Preparation, Structure, and Properties of Chitosan Microtubes

Abstract

Procedures were developed for forming hollow cylindrical structures with the wall thickness in the micrometer range (microtubes) from chitosan solutions in citric, lactic, and glycolic acids. The procedures are based on the phase-transfer neutralization induced by the transport of ions (hereinafter, ion-induced reaction), occurring at the liquid–liquid or solid–liquid interface, namely, on the polymer-analogous conversion of the salt form of the polymer to the base form in a NaOH or triethanolamine medium or formation of a water-insoluble polyelectrolyte complex with sodium dodecylbenzenesulfonate. Comparative analysis of the dependences of the morphological, structural, elastoplastic, physicomechanical, and biological properties of the structures on the reaction conditions and kind of the organic acid and neutralizing agent was made. The microtubes prepared from a chitosan solution in glycolic acid by ion-induced neutralization at the solid–liquid interface in a NaOH or triethanolamine medium exhibit the optimum levels of strength and elasticity, comparable with those of a fragment of human carotid artery and xenopericardial patch. The hemo- and biocompatibility and controlled biodegradation of these materials make them promising as analogs of biodegradable blood vessel implants.