In the last ten years, polysaccharide hydrogels have been one of the most promising systems to deliver therapeutic proteins, including hormones, growth factors, gene vectors, or monoclonal antibodies, due to their capacity to avoid or slow down the biodegradation of these biomolecules and/or sustain their release. The use of biodegradable and bioabsorbable natural polymers for the preparation of drug delivery systems is a strategy that has been widely used over the last 50 years. Of note, some of these polysaccharides are sensitive to changes in the biological media (such as pH, temperature, ion concentration changes, etc.) also being susceptible...