Cell Adhesion and Degradation Behaviors of Acetylated Chitosan Films

Abstract

Chitoan, which is derived from chitin, is a linear heteropolysaccharide composed of β-1,4-linked D-glusosamine (GlcN) and N-acetyl-D-glucosamine (GlcNAc) with various compositions of these two monomers. The degree of acetylation (DA) represents the portion of GlcNAc units to total number of units. DA of chitosan influences not only the physicochemical characteristics, but also the biodegradability and biocompatibility. We synthesized DA-controlled chitosans (from 10% to 90%) by the acetylation reaction of deacetylated chitosan (DA ∼ 10%) and acetic anhydride with different ratio. The DA value of the chitosans was characterized by solid state 13C NMR and FT-IR spectroscopies. Surface properties of chitosan films with different DA value were investigated by the measurements of water contact angle and Zeta potential. The cell compatibility of the acetylated chitosans was estimated by cell culture using NIH/3T3 mouse fibroblasts and C28/I2 human chondrocytes. It was observed that the cell adhesion and growth decreased on the acetylated chitosan film surfaces with increasing DA value, probably owing to the increased number of acetyl groups leading to the increased hydrophobicity and reduced positive charge on the film surfaces. The degradation behavior of the acetylated chitosan films was also investigated in the solutions of lysozyme and/or N-acetyl-β-D-glucosaminidase, which are enzymes for chitosan existed in the human body. The degradation rate of the films with different DA value was observed as follows: 50 % > 30 % ≈ 70 % > 90 % > 10 %. Modifying the DA of chitosan provides a powerful means for controlling biodegradation and biocompatibility and can be optimized for tissue engineering applications.KeywordsChitosanDegree of acetylation (DA)Surface propertiesCell adhesionDegradation