Precision 3D printing of chitosan-bioactive glass inks: Rheological optimization for enhanced shape fidelity in tissue engineering scaffolds

3D printing technology in tissue engineering applications provides several advantages for scaffold development, especially with natural materials, such as chitosan, which provides a biomimetic environment for cellular growth. However, chitosan hydrogel-based inks still show poor printing fidelity. In this article, we overcame this challenge by incorporating bioactive glasses (BG) nanoparticles (up to 5 wt%) into the chitosan hydrogel. The resulting inks were characterized by rheological tests, while their processability was evaluated through measurements of shape fidelity. An indirect cytotoxicity assay was also conducted to evaluate the cell viability of the printed scaffolds. The results indicated that adding BG nanoparticles to the chitosan-based ink modified its rheological properties and improved its shape-fidelity during 3D printing, which we suggest are consequences of hydrogen bonds established between the glass and the chitosan chains. Also, cytotoxicity assessment demonstrated that the resulting scaffold exhibits high cell viability. In conclusion, the proposed composite ink has optimized rheological properties for 3D printing and is promising for applications in tissue engineering.