Hydrogel Formation Using New L-Lysine-Based Low-Molecular-Weight Compounds with Positively Charged Pendant Chains

✍ Scribed by Masahiro Suzuki; Mariko Yumoto; Mutsumi Kimura; Hirofusa Shirai; Kenji Hanabusa

• Book ID: 102255177
• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: German
• Weight: 152 KB
• Volume: 86
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200390179

✦ Synopsis

Abstract

Low‐molecular‐weight compounds based on L‐lysine with alkylpyridinium or ‐imidazolium groups have been synthesized and studied for their gelation behavior in H~2~O. Most compounds formed gels below a concentration of 2.5 weight‐%, the pyridinium bromide 2a and the 1‐methyl‐1__H__‐imidazolium bromide 3 even at 0.1 weight‐%. The minimum gel concentration (MGC) necessary for hydrogelation increased with increasing length of the Lys N^α^‐alkanoyl chain, but the gelation ability concomitantly decreased. Electron‐microscopic images demonstrated that these hydrogelators create a three‐dimensional network in H~2~O by entanglement of self‐assembled nanofibers. A fluorescence study with 8‐anilinonaphthalene‐1‐sulfonic acid (ANS) proved that some hydrophobic aggregates are formed at hydrogelator concentrations below an MGC of less than 50 μM (0.004%). FT‐IR, ^1^H‐NMR, and Fluorescence studies indicated that the driving forces for the self‐assembly into nanofibers are mainly hydrophobic interactions and H‐bonding between amide groups.