Construction Of Direct Electrochemical DNA Sensor And Its Application In Deep Sea

DNA electrochemical biosensors are widely used in genomics,environmental monitoring,drug screening and food analysis,especially in the field of biomedicine and biology.Thus,it develops rapidly and has a promising applications in clinical diagnosis.Electrochemical signals usually come from enzyme/mimic catalysis and external/labeling electrochemical active molecules.In this thesis,the electrochemical active molecule labeled DNA is used as a direct signal for readout,the DNA walker with multiple DNAzyme cores is generated by rolling circle amplification(RCA)for signal amplification,achieving sensitive and selective detection of the target.Simultaneously,reagentless electrochemical DNA sensor based on direct signal combines the target-induced configuration switch for in-situ detection of functional genes in the deep sea.The specific works are listed as follows:(1)A multipedal DNA walker(m-DNA walker)with multiple DNAzyme cores was constructed with the assistance of RCA for highly sensitive electrochemical biosensing.We designed a three component DNA complex as a swing strand,the RCA primer and a recognition element to target in the DNA walker system.Comparing with the single foot DNA walker,the m-DNA walker protocol not only demonstrated the rapid cleavage rate but also proved a low ratio of the swing strand to the track.Therefore,this work shows a novel construction method of a binding multipedal DNA walker based on multiple DNAzyme cores,and opens up a new direction for signal amplification in biosensing.(2)A reagentless multiple channel DNA electrochemical platform was fabricated for in-situ simultaneous detection of functional targets in the deep sea.According to the target sequence,the DNA probe was designed and tested at low temperature and complex environment.In terms of instrument and encapsulation,different modules are developed around data transmission,storage and instrument control to determine the structure and details of the biosensor.Also,the encapsulation and pressure-resistant experiments were conducted.After that,it is expected to carry out the alignment experiment,and fianlly realize the in-situ detection of the targets in the deep sea.