Several methods have recently been reported for the preparation of redox-sensitive hydrogels using enzymatic reactions, which are useful for encapsulating sensitive materials such as proteins and cells. However, most of the reported hydro gels is difficult to add further function efficiently, limiting the application of the redox-sensitive hydrogels. In this study, peptide sequences of HHHHHHC and GGGGY (Y-tag) were genetically fused to the N- and C-termini of streptavidin (C-SAY), respectively, and C-SA-Y was mixed with horseradish peroxidase and thiol-functionalized 4-arm polyethylene glycol to yield a redoxsensitive C-SA-Y immobilized hydrogel (C-SA-Y gel). The C-SA-Y immobilized in the hydrogel retained its affmity for biotin, allowing for the incorporation of proteins and small molecules to hydrogel via biotin. C-SA-Y gel was further prepared-within a water-in-oil (w/o) emulsion system to yield a nanosized hydrogel, to which any intracellular and cytotoxic agent can be modified, making it a potential drug delivery carrier.