Application Study Of Biosensor Based On AC Electrokinetic Effect In Food Safety Detection

Food safety is closely related to human health.How to detect the harmful substances in food quickly and efficiently has become the main challenges for the researchers.At present,traditional detection technology of food safety has some disadvantages,such as complicated operation,expensive equipment and long detection time,while the emergence of biosensors have made further progress in food safety detection.However,the traditional biosensors rely on the natural diffusion movement of biomolecules,and the detection time is too long,which greatly limits the development of point-of-care detection.In order to solve the problems in the traditional detection technology for food safety and the existing biosensors,in this dissertation,a biosensor based on alternating current electrokinetic effect is studied.And it can accelerate the enrichment of the measured target molecules and realize the quantitative detection of biomolecules by detecting the changes of interface capacitance and other electrical parameters of interdigital electrodes.In this dissertation,the relevant theories of alternating current electrokinetic effect were firstly analyzed,and then the corresponding recognition mechanism was designed for two markers,bisphenol A and nitrite,which have completely different properties.Then the corresponding biosensors were constructed to realize the quantitative detection of these two markers.The self-assembly technology was used in detection of bisphenol A,a self-assembled monolayer was established on the surface of the interdigital electrodes,and then antibody of bisphenol A was coated on the self-assembled monolayer.The enrichment of bisphenol A was realized by using alternating current electrokinetic effect.At the same time,the change signal of the sensing electrode's capacitance was obtained.And the detection of bisphenol A at nanomolar levels was successfully achieved within1 minute by analyzing the law of change.Sensitive membrane sensing technology was used in the detection of nitrite.The film of chrome-black T was modified to the surface of the nanogold film interdigital electrodes firstly,and then the film of chrome-black T had the precise identification to nitrite ions.The rapid enrichment of nitrite ions was realized by using alternating current electrokinetic effect.Detection of capacitance signal after the film of chrome-black T combined with nitrite ions was realized by the interdigital electrodes.The detection limit of 10^-5mol/L.Compared with the traditional detection technology of food safety,the biosensor based on the alternating current electrokinetic effect proposed in this dissertation not only has the advantages of high sensitivity and selectivity,but also the detection time is much shorter(only 1 minute),the experimental equipment and the operation are simpler.These advantages are beneficial to point-of-care detection of food safety.