Investigation On The Synthesis And Application Of Peroxidase Mimetics Derived From Heteroatom Doped Carbon Nanomaterials

Natural enzymes are widely applied in the fields of medicine,chemical industry and biotechnology owing to their excellent characteristics such as high catalytic efficiency,strong specificity and good selectivity,etc.Nevertheless,most natural enzymes are essentially composed of bioactive proteins,which make them be apt to suffer from easy denaturation by harsh environment,poor stability and storage difficulty and thus limit their generalized applications.Therefore,developing artificial enzymes with high stability,low manufacturing cost and excellent catalytic performance to replace natural enzymes has become an extremely urgent task.With the rapid development of nanomaterial technology in recent years,nanoenzymes gradually came into the scientist domain.Since Yan's group first found that Fe₃O₄ nanoparticles possess the peroxidase-like activity in 2007.More and more nanoparticles have been explored to possess the peroxidase-like activity,covering noble metals,carbon-based nanomaterials,transition metal oxides,metal sulfide,metal-organic framework materials(MOFs)and some composite materials.Compared with natural enzymes and other traditional mimetic enzymes,nanoenzymes can organically combine catalytic performance with its own unique physical and chemical properties,which can not only exhibit catalytic activity similar to that of natural enzymes,but also exhibit unique properties of nanomaterials themselves,thus endowing more new functions to mimetic enzymes.Based on this,the novel peroxidase mimetic was developed and studied by heteroatom doped carbon nanomaterials in this paper,which was further applied in the colorimetric detection of hydrogen peroxide and glucose.(1)S-doped reduced graphene oxide(denoted by S-r GO)was synthesized via a facile hydrothermal reaction by employing Na₂S and GO as precursors without any templates or surfactants,and further studied systematically its peroxidase-like activity and application in the determination of hydrogen peroxide and glucose.The peroxidase-like activity of S-r GO was greatly boosted compared to the pristine r GO,demonstrating the peroxidase-like active sites were dominantly originated in sulphur containing groups.The steady-state kinetic studies further indicated that S-r GO has a good affinity for H₂O₂.In view of the outstanding performance of S-r GO as peroxidase mimetic,a simple and sensitive colorimetric detection platform for H₂O₂and glucose had been successfully established.The experimental results showed that the detection platform had wider linear range and lower detection limit.Furthermore,the practical applicability of the proposed sensor was further validated by measuring glucose concentration in human serum.(2)Fibrous Cu-MOF were successfully prepared by a simple hydrothermal method,using Cu(NO₃)₂·3H2O and H₃BTC as the raw materials.Then,melamine acted as the nitrogen source,mixed it with the prepared Cu-MOF at a ratio of 3:1 to prepare Cu@N-CNFs under the condition of calcination at 900 ^oC,N₂ atmosphere.The introduction of N atom not only offered the active sites,but also produced more defects on the surface of the carbon materials.The porous structure with large specific surface area made Cu@N-CNFs exhibit better peroxidase-like activity.When the TMB chromogenic reagent was added to the Cu@N-CNFs-H₂O₂ buffer solution system,we could observe the obvious blue change within 300 s.Furthermore,we studied the kinetic behavior of Cu@N-CNFs as peroxide-mimetics.The results showed that Cu@N-CNFs exhibited good affinity for both TMB and H₂O₂.Based on the above excellent characteristics,a simple and sensitive visual colorimetric system was established for quantitative detection of glucose with glucose oxidase,and which was successfully applied to the actual sample detection.