applications either for controlled delivery of therapeutics and tissue engineering. However, hydrogels composed of pure HA have poor mechanical properties, making a crosslinking step necessary to improve their performance for instance by reacting the carboxyl groups of HA using conventional coupling strategies. CS is a natural polysaccharide derived from the chitin of crustacean shells. It is composed of β (1→4)-linked glucosamine and N-acetyl glucosamine repeating units bearing amino groups, which confer pH responsiveness as well as versatility for further chemical functionalization. In drug delivery, gel-sol transition of hybrid CS hydrogels under mild acidification can be used to achieve triggered drug release. In this context, by leveraging the pH reduction between tumor and healthy tissues, intratumorally injected hydrogels could spread within the tumor mass to facilitate drug distribution and increase the therapeutic effects.