Research And Development Of Colloidal Gold-based Immuochromatography Assay Strip Of HCG

In this thesis, monodispersional nanogold collid was synthesized firstly according to Frens Method. The optimal conditions were established as follows: The electrothermal box was used as heater; reducing reagent must enter quickly and once-off; for colloidal gold of 20 nm, we used reducing reagent with 1ml as colloidal gold of 40 nm we used reducing reagent with 0.7 ml; mixed acutely; reducing reagent was added after HAuCl4 keeped boiling for 2 min; use glass stirrer; reducing reagent was warmed up 80℃before adding. Then using UV-visible light measurements and transmission electron microscopy (TEM) to assess colloidal gold's quality. Preparation of the antibody-colloidal gold probe (conjugate) specific to hCG and its purified method was also presented in this paper. Nanogold particles combined with antibodies were characterized by UV-visible light absorption spectra and fluorescence spectroscopy.In addition, the effect of Tween-20, sucrose, PEG and BSA in treating reagent and proteide's concentration, ion strength on NC membrane are confirmed. With visual observation, we ensured two test limit for hCG. For 25mIU/ml limit of hCG: the diameter of colloidal gold is 20nm, conjugate's OD520 nm is 5.0, test line proteide's concentration is 1.0mg/ml, test line's NaCl concentration is 8.5g/L, conjugate's pH is 9.0. And for 1500mIU/ml limir of hCG: the diameter of colloidal gold is 40nm, conjugate's OD520 nm is 2.0, test line proteide's concentration is 0.5mg/ml, test line's NaCl concentration is 9.5g/L, conjugate's pH is 9.2. The stabilization of the strip is reliable after high temperature and three months. The cross-reaction exprement and the repeation exprement of the stips are available for clinic test. Also the strip's result showed the NC membrane made in China was as good as import NC membrane.