Study On Rapid Nucleic Acid Detection Based On Nucleic Acid Nanostructure And Potential Assistance

Rapid nucleic acid detection for disease identification can greatly reduce the waiting time of patients in return avoid missing the best treatment time.Therefore,the rapid detection of nucleic acid is of great significance to life and health.Among the existing nucleic acid detection technologies,gene sequencing and nucleic acid amplification technologies all require a long detection time recorded in hours.Electrochemical detection has been widely studied and applied to nucleic acid detection because of its advantages of high sensitivity,simplicity and rapidity.In this paper,a series of studies for rapid nucleic acid detection based on nucleic acid nanostructure and potential assistance are carried out based on electrochemistry.At first,the DNA tetrahedron has developed a broad spectrum of applications in biosensor construction thanks to its excellent mechanical rigidity and structural stability.However,how to construct a highly sensitive biosensor using a DNA tetrahedron is still a challenge.In this work,an ultrasensitive electrochemical biosensor based on a DNA tetrahedral nanostructure was developed with the help of synergy from proximity-dependent hybridization.To decrease the steric hindrance of DNA tetrahedra to proximity-dependent hybridization,the detection signal was set on the inclined side chain structure of a DNA tetrahedral sensing system.Additionally,when the target hybridized with the DNA probe,the ferrocene(Fc)labeled on the end of the DNA probe was driven close to the surface of the biosensor,providing a sensitive faradaic current.The experimental results exhibited a good linear relationship from 1 fM to 10 pM with a linear correlation coefficient of 0.9977,and a high sensitivity with a detection limit of 0.2 fM.Our DNA biosensor also showed good stability according to electrode characterization and target detection at different time scales and the anti-jamming capabilities in a complicated biological extraction environment were excellent.The electrochemical sensing system established here has greatly improved the detection sensitivity of a DNA biosensor based on a DNA tetrahedron,which will further promote its practical applications.However,nucleic acid detection techniques based on nucleic acid hybridization are mostly dependent on passive hybridization which require hours for nucleic acid hybridization.While with the help of electric field,the nucleic acid migration rate and collision probability increase,which can greatly accelerate the hybridization reaction between nucleic acids.Herein,a novel potential-assisted enzyme-free ratiometric electrochemical biosensor was established.By compressing hybridization time from hours to 90 s,the biosensor achieved ultra-fast nucleic acid detection.In addition,the established ratiometric biosensor exhibited a good linear relationship in the concentration range of 1.0×10-13 M,1.0×10-12 M,1.0×10-11 M,1.0×10-10 M,1.0×10-10 M,and 1.0×10-9 M.The detection limit(LOD)is 1.2×10-14 M(S/N=3),showing a higher sensitivity than that under single signal detection.This method avoided the use of enzymes,and avoided the refrigeration transportation difficulty and high price caused by the use of enzymes,reducing the experimental cost And no nucleic acid amplification steps are required in the whole experiment,which reduces the possibility of aerosol contamination due to improper operation during the experiment.This method provides a theoretical basis for the application of ultra-fast electrochemical biosensor in the field detection of nucleic acid,and will play an important role in the rapid screening of DNA-induced diseases.