Supramolecular assemblies of bile acid derivatives

Abstract

In the early literature, self-associative behaviors of bile acids and bile acid salts were known. Owing to their amphiphilic nature, bile acids can form supramolecular self-assemblies in the form of micelles, helical microfibrils, or gel-like viscoelastic materials depending upon the concentrations and conditions. But for our case, it is not just viscoelastic material but a very strong and completely transparent gel (Fig. 1.12) which is stable for several months. Using hydrophobic fluorescent probes, we have been able to throw some light into the gelation process. On the basis of the above fluorescence experiments, it may be hypothesized that gelation is a two-step process, at least for our system, where in the first step a loosely packed network forms, which in the next step tightens up to form a strong gel network. An analogy could be made to the protein folding process. Figure 1.12: Photograph of transparent gel with colored background.