Multifunctional Hybrid Nanocomposite Hydrogel Releasing Different Biomolecular Species Triggered with Different Biochemical Signals Processed by Orthogonal Biocatalytic Reactions.

A micro/nanoshaped system composed of alginate microspheres (microgels) decorated with silica oxide nanoparticles functionalized with nitroavidin was used for on-demand biomolecule release stimulated by different input signals. Enzymes preloaded in the microgels processed the applied signals producing either basic pH locally near the microspheres or generating H 2 O 2 inside the hydrogel, or both simultaneously. The pH increase resulted in cleavage of the affinity bonds between nitroavidin and biotin, then releasing the latter. The H 2 O 2 produced resulted in oxidative cleavage of cross-linking bonds in the alginate matrix, then opening pores and releasing a loaded model protein (bovine serum albumin).