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The properties of supramolecular hydrogels of cationic phenylalanine derivatives are modified by multicomponent formulation with anionic amino acids. 

We report the synthesis and structure of single-walled aluminosilicate nanotubes with microporous zeolitic walls. This quasi-one-dimensional zeolite is assembled by a bolaform structure-directing agent (SDA) containing a central biphenyl group connected by C 10 alkyl chains to quinuclidinium end groups. High-resolution electron microscopy and diffraction, along with other supporting methods, revealed a unique wall structure that is a hybrid of characteristic building layers from two zeolite structure types, beta and MFI. This hybrid structure arises from minimization of strain energy during the formation of a curved nanotube wall. Nanotube formation involves the early appearance of a mesostructure due to self-assembly of the SDA molecules. The biphenyl core groups of the SDA molecules show evidence of π stacking, whereas the peripheral quinuclidinium groups direct the microporous wall structure. 

Abstract Self‐assembled peptide materials have emerged as promising bioinspired tools for applications that include regenerative medicine, drug delivery, antimicrobial and vaccine development, optics, and catalysis. Peptide self‐assembly mediated by noncovalent hydrogen bonding, coulombic, hydrophobic, and aromatic interactions gives rise to a variety of supramolecular structures that reflect on the nature of the constituent peptides. The emergent properties of these supramolecular peptide materials often depend on the multivalent presentation of functional appendages on the self‐assembled scaffold. For example, the multivalent display of cell‐signaling motifs on self‐assembled peptide nanofibrils provides materials that are excellent extracellular matrix mimetics for tissue engineering applications. This review includes a discussion of chemical strategies that address the challenge of appending functional signal motifs in a multivalent display on self‐assembled peptide and protein materials. In addition, recent examples of supramolecular peptide materials that rely on the multivalent display of chemical signals for the desired applications are presented. Collectively, this discussion illustrates the potential of self‐assembled peptides as sustainable materials to address challenges in contemporary materials science and provides principles for the design of next‐generation agents for a variety of applications. 

Amphipathic peptides with amino acids arranged in alternating patterns of hydrophobic and hydrophilic residues efficiently self‐assemble intoβ‐sheet bilayer nanoribbons. Hydrophobic side chain functionality is effectively buried in the interior of the putative bilayer of these nanoribbons. This study investigates consequences on self‐assembly of increasing the surface area of aromatic side chain groups that reside in the hydrophobic core of nanoribbons derived from Ac‐(XKXE)₂‐NH₂peptides (X = hydrophobic residue). A series of Ac‐(XKXE)₂‐NH₂peptides incorporating aromatic amino acids of increasing molecular volume and steric profile (X = phenylalanine [Phe], homophenylalanine [Hph], tryptophan [Trp], 1‐naphthylalanine [1‐Nal], 2‐naphthylalanine [2‐Nal], or biphenylalanine [Bip]) were assessed to determine substitution effects on self‐assembly propensity and on morphology of the resulting nanoribbon structures. Additional studies were conducted to determine the effects of incorporating amino acids of differing steric profile in the hydrophobic core (Ac‐X₁KFEFKFE‐NH₂and Ac‐(X_1,5KFE)‐NH₂peptides, X = Trp or Bip). Spectroscopic analysis by circular dichroism (CD) and Fourier transform infrared (FT‐IR) spectroscopy indicatedβ‐sheet formation for all variants. Self‐assembly rate increased with peptide hydrophobicity; increased molecular volume of the hydrophobic side chain groups did not appear to induce kinetic penalties on self‐assembly rates. Transmission electron microscopy (TEM) imaging indicated variation in fibril morphology as a function of amino acid in the X positions. This study confirms that hydrophobicity of amphipathic Ac‐(XKXE)₂‐NH₂peptides correlates to self‐assembly propensity and that the hydrophobic core of the resulting nanoribbon bilayers has a significant capacity to accommodate sterically demanding functional groups. These findings provide insight that may be used to guide the exploitation of self‐assembled amphipathic peptides as functional biomaterials.