| Nanosturctured materials have special physical and chemical properties, which can promote the direct electron transfer between electrode surface and the active center of biomolecule and maintain biomolecule's biological activities as well. Therefore, the application of nano-technology on electrochemical analysis of biological molecules is a promising field, in which we can establish some new technologies, new theories and new methods.In this thesis, water soluble CdTe quantum dot (QD) was prepared and some biosensors were constructed based on it. The electrochemical behaviors and catalytic properties of the biosensors were studied. The main contents and results are summarized as follow:(1) Glucose oxidase (GOD) was immobilized on the surface of water-soluble CdTe nanoparticles to fabricate GOD CdTe QD carbon paste electrode (GOD/CdTe/CPE). The direct electrochemistry of GOD was realized by thenanocomposite modified electrode. The modified electrode can be used as a sensor for glucose and the linear range of detection was 0.05 mM 0.32 mM with a detection limit of 8.4×10-7 M. The sensor exhibited high sensitivity with good reproducibility and stability.(2) Direct electrochemistry of horseradish peroxidase (HRP) was realized by the immobilization on the surface of water-soluble CdTe nanoparticles in carbon paste matrix. Based on it, a sensor for hydrogen peroxide determination is achieved. The linear range of detection was 1.0×10-51.4×10-4 M, with a detection limit of 0.02 mM. The sensor exhibited high sensitivity, good reproducibility, and long term stability.(3) Myoglobin (Mb) was immobilized on the surface of water-soluble CdTe QDs, and its direct electrochemistry was realized. The resulted Mb CdTe QD carbon paste modified electrode (Mb/CdTe/CPE) can be used as a biosensor for hydrogen peroxide detection. The calibration ranges from 5.0×10-5 M to 3.0×10-4 M, with a detection limit of 2.8×10-5 M. The biosensor exhibits high sensitivity, good reproducibility and stability. |
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