Catalytic Properties of a Nanozyme Based on Silver Nanoparticles Immobilized into a Polymethacrylate Matrix

The catalytic peroxidase-like properties of silver nanoparticles (Ag NPs) immobilized into a polymethacrylate matrix (PMM) were studied. The Ag NPs were prepared by thermal reduction of silver cations preimmobilized in a PMM. The morphology of the nanocomposite was studied using scanning electron microscopy (SEM), and the average size of the synthesized individual spherical nanoparticles was 18 ± 5 nm. It was demonstrated that silver nanoparticles immobilized in a polymethacrylate matrix (PMM–Ag0) exhibited pronounced peroxidase-like activity in the oxidation reaction of a chromogenic substrate, indigo carmine, under the action of H2O2. The Michaelis–Menten model was used to estimate the kinetic parameters of the reaction. The Michaelis constants (Km) of 0.1 and 1.0 mM for indigo carmine and H2O2, respectively, indicated a strong affinity of the substrates to silver nanoparticles in PMM.