Bio-nanopore Sensor Analysis Based On DNA Probes

In recent years,with the rapid development of various disciplines and the interdisciplinary,the level of scientific research has reached the level of micro molecules.Therefore,single molecule detection technology has become a challenging research field developed by researchers.Nano-channel single molecule detection technology is a single molecule analysis technology developed in the mid-1990s.The technique has been widely used to detect various substances,such as metal ions,proteins and polypeptides,due to its fast speed and no need of fluorescent labeling.In the past two decades,nano-channel single-molecule detection technology has made remarkable achievements and been widely used in many fields.This paper mainly focuses on the following two aspects:1.Copper ions were detected by?-hemolysin nanoporeCopper is an essential trace element for living things.In humans,a lack of copper can cause anemia,liver or kidney damage,Wilson's disease and other conditions.But too much copper can also cause diarrhea,vomiting and cirrhosis of the liver.Therefore,the detection of copper ions is of great significance to us.Here,we provide a simple and effective strategy for sensitive detection of copper ions(Cu²⁺)using?-hemolysin nanopores,and more importantly,real-time monitoring of click response.Here,we designed two single-stranded DNA?ssDNA?as preprobes,one is azide modified(C₁₀),the other is alkynyl modified?C₆?.When the presence of copper ions(Cu²⁺),two kinds of ssDNAs catalyzed by copper???azide-acetylene cycloaddition?CuAAC?click reaction,and formed a kind of bifurcation of DNA.Specific blocking current events occur when the forked DNA passes through the?-hemolysin nanopore??-HL?.This method does not require any marking or signal amplification,so as to achieve the purpose of high selectivity and sensitivity measurement of copper ions(Cu²⁺).More importantly,the?-hemolysin nanopore platform enables real-time monitoring of click reactions at the monolecular level by recording the blocking current events of bifurcated DNA.2.Multicomponent assays were performed u detected by?-hemolysin nanopore.Protein tumor markers in human body have been widely used in the early diagnosis of diseases.Three protein tumor markers,namely platelet derived factor?PDGF-BB?,vascular endothelial growth factor(VEGF₁₆₅)and Thrombin,are involved in the pathogenesis and progression of many angiogenic dependent diseases,including liver cancer.However,reliable diagnosis of complex diseases often requires simultaneous analysis of multiple markers in a single sample.A novel assay for detection of three protein tumor markers based on alpha-hemolysin nanopores was developed.Three different double-stranded DNA probes were designed to convert the protein activity information into DNA concentration signal.The three different double-stranded DNA probes were detected by using the alpha-hemolysin nanopore,producing different blocking current events,so as to achieve the purpose of simultaneous detection.This method plays an important role in detecting cancer-related tumor markers in very small samples at the same time and is of great significance for the early diagnosis of cancer.