Processing and Properties of Chitosan Inks for 3D Printing of Hydrogel Microstructures

Area of Science:

• Biomaterials Engineering
• Polymer Science
• Biomedical Fabrication

Background:

• Precise control over natural polymer properties and 3D structure fabrication is crucial for biomedical applications.
• Chitosan, a versatile natural polysaccharide, holds significant potential for tissue engineering and drug delivery systems.

Purpose of the Study:

• To report the 3D printing of complex chitosan structures in air at room temperature.
• To comprehensively characterize the 3D printing process, analyzing ink properties and printing parameters.
• To investigate the impact of neutralization on hydrogel formation and mechanical properties.

Main Methods:

• 3D printing of chitosan inks directly in air and at room temperature.
• Analysis of ink rheological properties, solvent evaporation, and neutralization effects.
• Characterization of printing parameters: nozzle diameter, robot velocity, and applied pressure.
• Mechanical testing of neutralized chitosan filaments and scaffolds.

Main Results:

• Successful printing of complex 3D structures including filaments, scaffolds, and intricate shapes.
• Identification of optimal processing parameters for various structures through a processing map.
• Chitosan ink's residual acids minimize shrink-induced shape deformation.
• Neutralized chitosan filaments exhibit high tensile strength (∼97 MPa dry) and strain at break (∼360% wet).

Conclusions:

• The developed fabrication approach enables the creation of complex 3D structures from natural polymers with tunable properties.
• This method provides guidelines for optimizing aqueous-based ink design and fabrication for biomedical applications.
• Opens new avenues for advanced tissue engineering scaffolds and drug delivery systems.