Structures In Aqueous Media Research Articles

Green-synthesized Ag hierarchical assemblies for SERS detection of rhodamine dye

This study presents a simple benchtop synthetic protocol for the fabrication of silver (Ag) hierarchical structures in aqueous media using environmentally friendly and inexpensive reagents under mild experimental conditions. Natural organic acids that are known to be present in plants were employed as reducing and morphology-directing reagents. SEM and TEM imaging revealed that the products are three-dimensional hierarchical structures that were formed from self-assembly of smaller nanoparticles. They are generally spherical in shape, measure around 1.5 to 5 μm in size, and possess highly roughened surfaces due to the interstitial gaps between their nanoparticle subunits. Their hierarchical architecture allows for strong absorption of light in a broad range of wavelengths that extends to the near-infrared region. In addition, their surface morphology has an abundance of hot spot regions, which are capable of inducing strong SERS enhancement effects. The green-synthesized Ag nanostructures showed remarkable SERS activity when used as substrates for the detection of rhodamine 6G dye, a highly toxic water contaminant, even at a concentration as low as 10–8 M. Overall, this study does not only provide a greener approach to Ag hierarchical structures, but also demonstrates the immense potential of these nano-assembled architectures in the sensitive detection of organic dye pollutants.

Red-light-controlled supramolecular assemblies of indigo amphiphiles at multiple length scales

Amphiphilic molecules functionalized with photoresponsive motifs have attractive prospects for applications in smart functional bio-material ranging from cell-material interfaces to drug delivery systems owing to the precisely controllable functionality of self-assembled hierarchical supramolecular structures in aqueous media by a non-invasive light stimulation with high temporal- and spatial-resolution. However, most of reported photoresponsive amphiphiles are triggered by bio-damaging UV-light, which greatly limits the potential in bio-related applications. Herein, we present newly designed red-light controlled N,N’-diaryl-substituted indigo amphiphiles (IA), exhibiting excellent photoswitchablity and photostability with dual red-/green-light in organic media. Meanwhile, aqueous solutions of IA assembled into supramolecular structures in both microscopic and macroscopic length-scale, though the photoresponsiveness of IA is slightly compromised in aqueous media. At macroscopic length-scale, morphological changes of IA macroscopic scaffold prepared by a shear-flow method can be fine adjusted upon red-light irradiation. Moreover, the preferential attachment of live h-MSCs to IA macroscopic scaffold surface also indicates a good biocompatibility of IA macroscopic scaffold. These results provide the potential for developing the next generation of red-light controlled soft functional materials with good biocompatibility.

Cooperative dissolution of peptidomimetic vesicles and amyloid β fibrils.

The aggregation of amyloid proteins in the brain is a significant neurotoxic event that contributes to neurodegenerative disorders. The aggregation of amyloid beta (Aβ), particularly Aβ42 monomers, into various forms such as oligomers, protofibrils, fibrils, and amyloid plaques is a key pathological feature in Alzheimer's disease. As a result, Aβ42 is a primary target and the development of molecular strategies for the dissolution of Aβ42 aggregates is considered a promising approach to mitigating Alzheimer's disease pathology. A set of pyrene-conjugated peptidomimetics derived from Aβ14-23 (AkdcPy, AkdmPy, and AkdnPy) by incorporating an unnatural amino acid [kd: cyclo(Lys-Asp)] were studied for their ability to modulate Aβ42 aggregation. AkdcPy and AkdmPy formed vesicular structures in aqueous media. The vesicles of AkdmPy loaded with the neuroprotective compound berberine (Ber), dissipated mutually in the presence of preformed Aβ42 fibrils. During this process, the active drug Ber was released. This work is expected to inspire the development of drug-loaded peptidomimetic-based therapeutic formulations to modulate disorders associated with amyloid toxicity.

Controlled Supramolecular Assemblies of Chiral Cyclometalated Gold (III) Amphiphiles in Aqueous Media.

Invited for this month's cover are the collaborating groups of Prof. Man-Kin Wong and Dr. Franco King-Chi Leung from The Hong Kong Polytechnic University. The cover picture illustrates chiral gold (III) amphiphiles assemble into tubular supramolecular structures in aqueous media through counterion controlled pathway. The nanostructures were further demonstrated with good cytocompatibility in aqueous media. More information can be found in the Research Article by Man-Kin Wong, Franco King-Chi Leung, and co-workers.

Assessing the Suitability of a Dicationic Ionic Liquid as a Stabilizing Material for the Storage of DNA in Aqueous Medium.

The present study has been undertaken with an objective to find out a suitable medium for the long-term stability and storage of the ct-DNA structure in aqueous solution. For this purpose, the potential of a pyrrolidinium-based dicationic ionic liquid (DIL) in stabilizing ct-DNA structure has been investigated by following the DNA-DIL interaction. Additionally, in order to understand the fundamental aspects regarding the DNA-DIL interaction in a comprehensive manner, studies are also done by employing structurally similar monocationic ionic liquids (MILs). The investigations have been carried out both at ensemble-average and single molecular level by using various spectroscopic techniques. The molecular docking study has also been performed to throw more light into the experimental observations. The combined steady-state and time-resolved fluorescence, fluorescence correlation spectroscopy, and circular dichroism measurements have demonstrated that DILs can effectively be used as better storage media for ct-DNA as compared to MILs. Investigations have also shown that the extra electrostatic interaction between the cationic head group of DIL and the phosphate backbone of DNA is primarily responsible for providing better stabilization to ct-DNA, retaining its native structure in aqueous medium. The outcomes of the present study are also expected to provide valuable insights in designing new polycationic IL systems that can be used in nucleic acid-based applications.

Red-light controlled supramolecular co-assembly transformations of stiff stilbene and donor acceptor stenhouse adduct amphiphiles

Amphiphiles are of great interest in the search of biomimicking supramolecular assembly for their assembling into complex and hierarchical structures in aqueous media across multiple length-scale. Incorporations of photoswitching units into amphiphiles provide a means to control the morphology of the resultant assembled structures by light irradiation, which is non-invasive and generally biocompatible. The use of light to induce morphological changes offers several extra merits, including selective excitation of photoswitches by different wavelengths, high temporal- and spatial-resolution. Macroscopic soft materials assembled from donor-acceptor Stenhouse adducts (DASA) amphiphiles (DA) in aqueous media are generally suffered from absorption peak broadening due to aggregation and requires strong white-light irradiation to induce a morphological change. Herein, we provide a new strategy for the restoration of red-light sensitivity of DA in aqueous medium, which requires a co-assembly system of DA with a six-membered fused ring stiff stilbene amphiphile (6SA). This 6SA:DA co-assembly forms supramolecular structures in both microscopic and macroscopic length-scale. Morphological changes of these supramolecular structures can be fine adjusted with red-light irradiation. The structural design, supramolecular assemblies and co-assemblies, and macroscopic scaffolds of photoresponsive SA and DA could enable potential visible-light controlled soft functional materials with improved biocompatibility and photosensitivity.

Formation of supramolecular structures in aqueous medium by noncovalent interactions between surfactant and resorcin[4]arene

Self-assembly of molecular elements through non-covalent interactions plays a central role in supramolecular chemistry. The intermolecular interactions between macrocyclic and open-chain amphiphilic building blocks have been of large interest for last decade, since their mixed assembly is an example of building nanostructures by supramolecular bottom-up synthesis. Here we report that noncovalent interactions of viologen-based resorcin[4]arene cavitand with sodium dodecyl sulphate can enable self-assembly into highly-ordered supramolecular structures. A set of physicochemical methods was used to study the aggregation and binding properties of the supramolecular system based on these components. It was found that in this system the morphological transitions are observed depending on the ratio of the components of the system. The effectiveness of the mixed compositions as carriers for hydrophilic doxorubicin and hydrophobic antioxidants rutin and quercetin was evaluated, and a high loading efficiency of drugs and the ability to sustained release were found for the equimolar system. This study demonstrates features of such supramolecular structures, highlighting their potential applications in drug delivery.

Structural adaptations in the bovine serum albumin protein in archetypal deep eutectic solvent reline and its aqueous mixtures.

The global concern over the environmental impact and challenges associated with the use of conventional solvents in biotransformation processes have pushed the search for alternative solvents. Recently, deep eutectic solvents (DESs) have appeared as a promising replacement with better biocompatibility and have been postulated to hold great potential in protein engineering and crystallization processes. In this context, herein, we have investigated the effect of reline (a choline chloride : urea mixture in 1 : 2 proportion) DES in its pure and hydrated forms on the structural stability and conformation of the bovine serum albumin (BSA) protein using all-atom molecular dynamics simulations. We observe a substantial overall expansion of the BSA structure with a simultaneous increment in the solvent accessible surface area, signifying the influence of reline on the BSA tertiary structure. These induced structural perturbations are quite pronounced in reline-water mixtures. Concomitantly, a notable reline concentration-dependent disruption of the BSA secondary structure through the melting of α-helices, mainly driven by H-bonding interactions, is observed. In the presence of pure reline, significant rigidity in the protein backbone is also observed. Thus, despite the expansion, the BSA tertiary structure in pure reline is found to be most close to the native protein structure and remains in a partially folded state at all the studied reline concentrations. In pure reline, BSA-urea hydrogen bonding is more prevalent than BSA-[Ch]+. We also observe that in aqueous reline systems, the BSA-water hydrogen bonds are mostly compensated by BSA-urea hydrogen bonds. The aqueous re-equilibration of these partially denatured protein conformations showed a significant recovery of secondary and tertiary structures, where the recovery is most profound for the BSA conformation extracted from pure reline.

Hemolytic, Biocompatible, and Functional Effect of Cellularized Polycaprolactone-Hydrolyzed Collagen Electrospun Membranes for Possible Application as Vascular Implants.

In search of bioactive vascular prostheses that exhibit greater biocompatibility through the combination of natural and synthetic polymers, tissue engineering from a biomimetic perspective has proposed the development of three-dimensional structures as therapeutic strategies in the field of cardiovascular medicine. Techniques such as electrospinning allow obtaining of scaffolds that emulate the microarchitecture of the extracellular matrix of native vessels; thus, this study aimed to evaluate the biological influence of microarchitecture on polycaprolactone (PCL) and hydrolyzed collagen (H-Col) electrospun scaffolds, which have a homogeneous (microscale) or heterogeneous (micro-nanoscale) fibrillar structure. The hemolytic, biocompatible, and functional effect of the scaffolds in interaction with an in vitro fibroblast model was determined, in view of its potential use for vascular implants. Scaffolds were characterized by scanning electron microscopy and atomic force microscopy, Fourier transform infrared spectroscopy, wettability, static permeability, tensile test, and degradation. In addition, direct and indirect 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays were used to identify the cell viability of fibroblasts, fluorescence assays were performed to establish morphological changes of the cell nuclei, and the hemolytic effect of the scaffolds was calculated. Results showed that ethanol-treated biocompositescaffolds exhibited mass losses lower than 6.65% and slow wettability and absorption, resulting from an increase in secondary structures that contribute to the crystalline phase of H-Col. The scaffolds demonstrated stable degradation in saline during the incubation period because of the availability of soluble structures in aqueous media, and the inclusion of H-Col increased the elastic properties of the scaffold. As regards hemocompatibility, the scaffolds had hemolysis levels lower than 1%; moreover, in terms of biocompatible characteristics, scaffolds exhibited good adhesion, proliferation, and cell viability and insignificant changes in the circularity of the cell nuclei. However, scaffolds with homogeneous fibers showed cell agglomerates after 48 h of interaction. By contrast, permeability decreased as the incubation period progressed, because of the cellularization of the three-dimensional structure. In conclusion, multiscale scaffolds could exhibit a suitable behavior as a bioactive small-diameter vascular implant.

Self‐Assembly of Photoresponsive Molecular Amphiphiles in Aqueous Media

AbstractAmphiphilic molecules, comprising hydrophobic and hydrophilic moieties and the intrinsic propensity to self‐assemble in aqueous environment, sustain a fascinating spectrum of structures and functions ranging from biological membranes to ordinary soap. Facing the challenge to design responsive, adaptive, and out‐of‐equilibrium systems in water, the incorporation of photoresponsive motifs in amphiphilic molecular structures offers ample opportunity to design supramolecular systems that enables functional responses in water in a non‐invasive way using light. Here, we discuss the design of photoresponsive molecular amphiphiles, their self‐assembled structures in aqueous media and at air–water interfaces, and various approaches to arrive at adaptive and dynamic functions in isotropic and anisotropic systems, including motion at the air–water interface, foam formation, reversible nanoscale assembly, and artificial muscle function. Controlling the delicate interplay of structural design, self‐assembling conditions and external stimuli, these responsive amphiphiles open several avenues towards application such as soft adaptive materials, controlled delivery or soft actuators, bridging a gap between artificial and natural dynamic systems.

Self-Assembly of Photoresponsive Molecular Amphiphiles in Aqueous Media.

Amphiphilic molecules, comprising hydrophobic and hydrophilic moieties and the intrinsic propensity to self‐assemble in aqueous environment, sustain a fascinating spectrum of structures and functions ranging from biological membranes to ordinary soap. Facing the challenge to design responsive, adaptive, and out‐of‐equilibrium systems in water, the incorporation of photoresponsive motifs in amphiphilic molecular structures offers ample opportunity to design supramolecular systems that enables functional responses in water in a non‐invasive way using light. Here, we discuss the design of photoresponsive molecular amphiphiles, their self‐assembled structures in aqueous media and at air–water interfaces, and various approaches to arrive at adaptive and dynamic functions in isotropic and anisotropic systems, including motion at the air–water interface, foam formation, reversible nanoscale assembly, and artificial muscle function. Controlling the delicate interplay of structural design, self‐assembling conditions and external stimuli, these responsive amphiphiles open several avenues towards application such as soft adaptive materials, controlled delivery or soft actuators, bridging a gap between artificial and natural dynamic systems.

Photoresponsive polymeric actuator cross-linked by an 8-armed polyhedral oligomeric silsesquioxane

A photoresponsive hydrogel consisting of stilbene dye (Sti; 4,4′-disubstituted stilbene), an 8-armed core molecule (POSS; polyhedral oligomeric silsesquioxane having eight amino groups), and bifunctional poly(ethylene glycol) (PEG) showed large and fast deformation derived from its highly symmetrical structure in aqueous media. The polymeric hydrogel with an 8-armed POSS (POSS-Sti; cross-linked polymer obtained from polycondensation reaction between POSS and PEG-modified Sti) showed a large deformation upon photostimulation (UV-A (λ = 350 nm) and UV-C (λ = 280 nm)). The bending deformation can be repeated at least ten times. On the other hand, the control hydrogel without Sti dye (POSS-PEG; polymer prepared from the polycondensation reaction between POSS and PEG) did not show any deformation upon photoirradiation. However, the TPEG-Sti hydrogel (Sti cross-linked with a 4-armed core molecule (TPEG; tetra-armed poly(ethylene glycol))) showed a smaller deformation compared to the POSS-Sti hydrogel with the 8-armed core molecule. The larger deformation of the POSS-Sti hydrogel was discussed in detail. The photoisomerization of the Sti units drives swelling/shrinking and the change in the Young’s modulus of the POSS-Sti hydrogel upon UV irradiation, where a stacked assembly of the Sti dye molecules acts as a cross-linking point. The photoisomerization of the Sti dye results in the association/dissociation of the Sti assembly, and the increase/decrease in the cross-linking density dramatically alters the volume of the POSS-Sti hydrogel, causing the efficient assembly of the Sti units because of their highly symmetric structure and the high density of the Sti dye derived from the 8-armed POSS core structure.

Engineered Polymersomes for the Treatment of Fish Odor Syndrome: A First Randomized Double Blind Olfactory Study.

Trimethylamine (TMA) is a metabolite overtly present in patients suffering from trimethylaminuria (TMAU), a rare genetic disorder characterized by a strong “fishy” body odor. To date, no approved pharmacological treatment to sequester excess TMA on the skin of patients exists. Here, transmembrane pH gradient poly(isoprene)‐block‐poly(ethylene glycol) (PI‐b‐PEG) polymersomes are investigated for the topical removal of TMA. PI‐b‐PEG amphiphiles of varying chain length are synthesized and evaluated for their ability to form vesicular structures in aqueous media. The optimization of the PI/PEG ratio of transmembrane pH gradient polymersomes allows for the rapid and efficient capture of TMA both in solution and after incorporation into a topical hydrogel matrix at the pH of the skin. A subsequent double blind olfactory study reveals a significant decrease in perceived odor intensity after application of the polymersome‐based formulation on artificial skin substrates that has been incubated in TMA‐containing medium. This simple and novel approach has the potential to ease the burden of people suffering from TMAU.

Physicochemical properties of soy protein isolates-cyanidin-3-galactoside conjugates produced using free radicals induced by ultrasound.

Free radicles produced by ultrasound were used to produce soy protein isolate (SPI)-cyanidin-3-galactoside conjugates. The conjugation between SPI and cyanidin-3-galactoside was confirmed by the increased ratio of bound polyphenol and the disappearance of cyanidin-3-galactoside's absorption peak in ultraviolet-visible spectrum. Conjugation with cyanidin-3-galactoside resulted in breakdown of SPI aggregate, which also led to a decrease in particle size and an increase in fluorescence intensity. Conjugation disrupted the hydrogen bonds of SPI as indicated by the lowest band intensity at 1646, 1533 and 3300-3450cm-1 on FTIR spectra. Conjugation also increased the electrostatic repulsion and decreased the hydrophobic interactions between SPI molecules. The SPI-cyanidin-3-galactoside conjugate had higher solubility and less aggregated structure in aqueous medium. The aqueous dispersions and solid powders of these conjugates had better thermal stability than that of SPI.

Polysaccharide Chain Length of Lipopolysaccharides From Salmonella Minnesota Is a Determinant of Aggregate Stability, Plasma Residence Time and Proinflammatory Propensity in vivo.

Lipopolysaccharides (LPS) originate from the outer membrane of Gram-negative bacteria and trigger an inflammatory response via the innate immune system. LPS consist of a lipid A moiety directly responsible for the stimulation of the proinflammatory cascade and a polysaccharide chain of variable length. LPS form aggregates of variable size and structure in aqueous media, and the aggregation/disaggregation propensity of LPS is known as a key determinant of their biological activity. The aim of the present study was to determine to which extent the length of the polysaccharide chain can affect the nature of LPS structures, their pharmacokinetics, and eventually their proinflammatory properties in vivo. LPS variants of Salmonella Minnesota with identical lipid A but with different polysaccharide moieties were used. The physical properties of LPS aggregates were analyzed by zetametry, dynamic light scattering, and microscopy. The stability of LPS aggregates was tested in the presence of plasma, whole blood, and cultured cell lines. LPS pharmacokinetics was performed in wild-type mice. The accumulation in plasma of rough LPS (R-LPS) with a short polysaccharidic chain was lower, and its hepatic uptake was faster as compared to smooth LPS (S-LPS) with a long polysaccharidic chain. The inflammatory response was weaker with R-LPS than with S-LPS. As compared to S-LPS, R-LPS formed larger aggregates, with a higher hydrophobicity index, a more negative zeta potential, and a higher critical aggregation concentration. The lower stability of R-LPS aggregates could be illustrated in vitro by a higher extent of association of LPS to plasma lipoproteins, faster binding to blood cells, and increased uptake by macrophages and hepatocytes, compared to S-LPS. Our data indicate that a long polysaccharide chain is associated with the formation of more stable aggregates with extended residence time in plasma and higher inflammatory potential. These results show that polysaccharide chain length, and overall aggregability of LPS might be helpful to predict the proinflammatory effect that can be expected in experimental settings using LPS preparations. In addition, better knowledge and control of LPS aggregation and disaggregation might lead to new strategies to enhance LPS detoxification in septic patients.

Tunable Self-Assembled Nanostructures of Electroactive PEGylated Tetra(Aniline) Based ABA Triblock Structures in Aqueous Medium.

PEGylated tetra(aniline) ABA triblock structure PEG-TANI-PEG (2) consisting of tetra(aniline) (TANI) and polyethylene glycol (PEG) was synthesized by coupling the tosylated-PEG to boc-protected NH2/NH2 TANI (1) through a simple nucleophilic substitution reaction. Deprotection of 2 resulted in a leucoemeraldine base state of TANI (2-LEB), which was oxidized to stable emeraldine base (2-EB) state. 2-EB was doped with 1 M HCl to emeraldine salt (2-ES) state. FTIR, 1H and 13C NMR and UV-Vis-NIR spectroscopy, and MS (ESI) was used for structural characterization. The synthesized triblock structure exhibited good electroactivity as confirmed by CV and UV-Vis-NIR spectroscopy. Self-assembling of the triblock structure in aqueous medium was assessed by DLS, TEM, and SEM. Spherical aggregates were observed with variable sizes depicting the effect of concentration and oxidation of 2-LEB. Further, the aggregates showed acid/base sensitivity as evaluated by doping and dedoping of 2-EB with 1 M HCl and 1 M NH4OH, respectively. Future applications in drug delivery and sensors are envisaged for such tunable self-assembled nanostructures in aqueous media.

Electrochemical Cycling Induced Amorphization of Cobalt (II, III) Oxide (Co3O4) for High Surface Area Electrode of Water Oxidation

Electrocatalyst’s activity critically depends on the chemical coordination structure around the active sites. Amorphous materials are having different local short-range structure than their counter crystalline materials which can be tuned by the synthesis process. Traditional synthesis of amorphous materials, involving multi-temperature quench processing, is unsuitable as it results in less porosity and surface area. In this context, room temperature synthesis of high surface area amorphous materials with high activity are desirable. Here we have demonstrated the synthesis of high surface area amorphous Co3O4 at room temperature via electrochemical ion intercalation/deintercalation and surface oxidation/reduction cycles and their performance in electrocatalytic oxygen evolution reaction (OER). In Li-ion intercalation/deintercalation (Li/D-Li) cycles in Co3O4 expansion and contraction of the structure induces amorphization of Co3O4 by the pulverization of crystal structure in non-aqueous medium. While during the fast surface oxidation/reduction (Ox/Red) the crystalline nuclei formation and its growth in oxide state is hindered thereby leading to formation of metastable amorphous structure in aqueous medium. The OER specific activity for Li/D-Li-Co3O4 is ~35 times, which is superior to Ox/Red- induced amorphization which is ~25 times higher than their crystalline Co3O4. The superior OER metrics with Li/D-Li-Co3O4 is attributed to Li-ion intercalations inside Co3O4 structure which generates higher bulk-oxygen vacancies upon Li/D-Li- leading to higher conductivity and reduction in overall charge-transport resistance through electrocatalyst. On the other hand, Ox/Red- induced amorphization is restricted to surface or near-surface only with formation of small amount of metallic Co which hampers in increase of active sites for OER. However, in general both amorphization process leads to increase in Co (II) sites which is responsible for increased OER activity over crystalline Co3O4. Additionally, the above study demonstrates the utility of multicycle lithiation/de-lithiation over surface oxidation/reduction technique for obtaining amorphous OER electrocatalysts

Textile cosmetic pads based on psyllium and protein colloid in combination with the horsetail extract

The basic purpose of this research work was to develop a care/healing cosmetic pads where a horsetail water extract was selected as a healing/care compound. Together with this, psyllium and keratin (protein colloid) were used as natural compounds capable to form a gel-like structure in aqueous media, so they were explored as i) carriers of a care/healing compound (horsetail extract), and as ii) “binding element” (due to relatively high viscosity) in-between the healing compound and the textile substrate (i.e. non-woven viscose) itself. Such functionalization system was relatively easily applied onto the non-woven viscose substrate. In this way the final product i.e. the cosmetic pad was created showing good ant oxidative activity, storage stability and biodegradability. The latest is extremely important for environmentally friendly products.

HETEROSTRUCTURES OF SILVER AND ZINC BASED LAYERED DOUBLE HYDROXIDES FOR POLLUTANT REMOVAL UNDER SIMULATED SOLAR LIGHT

Nitrophenols are among the most hazardous refractory pollutants showing high stability and solubility in water. This work presents heterostructures of nanoparticles of silver/zinc based layered double hydroxides as efficient photocatalysts for degrading 4nitrophenol (4-NPh), from aqueous solutions under irradiation with solar light. ZnAl-layered double hydroxides (ZnAl-LDHs) with Zn/Al = 2:1 and Zn/Al = 3:1 ratios were synthesized, characterized by XRD, FTIR, SEM and TEM and further used as precursors to form mixed oxides after calcination at 550 C. Based on the capability of the calcined LDHs to reconstruct their layered structure in aqueous media, AgNO3 solutions were used to obtain Ag nanoparticles directly on ZnAl-LDHs matrices. The calculated value of the band gap of Ag/ZnAl-LDHs was ~ 3.1 eV, revealing that these materials might successfully act as photocatalysts under solar light irradiation. The photocatalytic tests performed on the decomposition of 4-NPh aqueous solutions indicate that on Ag/ZnAl-LDH (3:1)87% of 4-NPh was degraded after 6 h under irradiation with solar light.

Self-assembled micro-fibres by oxime connection of linear peptide amphiphiles.

Linear peptide amphiphiles are excellent biocompatible scaffolds for the hierarchical self-assembly of one-dimensional nano-structures in aqueous media. However, their structural exploration and screening of self-assembling properties are often limited by time-consuming synthesis and purification steps. We here describe the application of an oxime bond as a powerful synthetic tool towards the conjugation of peptide heads bearing a hydroxylamine group with hydrophobic aldehyde tails. This methodology allowed the quick preparation of a small library of oxime-connected peptide amphiphiles, whose supramolecular screening revealed nano-to-micro-fibrillation with dependency on their chemical structure. These results demonstrate the simplicity and the synthetic potential of the oxime conjugation for the preparation of peptide amphiphiles with improved self-assembling capabilities.