Study Of High-sensitivity Biosensor Based On Nanomaterials

The main idea of the research was to explore novel nanomaterials and put them into the use of preparing sensitive biosensor for the determination of bio-macromolecular. Compared with traditional biosensors, the novel biosensors showed high sensitivity, rapidity and simplicity so that it could be widely used in the field of biological analysis. This paper consists of two parts besides the preface:1. A novel and sensitive electrochemiluminescence (ECL) immunosensor based on CdS quantum dots (QDs)-carbon nanotubes (CNTs) and gold nanoparticles-chitosan (GNPs-CHIT) was presented. CdS QDs ECL was much enhanced by combing polydiallyldimethylammonium chloride functionalized CNTs. GNPs-CHIT nanohybrids was used to construct an effective antibody immobilization matrix with excellent stability and bioactivity. The principle of ECL detection for target human IgG is based on the increment of steric hindrance after immunoreaction, which resulted in the decrease in ECL intensity. The linear response range was between 0.006 and 150 ng mL-1, and the detection limit was 0.001 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.2. The highly intense ECL from a unique nanostructure of Au/silica/CdSe-CdS-QDs was developed, and an ultrasensitive ECL immunosensor for CEA detection was prepared. Several advantages of the proposed method should be highlighted. Firstly, this is the first report of a greatly enhanced ECL from a new class of QDs/metal super structure which was explored and applied to biosensing, which opened a new avenue to enhanced QD ECL. Secondly, the unique superstructure not only enhanced the ECL intensity by 17 orders of magnitude, compared with the pure QDs, but also greatly decreased the toxicity, which provided an ideal alternative ECL reagent in bioanalysis. Thirdly, both APS and gold NPs as cross-linkers for Ab immobilization could significantly amplify the ECL signal. Fourthly, integrating the multiple-amplification techniques, it had a highly sensitive ECL detection with specific immunoreaction, the immunosensor showed remarkable enhancement in both detection sensitivity and linear range, which might become an attractive approach for clinical detection of protein. The ECL intensity varied linearly with the concentration of CEA between 0.32 pg mL-1 and 10 ng mL-1,and the detection limit was 0.064 pg mL-1.