Preparation and characterization of chitin beads as a wound dressing precursor

Chitin was dissolved in N, N‐dimethylacetamide/5% lithium chloride (DMAc/5%LiCl) to form a 0.5% chitin solution. Chitin beads were formed by dropping the 0.5% chitin solution into a nonsolvent coagulant, ethanol. The beads were left in ethanol for 24 h to permit hardening, consolidation, and removal of residual DMAc/5%LiCl solvent in order to give spherical chitin beads uniform size distribution. The ethanol‐gelled chitin beads had an average diameter of 535 μm. The chitin beads were subsequently activated in 50% (w/v) NaOH solution and reacted with 1.9 M monochloroacetic acid/2‐propanol solution to introduce a carboxymethylated surface layer to the chitin beads. The bilayer character of the surface‐carboxymethylated chitin (SCM‐chitin) beads was verified by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and confocal microscopy. The bilayered SCM‐chitin beads were found to absorb up to 95 times their dry weight of water. These SCM‐chitin beads have potential as a component of wound dressings. © 2000 John Wiley & Sons, Inc.