Fig. 1

Basic principles of detection technology. Figure 1a shows the basic principle of the HDA amplification technique: after the double-stranded DNA is deconvoluted using a helicase, a partial single-stranded sequence is created, and the single-stranded binding protein (SSB) binds to the newly formed single-stranded strand, and subsequent primers bind to the single-stranded strand and amplify it under the action of DNA polymerase. Figure 1b shows the basic principle of RPA amplification: Introduce tetrahydrofuran modification sites into the probe and modify the 3 ‘end to prevent elongation. When the probe is paired with the target DNA product amplified by the primer with a marker at the 5 ‘end, Nfo cuts the probe to form free 3’ - OH, which can be used as the primer to continue to extend, and the Synthon generation target DNA sequence; So the target DNA sequence of the offspring will also carry markers. SSB bind to the replaced DNA strand to prevent further replacement. Figure 1c shows the basic principle of the LFT technique: the digoxin antibody is fixed to the membrane in a strip (T-line) and the colloidal gold labelling reagent is adsorbed onto the gold pad. When the antigen to be tested is added to the sample pad at one end of the strip, the sample moves forward by capillary action, dissolves the colloidal gold labelling reagent on the binding pad and reacts with each other, and then moves to the area of the fixed antigen or antibody when the conjugate of the antigen to be tested and the gold labelling reagent When the sample is moved to the area of the fixed antigen or antibody, the conjugate of the test article and the gold standard reagent is specifically bound and retained on the test strip, which can be observed by the naked eye