title: Self-assembly of chemically engineered hydrophilic dextran into microscopic tubules.
abstract: Although macromolecular self-assemblies are mostly fabricated from amphiphilic copolymers, here we report a tubular structure self-assembled solely from hydrophilic dextran-derived homopolymers via electrostatic interaction. To obtain tubular structures, we prepared two oppositely charged dextran derivatives by incorporating 2-bromoethylamine (Dex-BH) and chloroacetic acid (Dex-CA) into dextran, and their structures were confirmed using Fourier transform infrared spectroscopy. The two oppositely charged dextran derivatives self-assembled into microsize tubules when mixed in a pH 4.0 buffer solution. The tubular self-assemblies were sensitive to both pH and salt concentrations. Scanning electron microscopy and light microscopy confirmed that the tubules have hollow structures up to 100 microm long with a diameter between 600 nm and 2 microm. The X-ray study did not reveal any ordered molecular organization. This paper explores the mechanism of the tubule self-assembly and suggests a model.
authors.affiliation: Fiber and Polymer Science Program, Department of Fiber Science & Apparel Design, Cornell University, Ithaca, New York 14853-4401, USA.
authors.forename: Guoming
authors.initials: G
authors.lastname: Sun
authors.forename: Chih-Chang
authors.initials: CC
authors.lastname: Chu
mesh_terms: D003460:Crystallization / Q000379:methods*; D003911:Dextrans / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D046911:Macromolecular Substances / Q000737:chemistry; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003911:Dextrans; D046911:Macromolecular Substances