ABSTRACT
Bioprinting is a relatively recent additive manufacturing technique that enables the generation of biomimetic and organism-compatible 3D structures. It also makes it possible to study drugs in 3D tissues that retain biological properties better than current cell cultures because they more closely resemble the organism’s original tissues. It has evolved considerably over the years, and in the future, it will be the technology responsible for ending the shortage of organ donations and the problems of transplant incompatibility. It is based on the use of hydrogels as a printing matrix to form scaffolds, where the cells that will proliferate and form part of the new tissue created will be included. These hydrogels are hydrophilic and cross-linked polymers, biocompatible, with high water absorption and biofluidic capacity, and comprising a wide range of physical and biological properties. They form bioinks that can generate three-dimensional structures thanks to their different properties and various cross-linking systems. In addition, there are various printing methods, each suitable for different purposes. This chapter reviews all these aspects to provide an overview of hydrogels, as well as their rheological properties, the types of bioink currently used, how they are cross-linked, and the different bioprinting techniques available.
