Research On Electrochemical Electrodeless Glucose Sensor Based On Printed Electrodes

Diabetes is a chronic disease characterized by high blood sugar,which can lead to heart disease,blindness,amputation and other complications.It is serious harm to human health.Blood glucose level monitoring is significant for the treatment,control,and reduction of the risk of complications in diabetes mellitus.At present,the researchers have developed a number of glucose enzyme biosensors,such as current,colorimetric method,fluorescent,chemiluminescence,etc.These sensors had high selectivity and specificity,but the enzyme was susceptible to degeneration during using,resulting in poor reproducibility of the test results.Therefore,it was necessary to establish a good stability of the enzyme-free glucose biosensor.In the second chapter,based on the in situ preparation of copper nanowires(Cu NWs)modified screen printed carbon electrode(SPCE),a novel enzyme-free electrochemical biosensor with simple and fast response and high sensitivity was constructed.Natural killer(NK)cells are the innate immune system effects of lymphocytes and are also involved in dendritic cells,macrophages,T cells and endothelial cells interacting with regulatory cells.NK cells have great potential in improving hematopoietic and solid organ transplantation,promoting anti-tumor immune therapy,controlling inflammation and autoimmune diseases.At present,most of the domestic and foreign use of flow cytometry,enzyme reaction colorimetric and isotope labeling and other methods to detect NK cell activity.Flow cytometry and enzyme reaction colorimetric method are more sensitive,but the operation process is more complex;isotope labeling method is highly sensitive,easy to operate,but easy to pollute the environment,affecting the health of staff.Therefore,it is very important to establish a rapid and simple method for detecting NK cells.In the third chapter of this paper,the electrochemical detection of Pb2+ and NK cells based on bismuth film modified SPCE was studied.The first part is the introduction,the principle and classification of biosensors were briefly introduced firstly.And the electrochemical biosensors and the development of electrochemical glucose biosensors were described in detail.Secondly,the quantum dots and nanowires and their preparation methods were briefly introduced.Then,the formation and application of polymer micelles were introduced.Subsequently,NK cells and detection methods were reviewed.Then,the screen printing technique and its application in the sensor were introduced.Finally,the background,purpose and content of this paper were describle.The second part constructs an in-situ preparation of Cu NWs modified SPCE for the detection of enzyme-free glucose.Firstly,through electrochemical method,Cu(II)deposition on the surface of SPCE by electrochemical method,and then was placed in the(NH4)2S2O8 and NaOH mixed solution,the in-situ growth of SPCE on the surface of copper hydroxide nanowires(Cu(OH)2NWs),followed by high temperature heating and electrochemical reduction to transform it into Cu NWs,and finally by the electrochemical method for glucose detection.The experimental results showed that the response current of the sensor was in good linearity with the concentration of glucose in the range of 0.01-2.0 mM,and the detection limit was as low as 2?M(S/N= 3),in the determination of 2 mM parallel glucose solution 6 times,the relative standard deviation(RSD)was 4.7%.The method has high sensitivity,simple operation and can be effectively used for the detection of glucose.In the third part,we studied the electrochemical detection of Pb2+ and NK cells based on bismuth film modified SPCE.In this study,the polymer micelles supported by folic acid-loaded PbS quantum dots(PbS QDs)were first targeted to uptake by NK cells by folate receptor-mediated endocytosis,followed by centrifugation,nitric acid dissolution,Finally,the detection of NK cells by Pb2+ was achieved by square wave anodic stripping voltammetry using bismuth film modified SPCE.In this paper,a low-cost,highly sensitive electrochemical modified electrode for Pb2+ was constructed.The experimental results show that the modified electrode has been successfully used to detect Pb2+,and the response current has a good linear relationship with Pb2+ in the concentration range of 0.3-90 ?M.The detection limit is as low as 0.1 ?M(S/N = 3).The electrode is expected to be used next to the electrochemical detection of NK cells.