An environmentally benign approach to achieving vectorial alignment and high microporosity in bacterial cellulose/chitosan scaffolds

Bacterial cellulose (BC) nanofibers secreted by Komagataeibacter xylinus 10245 were applied alone or in combination with chitosan to prepare highly aligned and porous scaffolds through a combined liquid nitrogen-initiated ice "templating" and freeze-drying process. Their morphology and physical properties were controlled by adjusting the concentration of chitosan over a range of 1, 1.5, and 2% (wt%) and analyzed by Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET), and X-ray diffraction methods. The SEM images confirmed a distribution of fibrils vectorially aligned in the freezing axis direction, while chitosan contributed to the development of a dense network, superior mechanical properties, and biomedical relevance of the final scaffolds. It was found that as the chitosan concentration increased, the crystallinity index decreased from 89% to 79% likely because of strong intermolecular bonding. However, the scaffolds containing chitosan demonstrated excellent shape recovery and structural stability after compressive tests and may act as excellent scaffolds for potential cartilage tissue engineering applications.