2626 results about "Aptamer" patented technology

The present invention concerns methods and compositions for stably tethered structures of defined compositions, which may have multiple functionalities and/or binding specificities. Particular embodiments concern homodimers comprising monomers that contain a dimerization and docking domain attached to a precursor. The precursors may be virtually any molecule or structure, such as antibodies, antibody fragments, antibody analogs or mimetics, aptamers, binding peptides, fragments of binding proteins, known ligands for proteins or other molecules, enzymes, detectable labels or tags, therapeutic agents, toxins, pharmaceuticals, cytokines, interleukins, interferons, radioisotopes, proteins, peptides, peptide mimetics, polynucleotides, RNAi, oligosaccharides, natural or synthetic polymeric substances, nanoparticles, quantum dots, organic or inorganic compounds, etc. Other embodiments concern tetramers comprising a first and second homodimer, which may be identical or different. The disclosed methods and compositions provide a facile and general way to obtain homodimers, homotetramers and heterotetramers of virtually any functionality and/or binding specificity.

The present invention provides methods and compositions for attenuating expression of a target gene in vivo. In general, the method includes administering RNAi constructs (such as small-interfering RNAs (i.e., siRNAs) that are targeted to particular mRNA sequences, or nucleic acid material that can produce siRNAs in a cell), in an amount sufficient to attenuate expression of a target gene by an RNA interference mechanism. In particular, the RNAi constructs may include one or more modifications to improve serum stability, cellular uptake and/or to avoid non-specific effect. In certain embodiments, the RNAi constructs contain an aptamer portion. The aptamer may bind to human serum albumin to improve serum half life. The aptamer may also bind to a cell surface protein that improves uptake of the construct.

The invention provides methods and compositions for detecting and/or quantifying nucleic acid oligonucleotides. These methods and compositions are useful for detecting and quantifying diagnostic and/or therapeutic synthetic target oligonucleotides, such as aptamers, RNAi, siRNA, antisense oligonucleotides or ribozymes in a biological sample.

Some aspects of this disclosure provide compositions, methods, systems, and kits for controlling the activity and/or improving the specificity of RNA-programmable endonucleases, such as Cas9. For example, provided are guide RNAs (gRNAs) that are engineered to exist in an “on” or “off” state, which control the binding and hence cleavage activity of RNA-programmable endonucleases.

Materials and methods are provided for producing and using aptamers useful as oncology therapeutics capable of binding to PDGF, PDGF isoforms, PDGF receptor, VEGF, and VEGF receptor or any combination thereof with great affinity and specificity. The compositions of the present invention are particularly useful in solid tumor therapy and can be used alone or in combination with known cytotoxic agents for the treatment of solid tumors. Also disclosed are aptamers having one or more CpG motifs embedded therein or appended thereto.

The invention discloses a gene control device and method based on CRISPR-Cas9. The device comprises a nucleotide sequence, wherein the nucleotide sequence is an sgRNA itself or can be transcribed into an sgRNA, the sgRNA structurally comprises a first part bonded with inactivated Cas9 protein and a second part connected to the 3'end of the first part, the 5'end of the first part is provided with an antisense sequence, and the second part is an aptamer sequence part which comprises a ligand binding part and an aptamer stem part; when no ligand exists, the aptamer sequence is pair-bonded with the aptamer stem part; when a ligand exists, the aptamer sequence is dissociated from the aptamer stem part so as to be pair-bonded with a target DNA. By integrating an RNA riboswitch bonded with a specific biological signal into the sgRNA, a bridge of cell signal intensity and gene expression intensity is established, any target gene can be activated or silenced on the basis that biological signal identification is achieved, and artificial connection is built between signal ligands and cytogene.

Materials and methods are provided for target validation by gene knock-down with intracellularly expressed aptamers and siRNAs. The aptamers produced by the materials and methods of the invention are useful in target validation for therapeutics development.

The invention provides a method used for simultaneous detection of three food-borne pathogenic bacteria based on multicolor upconversion fluorescence labeling. According to the method, three upconversion materials with differentiable fluorescence spectrums are used for forming multicolor upconversion fluorescent nanoprobes via respective connection with aptamers of staphylococcus aureus, vibrio parahaemolyticus, and salmonella, and complementary oligonucleotide single chains of the aptamers are connected with magnetic nanoparticles so as to form nano-composites. When bacteria to be tested are in a detection system, double chain unwinding is realized because of specific binding of the pathogenic bacteria with corresponding aptamers; it is possible to realize simultaneous quantitative determination of staphylococcus aureus, vibrio parahaemolyticus, and salmonella by monitoring upconversion fluorescence signal strength at 477nm, 550nm, and 660nm, detection linear range ranges from 50 to 1000000cfu/ml, and detection limits are 25cfu/ml, 10cfu/ml, and 15cfu/ml respectively. The method is used for detection of pathogenic bacteria, is high in sensitivity, is rapid and convenient, and can be used for detection of the three pathogenic bacteria in food such as milk and shrimp meat; and results are accurate and reliable.

Compositions for inducing or enhancing immunogenicity of a tumor comprise bi- and multi-specific aptamers binding to a tumor cell and an immune cell. These compositions have broad applicability in the treatment of many diseases, including cancer.

The invention relates to a circulating tumor cell detection chip and an application thereof. The above micro-fluidic chip is combined with deterministic lateral displacement and specific bio-affinity identification principles to realize synergistic high-efficiency and high-purity capturing and detection of circulating tumor cells in peripheral blood. A triangular microcolumn array modified with affinity identification molecules, such as a nucleic acid aptamer or antibody, and having a specific geometric arranging shape, is designed in the micro-chip. The rotating angle, the distance, the offset angle and other parameters of triangular arrays are regulated to control the flow behaviors of different dimensions going through micro-channels. The chip can realize three functions in order to improve the capture efficiency and the purity of the circulating tumor cells. A gas-driven sample introduction system is also designed in the invention, and can realize simultaneous control of a plurality of fluid paths through one gas pressure path.

The invention discloses a targeted artificial TS/MDEP protein nucleic acid aptamer and a sequence thereof. A new combinatorial chemistry technology SELEX (Systematic Evolution of Ligands by Exponential Enrichment) is applied, the TS/MDEP protein serves as a target protein, and a DNA aptamer capable of being in specific binding to the TS/MDEP protein is screened from a single-chain RNA random library. The aptamer can form a special stem-loop structure in a random sequence area and can be in specific and high-affinity binding to the TS/MDEP protein or targeted binding to gastric cancer cells. The RNA aptamer provides a specific and efficient marker molecule for the gastric cancer diagnosis and treatment field, as well as a new choice for developing gastric cancer diagnosis reagents and gastric cancer treatment medicines.

Methods are described for assembly of DNA aptamer-magnetic bead ('MB') conjugate plus aptamer-quantum dot ('QD') aptamer-fluorescent nanoparticle or other aptamer-fluorophore, aptamer-chemiluminescent reporter, aptamer-radioisotope or other aptamer-reporter conjugate sandwich assays that enable adherence to glass, polystyrene and other plastics. Adherence to glass or plastics enables detection of surface-concentrated partitioning of fluorescence versus background (bulk solution) fluorescence in one step (without a wash step) even when the external magnetic field for concentrating the assay is removed. This assay format enables rapid, one-step (homogeneous) assays for a variety of analytes without wash steps that do not sacrifice sensitivity.

The invention relates to a method for screening an aptamer specifically bound with an alpha-fetoprotein by using a capillary electrophoresis technology. The method comprises the following steps of designing and establishing a random oligonucleotide library; enriching oligonucleotides which can be bound with alpha-fetoprotein by combining a capillary electrophoresis technology and an SELEX (Systematic Evolution of Ligands by Exponential Enrichment) screening method; and cloning, sequencing, and carrying out capillary electrophoresis analysis and immunofluorescence verification to finally obtain oligonucleotides which can be specifically bound with the alpha-fetoprotein, namely the aptamer. The invention provides an efficient and specific aptamer screening method. The method has the advantages that the screening time is shortened by means of the advantage of the capillary electrophoresis technology, and the screening operation can be finished through four rounds of circulation; and meanwhile, the non-specific screening caused by a matrix effect is reduced.

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.

The invention discloses construction of an aptamer sensor based on an Au NPs and DNA circulation double amplification technique, and an application of the aptamer sensor in adenosine detection, and belongs to the technical field of aptamer sensing. A detection system comprises an adenosine aptamer, probe DNA crossbred with the aptamer, Au NPs labeled hairpin structure DNA, and hairpin structure DNA assembled on the surface of a gold flake. When adenosine does not exist, Au NPs labeled DNA keeps the hairpin structure and cannot be crossbred with hairpin DNA on the surface of the gold flake, and Au NPs cannot be captured onto the surface of the gold flake. When adenosine exists, adenosine is combined with the adenosine aptamer, probe DNA is released from an aptamer/probe DNA double chain, and crossbred with Au NPs labeled hairpin DNA to allow Au NPs labeled hairpin DNA to be subjected to cycle opening; Au NPs labeled DNA subjected to the cycle opening is crossbred with DNA on the surface of the gold flake to capture Au NPs onto the gold flake; replaced probe DNA initiates the next DNA chain replacement reaction; in such circulation, a single adenosine molecule can initiate a large amount of Au NPs to be assembled onto the gold flake; a reinforced SPR (Surface Plasmon Resonance) signal is obtained; and the aptamer sensor is used for high sensitivity detection of adenosine.

The invention discloses a detection method of a kanamycin residue based on a nucleic acid aptamer, and belongs to the technical field of analytic chemistry. The method comprises the steps that by using a sulfydryl covalent modification mode, ssDNA (single-stranded Deoxyribonucleic Acid) complementary with the two ends of a kanamycin aptamer is modified on the surfaces of AuNPs (Gold Nanoparticles) respectively; two kinds of functionalized AuNPs are obtained; the kanamycin aptamer is added and pairwise bound with ssDNA on the surfaces of the functionalized AuNPs; spatial distances among the AuNPs are closed; the AuNPs are mediated to be aggregated; after the AuNPs are mixed with kanamycin samples with different concentrations, specific binding between kanamycin and the aptamer allows an aggregation to be disaggregated, which is manifested by a change of an AuNPs characteristic absorption peak in an ultraviolet-visible spectrum; and the kanamycin residue is detected by using a relation between a change of the absorbency at a 527-nanometer part and the concentration of the kanamycin. The method is good in repeatability and stability, easy to operate and high in sensitivity, and can be used for directly determining the kanamycin residues in samples such as pretreated milk.