Optimization of Printability Parameters of Chitosan Ink for Microextrusion-based 3D Bioprinting

Abstract

Chitosan as 3D printing material has been explored extensively. The viscosity of the lower concentration of the material is not suitable for microextrusion-based 3D printing, whereas higher concentrations are associated with needle clogging and high extrusion pressure requirements, limiting its application for tissue engineering and high-resolution printing. We prepared the low concentration chitosan ink and gelled it using heat treatment to optimize the printing parameters. This study aims to optimize printability parameters for microextrusion-based 3D printing using heat-treated chitosan ink dissolved in an alkali solvent. Various concentrations of heated chitosan ink (1-4%) were prepared and analyzed for their rheological and mechanical properties. The ink exhibited shear thinning behavior, crucial for extrusion-based printing. Rheological analysis indicated that higher concentrations (2.5% and 3%) had viscosities suitable for filament formation.  Mechanical characterization demonstrated that higher chitosan concentrations provided better compressive strength, with 4% chitosan exhibiting the highest strength. The study also optimized printing parameters such as extrusion pressure, layer height, and print speed. Emphasizing the importance of ink concentration and extrusion parameters, the study found that 4% chitosan ink at 35°C is optimal for maintaining structural integrity in 3D printed constructs. These findings underscore the necessity of optimizing ink concentration and printing parameters to achieve high-quality 3D printed constructs suitable for biomedical applications.