Chapter 25 - Hydrogels for development of bioinks

Abstract

This chapter discusses the state-of-the-art of the application of hydrogels as bioinks in bioprinting processes. Three groups of techniques which are commonly used by commercial bioprinters have been included: material extrusion, vat photopolymerization, and material jetting. The main characteristics of each group are described to understand their limitations, potential benefits and how the properties of the hydrogels must be adapted for every type of bioprinting technique. Although the biocompatibility of the hydrogel is a mandatory requirement, it is not enough to ensure the possibility of using it as a bioink. Additional specifications must be taken into account in terms of the processability of the material and its final stability. Alginate, hyaluronic acid, gelatin and silk fibroin, among others, are the most explored options to formulate bioinks. This chapter discusses the available materials, their limitations and some interesting results of their applications for obtaining scaffolds for tissue engineering.