10 results about "DNA walker" patented technology

The application discloses a three-dimensional DNA walker biosensor based on SERS as well as a preparation method and application thereof, relates to the technical field of biosensors, and is used for detecting target lncRNA. The biosensor comprises an MB\@DNA\@Au\@Ag compound, a 3D DNA walker and an aptamer. The nucleotide sequence of the ssDNA linker is shown in SEQ ID NO:1. The nucleotide sequence of the 3D DNA walker is SEQ ID NO:7 or SEQ ID NO:8 or a corresponding reverse complementary sequence. The biosensor realizes isothermal autonomous walking of the three-dimensional DNA walker and releases MGITC coded Au@Ag SERS nanolabels through TapSAKI triggered strand displacement and Nb.BbvCI enzymatic cleavage, thereby generating a'signal-on' type Raman output. The detection limit of the biosensor for the AKI early diagnosis potential biomarker TapSAKI is as low as 1.16 fM, and reliable quantification can be realized in the range of 4.30-850 fM. Compared with RT-qPCR (LOD is about 0.26 pM), the biosensor is improved by about 2.3 orders of magnitude in the detection limit of molar concentration.

This application discloses a colorimetric detection kit for hepatitis D virus based on a logic-manipulated three-dimensional DNA walker and its application. The colorimetric detection kit includes a DNA walker comprising a walking strand W, a first locking strand L1, a second locking strand L2, an orbital strand Tr, and gold nanoparticles (AuNPs). The detection method involves mixing the sample to be tested with the DNA walker and adding a Mg-containing... 2+ After incubating in buffer solution at room temperature for 1 hour, observe the color change or measure A. 620 / A 520 Quantification is performed using ratios. The detection kit and method in this application require no reverse transcription, no protease, and no temperature control equipment. The results are visible to the naked eye and the operation is simple. The dual-target "AND" logic design provides high specificity.

This invention relates to the field of biodetection technology, specifically to a non-isolated digital multiplex detection method based on a DNA walker and TdT enzyme amplification. The method first utilizes coding microspheres with capture elements coupled to their surface to specifically bind to target miRNAs or proteins in the sample; then, specific guide DNA (gDNA) corresponding to the target molecule is released through enzymatic digestion or thermal denaturation; the gDNA then... Pf Under the action of Ago endonuclease, the DNA walker on the surface of the encoded microspheres is activated, cyclically cutting the orbital strand to generate multiple DNA fragments with 3'-hydroxyl ends. Finally, TdT enzyme is used to extend fluorescently labeled nucleotides at the hydroxyl ends, achieving in-situ signal amplification, and digital quantitative analysis is performed on the fluorescence signal of the encoded microspheres. This invention achieves high-sensitivity detection of multiple targets in a single reaction without chamber isolation, with detection limits for each target molecule reaching the fM or fg / mL level, providing an effective technical means for the early screening of major diseases such as Alzheimer's.

The application discloses a method for fluorescent analysis of APE1 enzyme based on a three-dimensional multi-legged DNA walker constructed by double gold balls. AuNPs as a basis to construct two systems, one of which is to modify the walker chain to AuNPs according to 500:1 to serve as a walker, named AuNP-W; the other is to modify the Sub chain to AuNPs according to 1000:1 to serve as a track, named AuNP-T. In addition, endogenous ATP serves as the driving force for the continuous walking of the DNA walker. 2+ buffer to anneal AuNP-W and Block chain to form double-stranded AuNP-W / B; use TAE / Mg 2+ buffer to anneal AuNP-T and ATP aptamer chain Apt (containing FAM fluorophore) to form double-stranded AuNP-S / A; mix AuNP-W / B, AuNP-S / A and ATP according to a certain proportion to obtain a biosensor for fluorescent analysis and detection of APE1 enzyme, add APE1 enzyme with different concentrations, and perform real-time fluorescent quantitative analysis under the condition of 37 DEG C to measure the fluorescence curves corresponding to APE1 enzyme with different concentrations; add the sample to be measured into the biosensor for fluorescent analysis and detection of APE1, set the same detection conditions, measure the fluorescence curves of different samples to be measured, and obtain the specific detection results of APE1 enzyme.

The invention discloses a circulating miR-375 high-sensitivity electrochemical detection device and a circulating miR-375 high-sensitivity electrochemical detection method based on a three-foot DNA walker. According to the device, a large number of probes B are generated through a strand displacement amplification technology, and chain extension and specific splitting decomposition of Nb. BbvCI in the presence of target miR-375 are initiated by utilizing Klenow polymerase. After the probe B is hybridized with the Block chain, the inactive three-chain DNA walker is activated. The activated walker moves on a gold electrode interface supported by the TDN, and the Fc labeled probe is cracked to generate an electrochemical signal. And a square wave voltammetry method is adopted to detect signals, so that high-sensitivity detection of the circulating miR-375 is realized. The method has high selectivity, only miR-375 can cause obvious signal change, and other interference sequences and mismatched sequences are not obviously influenced. The method shows good performance in clinical samples, can distinguish glioma patients in different stages, and has important clinical application value.

The application belongs to the technical field of cell detection, and particularly relates to a bionic Taraxacum isothermal amplification system and application thereof. The bionic Taraxacum isothermal amplification system is composed of six-legged DNA walker, nonlinear DNA self-assembly technology and an asymmetric carrier, AuFe Janus nanoparticles, with high signal probe loading efficiency, and shows significant amplification efficiency. Compared with a traditional isothermal amplification system, the amplification efficiency of the bionic Taraxacum isothermal amplification system is increased by about 6.72 times.

The invention discloses a preparation method of a spherical DNA nano machine for detecting O6-methylguanine-DNA methyltransferase (MGMT) and application of the spherical DNA nano machine in detection of the expression level of tumor cells MGMT. The method comprises the following steps: firstly, designing a DNA walker with MGMT recognition and signal amplification functions, and fixing the DNA walker on the surface of a gold nanosphere through sulfydryl modification to construct a spherical DNA nanomachine; when the MGMT interacts with a DNA Walker chain, a methylated basic group G on DNA enzyme can be repaired, so that the activity of the DNA enzyme is recovered, an enzyme digestion reaction is initiated, a Track chain marked with a fluorophore is broken and released, a fluorescence signal change is generated, and high-sensitivity detection of the MGMT is realized. The method can effectively detect the MGMT protein in a low concentration range, and has a good biomedical application prospect.

The application relates to a preparation method and application of an electrochemical sensor for sensitive detection of lead ions based on a metal nanocomposite. 2+ The introduction of the target Pb 2+ triggers the S-DNA cleavage of the DNAzyme to cut off a single-strand DNA, and simultaneously initiates the DNA Walker effect to obtain a large amount of single-strand DNA. The supernatant after magnetic separation is added dropwise on an electrode modified with HP1, after incubation, the single-strand DNA serves as an initiation chain to initiate the CHA signal amplification reaction, so that more and more signal probes are connected to the electrode surface, and the electrical signal in the system is enhanced. The quantitative analysis of lead ions is realized by using the change of the electrical signal corresponding to the change of the methylene blue concentration on the electrode surface before and after the addition of Pb 2+ The prepared electrochemical sensor has high sensitivity, a wide detection range, good selectivity and excellent practical application capability.

This invention relates to a fluorescence detection method for Staphylococcus aureus based on a navigation-type DNA walker and a fluorescence regulation mechanism. It utilizes a dual-enzyme recognition reaction system of exonuclease I and exonuclease III to identify and distinguish samples containing / without Staphylococcus aureus. Samples containing Staphylococcus aureus generate an efficient fuel chain in the dual-enzyme recognition reaction system, causing the DNA walker to shift along its trajectory, further triggering fluorescence resonance energy transfer, ultimately obtaining an amplified fluorescence signal correlated with the target concentration. The concentration of Staphylococcus aureus in the contaminated sample is determined based on the relationship between fluorescence intensity and Staphylococcus aureus concentration. This invention improves the controllability and efficiency of the DNA walker, reducing the risk of derailment and interruption. The detection range is 9-90 CFU / mL. ‑1 Within its detection range, the accuracy of quantitative detection reaches 100%, and the reproducibility and recovery rate exceed 98%, capable of detecting substances containing 2 CFU / mL. ‑1 The sample of Staphylococcus aureus.

The invention relates to an aptamer for specifically recognizing tetrodotoxin and application of the aptamer, and belongs to the technical field of detection. The cyclic divalent aptamer disclosed by the invention has good affinity and specificity and good thermal stability, is not interfered by impurities such as ion strength and protein in globefish meat and serum during tetrodotoxin detection, and has high conformational stability. Based on the annular bivalent aptamer, the invention further designs an aptamer sensor based on a 3D-DNA walker, the aptamer sensor can specifically detect low-concentration tetrodotoxin, the detection limit is 0.02 ng / mL, the detection time is 1 h, and the detection sensitivity is high. Other marine toxins such as gonyautoxin (GTX), dinophysiotoxin (DTX), sea anemone toxin II (ATX-II), anabaena toxin-a (ATX-a) and microcystin (MC-LR) cannot be detected, and the specificity is good.