199 results about "DNA Aptamers" patented technology

The present invention includes the selection and isolation of thioaptamers that target the signaling protein TGF-β1, compositions of such thioaptamers and the use of such thioaptamers to either block or enhance signal transduction of the TGF-β1 protein and thus function as, e.g., immunomodulatory agents. Thioaptamers may also be targeted alone or in combination with other thioaptamers against the ligand, the receptors, the ligand trap protein(s) and / or the co-receptors to modulate TGF-β signaling pathway.

Compositions and methods for modifying genetic material are provided. One embodiment provides aptamers capable of binding to a site-specific DNA binding moiety to facilitate the exchange of homologous genetic information between a donor molecule and the desired target locus (aptamer-guided gene targeting or AGT). One embodiment provides an oligonucleotide containing a aptamer, preferably a DNA aptamer at the 5′ end. The oligonucleotide also contains a region of homology, also referred to as donor DNA, to a desired nucleic acid, locus, or gene. The DNA binding moiety can be a nucleic acid, a protein, or a complex of proteins. In a preferred embodiment the DNA binding moiety is a homing endonuclease that cuts DNA to facilitate the modification of the DNA by the donor DNA.

Compositions and methods for modifying genetic material are provided. One embodiment provides aptamers capable of binding to a site-specific DNA binding moiety to facilitate the exchange of homologous genetic information between a donor molecule and the desired target locus (aptamer-guided gene targeting or AGT). One embodiment provides an oligonucleotide containing a aptamer, preferably a DNA aptamer at the 5′ end. The oligonucleotide also contains a region of homology, also referred to as donor DNA, to a desired nucleic acid, locus, or gene. The DNA binding moiety can be a nucleic acid, a protein, or a complex of proteins. In a preferred embodiment the DNA binding moiety is a homing endonuclease that cuts DNA to facilitate the modification of the DNA by the donor DNA.

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 discloses a method for preparing a meso-porous silicon nano medicine carrier with cell specificity target, reduction responsiveness and triple anticancer treatment effects. The method comprises the following steps: firstly, synthesizing meso-porous silicon nano particles by using a gel dissolution method, subsequently, introducing a disulfide bond onto the surface of a meso-porous silicon nano reservoir by using a chemical modification method, innovatively fixing cytochrome C with an apoptosis-inducing function onto the surface of the meso-porous silicon nano reservoir, blocking meso-porous channels with medicines, finally modifying DNA (Deoxyribose Nucleic Acid) aptamer single chain molecules (AS1411, with a cancer cell apoptosis-inducing function) onto the surface of a meso-porous silicon / cytochrome C nano composite system, and taking the system as specificity ligand of a receptor (nucleolin protein) which is overexpressed on the surface of liver cancer cytomembrane, thereby establishing a multifunctional composite type nano medicine carrier system for achieving triple anticancer treatment under combined action of medicines, blocking substances and target molecules inside meso-pores.

The present invention discloses a single-stranded DNA aptamer modified SiO2 / Fe3O4 magnetic microsphere preparation method, which comprises: (1) adopting a chemical co-precipitation method to obtain Fe3O4 magnetic nanoparticles; (2) adopting a sol-gel method to obtain SiO2 / Fe3O4 magnetic microspheres; (3) obtaining -NH2 modified SiO2 / Fe3O4 magnetic microspheres; (4) dispersing the -NH2 modified SiO2 / Fe3O4 magnetic microspheres in water to obtain -COOH modified SiO2 / Fe3O4 magnetic microspheres; and (5) dispersing the -COOH modified SiO2 / Fe3O4 magnetic microspheres in a Tris-HCl buffer solution to obtain the aptamer modified SiO2 / Fe3O4 magnetic microspheres.

The invention relates to a bioelectrochemical sensor for detecting tumor markers and a preparation method thereof. It is a three-electrode system sensor, which is characterized in that the counter electrode in the three electrodes is a platinum electrode, the reference electrode is a saturated calomel electrode, and the working electrode is a gold electrode, and the gold electrode is decorated with two tumor markers The complementary DNA strand of the DNA aptamer, that is, the cDNA strand, is labeled with an electrochemical probe ferrocene molecule at the end of the cDNA strand. The novel bioelectrochemical sensor for detecting tumor markers of the present invention combines the characteristics of highly specific binding of DNA aptamers to target proteins and high sensitivity of electrochemical detection methods, making early diagnosis of cancer possible.

The present invention relates to a carbon nanotube transistor biosensor with aptamers and a method for detecting a target material using the same, more particularly to a carbon nanotube transistor biosensor recognizing the target material, i.e., a specific molecule (such as a protein, a peptide, an amino acid, and an organic / inorganic compound) by using DNA aptamers and a method for screening a target material using the same. In the biosensor of the present invention, the aptamers binding specifically to a particular protein are adsorbed on a carbon nanotube constituting the channel domain of carbon nanotube transistor to easily detect / identify a particular protein via the electric conductivity of carbon nanotube that varies if the particular protein is exposed to corresponding aptamers.

The invention discloses a method for detecting low-concentration mercury ions based on a DNA modified SERS substrate. The method comprises the following steps: preparing uniform gold-covered silicon dioxide nano particles by a fractional step method and fixing nano particles with a core-shell structure on a quartz glass sheet by a coupling agent to construct an SERS substrate; modifying single-chain DNA molecules on the surfaces of gold shell layers of the gold-covered silicon dioxide nano particles through sulfydryls; immersing the prepared DNA aptamer modified SERS substrate into a solution containing the mercury ions; washing with de-ionized water; by taking an SERS signal specific value of a G basic group and an A basic group as spectrum standard measurement of DNA at a metal surface state, realizing quantitative and specific detection on the mercury ions by analyzing a characteristic Raman peak and the change of the specific value. Compared with the prior art, the method has the following advantages that the sensitivity of the method is high, the detection lower limit is about 50nM, the measurement operation is simple, the cost is low, and the real-time and rapid measurement can be realized.

The invention discloses a single-chain DNA aptamer specifically recognizing streptomycin and application of the DNA aptamer, belonging to the field of biochemistry and molecular biology, analytical chemistry and combinatorial chemistry. The invention provides a method for preferably selecting the streptomycin aptamer by using an improved magnetic bead SELEX technology and four single-chain DNA aptamers with high appetency with the streptomycin and sequences of A1, A3, A6 and A12, and provides a high-specificity detection recognition element with the advantages of better stability, high sensitivity, low cost, and easy preparation, modification and mark for the detection of residue of the streptomycin, especially streptomycin in foods.

The invention relates to a novel DNA aptamer modified bioelectrochemical sensor and a preparation method thereof. The novel bioelectrochemical sensor is of a three-electrode system. The invention is characterized in that in the three electrodes, the counter electrode is a platinum electrode, the reference electrode is a saturated calomel electrode, and the working electrode is a gold electrode; and a DNA aptamer chain is modified on the gold electrode. The novel DNA aptamer modified bioelectrochemical sensor combines the characteristics of the high specificity of the DNA aptamer and the high sensitivity of an electrochemical detection method and ensures that the early diagnosis of cancer cells becomes possible.

The invention discloses a construction method and application of SERS aptasensor based on nano-assembly structure. The method comprises the following steps: respectively modifying surfaces of gold nano-rod and gold nano-particle with two kinds of DNA complementary with an ochratoxin A aptamer segment part to form two nano-probes; then assembling an assembly nano-structure under complementary pairing connection of the two nano-probes and the DNA aptamer, and labeling a Raman beacon molecule on the assembly nano-structure; and adding a solution of a substance for detecting, and detecting the concentration of the assembly nano-structure by utilizing the fact that the SERS signal intensity of the assembly nano-structure is influenced by the substance for detecting. By adopting the method, reaction in a liquid environment is uniform, the detection has high sensitivity and high specificity, only one-step reaction is required, and the operation is simple.

The present invention relates to a carbon nanotube transistor biosensor with aptamers and a method for detecting a target material using the same, more particularly to a carbon nanotube transistor biosensor recognizing the target material, i.e., a specific molecule (such as a protein, a peptide, an amino acid, and an organic / inorganic compound) by using DNA aptamers and a method for screening a target material using the same. In the biosensor of the present invention, the aptamers binding specifically to a particular protein are adsorbed on a carbon nanotube constituting the channel domain of carbon nanotube transistor to easily detect / identify a particular protein via the electric conductivity of carbon nanotube that varies if the particular protein is exposed to corresponding aptamers.

Methods are described for improvement of the serum half life of therapeutic nucleic acids by 3′ conjugation to useful target proteins, or other large molecules with useful function. In one embodiment, a 3′ A, C or G overhang is added to ds-DNA and the primary amines conjugated using biocompatible bifunctional linkers to proteins. The resulting nucleic acid-3′-conjugates are serum nuclease-resistant and retained in vivo for long periods without rapid kidney clearance. Further, the choice of conjugate imparts additional functionality to the nucleic acid-3-conjugate. For example, if the protein in the DNA-protein conjugate is the first component of the complement cascade (Clq or Clqrs) and the DNA aptamer has been developed against surface components of a target cell, it can be used to treat bacterial or parasitic infections and cancers. If the protein is serum albumin or another common (nonimmunogenic) blood protein and the aptamer is directed against a toxin or venom, the aptamer-protein conjugate can be used as an antidote that binds and neutralizes the toxin or venom. Similar DNA (aptamer)-nanotube, -enzyme, and -toxin conjugates could also be used to target and selectively kill bacteria, parasites, and cancer cells in vivo. If the protein is an Fc antibody fragment or C3b protein from the complement system and the aptamer is developed against a bacterial cell capsular material, other cell surface component or viral cell surface component, then the aptamer-3′-protein conjugate can aid in opsonization of the target cells or viruses by phagocytic leukocytes.

The invention discloses a DNA (Deoxyribose Nucleic Acid) aptamer for detecting grouper iridovirus infection, as well as a screening method and an application of the DNA aptamer. Two inverse screening steps are introduced in each screening process; first, a single-stranded DNA library of the former screening process is bound with normal cells to remove nonspecific ssDNA (single-stranded DNA) bound with the normal cells of a grouper; then, supernatant is bound with grouper iridovirus infected cells for screening; and ssDNA separated from the grouper iridovirus infected cells is bound with the normal cells for separation to obtain the supernatant. A PCR (Polymerase Chain Reaction) amplification library prepares the single-stranded DNA library. The above screening flow is repeated; compared with the number of the normal cells in the first screening process, the number of the normal cells in the screening process is increased by 2-6 times; compared with binding time of the library and the cells in the first screening process, the binding time of the library and the cells in the subsequent screening process is increased to 1h from 0.5h; and the binding time of the library and the virus infected cells is shortened to 0.5h from 1h to improve the screening efficiency of each process.

The invention discloses a DNA (Deoxyribose Nucleic Acid) aptamer for detecting grouper iridovirus infection, as well as a screening method and an application of the DNA aptamer. Two inverse screening steps are introduced in each screening process; first, a single-stranded DNA library of the former screening process is bound with normal cells to remove nonspecific ssDNA (single-stranded DNA) bound with the normal cells of a grouper; then, supernatant is bound with grouper iridovirus infected cells for screening; and ssDNA separated from the grouper iridovirus infected cells is bound with the normal cells for separation to obtain the supernatant. A PCR (Polymerase Chain Reaction) amplification library prepares the single-stranded DNA library. The above screening flow is repeated; compared with the number of the normal cells in the first screening process, the number of the normal cells in the screening process is increased by 2-6 times; compared with binding time of the library and the cells in the first screening process, the binding time of the library and the cells in the subsequent screening process is increased to 1h from 0.5h; and the binding time of the library and the virus infected cells is shortened to 0.5h from 1h to improve the screening efficiency of each process.

The invention discloses a DNA (Deoxyribose Nucleic Acid) aptamer for detecting grouper iridovirus infection, as well as a screening method and an application of the DNA aptamer. Two inverse screening steps are introduced in each screening process; first, a single-stranded DNA library of the former screening process is bound with normal cells to remove nonspecific ssDNA (single-stranded DNA) bound with the normal cells of a grouper; then, supernatant is bound with grouper iridovirus infected cells for screening; and ssDNA separated from the grouper iridovirus infected cells is bound with the normal cells for separation to obtain the supernatant. A PCR (Polymerase Chain Reaction) amplification library prepares the single-stranded DNA library. The above screening flow is repeated; compared with the number of the normal cells in the first screening process, the number of the normal cells in the screening process is increased by 2-6 times; compared with binding time of the library and the cells in the first screening process, the binding time of the library and the cells in the subsequent screening process is increased to 1h from 0.5h; and the binding time of the library and the virus infected cells is shortened to 0.5h from 1h to improve the screening efficiency of each process.

The invention discloses nucleic acid aptamers specifically combined with beta-amyloid precursor protein lyase 1 and an application of the nucleic acid aptamers. The nucleotide sequences of the nucleic acid aptamers are any one of SEQ ID NO: 1 and SEQ ID NO: 2. The nucleic acid aptamers or chemical modifiers of the nucleic acid aptamers serving as BACE1 inhibitors can be applied to preparing drugs for treating Alzheimer's disease. The DNA aptamers A1 and A4 which can be combined with BACE1 with high affinity are successfully screened by virtue of an SELEX technology in the research, and the aptamers have the effect of inhibiting the in vitro activity of the BACE1. The nucleic acid aptamers are used for providing a research basis on development of novel potent and specific BACE1 inhibitors and providing novel methods and concepts to treatment of AD.

The present invention discloses the preparation of a two-color fluorescent gold bearing carbon dot and application of the two-color fluorescent gold bearing carbon dot in visual inspection. The preparation of the gold bearing carbon dot is mainly as follows: a chloroauric acid solution and a glutathione solution are mixed and diluted with pure water; the mixed solution is heated while stirring for 1.5-2h in an oil bath at 80-100 DEG C, the mixed solution is hotly transferred into a conical flask containing glucose for heating for 20-25min at high fire in a domestic microwave oven; the resulting yellowish-brown product is dissolved with purified water, and centrifuged, the supernatant is dialyzed for 24hto obtain the product. Based on the nature of mimetic enzyme of peroxidase of the gold bearing carbon dot, the content of prostate cancer antigen in serum of patients with prostate cancer antigen can be detected by covering of two-color fluorescent gold bearing carbon dot catalytic surface sites by DNA aptamer and prostate cancer antigen specific effects, and fast visual detection of the prostate cancer antigen can be achieved. The method is simple, easy in operation, high in sensitivity, and has important significance in clinical medicine.

It is an object of the present invention to provide nucleic acid molecules that enable highly sensitive detection of ligands (e.g., patulin). It is another object of the present invention to provide a screening method for nucleic acid molecules that enable highly sensitive detection of ligands (e.g., patulin), and a method for screening for nucleic acid molecules used for the optimization of nucleic acid molecules that enable highly sensitive detection of ligands (e.g., patulin). It is a further object of the present invention to provide a method for effectively removing ligands from samples containing ligands (e.g., patulin). According to the present invention, there is provided a loop-structured nucleic acid molecule for detection of ligands (e.g., patulin) having a DNA aptamer and a DNAzyme, wherein the sequence is modified between the DNA aptamer region and the DNAzyme.

The invention provides a group of single-stranded DNA nucleic acid aptamers of fumonisin B1. Each aptamer is obtained by carrying out screening, amplification, sequencing, and analysis on affinity and specificity on a random original single-stranded DNA library with the combination of an SELEX (systematic evolution of ligands by exponential enrichment) technology and a magnetic bead with fumonisin B fixed on the surface. As a special efficient distinguishing aptamer of fumonisin B, the group of DNA aptamers provides a new choice for developing a method for replacing the existing methods which are used for detecting fumonisin B by depending on an antibody, and can be used for analyzing and detecting or separating the fumonisin B in the environment of enriched food. The nucleic acid aptamer is small in molecular weight, low in chemical synthesis cost, easy to mark, strong in affinity and specificity, reversible in degeneration renaturation, high in speed, and suitable for repeated use, room-temperature transportation and long-term storage.

Mycotoxin-deactivating aptamers, especially DNA aptamers, bind to mycotoxins in feed and feed ingredients resulting in the reduction or elimination of toxic and carcinogenic effects of mycotoxins. The invention also discloses a composition comprising a mycotoxin-deactivating aptamer, a binding agent, a biotransforming agent and an antioxidant for detoxifying mycotoxins in feeds. In addition, the invention teaches the methods of preparing said mycotoxin-deactivating aptamer-based composition and also the methods of using it as a feed additive. Furthermore, the invention relates to the use of said mycotoxin-deactivator / s alone, or in a composition comprising said aptamers and other mycotoxin-detoxifying agents, in feeds and feed ingredients for detoxifying the major mycotoxins such as aflatoxins, deoxynivalenol, zearalenone, fumonisins and ochratoxin A.

The invention relates to a fast ultra-sensitive LM (listeria monocytogene) detector based on nanochannel confinement characteristics and constructed according to the nature of specific identification between a target molecule and an aptamer of the target molecules. The invention further relates to a method for detecting the LM by taking potassium ferricyanide ions as probe ions and taking an LM DNA modified porous alumina membrane as an electrode for assembling a self-made electrolytic tank. When LM is present and the concentration is lower, a current increasing value is remarkably reduced with the increase of the concentration; a current change value is reduced with increase of the LM concentration; when the LM concentration is in a range of 100-1,250 CFU / mL, a linear relation is formed between the LM concentration and the current increasing value; when the LM concentration is higher than 1,500 CFU / mL, the current change value becomes stable. Therefore, the lowest detection limit of the detection method for the LM can reach 100 CFU / mL, the linear range is 100-1,250 CFU / mL, and the detection can be completed within 10 min; a 108 CFU / mL of escherichia coli and staphylococcus aureus control experiment indicates that the method has high selectivity on the LM.

Disclosed are a DNA aptamer specifically binding to the Her2 (ERBB2) receptor involved in the onset of breast cancer, a composition for the suppression of cancer metastasis comprising the same as an active ingredient, and a composition for the diagnosis of cancer comprising the same as an active ingredient. Due to its binding mechanism being different from that of the conventional antibody, the aptamer can be effectively used for suppressing cancer metastasis and diagnosing cancer.

Disclosed herein are a DNA aptamer specifically binding to pLDH (Plasmodium Lactate Dehydrogenase), a composition for the diagnosis of malaria, comprising the same, and a diagnostic kit for malaria using the same. Superior in specificity and stability to antibodies which are conventionally used to diagnose malaria, the DNA aptamers specifically binding to pLDH (Plasmodium Lactate Dehydrogenase) in accordance with the present invention can be developed into biosensors which determine pLDH levels with high sensitivity and accuracy, greatly contributing to the diagnostic accuracy of malaria.

The invention discloses a nucleic acid medicine loading system for targeted therapy and a preparation method of the nucleic acid medicine loading system. The system is adduct consisting of DNA (deoxyribonucleic acid) aptamers as medicine carriers and targeted probes and anticancer medicine loaded onto the DNA aptamers. The targeted identification specificity, high stability and easy modification of the DNA aptamers are utilized, and the DNA aptamer-anticancer medicine adduct is prepared, so small molecule medicine is modified onto the DNA aptamers. The DNA aptamers are very stable at the solid state or low temperature liquid state (such as the temperature below 10 DEG C) and is suitable for being stored for a long time. The adduct maintains the identification specificity of the original DNA aptamers to targeted cancer cells, medicine can be conveyed to cancer cells in a targeted way and can be gradually released at the physiological temperature, the special killing and injury effect on the targeted cancer cells is generated, the side effect is reduced, and the curative effect is improved. The nucleic acid medicine loading system and the preparation method have the advantages that the preparation process is simple, economy is realized, the efficiency is high, and the preparation process is suitable for mass production and is particularly suitable for being used for preparing the targeted medication anticancer medicine.