Self‐Assembled Nanofibrillar Aggregates with Amphiphilic and Lipophilic Molecules

Abstract

Summary: This article gives a review on self-assembled nanofibrillar aggregates such as helical, twisted ribbon-like and tubular forms, those are produced in aqueous bilayer membrane and organogel systems. Two common features necessary for the chemical structure that yields special morphology are a chiral carbon atom and moieties feasible for intermolecular interactions although there are some exceptions. In aqueous systems, a hydrophobic effect is also an essential driving force for molecular aggregates in aqueous solution systems but almost disappear in organic media. More positive intermolecular interactions play an important role in molecular aggregation in organic media. Hydrogen bonding interaction is especially effective and many organogelators are classified into this category. Some lipophilic peptides have been investigated not only as organogelators but also with respect to their selfassembling behaviors. This latter property gives them distinct advantages compared with conventional gel systems because the gels include highly-ordered structures supramolecular functions like aqueous lipid membranes through molecular orientation. This article also introduces applicability of the organogel system.

Amphiphiles in aqueous solution: well beyond a soap bubble

“…It is noteworthy that the thickness of the aggregates corresponds to that of single-walled bilayer structures. 12 So far, a large number of amphiphiles forming fibrous aggregates based on distorted bilayers, also referred to as ribbons, have been reported. These include diacetylenic phospholipids, glycolipids with open or cyclic sugars and a different number and kind of unsaturation in the tail (double bonds, diacetylenic moieties), amino acid based amphiphiles as well as bolaamphiphiles and gemini surfactants.…”

“…More detailed reviews can be found elsewhere. 3,6,7,12 The ribbon-based aggregates can be morphologically classified into: (a) helical and tubular structures, featuring a cylindrical curvature, and (b) twisted ribbons with a Gaussian or saddle-like curvature 13 (Fig. 9a).…”

Advances in Switchable Supramolecular Nanoassemblies

“…As for other amphiphiles, these compounds spontaneously self-assemble into micelles and/or vesicles dependent on their packing parameter and solution conditions. [36][37][38][39] In accord, cryo-TEM images of "naked" 13 in a water/THF mixture (90:10, v/v) revealed the formation of long fibers with a ribbonlike structure. They consist of a thicker ((7.9 AE 1.3) nm) and a thinner part ((4 AE 0.6) nm) that results in a bandlike assembly as depicted in Figure 25.…”

Fabrication of Chiral Materials via Self‐Assembly and Biomineralization of Peptides

“…Through self‐assembly processes, chiral molecules can assemble into supramolecular structures, which are abundant in nature, for example, the DNA double helix, the triple helix of collagen, and the α‐helical coiled coil of myosin . In recent years, people have devoted vast efforts to studying chiral supramolecular structures formed by a variety of organic molecules, such as helical polymers, biomolecules, lipids and amphiphiles, among others . The fabrication of chiral materials and understanding their formation mechanism is one of the most intriguing topics in the fields of pharmacy, biochemistry and material science.…”