Synthesis and Mechanical Characterization of Chitosan Threads for Biomedical Applications

Abstract

Chitosan is a biopolymer widely used for many applications, especially in the biomedical field, due to its interesting properties like excellent sorption capability, biodegradability and biocompatibility. The presence of reactive groups in the structure of this biopolymer makes possible the attachment of different molecules. In this study a chitosan thread is synthesized, using a microfluidic technique with two merging channels of acidic chitosan and hydroxide, in order to use it as a controlled release device of drugs. Varying the flows of the fluids in the channels is possible to control the diameter of the thread, obtaining samples of medium and high molecular weight for each flow rate used in the synthesis. The obtained thread of chitosan was mechanically characterized performing tensile tests until failure and stress relaxation tests. An optical system of polarizers was set to visualize the alignment of the polymeric chains while the material is elongated during the tensile test. Young modulus is obtained for each type of sample to quantify the stiffness of the material, and relaxation times were calculated to observe the viscoelastic behavior. Alignment of the material was confirmed, since birefringence was shown.