| This research focuses on the application of gold nanomaterials in detection.Based on biomarked gold nanofilm and colloidal gold,two detection methods suitable for food safety and health assessment have been established.First,a tumor biomarker detection strategy based on the rectifying properties of asymmetric ion channels is designed: ion channels composed of gold nanoparticle films and porous anodic aluminum oxide films have ion-selective characteristics due to their heterogeneity.Among them,the gold nanoparticle film is a single-layer porous nanofilm formed by self-assembly.The characteristic of ion selection is the difference of ion current under different bias voltages(called rectification),and the rectification ratio is used as the detection signal of the target.The aptamer of MUC1 mucin is immobilized on the surface of the gold film as a capture probe.When the target passes through the ion channel,the aptamer shields the surface charge of the gold film through hybridization with the target,thereby weakening the rectification effect of the system.Therefore,the target can be sensed by the rectification change.Through the exploration and induction of the rectification change law of the composite film in response to the corresponding target protein concentration,it is found that the detection limit of the electrochemical sensor under the single-layer gold film system is 58.25 fg/m L,However,better detection sensitivity was found under the 8-layer gold film system,and its detection limit was as low as 0.0364 fg/m L,and it has good applicability and stability in the application of real serum sample detection.The monoclonal antibody produced by the enzyme-linked immunosorbent detection technology(ELISA)was connected with colloidal gold to prepare a gold-labeled antibody,and then a food safety factor immunochromatographic detection test strip was designed.The basic principle is: The strip-shaped reagent to be reacted is fixed on the paper base,and during the chromatographic process,a specific immune response intercepts and accumulates gold nanoparticles at the band to develop color.Based on this,the obtained ?-cyfluthrin monoclonal antibody was used to prepare colloidal gold immunochromatographic test strips,and the detection ability of the test strip in three real samples of spinach,celery and tea was erified: Under optimal conditions,the values of line elimination of the test strips in the three types of samples are 0.5 ?g/m L,1.0 ?g/m L and 5.0?g/m L,respectively.The values of line elimination reflect the strength of the matrix interference in each real sample to a certain extent.The interference is the weakest in the spinach sample and the strongest in the tea sample.The detection limit of the test strip has reached the limit standard in some foods stipulated in the national standard,and it has certain practical value.In the field of food detection,the above-mentioned two detection technologies based on biomarker gold nanoparticles constructed in this research have their own advantages.Among them,the electrochemical detection technology of gold nanofilm has very high sensitivity and suitable for trace matter detection;while the colloidal gold test strip has strong specificity,short detection time,simple operation,so it is suitable for rapid detection. |
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