20 results about "DNA single strand" patented technology

The application discloses a functional nucleic acid probe and a preparation method and application thereof. The preparation method comprises the following steps: forming a DNA sheet by self-assembly of a first DNA single strand and a second DNA single strand, and then combining the DNA sheet with a molecular beacon probe to prepare the functional nucleic acid probe; wherein the end of the first DNA single strand and the end of the second DNA single strand are complementary to each other; and the molecular beacon probe comprises an aptamer sequence of foodborne pathogenic bacteria. The fluorescence polarization method based on the functional nucleic acid probe provided by the application has the advantages of high sensitivity, strong specificity, short detection time and the like, and can be used for self-immediate monitoring of the content of foodborne pathogenic bacteria in drinking water or the content of foodborne pathogenic bacteria in environmental water, and has great application value and market value in family health and environmental protection and the like.

The application belongs to the technical field of biosensing and specifically relates to a biosensor for detecting active acetylcholinesterase and application thereof. The biosensor comprises nanotubes with nanometer apertures at tips for generating current blocking signals; and a ring bundle DNA tetrahedron carrier for loading a solution containing active acetylcholinesterase to be detected, wherein the ring bundle DNA tetrahedron carrier is TDN1 or TDN4, the sequences of the four DNA single strands in TDN1 are shown as SEQ ID NO. 1 to SEQ ID NO. 4, and the sequences of the four DNA single strands in TDN4 are shown as SEQ ID NO. 1, SEQ ID NO. 3, SEQ ID NO. 5 and SEQ ID NO. 6. The application utilizes a closed-loop DNA tetrahedron nanostructure anchored at two ends of an aptamer to generate a difference in current signals in a nanometer hole before and after the active AChE is combined, so that high-sensitivity and high-selectivity detection of the active AChE at a single-molecule level is achieved.

The invention relates to a polyarginine-DNA nanotube material as well as a preparation method and application thereof, and belongs to the technical field of biological medicines. Aiming at the technical problems of unstable structure, low cell uptake rate and easy degradation by nuclease caused by dependence on magnesium ions in the existing DNA nano-material, the invention provides a nano-tube material formed by self-assembly of four DNA single chains (Y1-Y4) according to a molar ratio of 1: 3: 3: 3 induced by polyarginine. The material can load p65 siRNA to form a composite preparation which is used for preparing a medicine for inhibiting lung inflammation. According to the polyarginine-DNA nanotube material disclosed by the invention, the stability and the cell uptake efficiency of the material are remarkably improved; the higher the polymerization degree of arginine is, the stronger the anti-inflammatory activity is; the compound preparation synergistically inhibits the expression of a proinflammatory factor through a dual mechanism of blocking an inflammatory pathway by polyarginine and silencing a p65 signal by p65 siRNA, and provides an efficient delivery carrier for the treatment of acute lung injury.

This invention belongs to the field of biomedical technology, specifically relating to a DNA hydrogel with a kissing hairpin cross-linking structure, its preparation method, and its applications. The first end of the DNA single strand is connected to a first sticky end carrying a nucleic acid aptamer that specifically recognizes TNF-α, and the second end is connected to a second sticky end. The two hairpin structures form an integrated hairpin structure through complementary base pairing at their sticky ends. The loop regions of multiple integrated hairpin structures are cross-linked through complementary base pairing to form a DNA hydrogel with a three-dimensional network backbone. This application utilizes the self-assembly of anti-TNF-α nucleic acid aptamers to form a hydrogel via DNA kissing hairpin cross-linking, achieving controllable drug release. Compared to various TNF-α monoclonal antibodies and fusion protein biopharmaceuticals, anti-TNF-α nucleic acid aptamers offer the advantages of both good targeting and low cost; the self-assembly of the hydrogel via DNA kissing hairpin cross-linking allows for a wider range of adjustable release and higher safety.

The present disclosure provides a tetrahedral framework nucleic acid modified by aptamer and transforming growth factor β3 and a preparation method thereof, belonging to the field of biomedicine. The tetrahedral framework nucleic acid modified by aptamer and transforming growth factor β3 combines transforming growth factor β3 through disulfide bonds, and sequences of four DNA single strands of the tetrahedral framework nucleic acid are shown in SEQ ID NO: 1-4, one of the four DNA single strands of the tetrahedral framework nucleic acid also comprises an extended aptamer sequence, and the extended aptamer sequence is shown in SEQ ID NO: 5.

The invention discloses a DNA cube-sialidase conjugate as well as a preparation method and application thereof, and belongs to the technical field of biological medicines. The main body of the conjugate is a DNA cube, and is formed by DNA single chains of an AB chain, an AE chain, an AD chain, an AC chain, an a chain, a chain b and an x chain which are respectively shown as SEQ ID NO: 1-7 through base complementary pairing assembly; the 5'end of the chain a or the chain b is complementary with a DNA cube support chain to form double chains, the 3 'end is free in a single-chain form, so that four nonadjacent vertexes of the DNA cube respectively extend to form a single-chain DNA section, and the 3' end of each single-chain DNA section is connected with sialidase. Sialic acid on the cell surface is subjected to targeted degradation through the DNA cube-sialidase conjugate, and the DNA cube-sialidase conjugate can be used for targeted degradation of sugar immune checkpoints on the surface of tumor cells, has high targeting property and action efficiency, and is expected to be used for enhancing immunotherapy.

The invention discloses a preparation method and application of a fluorescence sensing array based on an MOF material. The preparation method comprises the following specific steps: step 1, preparing Zr-MOF; step 2, obtaining single-stranded DNA1, DNA2, DNA3 and DNA4, and marking carboxyl fluorescein at 5'ends of the single-stranded DNA1, DNA2, DNA3 and DNA4; carrying out centrifugal treatment on the labeled DNA single chain, and respectively adding a TBE buffer solution to prepare a single-chain DNA1 solution, a single-chain DNA2 solution, a DNA3 solution and a DNA4 solution for later use; and 3, respectively adding the Zr-MOF prepared in the step 1 into the single-stranded DNA1 solution, the single-stranded DNA2 solution, the DNA3 solution and the DNA4 solution prepared in the step 2, and incubating at room temperature to obtain the fluorescent sensing array.

The application belongs to the technical field of biological medicine. More specifically, it relates to a preparation and application of in-situ imaging DNA-PROTAC based on strand displacement activation. The novel DNA-PROTAC provided by the application is designed by three modules, which are respectively recruitment module A (E3 ligase ligand-linker-clicking group), locking module B (aptamer-shielded chain double-stranded complex) and activation module C (DNA single strand), three physically separated components, so that the degradation activity is completely silent in the delivery stage. Only after the drug reaches the target area, the in-situ assembly of recruitment module A and locking module B can be triggered by adding activation module C to trigger the strand displacement reaction, thereby effectively avoiding the non-specific activity of traditional degrading agents in the whole body circulation, and significantly reducing the off-target toxicity. In addition, the application converts the large conjugate into multiple independent components with medium and small molecular weights by physical splitting, overcoming the macromolecular delivery barrier.

The present invention relates to a method and kit for removing linker self-linking products during sequencing library construction and for constructing a sequencing library. In particular, provided is a method and kit for the selective cleavage of DNA double strands and DNA single strands, a method and kit for selective cleavage by using DNA-RNA-DNA:cDNA heterozygous chains and DNA:cDNA double strands, and a method and kit for DNA and RNA library co-construction.

The present invention relates to the technical field of biological detection, in particular to a DNA tetrahedral fluorescent probe based on multivalent spatial pattern recognition and the use thereof. The fluorescent probe is of a tetrahedral structure, and comprises five DNA single strands, three DNA long strands and three DNA short strands complementary to the DNA long strands, wherein the three DNA long strands comprise a CY5 dye modifying the 3' end, and the three DNA short strands comprise a BHQ2 dye modifying the 3' end. The DNA tetrahedral fluorescent probe of the present invention can achieve multivalent recognition of a circular RNA and structurally matches same, and thus has enhanced specificity and sensitivity of circular RNA detection and is suitable for imaging and detection of circular RNAs.

The present invention discloses an ultrasensitive immunoassay method based on proximity nucleic acid amplification signal amplification in the field of medical detection technology, comprising the following steps: 1. immune binding; 2. enzymatic cleavage and release to release a hairpin DNA single strand; 3. complementary and enzymatic ligation to cyclize the circular DNA single strand by adding T4 ligase; 4. rolling circle amplification; and 6. detection, quantification and localization by qPCR and in situ oligonucleotide fluorescent labeling detection methods. The present invention uses the hairpin structure on the oligonucleotide DNA chain coupled to the antibody to protect the complementary sequence from generating nonspecific circular DNA single strands, and combines the rolling circle amplification technique to amplify the detection signal, thereby suppressing the intensity of the detection background signal while enhancing the specificity of the detection signal, further improving the sensitivity of the detection.

The present invention discloses a natural cyclic peptide RA-V & DNA tetrahedron immune adjuvant and its preparation method and application, which belong to the field of biomedicine. The immune adjuvant includes a Rubiaceae type cyclic peptide compound RA-V and a DNA tetrahedron, and the DNA tetrahedron is a DNA tetrahedron with an arm length of 15-30bp formed by a DNA single strand. The present invention constructs a nanostructure assembled from 4 DNA single strands and RA-V, which specifically activates the sGAS-STING pathway through the recognition of double-stranded DNA by cGAS protein, thereby enhancing the body's immune function and preventing diseases such as viral infections and tumors. At the same time, by utilizing the good biological properties of DNA nanostructures, RA-V & DNA tetrahedron can effectively target disease lesions and exert the immunotherapy effect of the disease, which has great application prospects.

The invention relates to DNA-silk fibroin hybrid hydrogel as well as a preparation method and application thereof. The method comprises the following steps: mixing a Y-type DNA single strand and an L-type DNA single strand in a buffer solution to obtain a DNA solution, and forming a DNA supramolecular network by cross-linking cohesive ends of the Y-type DNA single strand and the L-type DNA single strand; the preparation method comprises the following steps: mixing methacrylated silk fibroin and a photoinitiator with a DNA solution to obtain a DNA-silk fibroin premixed solution; mnO2 nanoparticles and Melatonin are added into the DNA-silk fibroin premixed solution, and a hydrogel solution is obtained; and carrying out photo-crosslinking on the hydrogel solution under the irradiation of ultraviolet light, so as to obtain the DNA-silk fibroin hybrid hydrogel loaded with MnO2 nanoparticles and Melatonin. Compared with the prior art, the introduction of the silk fibroin network can provide mechanical properties for the DNA hydrogel network and reduce the cost; the MnO2 nanoparticles can be used for remarkably removing ROS in cells; the Melatonin can be used for remarkably promoting autophagy of damaged mitochondria in cells.

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 invention discloses a space-limited double-foot DNA nano-motor with enhanced dynamics and a preparation method and application thereof. The preparation method comprises the following steps: annealing a specific DNA single chain to form a Cy5-substrate probe, a Cy3-substrate probe, a double-foot walker 1 and a double-foot walker 2; and respectively assembling the two substrate probes and the gold nanoparticles through a freezing method to obtain the DNA nano motor 1 and the DNA nano motor 2. The nano motor, a corresponding biped walker and a fuel chain form a detection system which is used for detecting messenger RNA (Ribonucleic Acid). The space confinement effect of the gold nanoparticles and the proximity effect of the biped walker are utilized, entropy-driven catalytic reaction kinetics is remarkably accelerated, ultra-high-sensitivity detection of survivin mRNA and TK1 mRNA is achieved, and the detection limits reach 501 aM and 314 aM respectively. And rapid and high-contrast in-situ imaging can be carried out on double mRNA in living cells.

The invention relates to the technical field of molecular biological experiments, in particular to a nucleic acid scavenger which comprises a solution A and a solution B. The solution A is an active oxygen source component in the nucleic acid scavenger, the main component of the solution A is urea peroxide (0.25%-3%), and the solution A can generate excessive oxygen free radicals and effectively destroy DNA single-chain and double-chain structures. The liquid B is a synergistic and auxiliary component in the nucleic acid scavenger, the main component is horse radish peroxidase (0.1%-1%), urea peroxide can be promoted to quickly release high-activity oxygen free radicals, and the purpose of scavenging nucleic acid molecules is achieved. According to the method, nucleic acid pollution including genome DNA and nucleic acid amplification product pollution in the laboratory can be effectively eliminated, chemical pollution to the environment cannot be caused, the method has the advantages of being non-toxic, harmless and easy and convenient to operate, and a safer and more effective anti-pollution scheme is provided for the molecular biology laboratory.

This invention discloses a molecular switch-type nucleic acid framework fluorescent probe and its application in the detection of ATP molecules, a biomarker for depression, belonging to the field of biodetection technology. The fluorescent probe of this invention has a tetrahedral structure, comprising three complementary DNA single strands and four additional DNA single strands forming the tetrahedral structure. The three complementary DNA single strands include a Cy3 dye modified with a central backbone, a phosphate group modified at the 5' end, and a Cy5 dye modified at the 3' end. The fluorescent probe of this invention is activated by ATP, rapidly responding to ATP to emit a fluorescent signal, and is deactivated by an endonuclease, automatically returning to its initial state. This probe enables dynamic cyclic detection of ATP molecules and can directly perform rapid, highly sensitive, and highly selective quantitative analysis of the purine neurotransmitter ATP in complex biological samples such as plasma and urine, providing an effective means for early screening of neurological diseases.

The present application relates to a kind of polyarginine-DNA nanotube material and its preparation method and application, belong to the field of biological medicine.The existing DNA nanomaterial is dependent on magnesium ion, which leads to unstable structure, low cell uptake rate and easy degradation by nuclease.The present application is formed by four DNA single strands (Y1-Y4) self-assembly according to the molar ratio 1:3:3:3 nanotube material induced by polyarginine.The material can load p65 siRNA to form a complex preparation, which is used for preparing a drug for inhibiting lung inflammation.The polyarginine-DNA nanotube material of the present application significantly improves the stability and cell uptake efficiency of the material;The higher the degree of polymerization of arginine, the stronger the anti-inflammatory activity;The complex preparation inhibits the expression of pro-inflammatory factors through the double mechanism of blocking inflammatory pathways by polyarginine and silencing p65 signal by p65 siRNA, providing an efficient delivery vector for the treatment of acute lung injury.

The application discloses an RNA response controlled-release DNA nanocarrier system, which comprises a DNA nanotube, a drug effective component and a nanodevice lock; the DNA nanotube comprises a tube wall and the nanodevice lock; the tube wall is unfolded in a rectangular shape; the nanodevice lock comprises a plurality of sealing chains, each of which is composed of two partially complementary DNA single strands, and the two DNA single strands are connected to two long sides of the tube wall; the sealing chains can undergo an isothermal chain displacement reaction with target RNA, open the nanodevice lock and unfold the tube wall; and the drug effective component is loaded in the inside of the DNA nanotube. The DNA nanotube is not easy to be enzymatically hydrolyzed, has high biocompatibility and is easy to be endocytosed by cells, and is used for wrapping the RNA drug with poor stability, so that the RNA drug is completely and sufficiently delivered to a target position; under the action of high expression of the RNA at the target position, the nanodevice lock on the DNA nanotube is rapidly opened, and the RNA drug is released.

The invention belongs to the technical field of biological medicines, and particularly relates to DNA hydrogel with a kiss hairpin cross-linked structure as well as a preparation method and application thereof. The first tail end of the DNA single strand is connected with a first sticky tail end carrying a specific recognition TNF-alpha nucleic acid aptamer, and the second tail end of the DNA single strand is connected with a second sticky tail end; the two hairpin structures form an integrated hairpin structure through complementary pairing of bases at the adhesive tail ends, and the annular areas of the multiple integrated hairpin structures form the DNA hydrogel with the three-dimensional net-shaped framework through complementary pairing and crosslinking of the bases. According to the application, the anti-TNF-alpha nucleic acid aptamer is self-assembled in a DNA kiss hairpin cross-linking manner to form the hydrogel, so that controllable drug sustained release is realized. Compared with a plurality of TNF-alpha monoclonal antibodies and fusion protein biological agents, the anti-TNF-alpha nucleic acid aptamer has the advantages of good targeting property and low cost; the hydrogel is formed through self-assembly in a DNA kiss hairpin cross-linking mode, the slow release adjustable range is larger, and the safety is higher.