyclization is observed, forming the dihydrothiazoles 5 or 6 as mixtures of cis (RS/SR)- and trans (RR/SS)-isomers with high diastereomeric excess. trans-(RR/SS)-Dihydrothiazoles 6 can be isolated as pure diastereoisomers by column chromatography. Surprisingly, dihydrothiazoles 5 can also be obtained by the treatment of 4-aryliden-5(4H)-thiazolones 2 with BF3·OEt2 in methanol in the absence of a base.

Fluorescent Orthopalladated Complexes of 4-Aryliden-5(4H)-oxazolones from the Kaede Protein: Synthesis and Characterization.

The goal of the work reported here was to amplify the fluorescent properties of 4-aryliden-5(4H)-oxazolones by suppression of the hula-twist non-radiative deactivation pathway. This aim was achieved by simultaneous bonding of a Pd center to the N atom of the heterocycle and the ortho carbon of the arylidene ring. Two different 4-((Z)-arylidene)-2-((E)-styryl)-5(4H)-oxazolones, the structures of which are closely related to the chromophore of the Kaede protein and substituted at the 2- and 4-positions of the arylidene ring (1a OMe; 1b F), were used as starting materials. Oxazolones 1a and 1b were reacted with Pd(OAc)2 to give the corresponding dinuclear orthometalated palladium derivates 2a and 2b by regioselective C-H activation of the ortho-position of the arylidene ring. Reaction of 2a (2b) with LiCl promoted the metathesis of the bridging carboxylate by chloride ligands to afford dinuclear 3a (3b). Mononuclear complexes containing the orthopalladated oxazolone and a variety of ancillary ligands (acetylacetonate (4a, 4b), hydroxyquinolinate (5a), aminoquinoline (6a), bipyridine (7a), phenanthroline (8a)) were prepared from 3a or 3b through metathesis of anionic ligands or substitution of neutral weakly bonded ligands. All species were fully characterized and the X-ray determination of the molecular structure of 7a was carried out. This structure has strongly distorted ligands due to intramolecular interactions. Fluorescence measurements showed an increase in the quantum yield (QY) by up to one order of magnitude on comparing the free oxazolone (QY < 1%) with the palladated oxazolone (QY = 12% for 6a). This fact shows that the coordination of the oxazolone to the palladium efficiently suppresses the hula-twist deactivation pathway.

Pd-Oxazolone complexes conjugated to an engineered enzyme: improving fluorescence and catalytic properties.

Different Pd-complexes containing orthometallated push-pull oxazolones were inserted by supramolecular Pd-amino acid coordination on two genetically engineered modified variants of the thermoalkalophilic Geobacillus thermocatenolatus lipase (GTL). Pd-lipase conjugation was performed on the solid phase in the previously immobilized form of GTL under mild conditions, and soluble conjugated Pd-GTL complexes were obtained by simply desorbing by washing with an acetonitrile aqueous solution. Three different Pd complexes were incorporated into two different genetically modified enzyme variants, one containing all the natural cysteine residues changed to serine residues, and another variant including an additional Cys mutation directly in the catalytic serine (Ser114Cys). The new Pd-enzyme conjugates were fluorescent even at ppm concentrations, while under the same conditions free Pd complexes did not show fluorescence at all. The Pd conjugation with the enzyme extremely increases the catalytic profile of the corresponding Pd complex from 200 to almost 1000-fold in the hydrogenation of arenes in aqueous media, achieving in the case of GTL conjugated with orthopalladated 4a an outstanding TOF value of 27 428 min-1. Also the applicability of GTL-C114 conjugated with orthopalladated 4b in a site-selective C-H activation reaction under mild conditions has been demonstrated. Therefore, the Pd incorporation into the enzyme produces a highly stable conjugate, and improves remarkably the catalytic activity and selectivity, as well as the fluorescence intensity, of the Pd complexes.

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore.

The stereoselective synthesis of truxillic bis-amino esters from polyfunctional oxazolones is reported. The reaction of 4-((Z)-arylidene)-2-(E)-styryl-5(4H)-oxazolones 2 with Pd(OAc)2 resulted in ortho-palladation and the formation of a dinuclear open-book complexes 3 with carboxylate bridges, where the Pd atom is C^N bonded to the oxazolone. In 3 the two exocyclic C=C bonds of the oxazolone are in a face-to-face arrangement, which is optimal for their [2 + 2] photocycloaddition. Irradiation of dimers 3 in CH2Cl2 solution with blue light (465 nm) promoted the chemo- and stereoselective [2 + 2] photocycloaddition of the exocyclic C=C bonds and the formation of cyclobutane-containing ortho-palladated complexes 4. Treatment of 4 with CO in a MeOH/NCMe mixture promoted the methoxycarbonylation of the palladated carbon and the release of the corresponding ortho-functionalized 1,3-diaminotruxillic bis-amino esters 5 as single isomers.

Heterochirality Restricts the Self-Assembly of Phenylalanine Dipeptides Capped with Highly Aromatic Groups.

The influence of stereochemistry on the self-assembly of phenylalanine (Phe) dipeptides bearing aromatic fluorenyl groups at both the N- and C-termini (Fmoc, OFm) has been investigated. For this purpose, Fmoc-d-Phe-l-Phe-OFm and Fmoc-l-Phe-l-Phe-OFm have been examined considering a wide variety of solvents, which differ in dielectric constant and volatility. Results reveal that replacement of l-Phe by d-Phe has a major impact on the self-assembly propensities, restricting drastically the structural diversity and polymorphism shown by the homochiral dipeptide. Thus, the analogous heterochiral dipeptide shows a great propensity to form micro/nanofibers, independently of the environmental conditions. Theoretical calculations revealed that the stability of antiparallel disposition is much higher (a factor of ca. 15) for Fmoc-d-Phe-l-Phe-OFm than that for Fmoc-l-Phe-l-Phe-OFm, which has been attributed to the hydrophobic core formed in the former. Overall, results suggest that control of the backbone chirality is a potent and versatile strategy to drive and finely tune the self-assembly propensities of highly aromatic peptides.

Evidence of the Reduced Abundance of Proline cis Conformation in Protein Poly Proline Tracts.

Proline is found in a cis conformation in proteins more often than other proteinogenic amino acids, where it influences structure and modulates function, being the focus of several high-resolution structural studies. However, until now, technical and methodological limitations have hampered the site-specific investigation of the conformational preferences of prolines present in poly proline (poly-P) homorepeats in their protein context. Here, we apply site-specific isotopic labeling to obtain high-resolution NMR data on the cis/trans equilibrium of prolines within the poly-P repeats of huntingtin exon 1, the causative agent of Huntington's disease. Screening prolines in different positions in long (poly-P11) and short (poly-P3) poly-P tracts, we found that, while the first proline of poly-P tracts adopts similar levels of cis conformation as isolated prolines, a length-dependent reduced abundance of cis conformers is observed for terminal prolines. Interestingly, the cis isomer could not be detected in inner prolines, in line with percentages derived from a large database of proline-centered tripeptides extracted from crystallographic structures. These results suggest a strong cooperative effect within poly-Ps that enhances their stiffness by diminishing the stability of the cis conformation. This rigidity is key to rationalizing the protection toward aggregation that the poly-P tract confers to huntingtin. Furthermore, the study provides new avenues to probe the structural properties of poly-P tracts in protein design as scaffolds or nanoscale rulers.

Meningioma-like Tumor of the Skin Revisited: A Distinct CD34+ Dermal Tumor With an Expanded Histologic Spectrum.

The term meningioma-like tumor of the skin (MLTS) was coined in 1993 to designate a particular whorled spindle cell superficial cutaneous tumor. No additional confirmed cases of this entity have been reported to date. Some authors have speculated that these cases might be cellular neurothekeomas. In order to delineate the histologic spectrum and the immunophenotype of this unusual tumor, we studied 5 cases, 2 previously unreported and the 3 original cases. The immunohistochemical findings of case 5, however, were limited to those from the original study. Clinically, the tumor presented as a reddish papule, plaque, or nodule, located in the extremities or trunk. The patient often referred to a recent growth of a longstanding lesion. Histologically, the characteristic whorled spindle and stellate dendritic cell population, commonly in a perivascular arrangement, and variable myxoid component, were consistently found in all cases. A prominent microvasculature was also a constant finding. The presence of large deciduoid cells was conspicuous in one case. A reticular pattern of multivacuolated cells giving a chordoma-like appearance was evident in another case. Tumor cells were diffusely positive for CD34 in all 4 cases studied, and negative for S-100, EMA, NKI-C3, CD68, and smooth muscle markers. No complete loss of retinoblastoma protein was found. No brachyury immunostaining was found in the case with chordoid features. No EWSR1 or NAB2-STAT6 gene fusions were found. From these findings, we demonstrate that MLTS is a distinct CD34 spindle cell benign dermal tumor, unrelated to cellular neurothekeoma, and exhibiting myxoid, deciduoid, or chordoma-like features.

Amyloid fibrils from organic solutions of an amphiphilic dipeptide.

Non-hydrated organic solutions of a diphenylalanine amphiphile blocked at the C-terminus with a fluorenylmethyl ester and stabilized at the N-terminus with a trifluoroacetate have been used to prepare amyloid fibrils. The solvent used to prepare the stock solution together with the co-solvent added enables regulation of the characteristics of the fibrils, which is important for their use in technological applications.

Topical paromomycin for New World cutaneous leishmaniasis.

BACKGROUND: Paromomycin-based topical treatments were shown to be effective in curing cutaneous leishmaniasis (CL) lesions caused by Leishmania major in Tunisia. Cure rates of an index lesion were approximately 80%. As a follow on, we conducted a similar Phase 3 trial in Panama to demonstrate the efficacy of these treatments against New World species. The primary objective was to determine if a combination topical cream (paromomycin-gentamicin) resulted in statistically superior final clinical cure rates of an index lesion compared to a paromomycin alone topical cream for the treatment of CL, primarily caused by Leishmania panamensis. METHODS: We conducted a randomized, double blind, Phase 3 trial of topical creams for the treatment of CL caused by Leishmania spp. Three hundred ninety nine patients with one to ten CL lesions were treated by topical application once daily for 20 days. The primary efficacy endpoint was percentage of subjects with clinical cure of an index lesion confirmed to contain Leishmania with no relapse. RESULTS: The clinical cure of the index lesion for paromomycin-gentamicin was 79% (95% CI; 72 to 84) and for paromomycin alone was 78% (95% CI; 74 to 87) (p = 0.84). The most common adverse events considered related to study cream application were mild to moderate dermatitis, pain, and pruritus. CONCLUSIONS: Superiority of paromomycin-gentamicin was not demonstrated. However, the approximately 80% cure rates for both topical creams were similar to those demonstrated in Tunisia and previously reported with parenteral antimonials.

Amyloid-like Fibrils from a Diphenylalanine Capped with an Aromatic Fluorenyl.

The self-assembly behavior of a diphenylalanine amphiphile blocked at the C-terminus with a 9-fluorenylmethyl ester and stabilized at the N-terminus with a trifluoroacetate (TFA) anion, TFA·FF-OFm, has been examined. At low peptide concentration (0.5 mg/mL), long amyloid-like fibrils, which come from the fusion of two or more helical ribbons and/or thinner fibrils, organized in bundles or as individual entities are detected. Microbeam synchrotron radiation infrared spectroscopy has shown that TFA·FF-OFm molecules in amyloid-like fibrils arrange, forming antiparallel ß-sheets. Alteration of the experimental conditions to prioritize the thermodynamic contribution with respect to the kinetic one in the self-assembly process inhibits the organization of amyloid-like structures in favor of the formation of conventional fibrous structures. On the basis of experimental observations, a structural model where the individual antiparallel ß-sheets are oriented in parallel has been proposed for TFA·FF-OFm amyloid-like fibrils.

Synthesis of cis-hydrindan-2,4-diones bearing an all-carbon quaternary center by a Danheiser annulation.

A straightforward synthetic entry to functionalized hydrindane compounds based on a rapid assembly of the core nucleus by a Danheiser cycloaddition is reported. Valuable bicyclic building blocks containing the fused five and six-membered carbocyclic ring system can be achieved in only four steps from a simple acyclic ß-keto ester.

Self-assembly of diphenylalanine with preclick components as capping groups.

Alkyne and azide, which are commonly used in the cycloaddition reaction recognized as "click chemistry", have been used as capping groups of two engineered diphenylalanine (FF) derivatives due to their ability to form weak intermolecular interactions (i.e. dipole-π and π-π stacking). In Poc-FF-N3, alkyne and azide act as N- and C-terminal capping groups, respectively, while such positions are exchanged in N3-FF-OPrp. The self-assembly of such two synthesized peptides has been extensively studied in their "pre-click" state, considering the influence of three different factors: the peptide concentration, the polarity of the medium, and the nature of the substrate. Poc-FF-N3 assembles into microfibers that, depending on the medium and the substrate, can aggregate hierarchically in supramolecular structures with different morphologies. The most distinctive one corresponds to very stable birefringent dendritic-like microstructures, which are derived from the ordered agglomeration of microfibers. These branched supramolecular structures, which are observed under a variety of conditions, are relatively uncommon in short FF sequences. At the molecular level, Poc-FF-N3 organizes in antiparallel ß-sheets stabilized by N-HO intermolecular hydrogen bonds and re-enforced by weak interactions between the azide and alkyne groups of neighbouring molecules. In contrast, N3-FF-OPrp exhibits a very poor tendency to organize into structures with a well-defined morphology. Theoretical calculations on model complexes indicate that the tendency of the latter peptide to organize into small amorphous agglomerates is due to its poor ability to form specific intermolecular interactions in comparison with Poc-FF-N3. The implications of the weak interactions induced by the alkyne and azide groups, which strengthen peptidepeptide hydrogen bonds and π-ladders due to the stacked aromatic phenyl side groups, are discussed.

Diversity and Hierarchy in Supramolecular Assemblies of Triphenylalanine: From Laminated Helical Ribbons to Toroids.

Microstructures from small phenylalanine-based peptides have attracted great attention lately because these compounds are considered to be a new class of tunable materials. In spite of the extensive studies on uncapped diphenylalanine and tetraphenylalanine peptides, studies on the self-assembly of uncapped triphenylananine (FFF) are very scarce and nonsystematic. In this work, we demonstrate that FFF assemblies can organize in a wide number of well-defined supramolecular structures, which include laminated helical-ribbons, leaflike dendrimers, doughnut-, needle-, and flower-shapes. These organizations are produced by the attractive or repulsive interactions between already formed assemblies and therefore can be controlled through the choice of solvents used as the incubation medium. Thus, the formation of the desired supramolecular structures is regulated through the protonation/deprotonation of the terminal groups, the polarity of the incubation medium, which affects both peptide···solvent interactions and the cavity solvation energy (i.e., solvent···solvent interactions), and the steric interactions between own assemblies that act as building blocks. Finally, the ß-sheet disposition in the latter structural motifs has been examined using both theoretical calculations and Fourier transform infrared spectroscopy. Results indicate that FFF molecules can adopt both parallel and antiparallel ß-sheets. However, the former one is the most energetically favored because of the formation of π-π stacking interactions between the aromatic rings of hydrogen-bonded strands.

Practical and Efficient Synthesis of α-Aminophosphonic Acids Containing 1,2,3,4-Tetrahydroquinoline or 1,2,3,4-Tetrahydroisoquinoline Heterocycles.

We report here a practical and efficient synthesis of α-aminophosphonic acid incorporated into 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroisoquinoline heterocycles, which could be considered to be conformationally constrained analogues of pipecolic acid. The principal contribution of this synthesis is the introduction of the phosphonate group in the N-acyliminium ion intermediates, obtained from activation of the quinoline and isoquinoline heterocycles or from the appropriate δ-lactam with benzyl chloroformate. Finally, the hydrolysis of phosphonate moiety with simultaneous cleavage of the carbamate afforded the target compounds.

Hierarchical self-assembly of di-, tri- and tetraphenylalanine peptides capped with two fluorenyl functionalities: from polymorphs to dendrites.

Homopeptides with 2, 3 and 4 phenylalanine (Phe) residues and capped with fluorenylmethoxycarbonyl and fluorenylmethyl esters at the N-terminus and C-terminus, respectively, have been synthesized to examine their self-assembly capabilities. Depending on the conditions, the di- and triphenylalanine derivatives self-organize into a wide variety of stable polymorphic structures, which have been characterized: stacked braids, doughnut-like shapes, bundled arrays of nanotubes, corkscrew-like shapes and spherulitic microstructures. These highly aromatic Phe-based peptides also form incipient branched dendritic microstructures, even though they are highly unstable, making their manipulation very difficult. Conversely, the tetraphenylalanine derivative spontaneously self-assembles into stable dendritic microarchitectures made of branches growing from nucleated primary frameworks. The fractal dimension of these microstructures is ∼1.70, which provides evidence for self-similarity and two-dimensional diffusion controlled growth. DFT calculations at the M06L/6-31G(d) level have been carried out on model ß-sheets since this is the most elementary building block of Phe-based peptide polymorphs. The results indicate that the antiparallel ß-sheet is more stable than the parallel one, with the difference between them growing with the number of Phe residues. Thus, the cooperative effects associated with the antiparallel disposition become more favorable when the number of Phe residues increases from 2 to 4, while those of the parallel disposition remained practically constant.

Electroactive polymer-peptide conjugates for adhesive biointerfaces.

Electroactive polymer-peptide conjugates have been synthesized by combining poly(3,4-ethylenedioxythiophene), a polythiophene derivative with outstanding properties, and an Arg-Gly-Asp (RGD)-based peptide in which Gly has been replaced by an exotic amino acid bearing a 3,4-ethylenedioxythiophene ring in the side chain. The incorporation of the peptide at the ends of preformed PEDOT chains has been corroborated by both FTIR and X-ray photoelectron spectroscopy. Although the morphology and topology are not influenced by the incorporation of the peptide at the ends of PEDOT chains, this process largely affects other surface properties. Thus, the wettability of the conjugates is considerably higher than that of PEDOT, independently of the synthetic strategy, whereas the surface roughness only increases when the conjugate is obtained using a competing strategy (i.e. growth of the polymer chains against termination by end capping). The electrochemical activity of the conjugates has been found to be higher than that of PEDOT, evidencing the success of the polymer-peptide links designed by chemical similarity. Density functional theory calculations have been used not only to ascertain the conformational preferences of the peptide but also to interpret the electronic transitions detected by UV-vis spectroscopy. Electroactive surfaces prepared using the conjugates displayed the higher bioactivities in terms of cell adhesion, with the relative viabilities being dependent on the roughness, wettability and electrochemical activity of the conjugate. In addition to the influence of the peptide fragment in the initial cell attachment and subsequent cell spreading and survival, the results indicate that PEDOT promotes the exchange of ions at the conjugate-cell interface.

Templating the self-assembly of pristine carbon nanostructures in water.

The low solubility of carbon nanostructures (CNs) in water and the need of ordered architectures at the nanoscale level are two major challenges for materials chemistry. Here we report that a novel amino acid based low-molecular-weight gelator (LMWG) can be used to effectively disperse pristine CNs in water and to drive their ordered self-assembly into supramolecular hydrogels. A non-covalent mechanochemical approach has been used, so the π-extended system of the CNs remains intact. Optical spectroscopy and electron microscopy confirmed the effective dispersion of the CNs in water. Electron microscopy of the hydrogels showed the formation of an ordered, LMWG-assisted, self-assembled architecture. Moreover, the very same strategy allows the solubilization and self-assembly in water of a variety of hydrophobic molecules.