title: From crab shells to smart systems: chitosan-alkylethoxy carboxylate complexes.
abstract: In this work, self-assembly of alkyl ethylene oxide carboxylates and the biopolymer chitosan into supramolecular structures with various shapes is presented. Our investigations were done at pH 4.0, where the chitosan is almost fully charged and the surfactants are partially deprotonated. By changing the alkyl chain length and the number of ethylenoxide units very different water-soluble complexes can be obtained, ranging from globular micelles incorporated in a chitosan network to formation of ordered multiwalled vesicles. The structural characteristics of these complexes can be finely controlled by the mixing ratio of chitosan and surfactant, i.e., simply by the solutions composition. For instance, the vesicle wall thickness can be varied between 5 and 50 nm just by varying the mixing ratio. Accordingly, we expect this system to be an outstanding carrier for hydrophilic compounds with tunable release time option. Moreover, an easy route for preparation of chitosan-based complexes in the solid state with controlled mesoscopic order is presented. This work opens the way to prepare biofriendly materials on the basis of chitosan and mild anionic surfactants which are rather versatile with respect to their structure and properties, allowing for preparation of complexes with highly variable structures in both aqueous and solid phase. Formation of such different structures can be exploited for preparation of carriers, which are able to transport hydrophilic as well as hydrophobic molecules. Furthermore, as chitosan is well known to exhibit antibacterial and anti-inflammatory properties, different applications of these complexes can be indicated, i.e., as drug delivery systems or as coatings for medical implants.
authors.affiliation: Stranski Laboratorium für Physikalische Chemie und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin , Straße des 17, Juni 124, Sekretariat TC 7, D-10623 Berlin, Germany.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Chiappisi
authors.forename: Sylvain
authors.initials: S
authors.lastname: Prévost
authors.forename: Isabelle
authors.initials: I
authors.lastname: Grillo
authors.forename: Michael
authors.initials: M
authors.lastname: Gradzielski
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*
chemical_list: D001704:Biopolymers; D048271:Chitosan