In this talk, we will discuss the investigation of a hydrogel platform exploiting dynamic multivalent interactions between biopolymers and nanoparticles. These materials exhibit viscous flow under shear stress (shear-thinning) and rapid recovery of mechanical properties when the applied stress is relaxed (self-healing), afford minimally invasive implantation in vivo though direct injection. The hierarchical construction of these biphasic hydrogels allows for multiple therapeutic compounds to be entrapped simultaneously and delivered with identical release profiles, regardless of their chemical make-up, over user-defined timeframes ranging from days to months. These materials enable novel approaches to immunomodulatory therapies such as vaccines and cancer immunotherapies that rely on precise and sustained release of complex mixtures of compounds. We demonstrate that these unique characteristics enable the development of vaccines that greatly enhance the magnitude, quality, and durability of the humoral immune response.