title: Combinatorial library of low molecular-weight organo- and hydrogelators based on glycosylated amino acid derivatives by solid-phase synthesis.
abstract: A combinatorial approach for the synthesis of supramolecular gelators as new organic materials is described herein. In the course of the development of a convenient and flexible solid-phase synthesis of the artificial glycolipids, some of these compounds were accidentally found to act as low molecular-weight gelators toward organic solvents. Using this combinatorial solid-phase synthesis of glycosylated amino acetates, screening and optimization of low molecular-weight organo/hydro-gelators were efficiently carried out. We found that an N-acetyl-galactosamine-appended amino acid ester (GalNAc-aa) efficiently gelates a broad spectrum of organic solvents. More interestingly, some GalNAc-aa derivatives displayed an excellent hydrogelation capability. Transmission electron microscopy, scanning electron microscopy, confocal laser scanning microscopy, and FT-IR were used for characterization of the gel structure. It is indicated that supramolecular fibers supported by strong hydrogen-bonding networks are entangled so that the resulting spaces can immobilize a number of solvent molecules effectively. In addition, the supramolecular hydrogel consisting of GalNAc-suc-glu(O-methyl-cyc-pentyl)(2) is stable even under high salt concentrations probably due to its nonionic character and as a result, a native protein is successfully entrapped in the gel matrix without denaturation.
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kiyonaka
authors.forename: Seiji
authors.initials: S
authors.lastname: Shinkai
authors.forename: Itaru
authors.initials: I
authors.lastname: Hamachi
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry*; D020650:Combinatorial Chemistry Techniques; D018360:Crystallography, X-Ray; D006420:Hemeproteins / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry*; D007202:Indicators and Reagents; D008706:Methemoglobin / Q000737:chemistry; D017348:Microscopy, Electron, Scanning Transmission; D008970:Molecular Weight; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000596:Amino Acids; D006420:Hemeproteins; D020100:Hydrogels; D007202:Indicators and Reagents; D008706:Methemoglobin