Catalytically Synthesized Prussian Blue Nanoparticles Defeating Natural Enzyme Peroxidase

We synthesized Prussian Blue (PB) nanoparticles through catalytic reaction involving hydrogen peroxide (H 2 O 2 ) activation. The resulting nanoparticles display the size-dependent catalytic rate constants in H 2 O 2 reduction, which are significantly improved compared to natural enzyme peroxidase: for PB nanoparticles 200 nm in diameter, the turnover number is 300 times higher; for 570 nm diameter nanoparticles, it is 4 orders of magnitude higher. Comparing to the known peroxidase-like nanozymes, the advantages of the reported PB nanoparticles are their true enzymatic properties: (1) enzymatic specificity (an absence of oxidase-like activity) and (2) an ability to operate in physiological solutions. The ultrahigh activity and enzymatic specificity of the catalytically synthesized PB nanoparticles together with high stability and low cost, obviously peculiar to noble metal free inorganic materials, would allow the substitution of natural and recombinant peroxidases in biotechnology and analytical sciences.