Study Of High-Sensitivity Biosensor Based On QDsComposites

The tumor, one of the malignant diseases, is a serious threat to human life and health, a large number of research and control data indicates that early diagnosis and early treatment is the most effective way to prevent tumor and reduce mortality. Electrochemiluminescence analysis has a lot of advantages ,such as high sensitivity, simple instrumentation, fast, wide linear range and automatic and so on, So it is more and more attractive to researchers. In this paper, two new methods are developed based on the magnetic nano-composites , realizing high effective detection of CEA .The following four main parts of this thesis can be studied:1 We have dealloyed a new composite with great magnetic and ECL property. Due to its good magnetic property, all the separation research can be done without much difficulty. And a new magnetic electrode is used to attract the composites in order to develop a new kind of biosensor. It will play a important role in the future research.2 A new kind of ECL biosensor used to detect CEA is developed based on the magnetic nanocomposites with fantastic ECL property. The linear response range was between 0.064 and 10 ng mL^-1, and the detection limit was 0.032 ng mL^-1. This approach offers obvious advantages of being simpler, faster and more stable compared with other immunosensors, which possesses great potential for protein detection in clinical laboratory. 3 A new kind of ECL immunosensor is developed based on CdSe/ZnS/Fe3O4/CNTs/IL film composite. With its good ECL properties, biocompatibility and stability, new kinds of biosensor can be prepared. The ECL intensity varied linearly with the concentration of CEA between 0.001 ng mL^-1 and 100 ng mL^-1,and the detection limit was 0.0004 ng mL^-1.4 A novel dendrimers/CdSe-ZnS-QD nano-clusters was newly explored and used as amplified ECL signal probe for versatile assays of cancer cells for the first time. This study has several significant advantages. Firstly, a large number of CdSe-ZnS QDs were assembled onto the novel dendrimer NCs due to the many functional amine groups of NCs, which could greatly amplify the QDs ECL signals. Secondly, high specificity of aptamers to target cells and bio-bar-code technique to avoid cross-reaction were used in the assays, which much favored for the improvement of selectivity and sensitivity. It is such an important research that has promising applications for the early and accurate detection of cancer cells.