Printability of hybridized composite from maleic acid-treated bacterial cellulose with gelatin for bone tissue regeneration

Bacterial cellulose (BC) has been widely used in bone tissue engineering (BTE) due to its good biocompatibility, proper mechanical strength, microporosity and biodegradability, and unique surface chemistry. However, the tight and entanglement fibers severely limit their applications when used as precursor to prepare bio-ink to construct printable BC-based hybridized composite for BTE. Herein, various concentrations (20%, 40%, 60%, and 80%) of maleic acid were used to treat BC to obtain homogeneous BC dispersions (termed as MA-BC). MA-mediated treatment could effectively release individual fibrils without impairing the inherent crystalline properties of BC. 60% MA-BC showed the best pre-treated performances, which were evidenced by the results of crystallinity index, mechanical properties, and surface wettability. Subsequently, MA-BC dispersion was used to hybridize with gelatin (MA-BC-gels) to prepare composite, which exhibited enhanced rheological properties, compression modulus, and extensively utilized as bio-ink for 3D bio-printing. Furthermore, MA-BC dispersions exhibited excellent biocompatibility, pronounced ability for alkaline phosphatase expression, and mineralized nodule formation and osteogenic-related genes expressions in vitro. Considering these excellent biological activities and 3D bio-printing performance, MA-BC-gels with superior osteogenic activities could be considered as promising composite to prepare scaffolds for bone tissue regeneration.