This paper highlights the key role played by solubility in influencing gelation and demonstrates that many facets of process depend on this vital parameter. In particular, we relate thermal stability ( T gel) minimum concentration (MGC) values small-molecule terms cooperative self-assembly gelator building blocks. By employing a van't Hoff analysis data, determined from simple NMR measurements, are able to generate calc reflect calculated temperature for complete solubilization networked...

The self-assembly of a fragment the amyloid beta peptide that has been shown to be critical in fibrillization studied aqueous solution. There are conflicting reports literature on Abeta (16-20), i.e., KLVFF, and our results shed light this. In dilute solution, NH 2-KLVFF-COOH is strongly influenced by aromatic interactions between phenylalanine units, as revealed UV spectroscopy circular dichroism. Fourier transform infrared (FTIR) reveals beta-sheet features spectra taken for more...

The self-assembly and hydrogelation properties of two Fmoc-tripeptides [Fmoc = N-(fluorenyl-9-methoxycarbonyl)] are investigated, in borate buffer other basic solutions. A remarkable difference is observed comparing Fmoc-VLK(Boc) with Fmoc-K(Boc)LV, both containing K protected by Nε-tert-butyloxycarbonate (Boc). In buffer, the former peptide forms highly anisotropic fibrils which show local alignment, hydrogels flow-aligning properties. contrast, Fmoc-K(Boc)LV branched that produce isotropic...

Fibrillation processes in peptides: Structural states the time-dependent self-assembly of an amyloid heptapeptide were resolved by single-molecule atomic force microscopy. Statistical analysis structures and their topological details revealed a continuous evolution polymorphs over time from initial small spherical micelles into protofilaments, helical ribbons, finally nanotube-like (see picture). Detailed facts importance to specialist readers are published as ”Supporting Information”. Such...

This is a novel example of tailor-made design hydrogels for anticancer drug release.

The conformation and self-assembly of two pairs model lipidated tripeptides in aqueous solution are probed using a combination spectroscopic methods along with cryogenic-transmission electron microscopy (cryo-TEM) small-angle X-ray scattering (SAXS). palmitoylated lipopeptides comprise C16-YKK or C16-WKK (with l-lysine residues) their respective derivatives containing d-lysine (k), i.e., C16-Ykk C16-Wkk. All four molecules self-assemble into spherical micelles which show structure factor...

The crystallization behavior of three double crystalline diblock copolymers containing poly(ε-caprolactone) and poly(p-dioxanone) has been studied via differential scanning calorimetry (DSC), polarized optical microscopy (POM), wide-angle X-ray scattering (WAXS). Crystallization melting temperatures enthalpies are compared among to those the corresponding homopolymers. Only one exotherm was observed for diblocks. DSC WAXS indicated that during isothermal PPDX crystallized first, followed by...

The crystallization of well-defined poly(l-lactide)-b-poly(ε-caprolactone) diblock copolymers, PLLA-b-PCL, was investigated by time-resolved X-ray techniques, polarized optical microscopy (POM), and differential scanning calorimetry (DSC). Two compositions were studied that contained 44 60 wt % poly(l-lactide), PLLA (they are referred to as L4411C5614 L6012C409, respectively, with the molecular weight each block in kg/mol superscript). copolymers found be initially miscible melt according...

A new class of water-soluble, amphiphilic star block copolymers with a large number arms was prepared by sequential atom transfer radical polymerization (ATRP) n-butyl methacrylate (BMA) and poly(ethylene glycol) methyl ether (PEGMA). As the macroinitiator for ATRP, 2-bromoisobutyric acid functionalized fourth-generation hyperbranched polyester (Boltorn H40) used, which allowed preparation polymers that contained on average 20 diblock copolymer arms. The synthetic concept validated AFM...

The synthesis of doubly thermoresponsive PPO−PMPC−PNIPAM triblock copolymer gelators by atom transfer radical polymerization using a PPO-based macroinitiator is described. Provided that the PPO block sufficiently long, dynamic light scattering and differential scanning calorimetry studies confirm presence two separate thermal transitions corresponding to micellization gelation, as expected. However, these ABC-type copolymers proved be rather inefficient gelators: free-standing gels at 37 °C...

This paper discusses the solid state and melt nanoscale structure of a series novel poly(ethylene glycol) (PEG) hybrid di- triblock copolymers, which contain amphiphilic β-strand peptide sequences. The block copolymers have been prepared via solid-phase synthesis, affording perfectly monodisperse segments with precisely defined α-amino acid sequence. Attenuated total reflection Fourier transform infrared spectroscopy X-ray scattering experiments indicate that self-assembly properties...

The self-assembly of a modified fragment the amyloid beta peptide, based on sequence Abeta(16-20), KLVFF, extended to give AAKLVFF is studied in methanol. Self-assembly into peptide nanotubes observed, as confirmed by electron microscopy and small-angle X-ray scattering. secondary structure probed FTIR circular dichroism, UV/visible spectroscopy provides evidence for important role aromatic interactions between phenylalanine residues driving beta-sheet self-assembly. beta-sheets wrap...

The self-assembly in aqueous solution of hybrid block copolymers consisting amphiphilic β-strand peptide sequences flanked by one or two PEG chains was investigated means circular dichroism spectroscopy, small-angle X-ray scattering, and transmission electron microscopy. In comparison with the native sequence, it found that secondary structure stabilized against pH variation di- tri-block PEG. Small-angle scattering indicated presence fibrillar structures, dimensions which are comparable to...

The self-assembly of tripeptides based on the RGD cell adhesion motif is investigated. Two containing Fmoc [N-(fluorenyl)-9-methoxycarbonyl] aromatic unit were synthesized, Fmoc-RGD and a control peptide scrambled sequence, Fmoc-GRD. used to via stacking interactions. hydrogelation properties two Fmoc-tripeptides are compared. Both form well defined amyloid fibrils (as shown by cryo-TEM SAXS) with β-sheet features in their circular dichroism FTIR spectra. peptides self-supporting hydrogels,...

This paper investigates dendritic peptides capable of assembling into nanostructured gels, and explores the effect on self-assembly mixing different molecular building blocks. Thermal measurements, small angle X-ray scattering (SAXS) circular dichroism (CD) spectroscopy are used to probe these materials macroscopic, nanoscopic length scales. The results from investigations demonstrate that in this case, systems with "size" "chirality" factors can self-organise, whilst "shape" cannot....

The surfactant-like peptide (Ala)(6)(Arg) is found to self-assemble into 3 nm-thick sheets in aqueous solution. Scanning transmission electron microscopy measurements of mass per unit area indicate a layer structure based on antiparallel dimers. At higher concentration the wrap unprecedented ultrathin helical ribbon and nanotube architectures.

Two-component systems capable of self-assembling into soft gel-phase materials are considerable interest due to their tunability and versatility. This paper investigates two-component gels based on a combination L-lysine-based dendron rigid diamine spacer (1,4-diaminobenzene or 1,4-diaminocyclohexane). The networked gelator was investigated using thermal measurements, circular dichroism, NMR spectroscopy small angle neutron scattering (SANS) giving insight the macroscopic properties,...

The solvent-induced transition between self-assembled structures formed by the peptide AAKLVFF is studied via electron microscopy, light scattering, and spectroscopic techniques. based on a core fragment of amyloid beta-peptide, KLVFF, extended two alanine residues. exhibits distinct twisted fibrils in water or nanotubes methanol. For intermediate water/methanol compositions, these are disrupted replaced wide filamentous tapes that appear to be lateral aggregates thin protofilaments....

A thermal transition is observed in the peptide amphiphile C16-KTTKS (TFA salt) from nanotapes at 20 °C to micelles higher temperature (the depending on concentration). The formation of extended by acetate salt this amphiphile, which incorporates a pentapeptide type I procollagen, has been studied previously [V. Castelletto et al., Chem. Commun., 2010, 46, 9185]. Here, proton NMR and SAXS provide evidence for TFA spherical high temperature. phase behavior, with Krafft separating insoluble...

A designed peptide amphiphile C16-KKFFVLK self-assembles into nanotubes and helical ribbons in aqueous solution at room temperature. remarkable unwinding transition, leading to twisted tapes, is observed on heating. Nanotubes re-form cooling.

The collagen production of human dermal and corneal fibroblasts in contact with solutions the peptide amphiphile (PA) C16–KTTKS is investigated related to its self-assembly into nanotape structures. This PA used antiwrinkle cosmeceutical applications (trade name Matrixyl). We prove that stimulates a concentration-dependent manner close critical aggregation concentration determined from pyrene fluorescence spectroscopy. suggests stimulation are inter-related.