Amino acid-grafted and N-acylated chitosan thiomers: Construction of 3D bio-scaffolds for potential cartilage repair applications

In this work novel three-dimensional (3D) scaffolds were developed with chitosan thiomer derivatives for potential soft tissue repair applications. Amino acid-grafted chitosan (cysteine, CHICys) and N-acylated chitosan (11-mercaptoundecanoic acid, CHIMerc) derivatives were synthesized by covalent coupling reaction and hydrogel scaffolds were produced by freeze-drying process. They were comprehensively characterized by swelling and degradation behaviors, NMR, FTIR and Raman spectroscopy, SEM and X-ray microcomputed tomography. The results demonstrated the synthesis of chitosan thiomers with distinct degree of thiol substitution (CHICys = 5% and CHIMerc = 26%), producing highly porous scaffolds (porosity >80%) with hierarchical interconnected 3D pore structures. Additionally, their physicochemical properties and architectural features were significantly tuned by the thiol-modifier, evidenced by the swelling degrees ranging from approximately 2300% (CHICys) to 1800% (CHIMerc) and chemical stability against degradation. Moreover, they exhibited cytocompatibility based on in vitro bioassays, which hold promise as suitable platform in soft tissue engineering applications. (C) 2018 Elsevier B.V. All rights reserved.