Synthesis and Characterization of Dextran–Tyramine-Based H2O2‑Sensitive Microgels

We report a type of polymer microgel that can undergo a rapid and highly sensitive volume change upon adding H2O2. Such a H2O2-sensitive microgel is made of dextran–tyramine and horseradish peroxidase (HRP), which are interpenetrated in chemically cross-linked gel networks of poly(oligo(ethylene glycol) methacrylates). Unlike the H2O2-sensitive microgels reported in previous arts that typically involve degradation processes related to H2O2-induced cleavability of specific bonds, the proposed microgels can shrink upon adding H2O2 owing to the HRP-catalyzed coupling reaction of tyramine residues via decomposition of H2O2. While a fast (