Vanadium Oxide-based Nanocomposites As Enzyme Mimetics And Their Applications In Biochemical Analysis

Nanostructured artificial enzymes(so-called nanozymes)are a new class of enzyme mimics.Due to their outstanding advantages,such as low cost,good tunability and high stability in catalytic activities,nanozymes have attracted much attention.With the rapid development of nanotechnology,the emergence of a large number of nanozymes has broadened the catalytic scope of biological enzymes,improved their stability in the external environment,and enriched the application field of natural enzyme.In this paper,the intrinsic enzyme mimic characteristics and catalytic behavior of V6O13 nanomaterials and their nanocomposites were investigated for the first time.The catalytic mechanism was also studied,and the colorimetric/fluorescent biosensors were established based on the nanozymes activities for the detection of corresponding targets in real samples.The main work is as follows:(1)V6O13 nanotextiles(NTs)with unique structure were synthesized by a facile solution-redox-based self-assembly method and the catalytic performance of the as-prepared V6O13 NTs was studied.For the first time,the intrinsic triple-enzyme activity of V6O13 NTs was demonstrated and the catalytic mechanism was investigated.A colorimetric biosensor for the detection of GSH was established based on the oxidase-like activity with a linear range of 2.5-30 ?M and detection limit of 0.63 ?M.A fluorescence system for the detection of H2O2 and glucose was established based on peroxidase-like activity with a linear range of 8.0-1600 ?M and 0.2-12 ?M,and detection limit of 6.41 ?M and 0.02 ?M,respectively.The detection systems were both accurate and sensitive,and successfully applied to the detection of GSH in health products and glucose in human serum samples.(2)Using reduced graphene oxide(rGO)as the carrier,V6O13-rGO nanocomposites were synthesized by hydrothermal method,which showed superior oxidase 'activity to single V6O13 nanomaterial.The catalytic properties of V6O13-rGO nanocomposites were studied.By introducing F-to increase the catalytic rate,the catalytic activity was further improved,and the enhancement mechanism of F-was investigated.The V6O13-rGO-TMB-F-colorimetric system was established for the direct detection of F-.The experiment conditions such as pH,temperature and reactant concentration were investigated.Under the suitable experiment conditions,the linear range of F-detetion was 0.02-3.5 mM,and the detection limit was 0.015 mM.The as-established detection system was successfully applied to the detection of F-in tap water.