# Peroxidase-Like Metal-Based Nanozymes: Synthesis, Catalytic Properties, and Analytical Application  
[PERSON]  
1 Institute of Cell Biology, National Academy of Sciences of Ukraine, 79005 Lviv, Ukraine; [EMAIL_ADDRESS] (O.D. ); [EMAIL_ADDRESS] (N.S. ); [EMAIL_ADDRESS] (R.S. ); [EMAIL_ADDRESS] (M.G.) [PERSON]  
1 Institute of Cell Biology, National Academy of Sciences of Ukraine, 79005 Lviv, Ukraine; [EMAIL_ADDRESS] (O.D. ); [EMAIL_ADDRESS] (N.S. ); [EMAIL_ADDRESS] (R.S. ); [EMAIL_ADDRESS] (M.G.) [PERSON]  
1 Institute of Cell Biology, National Academy of Sciences of Ukraine, 79005 Lviv, Ukraine; [EMAIL_ADDRESS] (O.D. ); [EMAIL_ADDRESS] (N.S. ); [EMAIL_ADDRESS] (R.S. ); [EMAIL_ADDRESS] (M.G.) [PERSON]  
1 Institute of Cell Biology, National Academy of Sciences of Ukraine, 79005 Lviv, Ukraine; [EMAIL_ADDRESS] (O.D. ); [EMAIL_ADDRESS] (N.S. ); [EMAIL_ADDRESS] (R.S. ); [EMAIL_ADDRESS] (M.G.) [PERSON]  
3 Department of Chemical Engineering, Ariel University, Kyriat-ha-Mada, Ariel 407000, Israel 3* 3* 3* 3* 3* 3* 3* 3* 3 3* 3 3* 3 3 3*  
measuring the generation of H\({}_{2}\)O\({}_{2}\). This principle is widely used in oxidase/peroxidase-based biosensors [4, 5]. To determine H\({}_{2}\)O\({}_{2}\), PO-catalyzed decomposition of H\({}_{2}\)O\({}_{2}\) may be detected with optical biosensors (in the presence of chromogenic substrates) or with amperometric biosensors. The wide practical application of natural PO is still limited, however, due to the high cost of the enzyme and fast enzyme inactivation in the presence of H\({}_{2}\)O\({}_{2}\). Artificial enzymes having PO activity, especially PO-like nanozymes (NZs) or \"nanoperoxidase\" (nanoPOs), are promising substitutes for natural PO, especially in biosensors [5, 6, 7, 8, 9, 10, 11]. Detailed information about NZs, including their definition, history, classification, advantages over natural enzymes, methods of obtaining them, and prospects for practical use, can be found in our recent review [12]. The catalytic properties of NZs strongly depend on the method of synthesis [12, 13, 14], chemical structure, particle size, shape, and surface morphology, which can be affected by electrical charge, coating type, doping, loading, and external fields [14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27]. The catalytic performance and efficiency of NZs are usually characterized by kinetic parameters (\(K_{M}\), \(V_{max}\), \(k_{cat}\), \(k_{cat}/K_{M}\) ratio, IC\({}_{50}\)) and morphological characteristics [7]. In most cases, the catalytic efficiency of NZs is lower compared to natural analogues, but some NZs can compete with natural enzymes [5, 6, 7, 19]. Nanoperoxidases can be prepared in different ways, such as sol-gel, hydrothermal and solvothermal methods, electrodeposition, chemical reduction, green synthesis, pyrolysis, polymerization, polycondensation, coprecipitation, laser dewetting, and others [7, 12]. For ultrafast preparation of NZs containing metal oxides of transition metals, such as ZnCo\({}_{2}\)O\({}_{4}\), NiCo\({}_{2}\)O\({}_{4}\), MnCo\({}_{2}\)O\({}_{4}\), NiMn\({}_{2}\)O\({}_{4}\), CoCu\({}_{2}\)O\({}_{4}\), and Co\({}_{3}\)O\({}_{4}\), a new synthetic method was proposed using basic deep eutectic solvents. In this method, the designed solvents act simultaneously as a solvent, a shape-control agent and a reactant [28]. Each method of NZ synthesis has advantages and drawbacks [7, 12, 13]. The chemical reduction method is the most popular due to its rapidity and simplicity. The morphology and particle-size distribution of the chemically synthesized NZs may be controlled by changing molar concentration of compounds, the type of reductant, and the temperature of the reaction [29]. The faster the synthetic process is carried out, the smaller the sizes of obtained NZs, and vice versa [30]. To obtain NZs of higher purity and stronger stoichiometric control, the coprecipitation method must be chosen [31].