3D printing of biopolymer-based hydrogels

Biopolymer-based hydrogels have found important applications in biomaterial, food, environment, cosmetics, electronics, and other areas. 3D printing technology, which is capable of fabricating bespoke, intricate material structures that cannot be achieved by conventional subtractive manufacturing techniques, can greatly extend the application of biopolymer hydrogels. This chapter outlines different 3D printing techniques in three categories (extrusion-based, inkjet, and laser-mediated) that are suitable for fabricating biopolymer hydrogels. The basic knowledge of biopolymers and hydrogels is included. The principles of these different 3D printing techniques are introduced, material property requirements are examined, and some examples of biopolymer hydrogels in 3D printing are highlighted. Different solidification/curing (through gelation, crosslinking, or polymerization) strategies are surveyed. Moreover, the benefits and limitations of each of these 3D printing techniques, as well as the future development of biopolymer hydrogel 3D printing, are discussed.