Self-assembly peptide-amphiphile molecules

Recently, Stupp and coworkers designed self-assembling peptide-amphiphile molecules, which form one-dimensional cylinders in aqueous solution having diameter of approximately 7 nm and micron scale lengths [7]. 

Figure 4.2 Self-assembling peptide amphiphiles (PA) used for biomimetic mineralization of HA/PA nanocomposite, (a) Chemical structure of the PA, comprising 5 regions (1) a hydrophobic alkyl tail (2) four cysteine residues that can form disulfide bonds to polymerize the self-assembled structure (3) a flexible linker region of three glycine residues (4) a single phosphorylated serine residue that was able to interact strongly with calcium ions and help direct mineralization of HA (5) the cell adhesion ligand ROD. (b) Molecular model of one single PA molecule, (c) Schematic showing the self-assembly of PA molecules into a cylindrical micelle.

Niece KL, Hartgerink JD, Donners J et al (2003) Self-assembly combining two bioactive peptide-amphiphile molecules into nanofibers by electrostatic attraction. J Am Chem Soc 125 7146-7147... 

Figure 14.10 Self-assembly of peptide-amphiphiles into nanofibers (a) a peptide amphiphile molecule with five distinct regions designed for hydroxyapatite mineralization, (b) a schematic of molecular self-assembly, and (c) a negatively stain transmission electron microscopy image of the nanofibers. Reprinted from Hartgerink et al. (2001). Copyright 2001 American Association for the Advancement of Science.

Peptide-amphiphile molecules self-assembled into nanofibers. Reprinted with permission from reference 4. Copyright 2002 National Academy of Sciences. 

Table 2 Designer self-assembling systems based on peptide amphiphiles molecules. ...

Supramolecular materials are architectures consisting of molecules that are able to self-assemble into larger constructs (Lehn, 2002). Polymers as well as small molecules are able to form self-assembled structures. Supramolecular materials based on small molecules such as peptides or peptide amphiphiles are also referred to as supramolecular polymers. Despite the importance of enzyme controlled self-assembly of small molecules, these materials will not be discussed here as they are not based on conventional polymers. More information on these materials can be found in the recent literature (Roy and Ulijn, 2010 Zelzer et al., 2013). 

In this chapter, we have surveyed a wide range of chiral molecules that self-assemble into helical structures. The molecules include aldonamides, cere-brosides, amino acid amphiphiles, peptides, phospholipids, gemini surfactants, and biological and synthetic biles. In all of these systems, researchers observe helical ribbons and tubules, often with helical markings. In certain cases, researchers also observe twisted ribbons, which are variations on helical ribbons with Gaussian rather than cylindrical curvature. These structures have a large-scale helicity which manifests the chirality of the constituent molecules. 

Synthetically lapidated peptides possess the self-assembly character of amphiphilic molecules and biological activity of the peptide headgroups. This enables interfaces to be assembled that dehver biofunctionality in a controllable way. Incorporation of peptide amphiphiles in hposomes greatly increases the uptake of synthetic dyes by cells, indicating their potential utility in targeted drag delivery. 

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