Construction Of Optical Sensing System Of Nanozymes And Their Analytical Applications

Natural enzyme, which is well known for efficient catalytic activity, specificity. and mild reaction conditions, has an important contribution to catalysis. However. its source limited, easy to heat inactivation, sensitive to light, heat, acid and alkali, leading to the restricted in practice. Therefore, exploiting a new material, which exhibits the enzymes catalytic activity similar to natural enzymes, becomes a hot research in recent years. The so-called analog enzyme is synthesized using a simple method of a class of non-protein molecules with natural materials. Nanoparticles have been reported intrinsic peroxidase activity since2007. Hereafter, nanoparticle-based analog enzyme attracts much attention, such as ferromagnetic nanoparticles, metal and metal oxide nanoparticles, carbon-based nanoparticles and nanocomposites. In this Paper, we develop and synthesis a more effectively catalytic activity and affinity nanoparticles as enzyme mimics, and be used to construct optical sensor systems.I. Chitosan stabilized silver nanoparticles (Ch-Ag NPs) were successfully synthesized by a one-step method and were found to possess intrinsic peroxidase-like activity, could catalytically oxidize substrates, such as TMB. OPD and ABTS, by H2O2to produce a typical color reaction such as from colorless to blue for TMB and from colorless to red for OPD. Our results demonstrate that the Ch-Ag NPs exhibit higher thermal and pH durance than HRP. which could be suitable in a wider range of harsh conditions. Results of electron paramagnetic resonance (ESR) suggest that the catalyse-mimic activity of the Ch-Ag nanostructures effectively catalyzed the decomposition of H2O2into OH radicals. Based on this finding, a simple, sensitive and selective visual and colorimetric method with TMB as substrate has been designed for glucose detection when combined with glucose oxidase (GOx). This colorimetric method can be used for detection of glucose in biological samples with a detection limit as low as100nM and a dynamic range from5.0×10-6to2.0×10-4M.2. In this paper, we reported the natural environment-friendly biological materials (eggshell membrane) doped magnetic nanoparticles (MCNMs). It was characterized by TEM. XRD, EDX. TEM images of the magnetite nanomaterials showed the multidispersed nanoparticles with an average diameter of around15-20nm. XRD indicated the crystalline structure of Fe3O4magnetite. EDX analysis revealed the presence of carbon, nitrogen and small amount of sulfur associated with the organic components among the magnetic nanoparticles, owing to the decomposition of ESM after hydrothermal treatment. MCNMs were demonstrated to possess both peroxidase-like and SOD-like mimic activity. The nanoparticles not only retain original magnetic properties but enhance catalytically activity toward H2O2. The Michaelis-Menten kinetics show that MCNMs exhibit higher affinity to TMB and H2O2, suggesting the doped with biological materials significantly improved the simulated activity in further.3. We provide a simple preparation, easy to operate and rapid separation method to synthesize the glycine derivatives of fullerene C60(Gly-C60) in situ by spontaneous combination of methods. Gly-C60shows the intrinsic peroxidase activity. The effect of pH and temperature show that Gly-C60exhibit higher tolerance than HRP. Moreover, Gly-C60show higher catalytic activity in the higher temperature range of45℃-70℃. Michaelis-Menten kinetics was used to investigate the mimetic peroxidase activity in further. Gly-C60simultaneously shows higher affinity to H2O2and TMB, proving that the derivatives of fullerene improved peroxidase activity. Based on this finding, a simple, sensitive and selective visual and colorimetric method with TMB as substrate has been designed for glucose detection when combined with glucose oxidase.