56results about How to "Highly specific detection" patented technology

The invention discloses a crRNA target point and CRISPR-Cas13a system for detecting an Ebola virus. The CRISPR-Cas13a system comprises Cas13a protein and crRNA, or a composite formed from the Cas13a protein and the crRNA, and the crRNA comprises an anchoring sequence being combined with the Cas13a protein and a guiding sequence targeted to the sequence of the target point of the Ebola virus; and the sequence of the target point of the Ebola virus is located at the 1001-1028th of the genome of the Ebola virus. The crRNA can realize high-sensitivity and high-specifity detection on the nucleic acid of the Ebola virus by activating Cas13a, and the sensitivity achieves 1 copy/test (1copy/test).

The invention provides a biosensor for detecting streptomycin based on an aptamer. The biosensor comprises a gold electrode, wherein an MB capture probe layer, HAP and an ssDNA layer are sequentially modified on the gold electrode. The invention also provides a preparation method of the biosensor. Based on specific recognition of the aptamer and the target, the sensor has the advantages of high detection speed, low detection limit, high specificity and the like, the defects of the conventional streptomycin detection method can be overcome, and rapid and accurate quantitative determination is realized.

The invention relates to a kit for detecting colorectal cancer and precancerous lesions and a use method thereof. The invention provides the kit for detecting colorectal cancer and precancerous lesions, and the kit comprises a nucleic acid separation and purification reagent, a DNA sulfite conversion reagent, a KRAS gene mutation detection reagent, an SDC2 and SFRP2 gene methylation detection reagent and a fecal occult blood detection reagent, wherein the nucleic acid separation and purification reagent is used for separating and purifying human DNA in a fecal sample; and the DNA sulfite conversion reagent is used for converting the partial purified human DNA into sulfite for subsequent detection of the methylation level of SDC2 and SFRP2 genes. The sensitivity of the kit for detecting thecolorectal cancer can reach up to 90% or more and the specificity is about 85%, thereby realizing high-sensitivity and high-specificity detection of the colorectal cancer; and the kit provided by theinvention can detect most precancerous lesions of the colorectal cancer to realize ultra-early detection of the colorectal cancer, and can greatly reduce missed diagnosis and missed detection rates of clinical existing methods when being used for assisting clinical diagnosis.

The invention relates to a DNA nano-molecule machine for exosome and surface protein analysis and application. The DNA nano-molecule machine comprises an identification probe generating response to asurface marker of an exosome, a signal probe containing two Toehold regions and a fuel probe capable of driving cycling of a strand displacement reaction. The exosome is subjected to polyvalent conjugation with a specific aptamer in the identification probe through the surface marker of the exosome, so as to release an initiating strand in the identification probe; the initiating strand invades the signal probe and drives branches of the strand to migrate and release a quenching strand through being conjugated with a Toehold region I, a fluorescence reporter group is liberated, and a concealedToehold region II is exposed; and the fuel probe starts up a Toehold-mediated strand displacement cyclic reaction through being conjugated with the Toehold region II, and continuous branch migrationand polyvalent recovery occur. Supersensitive quantitative detection on the exosome can be achieved; bi-color or multicolor analysis on two or more kinds of protein markers on the surface of the exosome can be achieved; and the operation is simple, the consumed time is short, the sample consumption is low, the sensitivity is high, and the specificity is good.

The invention provides a biosensor for detection of mercury ions based on aptamer. An electrode is modified by an HAP2 layer and an HAP1 and probe1 layer in order. The invention also provides a preparation method of the biosensor. The biosensor provided by the invention has stable performance and good electrode repeatability, thus being suitable for mercury ion detection in food safety and biosensor industrialization practical application.

The invention relates to the technical field of biosensors, in particular to a fluorescent biosensor for detecting triphosadenine based on rolling circle amplification and incision enzyme feedback amplification. The biosensor comprises two aptamer DNA sequences, a linear padlock probe, a connecting probe, an AP probe, a T4 DNA ligase buffer solution, exonuclease I, exonuclease III, a PBS buffer solution, dNTP, phi29 DNA polymerase and endonuclease IV. A preparation method of the fluorescent biosensor comprises the following steps: (1) constructing an annular template to prepare a compound probe; and (2) combining a compound probe with an incision enzyme and a target object to achieve signal amplification. The probe can be used for achieving detection of high specificity and ultra-sensitivity. The fluorescent biosensor is mild in reaction, fast to detect and good in repeatability.

The invention relates to the technical field of biosensors, especially relates to a fluorescent biosensor based on hybrid chain reaction amplification, and solves the problems in the prior art that the method for detecting ampicillin is low in specificity and sensitivity, and the cost is high. According to a biosensor for detecting the ampicillin based on an aptamer, a cyclic amplification effectis realized by the cooperation of Nb.BbcCI and a chain hybrid chain reaction, and Thioflavine-T and G-quadruplex are combined to generate fluorescence and a homogeneous reaction mixed solution. The preparation method comprises the following steps of preparing gold nanoparticles; modifying Walker and Track to the surfaces of the gold nanoparticles; mixing a labeled nanogold solution with the homogeneous reaction solution; performing hyperbranched hybrid chain reaction and fluorescent detection; carrying out high specificity detection on the target ampicillin by using the aptamer by utilizing the specific recognition of the aptamer; and using hyperbranched hybrid chain reaction amplification to achieve signal amplification.

The invention relates to the technical field of biosensors, and particularly relates to a biosensor for detecting exosome based on a nucleic acid aptamer. The biosensor comprises an aptamer PTK-7 Apt,CD63 Apt, a connector, a hairpin probe H1, a hairpin probe H2 and a CCRF-CEM. The invention also relates to a production method and an application thereof. Based on specific recognition of the nucleic acid aptamer and a target object, through connection of the connector, two chains of PTK-7 Apt and CD63 Apt are adjacent to each other to form a trigger, and the trigger further opens H1 and the H1opens H2 to trigger an HCR reaction so that amplification of chemiluminescence intensity signals is realized, and the aptamer biosensor is constructed. The sensor has advantages of a high detection speed, simplicity in operation, a low price, a low detection limit, high specificity and the like.

The invention relates to the technical field of biosensors, in particular to a biosensor for detecting miRNA through S specifically recognized by miRNA, conformation change of the S and rolling ring isothermal cycle amplification, and aims to solve the problems of low specificity and sensitivity and high cost of a method for detecting the miRNA in the prior art. According to the biosensor for detecting the miRNA, an electrode is sequentially modified with an S1 layer and an RCA product layer. The preparation method comprises the following steps: pretreating the electrode; modifying the S1 layer on the surface of the electrode; and modifying the RCA product layer on the surface of the electrode. The high-specificity detection on a target object is realized by utilizing the specific recognition of the miRNA; and three-step amplification of a target object signal is realized by using a DNAzyme and rolling ring isothermal amplification technology.

The invention belongs to the technical field of biosensors, and discloses a preparation method of an in-situ ratio photoelectrochemical immunosensor which is applied to detection of Cry1Ab protein in transgenic crops. Au NRs and MB are used as double sensitizers to realize double amplification of PEC signals. On the one hand, Au NRs modified CdTe QDs with an SPR effect is used as a photoelectric layer, so that initial signal amplification is realized; on the other hand, MB serving as a PEC signal enhancer is embedded into dsDNA, and secondary signal amplification is achieved. The concentration of Cry1Ab is quantitatively detected by taking the light current after the target object is added and the light current generated by the Ab2-CdSe QDs-dsDNA sensitized by the MB as a specific value respectively. The two signals are acquired at the same electrode and are mutually referenced, so that the interference of a solution matrix and environmental factors on the electrode is effectively reduced. The detection range of the photoelectrochemical sensor is 0.01-100 ng.mL <-1 >, and the detection limit is as low as 1.4 pg.mL <-1 >. The in-situ ratio PEC sensor constructed by the invention has good stability, selectivity and reproducibility, and realizes sensitive detection of Cry1Ab protein in transgenic crops.

The invention relates to a thermodynamic optimization-based high specificity nucleic acid hybridization method which is as follows: the method is mainly based on a nucleic acid reaction thermodynamic nearest neighbor model, DNA and RNA reaction thermodynamic parameters are calculated, the theoretical limit of the probe specificity can be theoretically illuminated, the specific differences and thermodynamic properties of different single base mutation can be calculated simultaneously, different nucleic acid reaction results can be simulated and predicted on a computer; and a theoretically optimized high specificity nucleic acid probe can be designed. The specificity of the probe designed according to thermodynamic calculation theoretically achieves optimal results; stability is good, the probe can be stored for a long time; the detection process is particularly simple; the detection time is short; the detection process is not influenced by ambient temperature and not influenced by solution salt ion concentration, and the thermodynamic optimization-based high specificity nucleic acid hybridization method can meet the clinical demand, and has a good application prospect in medical aspects.

The invention discloses a microRNA (Ribonucleic Acid) detection system and a microRNA detection method based on an exponential amplification reaction and Argonaute nuclease. The invention provides a microRNA (Ribonucleic Acid) detection system based on exponential amplification reaction and Argonaute nuclease, and the microRNA detection system comprises: (a) guide DNA (Deoxyribose Nucleic Acid), which is an amplification product obtained by amplifying a target object microRNA by adopting an exponential amplification reaction system; (b) an Argonaute nuclease, and a method for preparing the same; (c) the detection probe is provided with a fluorophore and a quenching group, and the detection probe comprises a region complementary to an amplification product obtained by amplifying the target microRNA by adopting the index amplification reaction system. According to the microRNA detection system provided by the invention, miRNA detection with single base specificity and high sensitivity as well as multiple miRNA detection and miRNA typing analysis are realized.

The invention discloses an enzyme-linked immunosorbent assay kit for detecting the concentration of the tumor marker DKK1. The enzyme-linked immunosorbent assay kit is composed of a porous plate coated with DKK1 monoclonal antibodies 1 with the model of 10C3, monoclonal antibodies 2 with the enzyme labeling model of 6E8, a chromogenic substrate and a substrate stop solution. The invention further discloses a preparation method and performance indexes of the enzyme-linked immunosorbent assay kit. The enzyme-linked immunosorbent assay kit matched with existing instruments in most hospitals is prepared by adopting the totally-domestic reagents, ultrahigh-sensitivity, high-specificity and low-cost detection of the concentration of DKK1 is achieved, large-scale general investigation of hepatocellular carcinoma is facilitated, and diagnosis can be carried out as early as possible to improve the health of all people of China.

The invention belongs to the technical field of biosensors and relates to a biological probe and detection method for detecting miRNA and application. The biological probe comprises a first arch probebody and a second arch probe body; the first arch probe body and the second arch probe body are both formed by complementary hybridization of terminal bases of two single-stranded linear molecules; the first arched probe body comprises a target miRNA binding sequence region, an endonuclease recognition sequence region and a DNA polymerase extension sequence region; oligonucleotide which is released through chain extension and a shear reaction of the first arch probe body and the target miRNA after binding is adopted as a secondary primer; the second arch probe body comprises a secondary primer binding sequence region, an endonuclease recognition sequence region and a DNA polymerase extension report sequence region; the second arch probe body is bonded with the secondary primer and then subjected to chain extension and a shear reaction to release a report sequence. The miRNA detection method based on mediation of the biological probe of the miRNA has the advantages of being high in sensitivity and specificity, simple in design, rapid in detection and low in cost.

The invention discloses a hybridoma cell strain secreting a monoclonal antibody against citrus tatter leaf virus, and an application of the monoclonal antibody thereof. A coat protein gene of citrus tatter leaf virus (CTLV) is cloned, and is expressed by a prokaryotic expression system; a BALB/c mouse is immunized with the expression-purified protein as an antigen, and a hybridoma cell strain 6C5 which can be subcultured stably and secretes a monoclonal antibody against CTLV is obtained through cell fusion, screening, and cloning, and the accession number is CGMCC No. 8779. The monoclonal antibody has an ascetic indirect ELISA titer of up to 10<-7>, and both the antibody type and subtype are IgG1, kappa chain. A dot-ELISA method for detecting CTLV in citrus established with the monoclonal antibody can detect the virus even when a diseased leaf is diluted by 1:640 times (w/v, g/mL). The acquisition of the hybridoma cell secreting monoclonal antibody against CTLV and its monoclonal antibody, and the establishment of a related serological detection method provide technical and material support for the diagnosis, prediction and scientific prevention and control of citrus viral diseases.

The invention provides an electrochemical sensor for detecting mercury ions based on aptamer conformation change. The electrochemical sensor comprises an electrode, wherein the electrode is successively modified with an HAP layer and a Helper layer; the invention also provides a biological preparation method based on specific identification of the aptamer. When the electrochemical sensor provided by the invention is applied to detection, the electrochemical sensor has the characteristics of high specificity, high sensitivity, low cost and rapid detection speed.

The invention discloses a real-time fluorescent nucleic acid isothermal amplification detection kit for mycobacterium tuberculosis as well as a special primer and a probe thereof, and belongs to the technical field of biomedical detection. The kit provided by the invention comprises a nucleic acid extracting solution, a detection solution a, a detection solution b, an SAT enzyme solution and the like, the nucleic acid extracting solution comprises an optimally designed specific capture probe extraction probe, target nucleic acid in a pretreated sample can be effectively enriched, extracted and purified, and the detection solution a, the detection solution b and the SAT enzyme solution which are added step by step are combined, and the high-sensitivity detection on the mycobacterium tuberculosis can be realized.

The invention relates to the technical field of electrochemical sensing analysis and detection and food detection and sensing, and relates to a magnetic COF surface molecular imprinting electrochemical sensor as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, preparing a Fe3O4 and COF composite material Fe3O4@COF by using a room temperature synthesis method, and then synthesizing the Fe3O4@COF@MIP composite material by using a surface imprinting method; and modifying the surface of a screen-printed electrode with the Fe3O4@COF@MIP in a dispensing manner, and thus, successfully preparing the electrochemical sensor based on a magnetic COF surface molecularly imprinted material. The sensor prepared by the invention can be used for high-selectivity and high-sensitivity detection of tetracycline.

The invention discloses a CRISPR-Cas13a system for detecting an SARS-CoV-2 69: 70del site and crRNA used by the CRISPR-Cas13a system. The system comprises a Cas13a protein and the crRNA; a target spot sequence of the SARS-CoV-2 69: 70del site is located at the 21753 site to the 21786 site of an SARS-CoV-2 genome, and 6 tacatg basic groups are deleted; and a crRNA sequence of the SARS-CoV-2 69: 70del site is as shown in SEQ ID NO: 3. Experiments prove that the crRNA provided by the invention can be used for realizing high-sensitivity and high-specificity detection on nucleic acid at the SARS-CoV-2 69: 70del site by activating the Cas13a, and the sensitivity reaches a single copy (1copy/test). The method has an important application value.