52646-27-2Relevant articles and documents
Sweet block copolymer nanoparticles: Preparation and self-assembly of fully oligosaccharide-based amphiphile
De Medeiros Modolon, Samuel,Otsuka, Issei,Fort, Sebastien,Minatti, Edson,Borsali, Redouane,Halila, Sami
scheme or table, p. 1129 - 1135 (2012/08/27)
The preparation of biocompatible nanocarriers that have potential applications in the cosmetic and health industries is highly desired. The self-assembly of amphiphilic block copolymers displaying biosourced polysaccharides at the surface is one of the most promising approaches. In the continuity of our works related to the preparation of "hybrid" amphiphilic oligosaccharide-based block copolymers, we present here the design of a new generation of self-assembled nanoparticles composed entirely of oligosaccharide- based amphiphilic block co-oligomers (BCO). These systems are defined by a covalent linkage of the two saccharidic blocks through their reducing end units, resulting in a sweet "head-tohead" connection. As an example, we have prepared and studied a BCO in which the hydrophilic part is composed of a free maltoheptaosyl derivative clicked to a hydrophobic part composed of a peracetylated maltoheptaosyl derivative. This amphiphilic BCO self-assembles to form spherical micelles in water with an average diameter of 30 nm. The efficient enzymatic hydrolysis of the maltoheptaose that constitutes the shell of the micelles was followed by light scattering and colorimetric methods.
Enzymatic synthesis of cellulose II-like substance via cellulolytic enzyme-mediated transglycosylation in an aqueous medium
Hattori, Takeshi,Ogata, Makoto,Kameshima, Yumiko,Totani, Kazuhide,Nikaido, Mitsuru,Nakamura, Takashi,Koshino, Hiroyuki,Usui, Taichi
scheme or table, p. 22 - 26 (2012/07/02)
The enzymatic synthesis of cellulose-like substance via a non-biosynthetic pathway has been achieved by transglycosylation in an aqueous system of the corresponding substrate, cellotriose for cellulolytic enzyme endo-acting endoglucanase I (EG I) from Hypocrea jecorina. A significant amount of water-insoluble product precipitated out from the reaction system. MALDI-TOF mass analysis showed that the resulting precipitate had a degree of polymerization (DP) of up to 16 from cellotriose. Solid-state 13C NMR spectrum of the resulting water-insoluble product revealed that all carbon resonance lines were assigned to two kinds of anhydroglucose residues in the corresponding structure of cellulose II. X-ray diffraction (XRD) measurement as well as 13C NMR analysis showed that the crystal structure corresponds to cellulose II with a high degree of crystallinity. We propose the multiple oligomers form highly crystalline cellulose II as a result of self-assembly via oligomer-oligomer interaction when they precipitate.
Controlled synthesis of amphiphilic rod-coil biodegradable maltoheptaose-graft-poly(ε-caprolactone) copolymers
Qiu, Xiongying,Wang, Caiqi,Shen, Juan,Jiang, Mingwei
experimental part, p. 1723 - 1729 (2011/09/12)
The controlled synthesis of novel amphiphilic biodegradable maltoheptaose-graft-poly(ε-caprolactone) copolymers was achieved through a three-step method. The first step consisted of partial silylation of the maltoheptaose hydroxyl groups. This protection step was followed by ring-opening polymerization of ε-caprolactone initiated from the remaining OH functional group of the partially silylated oligosaccharide. The third step involved the deprotection of the silylether group under mild conditions. The effects of varying the experimental conditions on grafting efficiency and graft length were investigated to ensure controlled polymerization of ε-caprolactone. The protection and deprotection of the TMS group during the entire procedure were carefully monitored with Fourier transform infrared (FTIR) and 1H NMR. The final graft copolymers were characterized by FTIR, 1H NMR, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC).
