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Supramolecular Interactions in Chitosan Gels
Author(s) -
Kato Kazuaki,
Schneider HansJörg
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200801103
Subject(s) - chemistry , malonic acid , chitosan , protonation , swelling , enantioselective synthesis , acetic acid , amino acid , hydrochloric acid , tartaric acid , covalent bond , supramolecular chemistry , organic chemistry , polymer chemistry , biochemistry , molecule , catalysis , chemical engineering , ion , engineering , citric acid
Chitosan gel particles show selective size changes with a large variety of effector compounds. Swelling induced by protonation of the chitosan amino groups is counteracted by non‐covalent cross‐linking with anions, depending on the structure of the acids. Thus, contraction amounts to 30 % with malonic acid, but to <1 % with the homologuous succinic acid, to 60 % with tartaric acid and to 51 % with 2,4‐dinitrophenol. With acetic acid expansion starts at around pH 6, whereas with, for example, hydrochloric acid swelling occurs at around pH 4. All size changes are essentially due to changes in water content. Basic amino acids, such as His, Lys and Arg, induce significantly enhanced expansion only in the presence of other acids as cofactors, therefore performing as logic AND gates. Enantioselective size changes are large with dibenzoyltartaric acid derivatives. Reducing the size of the gel particles allows the speed of size change to increase significantly; a similar sensitivity increase is achieved by the accompanying compartmentalization effect. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)