Study Of Non-enzymatic Biosensor Based On Nanophase Materails

Nanotechnology will become a revolution of human cognition and the industrial. Herein, nanotechnology applied in biosensor has caused the study interest of scientists over the world. Biosensors have developed to be a frontier and newly-interdisciplinary including chemistry, biology, physics and electronics. Due to its simplicity, high sensitivity and potential ability for real-time and on-site analysis, biosensors have been widely applied in various fields including clinical diagnosis, environment monitoring, food control and industrial process and so on.The application of nanometer materials will further improve the performance of biosensors, especially produce positive and far-reaching influence for non-enzymatic biosensors, and has a broad development prospects.The main work of this paper focuses on using nanometer material to fabricate and develop non-enzymatic biosensors, and applying their novel biosensors to detect p-D Glucose,H2O2 and NADH. The main points of this thesis are summarized as follows:1. The Ni (Ⅲ) had a good function for catalytic oxidation of glucose, which could oxidate glucose to glucolactone directly. A thin film of Ni nanoparticles modified electrode has been fabricated by electrodeposition. It was found that the Ni nanoparticles showed obvious electrocatalytic activity than conventional Ni materials. The modified was used to detection glucose at 0.6V in 0.1mol/L NaOH solution, the response current was good proportional to the concentration of glucose over the range 10.0μmol/L～2.5 mmol/L, with a detection limit of 5.0μmol/L(S/N= 3) and a response time of 3s. The preparation of the sensor is simple and has a lower cost, as well as can be used repeatedly.2. A new kind of room temperature ionic liquid (n-octylpyridinum hexafluorophosphate,OPFP) mixed with multiwall carbon nanotubes(MWCNT) and graphite powder composite eletrode was constructed based on the substitute of the paraffin oil. The optimal condition for preparation was selected as 1:5:4(mass ratio) for MWCNT, OPFP and graphite powder. The electrochemical behaviors of the MWCNT/IL/graphite composite electrode(MWCNT-CILE) was investigated by using K3 [Fe (CN) 6] as probe and compared with IL(OPFP)/graphite electrode(CILE) as mass ratio of 5:5. The result indicated that the novel composite electrode had a better response to H2O2 and NADH than CILE due to the high catalytic performance of MWCNT and the strong electronic transmission performance and collaborative catalysis of OPFP.3. Using the MWCNT/IL/graphite composite electrode(MWCNT-CILE) fabricated in Chapter 3 as a non-enzymatic glucose biosensor detect the concrntration of glucose in alkaline medium. It was observed that the novel composite electrode showed a higher response current to glucose after further oxidation in 0.5 mol/L H2SO4. Under the optimized condition, glucose was determined by chronoamperometry in in 0.1 mol/L NaOH supporting electrolyte at applied potential of 0.6V, the calibration curve is linear in the concentration range of 50.0μmol/L～8.0 mmol/L with a detection limit of 10.0μmol/L(S/N=3) and excellent sensitivity of 445.8μAmM-1 cm-2; the response time is less than 5 seconds. The non-enzymatic glucose biosensor exhibited fine reproducibility and stability. In addition, the biosensor can eliminate interference from ascorbic acid(AA) and uric acid(UA). Thus it has a practical application probable in detecting the blood sugar levels of glucose.