Reactive hydrogel forming formulations and related methods

Compositions and methods related to hydrogel tissue sealants are generally described. In certain embodiments, a hydrogel forming composition is provided in dry form (e.g., as one or more powder mixtures) and comprises at least an electrophilic polymer crosslinking agent and a nucleophilic polymer such as a protein that is capable of crosslinking with the crosslinking agent. One or more solvents able to dissolve the crosslinking agent and the protein can be provided and used to dissolve the hydrogel forming composition to facilitate crosslinking.