156 results about "DNA single strand" patented technology

The invention relates to a manufacturing method and application of an electrochemiluminescence sensor for detecting thrombin. Ruthenium bipyridine with active group is modified to the gold nanoparticle surface to form an electrochemiluminescence nanoparticle probe, which plays the role of amplifying electrochemiluminescence, and the upper part DNA single strand is modified on the working electrode surface to constitute an electrochemiluminescence sensor. The target analyte of thrombin is subjected to reaction with partial DNA double strands and then with DNA polymerase, Nb.BbvCI nicking enzyme and partial DNA single strand to obtain DNA hybrid solution which is added into the sensor, so as to increase electrochemiluminescence nanoparticle probes on the electrode surface and further lead to an enhanced electrochemiluminescence signal, and accordingly thrombin determination is realized. The inventive sensor has high selectivity and detection sensitivity.

The invention discloses a graft modified polymer material, a polymer material adsorbing mercury ions prepared from the same and a preparation method thereof. The graft modified polymer material is prepared by grafting a polymer substrate P to a monomer A or monomer B, wherein the molecular structure of the monomer A comprises at least one C=C double bond and at least one epoxy group; and the molecular structure of the monomer B comprises at least one C=C double bond and at least one anhydride group. The epoxy group or anhydride group on the surface of the graft modified polymer material reacts with the terminal amino of a DNA (Deoxyribonucleic Acid) single strand with an amino-modified terminal to obtain the polymer material adsorbing mercury ions. The preparation process of the invention is simple; the prepared material can adsorb mercury ions with high selectivity; the lower limit on concentration for removing mercury ions is extremely low; and the invention has good application prospects in terms of drinking water treatment, industrial wastewater advanced treatment, recycling of mercury ions, and the like.

The present invention discloses a nucleic acid aptamer, wherein the sequence of the nucleic acid aptamer comprises a DNA segment represented by any one sequence selected from a sequence 1, a sequence 2 and a sequence 3. The nucleic acid aptamer can further be various similar sequences with high homology or a derivative obtained from the sequence of the present invention. The invention further discloses a nucleic acid aptamer screening method, which comprises: synthesizing a random single-stranded DNA library and primers, carrying out SELEX screening, carrying out PCR amplification of library, preparing a DNA single strand library, and finally carrying out repeated screening, negative screening and multi-round screening to obtain the nucleic acid aptamer. The nucleic acid aptamer and the derivative thereof can be used in recognition of the prostate cancer cell strain PC-3 or preparation of kits, molecular probes and targeted mediums for prostate cancer detection, and can further be used in design and preparation of prostate cancer treatment drugs. Compared with the protein antibody, the nucleic acid aptamer of the present invention has advantages of high affinity, high specificity, no immunogenicity, capability of being chemically synthesized, small molecular weight, stability, easy storage, easy labeling and the like.

Provided is preparation of a water-soluble luminous silver nano cluster with double-stranded DNA as a template. Firstly, single-stranded DNA rich in cytosine base group is used, 6 cytosine base group loops are reserved in the single-stranded DNA, the total number of the cytosine base groups is 29, single-stranded DNA rich in guanine base group complements the single-stranded DNA and is added, the total number of the guanine base groups is 23, the double-stranded DNA with the 6 cytosine base group loops is formed through the annealing function and is used as the template, and synthesis is achieved through the method of adding sodium borohydride to restore silver nitrate. The preparation process is simple, easy to implement and environmentally friendly, and the preparation can be applied to the preparation of other luminous nano materials. In addition, new nano materials synthesized through the method have water solubility, a high quantum yield, light stability, good biocompatibility and other performance, and have potential wide application to the fields of biosensors, cell imaging, clinical medicine and the like.

The invention provides a fluorescence probe, the synthetic method and the use which is to test the cell hydroxyl free radical. The process is: a. heat and chloroauric acid of 150.0 weight concentration and back flow, with mixing, the sodium citrate of 5.0-7.0 is added into the solution to back flow for 10-20min, then to cool in room temperature to get the golden nanometer particle solution; b. mix the particle with the DNA single chain with 5'end modified fluorescein and 3'end modified sulfydryl according to 1:200-500, then to set in room temperature for 1224h, last to adjust the pH by the phosphoric buffer; next to mix the mixture with the 0.5-5mol/L NaCl according to 1:0.1-0.3(V/V) which is set in room temperature for 35-45h; last to centrifugate to remove the upper solution and the deposition is solved in the 0.1-0.3mol/L phosphoric buffer which is the fluorescence probe solution.

The invention discloses a preparation method of a DNA (Deoxyribonucleic Acid) targeting nano medicine-carrying molecule for a brain tumor. The preparation method comprises the steps that a DNA single strand is added to a Tris-MgCl solution and mixed, and reacts to form a DNA tetrahedron solution; the DNA tetrahedron solution and a targeting peptide solution are added to a mixed solution of a PBS (Phosphoric acid solution), a CuSO4 solution, a TCEP (Tris-(2-carboxyethyl)-phosphine) solution and a TBTA (Tert-Butyl 2,2,2-trichloroacetimidate) solution, and subjected to thermostatic reaction; a targeting DNA tetrahedron solution is obtained; a tumor medicine is added to the targeting DNA tetrahedron solution; constant temperature oscillation, centrifugation, and supernatant removal are conducted; and an obtained sediment is the DNA targeting nano medicine-carrying molecule. According to the preparation method, peptide molecules having specificity in the tumor are modified on DNA tetrahedrons via a point-and-click reaction, so that construction of a targeting DNA nano-carrier is realized; and the targeting DNA medicine-carrying molecule has extremely high specific recognition function, low cytotoxicity and good structural stability.

Provided are a composition for inducing DNA single strand breaks in DNA, the composition comprising a cytidine deaminase, an inactivated target-specific endonuclease, and a guide RNA, a method for inducing a single-strand break in DNA, using the same, a method for analyzing a nucleic acid sequence of a base-editing-introduced DNA, and a method for identifying (or measuring or detecting) a base-editing site, base-editing efficiency at an on-target site, an off-target site, and/or target specificity.

The present invention relates to one kind of method of detecting DNA crossbreeding and mispairing in raised sensitivity based on DNA base pairing principle. Nano gold particles in different sizes are used separately as the surfactant of quartz crystal microbalance and distinguishing amplifier as DNA detector. By means of the decoration of the metal surface of the quartz crystal microbalance with double-functional radical connecting agent, nano metal particles are fixed to the quartz crystal microbalance. Single-strand DNA probe is then fixed onto the nano metal decorated surface, and the DNA probe and the target DNA single strand to be detected are made to crossbred. The relatively longer target DNA has one part complementary with the probe DNA via being fixed onto the quartz crystal microbalance and the other part paired with the complementary DNA single strand connected to nano metal particles to raise the detection sensitivity to 10E(-16).

The invention discloses a hydrogel based on aptamer linking and a preparation method and application thereof. The hydrogel can connect different aptamers to realize the active targeting drug release to different cancer cells. The preparation method comprises the following steps: (1) connecting DNA single strand and acrylamide to obtain polymer chains, PS-A and PS-B; and (2) mixing the obtained PS-A, PS-B, an aptamer chain and an anticancer drug to obtain a drug loaded hydrogel. The hydrogel during preparation is directly mixed anticancer drugs, realizes drug entrapment during a self-assembly process. The hydrogel completes drug entrapment in the self-assembly process, is capable of specific recognition of cancer cells, achieves the targeting release of anticancer drug, and is suitable for targeted cancer therapy.

The embodiment of the invention discloses a detection method of ATP (Adenosine Triphosphate) content and an ATP aptamer sensor. The detection method of the ATP content comprises the following steps of: providing a gold electrode the surface of which is fixed with a DNA single strand, wherein the DNA single-stranded sequence is shown as SEQ ID No.1; providing part of DNA double strands, wherein the tail end of the first strand 3' in the partial DNA double strands is shown as SEQ ID No.2 and the tail end of the strand 5' is complementary to the second strand; immersing the gold electrode in the mixed liquor of the partial DNA double strands and a sample to be tested; by using Ru(phen)3<2+>, [Ru(bpy)2dppz]<2+> or [Ru(phen)2(dppz)]<2+> as an electrochemical luminescence probe, performing ECL (Electrochemiluminescence) detection on the gold electrode. By using aromatic ring with larger ruthenium compound ligand, the invention has the performance of embedding the DNA double-stranded structure and realizes detection of the ATP; and besides, the detection method does not need to use chemical marks and is simple.

The invention discloses a preparation method of a ratio electrochemical miR3123 aptamer sensor based on a Cu-MOF (copper-based metal organic framework) compound doped with BPNSs (black phosphorusnanosheets) and TH (thionine). The method comprises steps as follows: TH and a Cu-MOF precursor are subjected to a reaction for preparation of TH/Cu-MOF, and BPNSs/TH/Cu-MOF is prepared by drip coating ofthe BPNSs and applied to an electrode by drip coating; DNA single-stranded aptamers marked with Fc (ferrocene) are adsorbed on the BPNSs, and aptamer-BPNSs/TH/Cu-MOF is prepared; a target moleculemiR3123is bonded with the DNA single-stranded aptamers Fc-DNA, Fc-DNA is enabled to be separated from the BPNSs, and therefore, Fc electrochemical signals are weakened while TH signals are slightly affected; the ratio electrochemical miR3123aptamer sensor is constructed by fitting linear relation of current peak intensity ratio IFc/ITH and miR3123 concentration.

The invention provides a targeting nano carrier bearing nucleoside anti-tumor drugs and preparation method and application thereof. The targeting nano carrier comprises DNA tetrahedron, Affibody molecule and nucleoside anti-tumor drugs. The preparation method comprises the following steps: a, the nucleoside anti-tumor drugs are modified with phosphoramidite; B, synthesizing four DNA single strandsby DNA solid phase synthesis technology, integrating the nucleoside anti-tumor drugs into the 5 'ends of the four DNA single strands, and modifying NH2 at the 3' ends of one of the DNA single strands; C, linking the affibody molecule to the 3 'end of the NH2-modified DNA single strand through a linker; (d) mix and assembling that four DNA single strand in a molar ratio of 1: 1: 1: 1 to obtain DNAtetrahedron; and (d) assembling the four DNA single strands in a molar ratio of 1: 1: 1 to obtain DNA tetrahedron; Affibody targeting nanoparticles. The targeting nano carrier of the invention can precisely control the combined quantity of drugs, has faster tumor targeting ability and higher cell, tissue penetration ability, good pharmaceutical effect, and is suitable for popularization and application.

The invention discloses a PCR primer pair for identifying or assisting identification of an animal tissue / or an organ and application thereof. The primer pair provided by the invention is at least one from five PCR primer pairs for identifying or assisting identification of cattle, sheep, pig, chicken and duck tissue / or organ, wherein the PCR primer pair for identifying or assisting identification of pig tissue / or organ is always included. The five PCR primer pairs for identifying or assisting identification of cattle, sheep, pig, chicken and duck tissue / or organ respectively consist of two DNA single chains shown as a sequence 1 and a sequence 2, two DNA single chains shown as a sequence 3 and a sequence 4, two DNA single chains shown as a sequence 5 and a sequence 6, two DNA single chains shown as a sequence 7 and a sequence 8, and two DNA single chains shown as a sequence 9 and a sequence 10 in the sequence table. An annealing temperature of 62 DEG C is employed for the five primer pairs to complete all PCR identifications at once and at a same temperature; besides, the PCR primer pair has strong singularity and a short detection time.

The invention provides a drug for reducing myocardial damage caused by ischemia reperfusion or a drug for treating cardiac ischemic diseases. The drug is prepared by taking a DNA tetrahedron as an active ingredient and adding pharmaceutically acceptable auxiliary materials, wherein the DNA tetrahedron is a tetrahedral structure formed by hybridization of four DNA single strands according to the same amount of substance. The drug has good protection and repair functions on myocardium, inhibits apoptosis of myocardial cells, and has the good curative effect on myocardial infarction and other ischemic diseases.

The invention belongs to the field of DNA (deoxyribonucleic acid) biosynthesis, and in particular relates to a method for synthesizing a short single strand deoxyribonucleotide probe and application thereof. The short single strand deoxyribonucleotide probe can be used for detecting small non-coding ribonucleic acid (RNA) such as micro ribonucleic acid. The method comprises the following steps of: (1) preparing plasmids recombined with template DNA; (2) cutting and connecting the template DNA, performing enzyme digestion on the recombined plasmids to obtain the template DNA, and connecting the template DNA end to end to form a ring; (3) cutting a single strand, performing rolling-circle replication, cutting one strand of the template DNA by using nickase, adding polymerase to perform rolling-circle replication by taking annular DNA with a nick as a template, and amplifying to obtain a DNA single strand containing a neck ring-probe structure; and (4) preparing target short single strand DNA, cutting the product of the step (3) by using a type II incision enzyme to form a target single strand DNA probe and a byproduct DNA, and separating and purifying through PAGE (polyacylamide gel electrophoresis) to obtain a single strand DNA probe without mutation. The short single strand deoxyribonucleotide probe has wide applications in the fields of detection of small non-coding RNA and diagnosis and treatment of small non-coding RNA related diseases.

The present disclosure provides an electrochemical detection method for microRNAs based on rolling circle amplification mediated palladium nano-particles. MiRNAs to be tested are specifically bound toa DNA probe, and the exposed primer sequence A2 of the DNA probe and circular template DNA are subjected to rolling circle amplification so as to obtain a guanine-rich DNA single strand. The guanine-rich DNA single strand is used as a template, palladium salt and a reducing agent are added for reduction reaction, and then electrochemical detection is performed. The method of the present disclosure is useful for detecting miRNA-21, has a linear range of 50 aM to 100 fM, has an ultra-low detection limit of 8.6 aM, and has excellent selectivity at the same time.

The invention provides a frame nucleic acid nano luminous body with a customizable shape and a preparation method and application thereof. The preparation method comprises the following steps: S1, modifying hydrophobic groups on DNA single chains, and self-assembling the DNA single chains modified by the hydrophobic groups through DNA nano structure design to obtain a frame nucleic acid nano hydrophobic cavity with a customizable shape; and S2, mixing the frame nucleic acid nano hydrophobic cavity with hydrophobic fluorescent molecules or hydrophobic drug molecules dissolved in a specific solvent according to a certain mode to allow the hydrophobic fluorescent molecules or hydrophobic drug molecules to enter the frame nucleic acid nano hydrophobic cavity to prepare the frame nucleic acid nano luminous body with the customizable shape. The frame nucleic acid nano luminous body with the customizable shape not only solves the problem of lack of a novel nano fluorescent luminous body with precise and controllable size and appearance and precise quantifiable fluorescence intensity in the fluorescent imaging field, but also provides an excellent carrier for hydrophobic drug molecule delivery and a new research idea for the development of fluorescent imaging technology.

The invention discloses a micro-RNA-21 ultra-sensitive detection method based on double-enzyme signal cascade amplification. The method includes the steps: horseradish peroxidase enzyme-labeled probepreparation: coupling carboxylation polystyrene micro-spheres and horseradish peroxidase enzyme through DNA (deoxyribonucleic acid) single chains by an EDC (ethylene dichloride) carboxyl and amino coupling method; double-chain specific nuclease assisted target recycling: specifically cutting the DNA single chains complementarily paired with RNA (ribonucleic acid) to be detected in a probe by double-chain specific nuclease, triggering target circular reaction, releasing more horseradish peroxidase enzyme by cutting and amplifying signals; horseradish peroxidase enzyme signal amplification: collecting the horseradish peroxidase enzyme released in supernatant by cutting, adding a TMB (tetramethylbenzidine) chromogenic substrate, realizing naked-eye qualitative diagnosis by color change, and realizing enzyme-labeled quantification according to change of absorbance values. The difference of micro-RNA family members is effectively distinguished, and the method is suitable for community tumorscreening of high risk groups and has great application values in biomedical research and clinical diagnosis.

The invention provides a visual colorimetric sensor for detecting mercury ions. An H-DNA (Hinge-Deoxyribonucleic Acid) with a special hairpin structure is designed; in the presence of the mercury ions, a 3' end and a 5' end of the H-DNA are complementary and paired through a T-Hg<2+>-T structure, so that a stem part of the H-DNA is completely complementary and exonuclease III is triggered to shearthe stem part, and then more and more single-stranded DNAs containing rich guanine are generated; released Hg<2+> also reacts with the H-DNA to trigger enzyme digestion reaction; the cycle is carriedout so that the H-DNA is continuously sheared and more and more single-stranded DNAs containing G are generated; in the presence of hematin chloride, a DNA catalyzing enzyme is formed, and 3,3',5,5'-tetramethylbenzidine is catalyzed to react with H2O2, so that a blue product is generated and the mercury ions are visibly detected. The method provided by the invention is simple to operate, low in cost and short in time, can be used for rapidly and visibly detecting the content of the mercury ions in an environment water sample and is hopefully applied to detection of mercury in the environmentwater sample.

The invention provides a method for realizing genome editing and accurate and targeted knock-in of genes in fishes. A technology of producing DNA single-chain gap based on nicking enzyme is utilized,assisted with a set of homologous recombination repair factor RecOFAR, so as to realize high-efficient, accurate and targeted integration of genome editing and gene knock-in in the fishes. The problems that a current existing method is low in efficiency, and random mutation efficiency of target points is higher are overcome.

The invention discloses novel nanoparticles with core-shell structures. A preparation method comprises the following steps: (1) adding CTAB solution into a container, adding HAuCl4 solution, and then adding NaBH4 solution to obtain seed crystal; adding the CTAB solution into another container, sequentially adding the HAuCl4 solution, silver nitrate solution, L-AA solution and the seed crystal to prepare gold nanorods; (2) carrying out DNA modification on the gold nanorods to obtain gold nanorods stably protected by thiolated DNA; and (3) centrifuging the gold nanorods, dissolving the gold nanorods in the CTAB solution, sequentially adding SDS solution, the silver nitrate solution and the L-AA solution, and standing to obtain the novel nanoparticles with the core-shell structures. The nanoparticles disclosed by the invention are high in stability, thin silver covers the two ends of each core-shell structure, most of each connected DNA single strand is exposed outside, and each tip part has a higher surface plasma effect; and the nanoparticles have a high application value in the fields of bio-optoelectronics, biological nanometer detection and the like.

This invention relates to a method for constructing complex nanostructure with DNA molecules. The method comprises: selecting a single-stranded DNA as a scaffold chain, horizontally folding the DNA to obtain targeted structure, designing several short single-stranded DNAs as staple chains according to the folded scaffold chain, mixing the staple chains and the scaffold chain in solution, annealing, and self-assembling to obtain the target structure. This invention also discloses a method for metallization of DNA nanostructure with electronic device shape in the solution, and transferring it into air to obtain nanoscale electronic device. The method has such advantages as easy operation, and can construct symmetric or asymmetric highly complex DNA nanostructure that can be used in electronic industry.

The invention discloses a human pancreatic polypeptide aptamer, and a screening method and application thereof. The human pancreatic polypeptide aptamer is any one of Q10, 5'-Q11-FAM-3', 5'-Q12-FAM-3', 5'-BHQ1-Q13-3', 5'-Q14-BHQ1-3', 5'-SH-Q16-3' and 5'-SH-Q17-3'. The screening method comprises the steps of random library and primer synthesis, GO-SELEX screening, library PCR (polymerase chain reaction) amplification, DNA single-chain library preparation, repeated screening, negative screening, multi-round screening and the like. The human pancreatic polypeptide aptamer can be applicable to the preparation of a kit for detecting human pancreatic polypeptide, and has the advantages that the human pancreatic polypeptide aptamer has higher affinity and specificity than protein antibody; no immunogenicity exists; the chemical synthesis can be realized; the molecular weight is small; the stability is realized; the storage and the marking are easy, and the like.

A method of detecting increased levels of DNA single strand breaks in a eukaryotic cell sample, comprising the steps of: (a) contacting a eukaryotic cell sample to a water-soluble tetrazolium salt under conditions in which said tetrazolium salt is converted to a formazan dye in said cell sample in the presence of NADH or NADPH; and then (b) detecting the presence of the formazan dye in said cell sample, with decreased levels of the formazan dye indicating increased levels of DNA single strand breaks in the eukaryotic cell sample.