20 results about "Dna hairpin" patented technology

The present invention discloses a DNA nanomachine responsive to endogenous human apurinic / apyrimidinic nuclease, a preparation method and an application thereof, wherein the DNA nanomachine is composed of a DNA tetrahedron, an enzyme-activated DNA hairpin E-H1 and a DNA hairpin H2 labeled with Cy5 and BHQ2. When APE1 and target miR-224 coexist, the AP site in E-H1 is specifically recognized and cleaved, triggering a strand displacement reaction, resulting in the separation of Cy5 and BHQ2, and generating an enhanced fluorescence signal. The DNA nanomachine of the present invention has the advantages of high specificity, simple operation, cost-effectiveness and biocompatibility, and provides a new tool for early diagnosis and treatment monitoring of tumors.

The invention discloses a DNA tetrahedron gating logic nanometer machine and a preparation method and application thereof, and belongs to the technical field of biomedicine. According to the invention, a DNA tetrahedron gating logic nanometer machine DTDN is constructed, and the DNA tetrahedron gating logic nanometer machine DTDN is composed of two DNA tetrahedron nanometer structures functionalized by AS1411 aptamers. Each tetrahedron is loaded with a functional DNA hairpin structure, and the structure is composed of a stem-loop structure and an extended single-stranded tail containing an AP site. The framework gating strategy of DTDN enables efficient delivery of functional DNA hairpins, and also prevents signal leakage by blocking cohesive end sequences of HCR reactions. The cascade activated logic loop has high specificity and anti-interference capability, and can accurately activate a downstream regulation and control path. Therefore, the DTDN realizes synchronization of imaging and regulation, and a programmable, safe and accurate nucleic acid nano platform is provided for cancer diagnosis and accurate treatment based on a cGAS-STING signal channel.

The invention belongs to the technical field of nucleic acid detection and mass spectrometry, and particularly relates to a nucleic acid multiple analysis and detection platform based on full DNA mass coding and normal pressure mass spectrometry detection, and the platform constructs a non-enzyme cascade amplification system completely composed of DNA molecules. A group of DNA hairpin structure chains capable of responding to a target miRNA to be detected to trigger a hybridization chain reaction are designed, a DNA enzyme core with catalytic activity is formed in a product obtained by the hybridization chain reaction of the DNA hairpin structure chains and the target miRNA to be detected, the DNA enzyme can break a substrate chain and release a DNA fragment with characteristic quality coding, and a signal is directly read by virtue of a normal pressure mass spectrum, so that the target miRNA to be detected can be detected. Parallel recognition and quantitative detection of multiple miRNAs are realized; the reaction can be spontaneously completed in a homogeneous aqueous solution system, parallel recognition and accurate quantification of multiple miRNA molecules are realized, and a novel detection method with high compatibility and high sensitivity is provided for high-throughput nucleic acid detection and multi-marker diagnosis.

The present invention provides a circular DNA template precursor for detecting Clostridium difficile, a preparation method thereof and an application thereof. The circular DNA template precursor includes a three-dimensional self-assembly reaction using a reaction system composed of H1 and H2 hairpin probes and a trigger strand Trigger. The three-dimensional self-assembly reaction includes Trigger triggering the H1 hairpin structure to form a T / H1 intermediate, the H1 hairpin structure being unfolded and binding to H2 to produce an H1 / H2 structure, and the DNA template of H2 being cyclized to obtain the circular DNA template precursor. When Clostridium difficile toxin is present, the trigger strand Trigger can be released again, and can continuously catalyze the hairpin structure of the H1 DNA hairpin probe without being consumed. By adopting the technical scheme of the present invention, signal cascade three-stage amplification is realized through three-dimensional self-assembly-amplification reaction and silver-enhanced gold nanoparticles, so as to realize highly sensitive and highly specific detection of Clostridium difficile infection.

The present invention discloses a porous silicon deoxyribozyme fluorescent probe and its application in evaluating the anticancer activity of traditional Chinese medicine. The fluorescent probe comprises amino-modified porous silica nanoparticles, fluorescent molecules loaded in the nanoparticle pores, and DNA hairpins HP1 and HP2 covalently linked to the nanoparticle surface. The HP1 sequence contains a complementary sequence to the microRNA to be detected, and the HP2 sequence contains a zinc ion-specific deoxyribozyme cleavage site. After HP1 binds to the microRNA, the root is opened, the HP1 loop undergoes a conformational change, and binds to the HP2 loop nucleotide sequence. With the assistance of zinc ions, the zinc ion-specific deoxyribozyme is activated, which then cuts HP2 at the cleavage site, releasing the fluorescent molecules in the nanoparticle pores. The microRNA is detected based on the intensity of the fluorescent molecules. The probe can specifically and sensitively detect trace amounts of microRNA in a system.

The invention provides a method for detecting miRNA-21 based on CHA circuit and CpAgo protein catalytic combination, two DNA hairpins H1 and H2 are included, the 5'end of H1 is modified with an FAM fluorophore, and the middle is modified with a BHQ1 quenching group. The target microRNA specifically triggers CHA based on DNA, triggers a DNA circulation circuit and outputs a large amount of dsDNA, the microRNA is released to be used for a next circulation circuit, the dsDNA formed by H1 and H2 is recognized by two guide chains and CpAgo protein, a CpAgo-guide-dsDNA ternary complex is formed, the dsDNA is cut, a fluorophore and a quenching group are separated, and high-sensitivity detection of the microRNA is achieved. Finally, one-step rapid detection of microRNA is realized, and the problems of high detection cost, long time, low sensitivity and the like in the prior art are improved.

The invention relates to a preparation method and application of an electrochemical sensor for in-situ growth of AuPt nanoparticles based on a ZnNi bimetal organic framework. A modification material ZnNi-MOF (at) AuPtNPs is dropwise added to the surface of a pretreated electrode, then a DNA hairpin H1 is added and fixed to the modification material through a gold-sulfur bond, meanwhile, a 3D-DNA Walker effect can be started through a target Cd < 2 + >, and a large number of DNA single chains S1 are obtained. The method comprises the following steps: adding a supernatant and a DNA hairpin H2 subjected to magnetic separation to an electrode modified with a DNA hairpin H1 in a dropwise manner so as to generate a CHA cycle reaction, and then adding a DNA hairpin H3 and a DNA hairpin H4 in a dropwise manner so as to trigger a hyperbranched HCR signal amplification strategy, so that more methylene blue is connected to the electrode, and an electric signal in a system is enhanced. And quantitative analysis of cadmium ions is realized by using electric signal change corresponding to the concentration change of methylene blue on the surface of the electrode caused before and after addition of Cd < 2 + >. The prepared electrochemical sensor shows relatively high sensitivity, relatively wide detection range, good selectivity and excellent practical application capability.

The application discloses a detection kit based on a colorimetric method and application thereof, and the detection kit comprises two membrane protein recognition chains T1 and T2, two DNA hairpins H1 and H2 required for forming G-quadruplex, hematin required for a color developing reaction, hydrogen peroxide (H2O2) and ABTS. The membrane protein recognition chains T1 and T2 can anchor membrane proteins, and adjacent hybridization occurs when the membrane proteins dimerize, thereby triggering catalytic hairpin self-assembly of H1 and H2 to form a large number of G-quadruplex structures; when H2O2 exists, G-quadruplex / hematin formed by combining G-quadruplex and hematin can catalyze oxidation of ABTS to generate a color developing reaction. The detection kit has the characteristics of high sensitivity, good specificity, low cost, low dependence on equipment and simple operation in the detection of cell membrane protein dimerization, and also has good application performance in cell signal pathway visualization and rapid diagnosis of tumor cells at a bedside.

The invention discloses a preparation method of threose nucleic acid based on a self-pairing primer template. The method comprises the following operation steps: synthesizing a hairpin-shaped DNA template modified by biotin and hypoxanthine, and carrying out annealing treatment to realize template self-pairing; preparing a TNA sequence in a reaction system compatible with TNA extension and TNA cutting by taking the self-pairing DNA hairpin as a template; the TNA product and the template are separated through the magnetic beads, and the DNA template combined with the magnetic beads is recycled, so that the TNA product is recycled in multiple rounds of reactions, and the target TNA product is prepared in batches; the molecular weight of the product is detected through electrospray ionization mass spectrometry, and the prepared TNA is determined as an expected product. The invention provides a method for rapidly synthesizing a large amount of TNA sequences, the preparation period of TNA is shortened, and technical support is provided for application of TNA in the fields of biotechnology and biomedicine.

The invention discloses a combined probe and a preparation method and application thereof. The probe comprises a probe 1 and a probe 2, and the probe takes gold nanoparticles as a core and is grafted with a DNA hairpin through sulfydryl; a DNA hairpin of the probe 1 is provided with a lock, a DNA sequence part of the DNA hairpin is complementary with the microRNA, and a part of the DNA sequence is complementary with the DNA on the probe 2; after the lock on the DNA hairpin of the probe 1 is opened by the enzyme, the lock is complemented with the microRNA and then is complemented with the DNA hairpin of the probe 2, the microRNA is released and participates in the next cycle to form a three-dimensional network structure, and the enzyme and the microRNA are released by the same cell. The combined probe forms a three-dimensional network structure, has the function of detecting APE1 and microRNA-55 at the same time, is high in detection sensitivity, also has very high photothermal conversion efficiency, can specifically ablate tumor cells, and provides a powerful strategy for accurate diagnosis and targeted therapy of cancers.

The invention discloses a mitochondrial regulator based on nucleic acid reaction as well as a preparation method and application of the mitochondrial regulator. The mitochondrial regulator is composed of three different DNA hairpin structures, and is formed by self-assembly of a trigger DNA chain Photo modified with a photo-cleavable nitrobenzyl linking group and two linking DNAs of triphenylphosphine molecules metastably existing in a solution and marked with targeted mitochondria. The mitochondrial regulator can spontaneously react in a solution to be combined with a plurality of mitochondria and induce the mitochondria to aggregate and fuse after being irradiated by ultraviolet light, has good controllability and biocompatibility, is easy to biodegrade, does not influence the expression of protein on the surface of the mitochondria, and can be used for preparing the mitochondria regulator. The method has potential application prospects in clinical application in the fields of cell biology research and precise cancer diagnosis and treatment.

The invention discloses a fluorescent aptamer sensor for detecting DON in food based on HCR and DNAzyme triggering and a detection method, and relates to the technical field of food detection. The biosensor provided by the scheme is composed of a recognition unit, a signal conversion and primary amplification unit, a secondary amplification unit and a report unit, cDNA released by combination of DON and Apt firstly triggers primary HCR reaction for amplification, after DNAzyme is generated, an enzyme digestion product contains the whole cDNA sequence, secondary HCR can be re-triggered, cascade amplification is realized, the detection limit is remarkably reduced, and the detection efficiency is improved. The detection sensitivity is improved; besides, HCR reaction and enzyme digestion substrates are DNA hairpins with rigid two-dimensional structures, when no target exists, the aptamer closes cDNA, the H3 hairpin is kept in a closed state, FAM and BHQ-1 are close to each other to generate fluorescence quenching, background signals are extremely low, and high binding efficiency and anti-interference capability are achieved.

The invention discloses an HCR nucleic acid amplification-based ECL sensor for MRSA detection. The HCR nucleic acid amplification-based ECL sensor can be used for sensitive detection of MRSA. Through the strong interaction force between the aptamer and the MRSA, the release of the trigger chain is completed and the sensor is constructed subsequently, so that the influence of the large-size MRSA on the electrode is eliminated. The structure generated in the HCR process is firmly fixed on the surface of the electrode through the tetrahedron frame, and the upper layer space of the tetrahedron is fully utilized. Meanwhile, the two DNA hairpins on the DNA tetrahedron framework simultaneously generate the HCR process, so that the loss of the ECL signal is effectively avoided, and a guarantee is provided for orderly enhancement of the ECL signal. The designed ECL sensor effectively realizes sensitive detection of MRSA, and a new thought can be provided for structural design of a nucleic acid framework.

This invention relates to a kit and method for detecting anti-human insulin-like growth factor binding protein 7 (IGFBP-7) using a double-antibody sandwich principle combined with a nucleic acid probe self-assembly signal amplification method. The kit comprises three parts: 1) a capture domain formed by IGFBP-7 antibody 1 coated on the surface of an ELISA plate; 2) a tandem functional domain composed of biotin-labeled IGFBP-7 antibody 2, streptavidin, and biotin-labeled DNA primers; and 3) a fluorescence signal functional domain composed of two DNA hairpin probes. Compared with traditional ELISA methods, the method of this invention significantly improves detection sensitivity and features high specificity, high sensitivity, good stability, and strong versatility, as well as good clinical application value.

The invention relates to the technical field of biological detection, in particular to a single nucleotide mutation detection probe and method integrating a dynamic signal and an accumulated signal. The single nucleotide mutation detection probe comprises a DNA hairpin H1, an RNA base embedded hairpin Sub, a DNA single strand E1, a DNA single strand E2 and a DNA hairpin H2, wherein the DNA hairpin H1, the RNA base embedded hairpin Sub, the DNA single strand E1 and the DNA single strand E2 form a DNA enzyme structure; the 5'terminal of the DNA hairpin H2 is modified with carboxyl molecules, and the 3 'terminal of the DNA hairpin H2 is modified with ferrocene molecules. The hairpin probe recognition technology is combined with DNA enzyme, the purpose of cyclic detection is achieved through the thermodynamic chain competition effect, the sensitivity of single base mutation detection is improved through an electrogenerated chemiluminescence detection method for indirectly detecting a mononucleotide mutant by recognizing an intermediate product chain in a cyclic reaction, and the detection sensitivity of the mononucleotide mutant is improved. And the accuracy of single base mutation recognition is enhanced.

The application discloses a transcytosis DNA nanoframework material, a preparation method and application thereof, and the transcytosis DNA nanoframework material is assembled through a hybridization chain reaction of a DNA-containing polymer as a skeleton and DNA hairpins; the skeleton is prepared from at least acrylamide-modified DNA, diethylaminoethyl methacrylate and 3-methacrylamidophenylboronic acid as raw materials through polymerization and oxidation. The transcytosis DNA nanoframework material integrates transcytosis function and gene silencing function, and can be used for precise delivery and treatment of pancreatic cancer and other solid tumors rich in dense matrix barriers.

The invention designs a preparation method of a three-mode sensor based on a multifunctional Au (at) CeO2 and AuPt (at) Zn-C composite material. A double-chain structure formed by an aptamer chain and a complementary chain is connected to the surface of the magnetic bead, and when beta-lactoglobulin exists, the complementary chain falls off due to specific binding of the aptamer. In an electrochemical mode, a high-conductivity AuPt-coated Zn-C modified electrode is used, a complementary chain is combined with a DNA hairpin HP1 connected to the surface of the electrode and sheared under the action of Exo III, and MB / S1-Au-coated CeO2 is connected to the surface of the electrode through a part of left single-chain structures. In a blood glucose meter and a colorimetric mode, a complementary chain in an unopened double-chain structure is subjected to a hybridization chain reaction after HP2-Au at CeO2 and HP3 are added, cascade catalysis is carried out after a glucose solution is added, the change of the glucose concentration is caused, and a colorimetric reaction is further carried out. The beta-lactoglobulin is detected through electrochemical-glucometer-colorimetric signal responses, and the method has the advantages of being good in specificity, high in accuracy and the like.

The invention provides a hairpin probe combination and a kit for self-hybridization chain reaction for AFB1 detection, and belongs to the field of DNA amplification and detection. According to the self-hybridization chain reaction SHCR provided by the invention, the palindromic sequence is introduced into the stem part of the DNA hairpin probe, a traditional HCR system needing at least two DNA hairpin probes is simplified into an SHCR system needing only one DNA hairpin probe, and the SHCR system is used for detecting AFB1, so that the cost and the complexity of sequence design and operation are reduced; the aptamer can be further expanded to detection of other non-nucleic acid target substances by simply integrating corresponding aptamer sequences, and the application prospect is wide.

The invention discloses a pyrenyl HOF (PSA-HOF) / high-entropy metal hydroxide organic framework (HE-MHOF) electrochemical luminescence sensor for antibiotic resistance gene detection as well as a preparation method and application of the pyrenyl HOF / HE-MHOF electrochemical luminescence sensor, and belongs to the technical field of electrochemical luminescence analysis and detection. The method comprises the following steps: respectively modifying a glassy carbon electrode with PSA-HOF, HE-MHOF and a DNA hairpin H2 to obtain an H2-modified H2 / HE-MHOF / PSA-HOF / GCE electrode, co-incubating the modified electrode and an antibiotic resistance gene, and dispensing a DNA hairpin H1-Fc. And detecting the resistance gene ARGAMP in a PBS (phosphate buffer solution) containing potassium persulfate by adopting a three-electrode system. The prepared HE-MMOF / PSA-HOF system electrochemical luminescence sensor has the characteristics of simplicity, convenience and flexibility in operation, wide detection range, low detection limit, low detection cost and the like.

The invention discloses an ECL sensor based on RCA nucleic acid amplification for MRSA detection. The ECL sensor can be used for sensitive detection of MRSA. According to the invention, RCA nucleic acid amplification is combined with a DNA tetrahedral framework, and an ECL sensor for MRSA detection is designed. Firstly, a tetrahedral frame is fixed on the surface of a gold electrode, so that a stable basic condition is provided for the generation of RCA; secondly, two DNA hairpins on a DNA four-side frame are opened through combination and replacement of an MRSA aptamer, the upper layer space of the tetrahedral frame is fully utilized in the step, and the AuNCs capturing capacity of the sensor is improved. In the detection of the MRSA, the lowest detection concentration of the sensor is 1 CFU / mL, different bacteria can be specifically distinguished, and the excellent data shows that the sensor has great potential in the detection of the bacteria.