Chapter 15: Immuno-response and Hydrogels

Immune reactions affect tissue regeneration and restoration as well as the occurrence and resolution of inflammation around biomaterials. Various kinds of immunomodulating techniques are being developed to acquire optimized immune reactions for local tissue regeneration. The strategies for immunomodulation are different depending on the types of scaffolds, targeted tissue, conditions of hosts, etc. Hydrogels are the most biocompatible biomaterials for tissue engineering, as they can provide highly hydrated environments similar to natural conditions. In accordance with the tremendous increase in the use of 3D printing technologies, various types of hydrogels are being applied as printing materials in the field of tissue engineering. Implanted hydrogels inevitably induce immune reactions, which will influence 3D-printing-induced tissue regeneration eventually. Understanding the immune-properties of hydrogels is undoubtedly advantageous for designing and constructing the biocompatible 3D hydrogels. In this chapter, basic immuno properties of hydrogels such as collagen, gelatin and alginate are described, and the relationship between immune reactions and tissue regenerations is also discussed. Furthermore, several techniques for immunomodulation using the hydrogels to enhance healing and regenerative processes are introduced.