Later-flow Nano Gold-based Immunoassay For The Rapid Quantitative Detection With Tumor Makers

1980s, Nanotechnology was an emerging subject developed from multi-principles. And, the nano-immunochromatographic technology emerged in 1990s.It has found favor with people because of its fast, simple, visual and economical. Gold immunochromatographic assay (GICA) developed from an solid-phase membrane immunoassay on the basis of the combination of immunogold technology and chromatography. Then, the current GICA can only be applied to qualitative and semiquantitative detection, it cannot satisfy the demand of clinical quantitative detection. So, immunochromatographic assay is developing head for the direction of quantification, improving sensitivity and multivariate analysis. In this paper, we studied the application of GICA technology for the rapid quantitative detection with tumor markers, such as fibronectin and carcinoembryonic antigen. (1) 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 nano 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 nano gold and fibronectin and carcinoembryonic antigen. Experimental results showed that the best pH of them was 9, the best amount of them were respectively 7.2ug·ml-1,14.4ug·ml-1.(2) In this paper, double antibody sandwish method was used. Firstly, the specific antibody was fixed on nitrocellulose membrane, then put them in detection cards. The detection cards were inserted into the gold-bio apparatus for quantitative detection. The experimental results showed that the use of the test strips was simple, rapid, the sensitivity of FN and CEA test strips were respectively 200ng·ml-1,5 ng·ml-1, and the quantitative curve appered well-behaved linearity. They were of good stability, no cross reaction and all achieved clinical requirements.