| 1980s, Nanotechnology was an emerging subject developed from multi-principles, and it enjoyed a wide application prospect in materials, environment, chemistry, etc. Recently, nanotechnology gradually infiltrates through sciences and medicine field. The use of nano-biotechnology to research and resolve the concerned major issues, and to promote bio-nanotechnology and related technology, are becoming an important frontier of current theories in which the applications of immune nanotechnology in life sciences and medicine field attract greater attention. 1990s, colloidal gold immunochromatographic assay (GICA) developed from an solid-phase membrane immunoassay on the basis of the combination of immunogold technology and chromatography. In this paper, we studied the application of GICA technology in the detection of tumor markers, such as alpha-fetoprotein, carcinoembryonic antigen and fibronectin.(1) In this paper, Frens method was used to prepare colloidal golds with three different diameters of 20nm, 40nm, 70nm. They were prepared by controlled reduction of gold chloride with 1% sodium citrate solution according to the procedure described by Frens. Experimental results showed that the 20nm, 40nm colloidal golds were more suitable for doing immunochromatographic assay experiment. From the TEM map, we can clearly see that the 20nm colloidal gold particles have uniform size and good dispersion, the maximum visible absorption wavelength was at 521nm, a narrow peak shape also showed that the particles have relatively uniform particle size. The maximum absorption wavelength of 40nm colloidal golds was at 527nm.(2)Immunogold labeling technique was a new type of immune marking technology, which based on colloidal gold as a tracer. It was applied in antigen-antibody reaction. Because colloidal gold carried a negative charge in alkaline environment, under appropriate conditions,it can form firm combination with protein molecules through physical adsorption. In this paper, visual method was used to study the best pH and amount of antibody of the combination between colloidal gold and alpha-fetoprotein, carcinoembryonic antigen and fibronectin. Experimental results showed that the best pH of them was 9, the best amount of them were respectively 14.4ug·ml-1, 14.4ug·ml-1, 7.2ug·ml-1.(3) The reaction between antigen and antibody occured on antigen epitopes and antibody epitopes of the antigen-binding site, they are the complementary relationship in chemical structure and of spatial configuration. So the reaction of antigen-antibody is of high specificity, and a antigen molecule in generally has multiple epitopes, it can be combined with a number of antibody molecules. In this paper, double antibody sandwish method was used. Firstly, the specific antibody was fixed on nitrocellulose membrane, and immune colloidal gold was dried on conjugate pad; Secondly, absorbent paper, NC membrane, conjugate pad, sample pad were assembled on PVC board; Thirdly, the board was cut into 4mm wide test strips, then put them in detection cards. The experimental results showed that the use of the test strips was simple, rapid, the sensitivity of AFP, CEA and FN test strips were respectively 20ng·ml-1, 5 ng·ml-1, 100 ng·ml-1, they were of good stability and all achieved clinical requirements. There was no cross reaction with PSA, CA125, CA15-3, Ferritin, Human Albumin.
|
PDF Full Text Request