Self-assembled Cr₂O₃@nanogel/Au nanozymes to simulate peroxidase activity as a H₂O₂ sensor

The low temperature solvothermal method synthesized Cr₂O₃ NPs has not only peroxidase activity, but also oxidase activity. Then, the oxidase activity of Cr₂O₃ NPs is effectively shielded by nanogel immobilization using three monomers acrylamide, NIPAAM (N-isopropylacrylamide) and MBA (N,N'-methylene bisacrylamide) in HEPES (4-(2-hydroxyerhyl)piperazine-1-erhanesulfonic acid) buffer. Ultimately, the enzymatic activity of Cr₂O₃@nanogel/Au is significantly enhanced after doping Au NPs by SERS (Surface Enhanced Raman Spectroscopy) evaluation. A SERS strategy was proposed for the detection of H₂O₂ by Cr₂O₃@nanogel/Au. The linear range was 10^-8 mol·L^-1-10^-1 mol·L^-1.