A facile method for the preparation of chitosan-based scaffolds with anisotropic pores for tissue engineering applications

•A novel method was applied to generate anisotropic pores in chitosan hydrogels.•A speculative explanation for the pore formation was provided.•Diverse chitosan-based anisotropic porous scaffolds were prepared.•Micron-scale pores and nano-scale pores were obtained simultaneously.•These scaffolds showed great potential for tissue engineering applications. To date, great efforts have been made to prepare different kinds of isotropic tissue engineering (TE) scaffolds. However, little attention has been paid to anisotropic porous scaffolds in spite of many examples of their excellent performances. In this work, a facile method termed “ammonia-induced method” (AIM) was proposed and applied to generate anisotropic pores in chitosan (CS)-based scaffolds. The pore structures of these scaffolds were studied in detail. In order to clarify the rationale behind this process, a speculative explanation was provided on basis of the experimental results and the theory of Uras (Uras & Devlin, 2000). Compression tests indicated that the mechanical strengths of these scaffolds were sufficient for TE applications. In vitro cell culture showed that MC3T3-E1 cells cultivated in the pores of these scaffolds had positive proliferation potential. We anticipated that this novel AIM could inspire research not only in TE but also in other fields.