Preparation Of Multifunctional Nanozyme Composites And Study Of Biocatalytic Properties

In recent years,with the trend of cross-disciplinary integration research,nanomaterials have developed rapidly in the field of biological enzyme catalysis,and the excellent enzymatic catalytic activity of nanomaterials has also received extensive attention from more and more researchers.The excellent enzyme-mimicking activity of a variety of inorganic nanomaterials not only overcomes the limitations of classical antioxidants,showing long residence times in tissues,but also provides long-term protection at low doses,which researchers can use to prevent and treat diseases caused by oxidative stress.In addition,a variety of nanozymes have also been widely used in food hygiene,biomedicine,environmental protection and other fields.At present,many single nanoparticles have been shown to have good biological enzyme catalytic activity,Based on this situation,based on the preparation of a single nanoparticle,we designed and synthesized two nanozyme composites of core-shell type and bimetallic spherical structure,so that the prepared nanocomposites not only have the physical properties of a variety of nanoenzymes,but also show the synergistic catalytic activity of a variety of nanoenzymes.After a series of structural characterization,3,3’,5,5’-tetramethylbenzidine（TMB）was used to simulate enzyme catalysis,and the catalytic performance of the material was preliminarily evaluated,and finally Hep G2 cells were used to construct a oxidative damage model for oxidation experiment verification.The specific experimental content is as follows:1.Preparation of nanozyme composites:Cerium dioxide nanoparticles（Ce O₂ NPs）,Ferric oxide nanoparticles（Fe₃O₄ NPs）,gold nanoparticles（Au NPs）with high stability and uniform dispersion were first prepared at room temperature and pressure.Subsequently,based on the sol-gel method,Cetyltrimethylammonium bromide（CTAB）was used as a template agent,and mesoporous silica（silicon dioxide,Si O₂）was used for external structural coating wrapping to synthesize core-shell nanocomposites with complete and regular morphology.In addition,nanocomposites with bimetallic spherical structure were prepared by in-situ growth method,with Au NPs as the core and Ce（NO₃）₃·6H₂O added under heating conditions.2.Characterization of nanozyme composites:by transmission electron microscopy（TEM）,energy dispersive spectrometer（EDS）,X-ray diffraction（XRD）,UV/Vis spectrophotometer（UV-Vis）,particle size&Instruments such as Zeta potentiometers characterize their structural morphology as well as their elemental composition.The results show that the prepared nanoparticles and their nanocomposites are small in size,complete in structure and uniformly dispersed.3.Study on the biocatalytic performance of nanozyme composites:In this experiment,the enzyme activity of the prepared materials was first preliminarily evaluated,and TMB was used as the substrate,and nanomaterials were added in the presence of hydrogen peroxide to catalyze the substrate reaction.According to their generated products,enzyme-like activity evaluation was carried out,and the results showed that the enzymatic activity of core-shell nanocomposites was better than that of single nanoparticles and bimetallic spherical nanozyme composites.Subsequently,Hep G2 cells were used to evaluate the protective effect of nanomaterials on cells after oxidative damage by using hydrogen peroxide,and the results were consistent with the results of TMB simulation catalytic experiments,which further confirmed that the prepared nanozyme composites had good catalase activity.