Study On Fluorescent Europium Nanoparticles And Their Application In Immunoassay And The Development Of Functional Bitter Melon Beverage

The paper has studied preparation and characterization of polyelectrolyte coated fluorescent silica nanoparticles and their application in immunoassay in the first section.The new type of fluorescent nanolabel with its special quantum size effect and small dimension effect exhibits many different optical characteristics compared to the homogeneous single-molecule or large object, and thus has attracted great attention in biological research. In this paper, uniform silica nanoparticles have been synthetized via St?ber method, and fluorescent europium chelate with three kinds of ligand (i.e. dibenzoylmethane, phenanthroline and acrylic acid) has been prepared. The hydrosoluble silica nanoparticles adsorbed liposoluble europium chelate with strong fluorescence in the aid of ultrasonication and phase-transfer solvent, and were then coated by cationic polyelectrolyte polydiallyldimethylammonium chloride (PDAC) and anionic polyelectrolyte poly(acrylic acid) (PAA) one layer by one layer. The obtained fluorescent nanoparticles were charactered by transmission electron microscopy, ultraviolet spectrophotometer, infrared spectrophotometer, ?uorescence spectrophotometer, and Zeta potential. These nanoparticles have the advantages of uniform size, strong ?uorescence, good photostability and leakage free. Futhermore, the nanoparticles with rich carboxy groups resulting from PAA coated on their surfaces made the surface modification and bioconjugation easier. These properties altogether suggest their great potential in biology and medicine.Then, the fluorescent nanoparticles were used as probe and the magnetic microspheres were used as carrier. They were activaed by the carbodiimide cross-link technique, resulting in the conjunction of antibodies on them. And the immune composite was obtained through antigen-antibody reaction, which was finally used to detect the hepatitis b surface antigen.In the second section, the bitter melon (Momodica charanitia L.), a kind of healthy food, and the other three kinds of Chinese crude drug were used as the raw material to develop a kind of new bitter melon beverage. Firstly, the study focused on the main functional component. The method of detecting main component was established and the spectrophotometry was suitable for the determination of functional component. Then, based on the extraction rate, single-factor trial and orthogonal test were used to choose the optimum extraction process. And two optimum extraction processes were obtained. The taste and stability were studied in the present paper, involving clarification, elimination of bitter taste, and mixtion of the beverage. The processing techniques were optimized: using chitosan to clarify beverage, addingβ- cyclodextrin for embedding and using citric acid and sucrose to adjust the taste.The beverage studied in this paper with specific scent was delicate, faintly bitter, cool and refreshing , which is a kind of potential salable beverage.