Studies Of Construction Of Different Antimony Oxides And Their Electrochemical Sensing Behaviors Toward Nitric Oxide

Small biomolecules play an important role in human metabolism and life process,and are closely related to human health.Nitric oxide（NO）,a biological small molecule is a signal molecule,which is catalyzed by nitric oxide synthase（NOS）to produce L-arginine.Nitric oxide possesses many specific function in many physiological and pathological processes of the human body.Based on the concentration of NO in the cell,the biological effect shows duality,that is,the appropriate concentration of NO in the cell is very active in the anti-gene mutation and the body defense,and if its concentration in the cell is too high,DNA can be damaged and the gene mutation could occur.Thus,the detection of NO released from cells is important.However,real-time sensitive detection of NO is very challenging because of its trace concentration,short half-life,and extremely high activity to react with other molecules.Therefore,it is of great importance to explore the sensitive in situ real time detection methods of NO which are simple,accurate,and portable.Electrochemical method is simply operated and less expensive,which can provide the kinetic information of NO releasing from living cells.Since NO detection requires the electrode to recognize target molecules,it is necessary to develop suitable functional materials for construction of electrochemical sensing platform with high sensitivity and selectivity.Antimony oxides are widely used in ceramics,flame retardants,semiconductors,photoelectric materials and batteries,and show high theoretical capacity,high cycle stability and other excellent performance in the filed of batteries.Thus,we speculate that antimony oxides could also show excellent performance in NO electrochemical sensor.Up to date,there is no relevant report about its application in electrochemical sensor.In this thesis,different antimony oxides were synthesized by different methods,and the different small molecular sensing platforms were constructed for the detection of NO achieving high selectivity and good sensitivity.The main research contents and results are summarized as follows:1.Synthesis of Sb₂O₃ octahedral particles and its application in NO detection.In this work,Sb₂O₃ octahedral particles were successfully synthesized by the combination of room temperature solution approach and hydrothermal method.The composition and structure of Sb₂O₃ octahedral particles were characterized and analyzed.The glassy carbon electrode was modified by the Sb₂O₃ octahedral particles material to construct an electrochemical sensor for the detection of NO small molecules.In a detection range of 81 nm to 1.863μM,the detection limit and sensitivity of the sensor are 49.33 nM and 6.32μA cm^-2μM^-1（S/N=3）,respectively while showing a good selectivity.This strategy renders a new method to detect NO by a new functional material Sb₂O₃ based electrochemical sensing platform.2.Preparation of Sb₂O₃ nanowires and its application in detecting NO released from cells.In this study,Sb₂O₃ nanowires were successfully prepared by hydrothermal method.The morphology and crystal structure of the nanowires were characterized and analyzed.Glassy carbon electrode was modified with this material and the electrochemical sensor was constructed.The results show a low detection limit of 5.26 nM and high sensitivity of 25.24μA cm^-2μM^-1.It was further applied to in situ detect NO molecules released from lung cancer cells A549,and the relationship between the amount of NO released from the living cells and the amount of stimulants was studied,indicating that the amount of NO released from the cells was dependent on the amount of stimulatory drugs added.3.NO sensing behaviors of Sb₂O₄/rGO composites and its in situ detection of NO released from living cells.In this work,Sb₂O₄/rGO composites was successfully prepared by growing Sb₂O₄nanomaterials on graphene sheets,and the morphology and crystal structure of the composites were studied.The electrochemical sensor based on the composites was prepared and its electrochemical sensing behaviors for NO was studied and the reaction mechanism was analyzed.The sensor exhibits excellent catalytic activity and selectivity with a low detection limit of 3.98 nM and a high sensitivity of 74.59μA cm^-2μM^-1.The sensing platform was further used to investigate NO released from heathy cells HUVEC and cancer cells A549.The experimental results show that the ability of NO released by A549 cells is 5 times higher than that of healthy HUVEC.With simple preparation,good selectivity,low detection limit and high sensitivity,the sensing platform can detect NO molecules in living cells to provide important information for us to understand cancer and tumor,thus holding great promise for its application in the field of biomedicine.In brief,three kinds of antimony oxide materials were prepared to construct three different electrochemical sensors,which were applied to detect NO.The results show that Sb₂O₃ materials with different morphologies have different electrochemical catalytic effects on NO oxidation.In addition,the combination of Sb₂O₄ and rGO significantly improves the electrochemical active surface area and electrochemical catalytic activity of the material,demonstrating a significant synergistic effect on the detection of NO.Furthermore,the sensitivity and selectivity of the sensor for the detection of NO were improved.The research of this thesis provides a new idea for the design and preparation of less expensive and high performance NO electrochemical sensor.Perspectives for the further development of the NO sensors is offered in the end of this thesis.