8 results about "DNA single strand" patented technology

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.

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 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 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 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 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.