Fe₃O₄Nanoparticles Modified Electrode For Electrochemical Detection Of Glucose

Diabetes mellitus is a common and frequently-occurring disease, which seriously menaces the healthy of human being. Diagnosis and treatment of this disease become an important issue in health-care. Glucose biosensor is widely used in clinical practice, which is characterized in high specificity, high speed, simplicity and low cost etc. In this thesis, the electrochemical glucose sensor was prepared based on magnetic nanoparticle.The first chapter of this thesis, the principles and research status of the biosensors and electrochemical biosensors were summarized, and background and applications of nanomaterials was introduced in detail.The second chapter, magnetic Fe3O4nanoparticles and chitosan microspheres were prepared, and the influencing condition was investigated. The samples were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and microscopic imaging. The results showed that the Fe3O4nanoparticles were of anti-cubic spinel structure with grain size of25nm by calculated. The saturation magnetization (Ms) was61.3emu/g without any hysteresis and coercivity. The magnetic chitosan microspheres were spherical with a size of10～20μm, suitable for construction of micro-enzyme flow reactors.The third chapter, the CS/GOx/Nafion and Fe3O4-CS/GOx/Nafion modified electrodes prepared for electrochemical detection of glucose, taking advantage of the unique characters of nanoparticle and chitosan, including the good biocompatibility and film-forming of chitosan, large specific surface area, high surface activity and excellent conductivity of Fe3O4nanoparticles.Under optimal experimental conditions, the actual plasma samples of glucose and recovery ratio were measured; interferences from ascorbic acid and uric acid were investigated.The results showed that under the same experimental conditions, Fe3O4nanoparticles can significantly enhance the glucose response current, and the detection limit was decreased. The interference of ascorbic acid and uric acid was decreased obviously. The Fe304-CS/GOx/Nafion modified electrode showed the following characteristics: easy to prepare, low detection limit, suitable to detect the low concentrations of glucose and so on, and was expected to apply in clinical diagnosis and production process monitoring.