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Supramolecular peptide amphiphile (PA) nanofibers are polymerized with the polydiacetylene backbone while retaining the shape of the nanostructure. The polymerization of monomers in peptide amphiphile assemblies by a rigid conjugated backbone has led to mechanical robustness and insolubility, which are important properties for the patterning of these materials at the cellular state.

A phase diagram is constructed for self-assembling biologically active peptide amphiphiles. The changing solution conditions have resulted in phase transitions among these structures.

A strategy for the one-step fabrication of a nanostructured hybrid material containing oligo(p-phenylene vinylene) (OPV) segments and silicate is presented. The results indicate that the ordered and nanostructured environment leads to highly efficient energy transfer among organic components in these hybrid films.

A study of the aqueous solvation within self-assembled structures formed from peptide amphiphiles is conducted. The findings indicate that covalently bound fluorophores within an aggregate can interact with the external environment.

A series of amphiphilic molecules consisting of oligo(phenylene vinylene) (OPV) asymmetrically end-substituted with a hydrophilic poly(ethylene glycol) (PEG) segment and a hydrophobic alkyl chain is synthesized. This amphiphilic structure induces self-assembly into both thermotropic and lyotropic lamellar liquid crystalline (LC) phases.

The syntheses of convergent and divergent organic hybrid structures known as dendron rodcoils, which contain dendritic, rodlike segments, are explained. A number of catalyzed esterification reactions and silyl deprotection chemistry methods are used for the construction of these structures.

Research was conducted to perform direct templating of CdS as well as other semiconducting solids in the preordered environment of a nonionic amphiphilic mesophase, generating semiconductor-organic superlattices having both the symmetry and long-range order of the precursor liquid crystal. Results illustrate the importance of both chemical nature and structure of the amphiphile in direct templating. It is proposed that the interactions of polar segments in template molecules with the precipitated mineral and with its precursor ions are important conditions for direct templating.

Organic molecules can after inorganic microstructures, offering a very powerful tool for the design of novel materials. in biological systems, this tool is often used to create microstructures in which the organic manipulators are a minority component. Three groups of materials -- biomaterials, ceramics, and semiconductors -- have been selected to illustrate this concept as used by nature and by synthetic laboratories exploring its potential in materials technology. in some of nature's biomaterials, macromolecules such as proteins, glycoproteins, and polysaccharides are used to control nucleation arid growth of mineral phases and thus manipulate microstructure and physical properties. This concept has been used synthetically to generate apatite-based materials that can function as artificial bone in humans. Synthetic polymers and surfactants can also drastically change the morphology of ceramic particles, impart new functional properties, and provide new processing methods for the formation of useful objects. interesting opportunities also exist in creating semiconducting materials in which molecular manipulators connect quantum dots or template cavities, which change their electronic properties and functionality., The functionality of materials in macroscopic form is seldom achieved with pure chemical compounds that form single crystals. Many of nature's remarkable materials contain mixtures of molecules or microstructures in [...]

Nanostructured composites are a rich source of new materials for technology. The growth of stable semiconductor-organic superlattices based on cadmium sulphide and cadmium selenide is described. A liquid-crystalline phase created from non-ionic organic amphiphiles was used as template for the structures. Precipitation of the organic-inorganic solid occurs within the mesophase.The symmetry and long-range order of the liquid crystal are preserved.

Peptide amphiphiles (PAs) are a class of molecules comprised of short amino acid sequences conjugated to hydrophobic moieties that may exhibit self-assembly in water into supramolecular structures. We investigate here how mechanical properties of hydrogels formed by PA supramolecular nanofibers are affected by hydrogen bond densities within their internal structure by substituting glycine for aza-glycine (azaG) residues. We found that increasing the number of PA molecules that contain azaG up to 5 mol% in PA supramolecular nanofibers increases their persistence length fivefold and decreases their diffusion coefficients as measured by fluorescence recovery after photobleaching. When these PAs are used to create hydrogels, their bulk storage modulus (G′) was found to increase as azaG PA content in the supramolecular assemblies increases up to a value of 10 mol% and beyond this value a decrease was observed, likely due to diminished levels of nanofiber entanglement in the hydrogels as a direct result of increased supramolecular rigidity. Interestingly, we found that the bioactivity of the scaffolds toward dopaminergic neurons derived from induced pluripotent stem cells can be enhanced directly by persistence length independently of storage modulus. We hypothesize that this is due to interactions between the cells and the extracellular environment across different size scales: from filopodia adhering to individual nanofiber bundles to cell adhesion sites that interact with the hydrogel as a bulk substrate. Fine tuning of hydrogen bond density in self-assembling peptide biomaterials such as PAs provides an approach to control nanoscale stiffness as part of an overall strategy to optimize bioactivity in these supramolecular systems. supramolecular biomaterials. Hydrogen bonding is an important driving force for the self-assembly of peptides in both biological and artificial systems. Here, we increase the amount of hydrogen bonding within self-assembled peptide amphiphile (PA) nanofibers by substituting glycine for an aza-glycine (azaG). We show that increasing the molar concentration of azaG increases the internal order of individual nanofibers and increases their persistence length. We also show that these changes are sufficient to increase survival and tyrosine hydroxylase expression in induced pluripotent stem cell-derived dopaminergic neurons cultured in 3D gels made of these materials. Our strategy of tuning the number of hydrogen bonds in a supramolecular assembly provides mechanical customization for 3D cell culture and tissue engineering. [Display omitted] [ABSTRACT FROM AUTHOR]