The inorganic metal or metal-oxide nanoparticles (NPs) that mimic enzymes are of great interest due to improved physical and chemical properties compared with native enzymes. Here, we report that manganese dioxide (MnO₂)-Silk exhibit catalase, oxidase, and peroxidase-like activities. The MnO₂-Silk hybrid fibers effectively decomposed hydrogen peroxide (H₂O₂) and oxidized the typical horseradish peroxidase substrates, such as o-phenylenediamine (OPD), and 3,3′,5,5′- tetramethylbenzidine (TMB) in the presence or absence of H₂O₂. The oxidative properties of MnO₂-Silk fiber hybrid showed an enzyme-like behavior for the catalase-like activity, oxidase-like activity, and peroxidase-like activity. The operational stability of the MnO₂-Silk fiber hybrid over ten cycles showed a constant residual activity of about 25–30% after 2–3 cycles indicating that MnO₂-Silk fiber hybrid could be used as a satisfactory oxidoreductase enzyme mimics. Potentiometric titration was used to determine the surface charges of the MnO₂-Silk catalyst. Together, we identified the reactive species as Mn_1−x⁴⁺Mn_x³⁺O_2−x(OH)_x with a pK of approximately 5.2. Our results have implications on the understanding of the catalytic origin and interaction of metal oxides NP with various biomaterials.

模仿酶的无机金属或金属氧化物纳米颗粒（NPs）与天然酶相比由于具有改善的物理和化学特性而备受关注。在这里，我们报告说，二氧化锰（MnO ₂）-丝表现出过氧化氢酶，氧化酶和过氧化物酶样活性。MnO _2-真丝杂化纤维可有效分解过氧化氢（H ₂ O ₂）并氧化典型的辣根过氧化物酶底物，如邻苯二胺（OPD）和3,3'，5,5'-四甲基联苯胺（TMB）是否存在H ₂ O ₂。MnO ₂的氧化性质-丝纤维杂种对于过氧化氢酶样活性，氧化酶样活性和过氧化物酶样活性表现出酶样行为。MnO _2-真丝纤维杂种在10个循环中的运行稳定性表明，在2-3个循环后，其残留活性约为25–30％，这表明MnO _2-真丝纤维杂种可以用作令人满意的氧化还原酶模拟物。用电位滴定法测定MnO _2-丝催化剂的表面电荷。我们一起确定了反应性物种为Mn _{1− x} ⁴⁺ Mn _x ³⁺ O _{2− x}（OH）_xpK约为5.2。我们的结果对理解金属氧化物NP与各种生物材料的催化起源和相互作用具有影响。