| DNA is a fascinating biopolymer that can confer many special functions on nanomaterials due to its highly programmable properties and unique interactions at the bio-nano interface.In the molecular structure of DNA,two strands of deoxynucleotides are coiled around a common central axis,forming a double helix.DNA has perfect identifying characteristics and can be programmed and assembled in expected ways to form special structures with unique physical and chemical properties.The deoxyribose-phosphate chain is on the outside of the helix,and the base is facing in.As a unique biomaterial,DNA can be made into signal probe and capture probe after special labeling and modification by chemical methods,which can make it have more special properties.It can be applied in various sensing strategies combined with different materials.The field detection of transgenic detection and bacterial identification requires high efficiency,low consumption,convenience and accuracy of detection methods.Traditional methods are difficult to meet the requirements of field detection,and it is difficult to develop effective field detection methods.However,the electrochemical nucleic acid biosensor has the advantages of low cost,time-saving,portability,convenient operation and high sensitivity in nucleic acid target detection and analysis,so it has great application potential in field detection.Firstly,in order to develop our 2-D DNA probe electrochemical biosensor,we artificially synthesized RNAi transgenic maize plasmid DNA reference samples with stable properties,correct sequences and meeting requirements through a series of processes including design,verification,preparation and evaluation.From this DNA reference sample,ds RNA samples of in vitro transcription were successfully synthesized as the development standard sample of our sensor.Then,we developed an electrochemical biosensor（E-Biosensor）based on Poly A DNA probe to design and synthesize the RNAi transgenic maize ds RNA sample as the simulation detection target.The low concentration of RNAi mediated transgenic maize RNA was detected.The practicability of the method was verified in the analysis of long stem loop ds RNA at 1 p M-300 n M,and it had a good selectivity for the direct extraction of total RNA from transgenic maize.Moreover,by adding different signal probes,our sensor achieves the structural analysis of target RNA with different structures for the first time.It is worth mentioning that when RT-RPA technology is combined with our biosensor,the sensitivity is greatly improved and the detection limit is as low as 10 a M.Then,in order to solve the problem of bacterial recognition,we constructed a non-specific sensing array that adsorbed DNA fluorescent probes.The fluorescent sensor array consists of specific nanoreceptors（2D-NPs）coupled with DNA probes with eight binary-coded sequences for the recognition of protein markers and different bacterial pathogens.The non-specific sensing method can obtain a data set with the characteristics of the detection object,which can provide comprehensive information about the target molecule.Because the method is a nonspecific detection of a specific target,they can take multiple readings of a single molecule and collect large amounts of data to provide more detailed information and characteristic response patterns for analysis.This strategy improves the accuracy and reproducibility of the sensing technology with almost no bias.The hierarchical clustering tree based on Euclidean distance is established by Ward method.In summary,we have used n GO/SSDNA-FAM conjugates to provide rapid and sensitive bacterial fluorescence sensing.By using an array composed of n GO /ss DNA-TAMRA conjugates,unique fluorescent patterns were generated for different bacteria.The sensor array has shown excellent performance in distinguishing between pure bacteria and even mixed bacteria,with a classification accuracy of 100 percent. |
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