Supramolecular Gels from Conjugates of Bile Acids and Amino Acids and Their Applications

Hydrogels composed of low molecular weight molecules are gaining increasing importance in biomedical applications. In this work, we report the formation of injectable hydrogels from bile acid-amino acid conjugates. The hydrogelation ability was dependent on multiple factors such as the bile acid backbone, linkage between the bile acid and the amino acid, and pH. We have shown that the gelation properties depend on multiple noncovalent interactions and on the balance between hydrophobic and hydrophilic characteristics of the molecules. Crystal structures of lithocholyl-L-phenylalanine, lithocholylglycine, lithocholyl-L-valine, and lithocholyl-L-alanine were also determined and compared. Finally, the rigid hydrogel frameworks were utilized to produce inorganic-organic composite materials with gold and ZnO nanoparticles.