There are a variety of hydrogels commonly used in 3D bioprinting. Hydrogels are synthetic matrices made up of a network of hydrophilic polymers that absorb water and/or biological fluids. They can be created from a large number of water-soluble materials including synthetic polymers, proteins, and polysaccharides. The 3D structure of these hydrogels is due to crosslinking which forms a structure which is insoluble in environmental fluid. The resemblance to different biological tissues, due to the elasticity and the presence of a large amount of water, allows the use of hydrogels in the regeneration of several types of damaged tissues (e.g., fibrin hydrogel is seeded with neural cells to regenerate brain tissue, keratinocytes are seeded in collagen hydrogel to regenerate skin tissue)

This work in the form of patent landscape analysis englobes information which could be used as a reference by researchers in the fields of 3D bioprinting, biomaterials, tissue engineering and biomedical engineering, as well as those interested especially in formulation of hydrogels. The state of the art has been reviewed by introducing what has been patented in relation to hydrogel-based bioinks. Furthermore, a detailed analysis of the patentability of the used hydrogels, their preparation methods and their formulations, as well as the 3D bioprinting process using hydrogels, have been provided by determining publication years, classifications, inventors, applicants, owners, and jurisdictions. The patent classification codes reveal that most inventions intended for hydrogels used as materials for prostheses or for coating prostheses characterized by their function or properties. Knowledge clusters and expert driving factors indicate that the research based on biomaterials, tissue engineering and biofabrication is concentrated in the most patents. Finally, this work which gives an analysis of the past, present and future trends lead to various recommendations that could help one to plan and innovate research strategy.