Preparation of nanozyme/mof-based biomimetic structures with peroxidase- like activity for colorimetric detection of dopamine

The human body functions as a sophisticated system designed to maintain biological balance and respond to environmental stimuli. Enzymes, which constitute one of the fundamental components of this system, play a critical role in accelerating essential biochemical reactions in living organisms. However, the high production cost, sensitivity to environmental conditions, and structural instability of natural enzymes lead to various limitations during storage and application, thereby restricting their industrial and biomedical use. In recent years, efforts to overcome these challenges have increasingly focused on developing more robust, cost-effective, and reusable artificial enzymes. Among these, nanostructured artificial enzymes known as "nanozymes" have gained prominence due to their high surface area, multifunctionality, and biomimetic capabilities. To further enhance the catalytic performance of nanozymes, their integration with porous structures such as metal–organic frameworks (MOFs) has been shown to significantly improve the efficiency of biocatalytic systems. In this thesis, a layered MOF@nanozyme structure exhibiting biomimetic properties and high catalytic activity was developed using Fe₃O₄ and Ag nanoparticles. Initially, Fe₃O₄ magnetic nanoparticles were coated with silica (SiO₂) and subsequently decorated with Ag nanoparticles to obtain the Fe₃O₄@SiO₂@Ag structure. This structure was then coated with two types of MOFs, namely ZIF-8 and UIO-66, to produce composite nanozyme materials. The resulting structures were evaluated for the colorimetric detection of dopamine and for antibacterial activity. The findings demonstrated that the synthesized MOF@nanozymes not only function as highly active peroxidase-like biocatalysts but also serve effectively as biomarkers. Moreover, antibacterial assays revealed their efficacy against pathogenic microorganisms. Overall, the results indicate that MOF-supported nanozymes hold strong potential as multifunctional materials for biomedical and environmental applications.