CS acquires temperature-dependent gelation behavior. Therefore, the material can be easily injected at room temperature, and the rapid sol-gel transition at body temperature ensures the in situ local retention required by various biomedical applications. ALG, which is composed of alternating blocks of 1-4-linked α-L-glucuronic and β-Dmannuronic acid residues, is another polysaccharide featuring pH-responsiveness. Although water soluble, it can form hydrogels under mild conditions by ionotropic gelation in presence of divalent cations such as Ca 2+ . Gelation can also occur by polyelectrolyte complexation with positively charged polymers such as CS, resulting in composite materials with enhanced stiffness compared to single-component hydrogels. ALG has been optimized by various chemical modifications, such as the introduction of cysteine units, that enhanced its mucoadhesive properties and promoted hydrogel crosslinking, making it a good option for the sustained release of orally administered insulin. The incorporation of dopamine (DA) moieties enhanced the mechanical performance of ALG-based hybrid hydrogels promoting electrostatic interactions and crosslinking not only among polymer chains but also with DAcoated NPs dispersed in the matrix. The inclusion of phenolic moieties, such as tyramine (Tyr), has also been explored for enzyme-mediated crosslinking, resulting in a reticulated scaffold compatible with cell seeding and applicable to tissue engineering. Gums (e.g., gellan gum (GG), xanthan gum (XG)) have also been proposed for localized delivery owing to their bioadhesiveness and ability to undergo in situ gelation in the presence of ions. For example, a liposome/GG hybrid systems was described for intravesical instillation.