Wet-spun alginate/chitosan whiskers nanocomposite fibers: Preparation, characterization and release characteristic of the whiskers

Abstract

Incorporation of chitosan whiskers in alginate fibers was achieved by mixing homogenized chitosan whisker colloidal suspension with 6% w/v sodium alginate aqueous solution, followed by extrusion into fiber form by wet spinning. The chitosan whiskers were prepared by deacetylation of chitin whiskers which had been obtained by acid hydrolysis of chitin flakes from shrimp shells. The average length and width of the whiskers were 309 and 64 nm, respectively, with the average aspect ratio being ∼4.8. Study on the mechanical properties of the neat alginate and the alginate/chitosan whiskers nanocomposite yarns (30 individual fibers) revealed that, at 1.0% w/w, noticeable improvement in the tensile strength of the nanocomposite yarns was observed, at the expense of the elongation at break. The release of the whiskers from the nanocomposite yarns was dose-dependent and it occurred based on the surface erosion phenomenon. The release half-lives of the nanocomposite yarns containing 0.2% and 0.6% w/w of the whiskers were about 6 h and less than 1 h, respectively. Incorporation of the chitosan whiskers within the alginate yarns imparted the antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli to the resulting alginate/chitosan whiskers nanocomposite yarns, which rendered them as effectual wound dressing materials.