Research On Affinity Capacitive Biosensor Based On AC Electrokinetic Effect

Human health issues have always been the focus of the world,and the detection of biomarkers and disease pathogens closely related to human health has become the primary problem that humans need to face.As an advantageous tool for biomolecular detection,biosensors have made outstanding contributions to the cause of human health,but there are still many shortcomings.Especially in the field of point of care testing,the existing biosensors have the disadvantages of long detection time,labeling,complicated operation,high instrument requirements and high economic cost.In order to solve this series of thorny problems in biosensors,this paper will study affinity biosensors with advantages such as fast,label-free and high sensitivity.The alternating current electrokinetic effect excited by the alternating current and the interdigital electrodes are employed to accelerate the enrichment of biomolecules,and the quantitative detection of biomolecules is realized by measuring the interface capacitance of the electrode surface.In this paper,after analyzing the related theories of AC electrokinetic effect and capacitive sensing,the corresponding affinity sensors are designed for the two types of analytes,mi RNA-16 b and pathogen Escherichia coli.And the sensors are used for detecting these biomolecules.For the detection of mi RNA-16b,a cow's pregnancy marker,a 400?m wide PCB gold-plated interdigitated electrode coated DNA probe on the surface was used to detect mi RNA-16 b.The detection limit arrived fm scale,meanwhile,high sensitivity and high specificity was achieved.For the detection of pathogenic Escherichia coli,a 5?m wide glass substrate gold-plated interdigitated electrode coated nucleic acid as aptamer on the surface was used to detect E.coli,and the concentration of 100 CFU/ml E.coli was successfully detected.Compared with the traditional diagnostic system,the affinity capacitive biosensor based on AC electrokinetic effect proposed in this paper achieves high sensitivity and high specificity detection,and requires shorter detection time(30 seconds),lower cost of reagent and equipment and also device design and experimental operation are much simpler.These advantages make large-scale,rapid,on-site,real-time detection of biomarkers and disease pathogens possible in the future.