Fig. 1.

Schematic representation of the preparation of protein (cytochrome c or CCL21) - loaded alginate nanoparticles by the ionotropic gelation method. Alginate (in an aqueous solution), protein, and Pluronic F127 were combined prior to the addition of CaCl2, which induced the formation of cross-linked matrices in a pre- gelation state. The addition of Pluronic F127 strengthened the matrices of the alginate nanoparticles and prolonged the release of the protein payload. Incorporation of protamine sulfate allowed for the formation of a polyelectrolyte complex, which stabilized the alginate pre-gel nucleus into individual particles.