218results about How to "Realize highly sensitive detection" patented technology

The invention relates to a preparing method of a photoelectrochemical sensor based on sandwich cardiac troponin T marked by Ag2Se@CdSe and application, and belongs to the technical field of novel functional materials and biosensing detection. According to concrete contents of the preparing method and the application, CeO2-TiO2 composite nanometer materials with photoelectrocatalytic activity are used as optical activity substrate materials; Ag2Se@CdSe is used as an antibody marker; the sandwich photoelectrochemical sensor is prepared through the signal amplification effect of the marker Ag2Se@CdSe on the substrate materials, and is used for the high-sensitivity detection of the cardiac troponin T of myocardial damage specific marker. The method has the important significance on the early diagnosis and treatment of acute myocardial infarction.

The invention relates to an electrochemical method of detecting single-chain target DNA concentration based on G-quadruplex-heme compound and polymeric chain type amplification reaction, and belongs to the technical field of analytical chemistry. A capture probe and an auxiliary probe are designed, the two ends of the auxiliary probe each contain a nucleotide sequence complemented with the target DNA, and the middle of the auxiliary probe contains a base sequence capable of forming G-quadruplex. The capture probe and the target DNA recognize each other and are subjected to continuous polymeric chain type reaction to form chain-shaped polymer, the chain-shaped polymer is fixed to an electrode through the capture probe on the surface of the gold electrode, and a great number of G-quadruplex structures are introduced onto the surface of the electrode. Then, G-quadruplex and heme are combined to form the compound with powerful electrochemical signals, and the target DNA is detected through the corresponding relation among the electrochemical signals obtained through differential pulse voltammetry (DPV) scanning, the G-quadruplex-heme compound on the surface of the electrode and the concentration of the target DNA added into the system. HIV DNA in the sample is detected through the method, and an ideal effect is obtained. The electrochemical method has the advantages of being high in sensitivity and specificity.

The invention designs and synthetizes a supermolecule polymer framework material. The supermolecule polymer framework material is formed through self assembly in cyclohexanol by using naphthalimide functionalized pillar [5] arene as a subject and bilateral quaternization pillar [5] arene as an object, wherein the mole ratio of the subject to the object is 1:1. Through competitive coordination mechanism, the supermolecule polymer framework material (SOF-AP5-MJP5) and a metal supermolecule polymer framework material (M-SOF-AP5-MJP5) can respectively realize continuous response and high-sensitivity detection to Fe<3+> and H2PO4<->; the recognition performance has important application values in the field of ion recognition.

The invention belongs to the technical field of electroanalytical chemistry and specifically discloses a novel ionic liquid 4-hydroxy-1-methyl-1-(3-pyrrole propyl)-piperidine bromine salt and an electrochemical sensor based on an ionic liquid-graphene oxide composite nanometer material modified electrode. According to the invention, interface characteristics of the modified electrode are inspected by AC (alternating current) impedance spectroscopy and electrochemical behaviors of honokiol on the modified electrode are researched by voltammetry. As shown by the result, honokiol has a pair of reversible redox peaks on the modified electrode. Compared with a bare glassy carbon electrode, the modified electrode has the advantages that the peak current of the redox peaks of the honokiol on the modified electrode is greatly reinforced, a good linear relation is built between the peak current and honokiol of which the concentration is between 3.0*10<-8> and 1.0*10<-5> mol.L-1, and the detection limit is low. The electrochemical sensor prepared by the invention is successfully applied to the detection of honokiol in traditional Chinese medicine cortex magnoliae officinalis, so that the industrial prospect is good.

The invention discloses a method for detecting antitumor drugs by constructing an electrochemical sensor with two ratios in a same system. The method specifically comprises the following steps that 1, the antitumor drugs and two electrochemical active substances are added into a phosphate buffer solution to prepare a mixed solution; 2, a bare glassy carbon electrode is taken as a working electrode to be placed in an electrolyte solution containing the mixed solution to be stabilized for a period of time, and then square wave voltammetry detection is conducted; 3, ratios (I1 and I2) of peak currents of the antitumor drugs with the different concentrations to peak currents of the other two electrochemical active substances with the different current peak positions are obtained, linear equations are constructed for the concentrations of the antitumor drugs according to I1 and I2, and then the electrochemical sensor with two ratios can be developed. The method is easy to operate, mild in condition and high in antijamming property, stability and sensitivity, can be used for efficient detection on the anthracycline antitumor drugs in serum and has an important application prospect in the fields of bioanalysis and clinical diagnosis.

The invention discloses a method for detecting nucleic acid or cells based on enzymatic cycle amplification and nano-particle reinforced SPR (surface plasmon resonance). Strand displacement cycle amplification and rolling circle replication amplification are triggered by a target DNA (deoxyribonucleic acid), a double-signal amplification reaction is formed, a magnetic bead is taken as a DNA carrier and serves as a transfer station for signal amplification, a magnetic bead bio-barcode probe has a strand displacement cycle amplification reaction as a reaction unit and also increases the load capacity of a rolling circle replication product as a signal amplification carrier, a multi-stage signal amplification system is formed, high-sensitivity detection of the target DNA is realized with gold nano-particles as signal probes with an SPR technique, and the limit of detection can reach 1fM.

The invention relates to an acetylcholinesterase biosensor and an application thereof, and belongs to the technical field of electrochemical detection. The biosensor is produced through the following steps: 1, preparing a MnO2-nanoflakes composite nano-material and a Pd-Pt@MnO2-nanoflakes composite nano-material from KMnO4, CTAB, PdCl2, PEG400, H2PtCl6, sodium citrate and sodium borohydride used as initial raw materials through a water bath technology; and 2, immobilizing acetylcholinesterase by using chitosan (CS), and immobilizing acetylcholinesterase (AChE) on the surface of a Pd-Pt@MnO2 modified glassy carbon electrode through adopting physical adsorption to construct the electrochemical biosensor. The biosensor adopting an electrochemistry and enzyme sensing combination technology realizes high-sensitivity detection of methyl parathion and carbofuran pesticides, has the advantages of small amount of a required sample, short detection time, high sensitivity and low cost, and is suitable for analyzing and detecting pesticide residual.

The invention relates to a surface-enhanced Raman technology based on signal-off and used for detecting intracellular telomerase activity. According to the technology, graphene, carbon nitride, MoS2, SiO2 and the like are taken as carriers, nano-gole or nano-silver with controllable dimension and morphology or a composite magnetic nano-particle with a core-shell structure is supported by the carriers, and then a hairpin probe containing a telomerase primer and a Raman molecule beacon is fixedly disposed on the nano=particle surface, so that the high-sensitivity high-selectivity SERS detection method based on signal-off is established. When a target exists, the primer extends and generates a DNA chain with a repeat sequence under the effect of telomerase, and the DNA chain is hybridized with the probe molecule, then the DNA hairpin structure is opened, a Raman signal molecule with the single-chain labeled end is far away from a Raman substrate, the Raman signal is reduced, and high-sensitivity detection on telomerase is realized. The probe prepared by taking Hela cervical carcinoma cell as a model realizes intracellular telomerase activity detection and dynamic detection on intracellular telomerase activity variation under effect of a telomerase inhibiting medicament. By using multiple cells for imaging, the probe is confirmed to be capable of distinguishing tumor cells and normal cells.

The invention discloses a method for preparing a molecularly imprinted paper chip sensor through the click chemistry technology. The Adobe Illustrator CS4 is adopted for designing paper chip printing patterns, a wax springing printer is adopted for printing patterns in batches to paper, heating and wax melting are carried out to manufacture a hydrophobic wall, a working electrode, a reference electrode and a counter electrode are printed through the screen printing technology, and gold nanoparticles grow on the paper filter surface by the adoption of a seed growth method. Azide alkyl mercaptan is fixed to the paper fiber gold nano material surface and subjected to a click chemistry reaction with propargyl acrylate, a functional monomer of synthetic organophosphorus pesticide molecularly imprinted polymer is selected, template molecules, the functional monomer, quantum dots, the cross-linking agent, the pore-foaming agent, the initiator and the organic solvent of organophosphorus pesticides are evenly mixed according to a certain substance amount, a polymerization reaction is induced under 365nm ultraviolet light, and a paper fiber surface molecularly imprinted polymer film is prepared. High-selectivity, high-sensitivity, low-cost and real-time-detection for organophosphorus pesticide is achieved by the adoption of a photoinduced electricity chemical method.

The invention discloses a preparation method and application of an electrochemical biosensor based on a nucleic acid-like CoA-Au(I) coordination polymer capable of simulating peroxidase character. The preparation method comprises the following specific steps: (1) dissolving graphene into an acetic acid buffer solution and ultrasonically dispersing in an ultrasonic cleaner to obtain graphene dispersion liquid; (2) evenly mixing coenzyme A, chloroauric acid and a phosphoric acid buffer solution in a PCR pipe, continuously oscillating to enable gold ions to be reduced and obtaining a CoA-Au(I) coordination polymer in room temperature; (3) electrolytically depositing graphene on a bare glassy carbon electrode and then dropwise adding a CoA-Au(I) coordination polymer solution to be used for detecting hydrogen peroxide and hydrogen peroxide concentration in a biological sample. The electrochemical biosensor has the advantages of good specificity, high flexibility, quick detection speed, accurate and reliable result and low cost.

The present invention discloses a quaternary hybrid magnetic composite functional material and a preparation method thereof. The composite material is a quaternary hybrid of Ag@AgX, reduced graphene oxide and magnetic nanomaterials. First, the surface of the rGO is sequentially in situ deposited with Fe3O4, MnFe2O4, ZnFe2O4, CoFe2O4 and other iron-based magnetic nanomaterials and grown with AgX precipitate so as to obtain rGO / MFe2O4 / AgX ternary complex nanomaterials; and then the ternary complex nanomaterials are exposed to a mercury lamp to obtain the quaternary hybrid magnetic composite material rGO / MFe2O4 / Ag@AgX. The material not only has the magnetically responsive property and externally applied magnetic field controllability of magnetic particles, the high adsorption performance, electrical conductivity and other properties of graphene nanomaterials, the photocatalytic property of plasma material Ag@AgX, but also has the surface enhanced raman spectroscopy activity of Ag particles, and the synergistic effect between Ag@AgX and graphene materials enhances the photocatalytic property of Ag@AgX and the SERS activity of Ag, so that the detection limit of the substance to be detected is increased. The material has great potential application value on one-step concentration, magnetic separation, SERS detection and in situ photocatalytic degradation and other aspects of low concentrations of benzene ring organic pollutants in water.

The invention discloses an SERS sensor for integrated detection of tumor protein and nucleic acid markers and a preparation method thereof. The SERS sensor comprises a silver nanorod array substrate and an SERS probe, wherein the surface of the silver nanorod array substrate is modified with a tetrahedral DNA structure; the tetrahedral DNA structure is formed by self-assembling six DNA single chains, and three DNA single chains are arranged on three edges of the tetrahedral DNA structure, are respectively connected with three capture chains and are used for respectively and specifically binding nucleic acid and a protein marker. The detection limits of the SERS sensor for detecting nucleic acid and protein respectively reach the Amol / L magnitude and the fg / mL magnitude; the integrated detection of various nucleic acid and protein biomarkers in complex environments such as serum can be realized. The sensor disclosed by the invention is simple to prepare, high in detection sensitivity and good in reliability, can realize high-sensitivity detection of biomarkers with extremely low abundance in the early stage of lung cancer, and has good universality for various tumor biomarkers.

The invention relates to the technical field of a biosensor, and particularly relates to a fluorescence biosensor for detecting UDG (Uracil-DNA Glycosylase) on the basis of a polymerase-assisted feedback rolling circle amplification and endonuclease amplification fluorescence method. The invention aims to solve problems of both low specificity and low sensitivity of a method for detecting UDG in the prior art. The biosensor for detecting the UDG on the basis of a feedback rolling circle amplification technology achieves a rolling circle amplification effect on matching of phi29 polymerase andendonuclease IV, implements fluorescence resonance energy transfer of a fluorophore and a Quenching group and performs a homogeneous reaction on mixed liquid. A preparation method comprises: constructing a circular template and a composite probe; feeding back a rolling circle amplification signal and carrying out fluorescence detection. Specific hydrolysis of the UDG on a basic group U is utilized, and by utilizing such specific reaction, the UDG can be accurately measured and meanwhile, interference can also be avoided; by utilizing endonuclease IV circle amplification, a signal amplificationeffect is achieved.

The invention discloses a DNA electrochemical sensor based on target DNA repetitive sequence self enhancement and amplification signal. A signal probe is designed by a repetitive sequence clip of a detected target chain, thus, the volume of the signal probes combined with the target sequence is increased, and a compound is formed, when a capture probe on electrode surface is hybridized with the target sequence, the amplified signal probe is combined with the electrode surface, under the affinity function between the biotin treated by end labeling of the signal probe and the avidin modified on the horseradish peroxidase, multiple enzymes are combined with a 'sandwich' structure, finally, under the efficient catalytic action of the enzymes, H2O2 is catalyzed to oxidize the TMB, the oxidative product generates an amplified reduction current signal on the electrode, and the concentration of the target DNA is judged according to the magnitude of the current signal. In the experiment, based on the characteristics of self enhancement and amplification signal of the target chain of the repetitive sequence, the target chain with two sections of repetitive sequences is detected, and the method is high in sensitivity.

The invention discloses a method for capturing cells by the aid of magnetic nano-particles. The method includes that the magnetic nano-particles and samples with the circulating tumor cells (CTC) are blended with one another, the circulating tumor cells CTC and the magnetic nano-particles are combined with one another to obtain circulating tumor cells CTC with magnetic nano-particle markers, the samples with the circulating tumor cells CTC with the magnetic nano-particle markers flow through capillary tubes with the sectional inner diameters of 1 mm at the flow rate of 2-10 ml per hour, magnetic fields are applied to the peripheries of the capillary tubes when the samples flow through the capillary tubes, the circulating tumor cells CTC with the magnetic nano-particle markers can be deflected under the effects of the magnetic fields to be attracted by the magnetic fields, but normal cells which are not marked by the magnetic nano-particles in the samples can continue flowing through magnetic field zones to be collected by sample collecting pools; the magnetic fields on the peripheries of the capillary tubes are removed, the circulating tumor cells CTC, which are adsorbed on the walls of the capillary tubes, with the magnetic nano-particle markers are washed down by solution and are collected to obtain the tumor cells. The method has the advantages that the circulating tumor cells can be quickly captured by the aid of the method, and the method is easy and convenient to implement, easy to operate and high in universality.

The invention belongs to the fields of manometer functional materials, immunoassay and biosensing technique. The invention provides a preparation method of a copper sulphide / silicon dioxide doubly-weakened cadmium sulfide / carbon doped titanium dioxide insulin photoelectrochemical sensor. According to the method, the steric-hinerance effect of silicon dioxide as well as the competitive consumption effect of copper sulfide for electron donor ascorbic acid and the competitive absorption effect of copper sulfide for an excitation light source are specifically adopted, and photo-signals generated by a substrate cadmium sulfide / carbon doped titanium dioxide sensitization structure are doubly weakened, so that high sensitivity detection for insulin is realized. The method has the advantages of simple preparation, low cost, quick detection, high sensitivity and easy microminiaturization.

The invention discloses a lead ion alternating-current impedance sensor research based on a hybridization chain reaction (HCR) and TdT modulation double signal amplification. The research comprises the following specific steps: treating Au; modifying with HP; uniformly mixing reaction buffer, a hairpin probe H1 and a hairpin probe H2, and dripping the mixture onto the surface of an electrode; carrying out an HCR; then uniformly mixing TdT buffer, dATP, dGTP and TdT, and dripping the mixture onto the surface of the electrode; carrying out a TdT amplification reaction; and dropwise adding Pb<2+>, hemin, DAB and H2O2 in sequence, and marking as IP / G4 / HCR / Au for electrochemical impedance spectroscopy (EIS) detection. In the sensor preparation process, the influences of a series of sensors prepared by Pb<2+> concentration research on an electrochemical impedance signal are changed. The lead ion alternating-current impedance sensor research has the advantages of high sensitivity, high detection speed, accurate and reliable result and low cost.

The invention discloses a preparation method for synthesizing a silver nanocluster electrochemical biosensor based on a DNA signal amplification technique and an application of the electrochemical biosensor, wherein the preparation method comprises the following specific steps: (1) dissolving graphene in an acetic acid buffer solution, and carrying out ultrasonic dispersion in an ultrasonic cleaner to obtain a graphene dispersion liquid; (2) dissolving a phosphoric acid buffer solution, a DNA reaction solution after extension and a silver nitrate aqueous solution in secondary distilled water, and mixing in a PCR tube evenly, then carrying out ice bath incubation to make silver ions combined with DNA, then adding a sodium borohydride aqueous solution, carrying out sustained oscillation to make the silver ions reduced, and carrying out light shielding reaction at room temperature to obtain silver nanoclusters; and (3) electrodepositing the graphene onto a bare glassy carbon electrode, then dropwise adding the DNA-AgNCs solution, and carrying out light shielding assembly and rinsing to obtain the product. The silver nanocluster electrochemical biosensor can be used for detection of the concentration of hydrogen peroxide and TdT enzymes, and has the advantages of good specificity, high sensitivity, high detection speed, accurate and reliable results and low cost.

The invention discloses a photo-thermal release signal enhanced type thyroglobulin electrochemiluminescence immunosensor. According to a construction method of the sensor, a silicon-based titanium dioxide magnetic bead is used as a substrate to fix a thyroglobulin antibody, mesoporous silica marked thyroglobulin adsorbing bipyridyl ruthenium is used as a signal probe, and a competitive immunosensor is constructed through specific recognition between an antigen and the antibody. An electrode for modifying the antibody is placed into a mixed solution containing different concentrations of free antigens and a certain amount of signal probes, so that the free target antigen and the signal probe compete to bind the antibody, and a certain luminous intensity can be generated by combining the electrode of the signal probe. Under the irradiation of an 808 nm infrared laser, a sensing interface is rapidly heated, the dipyridyl ruthenium adsorbed by the mesoporous silica is released, and a luminous signal is remarkably enhanced along with the temperature rise, so that signal amplification is realized. As the concentration of the free target is increased, the number of the signal probes combined with the antibody is reduced, the luminous intensity is also reduced, and an electrochemiluminescence analysis method for the thyroglobulin can be established on the basis of the phenomenon.

The invention provides a preparing method and application of mimic enzyme with double catalysis functions based on a hemin mediation gold mineralization path. The one-pot type in-situ synthesis method is adopted, the hemin and chloroauric acid are mixed under the alkaline condition, then gold in-situ biological mineralization is achieved with the hemin as a reducing agent and a stabilizing agent, and a Hemin-AuNCs compound with Hemin peroxidase catalysis and gold catalysis activity is prepared. The function of a nano wire of the Hemin-AuNCs compound is brought into play, the electronic transmission capability of the Hemin catalysis reaction is promoted, meanwhile, the adsorption capability for a substrate is enhanced, and the catalysis activity of the Hemin-AuNCs compound is obviously higher than that of common Hemin by four or more times. Complex photoelectric instrument usage is not involved in the preparing method, and the beneficial effects that the catalysis activity is high, operation is simple, response is fast and cost is low are achieved. The cancer biomarker alpha fetoprotein immunoassay serves as the example, the Hemin-AuNCs compound is applied to marking of an AFP antibody, then, the enzyme linked immunosorbent assay is adopted, and high-sensitivity detection on the cancer biomarker alpha fetoprotein in blood is achieved through the enzymatic catalysis and gold catalysis silver deposition signal amplification path.

The invention discloses a multi-mode ionization source, a multi-mode ionization source system, a mass spectrum, and a method for analyzing a to-be-tested sample with the mass spectrum. The multi-mode ionization source comprises a capillary tube, an internal electrode, an insulating tube, an external electrode, a tee fitting, an insulating sleeve, a metal ring, a conductive member and a regulating member, wherein the outlet of the internal electrode in the axial direction is located between the insulating tube and the outlet of the outer electrode. The multi-mode ionization source can be easily switched between two modes of electrospray ionization and plasma ionization, which can effectively improve the efficiency of analysis and detection, avoid the complicated dismounting process of the ionization source and realize the highly sensitive detection of components in the complex sample. The multi-mode ionization source is especially suitable for a variety of polar and non-polar small molecule compounds.

The invention discloses a preparation method and a detection method of high-sensitivity paper capable of rapidly detecting algal toxin through Raman visualization and belongs to the technical field of nanometer materials and biochemical detection. The preparation method comprises the following steps: preparing an algal toxin antibody, preparing spherical and star-like nano particles, preparing a gold-labeled antibody with a Raman signal, assembling a paper-based Raman test strip and application in algal toxin detection. The invention provides a high-sensitivity paper-based Raman visualization method for rapidly detecting the algal toxin. The nano particles with the Raman signal are synthesized, the algal toxin antibody is labeled, and the method is used for performing high-sensitivity detection on the algal toxin by combining the immunogold labeling technique (ICA) with a Raman detection instrument.

The invention discloses a method for preparing a DNA self-assembly electrochemical biosensor through utilizing DSN and DNAzyme. According to the method, the complementary pairing principle of DNA and RNA is utilized; a functional probe with a hairpin structure is designed; when a target object (a to-be-detected sample microRNA) exists, the specific endonuclease (DSN) cuts the DNA part of a DNA-RNA hybrid, so that 8-17 NDAzyme is obtained; the 8-17 NDAzyme specifically identifies and cuts adenine ribonucleotide rA site in an H2 sequence fixed onto an electrode surface; after the electrode surface is specifically cut by the NDAzyme, a DNA sequence which is connected with the electrode surface is sequentially assembled with a sequence Link 1, a sequence Link 2, a sequence H3 and a sequence H4, so that the electrochemical biosensor can be formed so as to be used for target detection. The established method has high sensitivity and can be used for directly detecting the microRNA of a complex system.

The invention belongs to the field of micromolecular detection, and relates to a method and a kit for fluorescence detection of micromolecular mycotoxin based on a metal organic framework and upconversion nanoparticles. The method comprises the following steps: S1, obtaining an up-conversion nanoparticle probe modified with a micromolecular mycotoxin aptamer; S2, carrying out synthesis and activation of MIL-101 (Cr); S3, combining the micromolecular mycotoxin with the aptamer; and S4, carrying out signal detection: detecting a fluorescence signal of a product obtained by the reaction in the step S3 by adopting a fluorospectro photometer. The upconversion nanoparticles doped with rare earth are adopted, the fluorescence intensity is stable, the background value is low, and compared with other methods, the fluorescence detection kit does not need complex operation steps, is high in applicability, high in detection result sensitivity and good in specificity, and can be applied to rapid detection of on-site samples.

The invention discloses a method for detecting the activity of DNA methyltransferase based on single-ribonucleotide repair-mediated ligation-dependent cycling signal amplification. The method comprises the following steps: (1) adding a Dam MTase acted hairpin substrate to a resection reaction buffer solution, and carrying out a cleavage reaction to produce a 24-nt product; and (2) adding the cleavage product to an amplification reaction buffer solution, carrying out a cyclic linkage-dependent strand displacement amplification reaction to cyclically generate an enhanced fluorescent signal, anddetecting the intensity of the fluorescent signal to determine the activity of the Dam MTase. The method can effectively inhibit nonspecific amplification independent of a target and a template / primer, so the background signal is greatly reduced, and the index amplification of the signal is finally achieved. The method has a high sensitivity and a high specificity, and the lower detection limit can reach 4.8 * 10<-6> U / mL.

The invention discloses a boron-doped carbon-base fluorescent nano material, and a preparation method and application thereof. The surface B atom content of the nano material is 11.61%; and a hydrothermal process is utilized to prepare the boron-doped carbon-base (B-Cdots) fluorescent nano material which is used for detecting lead ions and copper ions. The simple hydrothermal synthesis process is adopted to synthesize the high-B-content B-Cdots fluorescent nano material, thereby effectively enhancing the B atom doping content, being beneficial to widening the application range of the carbon-base fluorescent material in environmental detection, solving the technical problem of demands for harsh experimental conditions by the synthesis of the B-doped nano material, and implementing the high-selectivity detection on heavy metal ions. The fluorescent experiment test indicates that the B-Cdots fluorescent nano material has favorable specific effects on Pb<2+> and Cu<2+>, and can implement high-sensitivity detection on the Pb<2+> and Cu<2+>. The product not only can be used for detecting heavy metal ions, but also can be used as a fluorescent probe for other fluorescent sensors and in the fields of pollutant treatment, preparation of fluorescent device materials and composite nano materials, and the like.

The invention relates to an electrochemical method for detecting androgen receptors based on an androgen receptor recognition element and a G-quadruplex hybridization chain amplification reaction, andbelongs to the technical field of analytical chemistry and clinical diagnosis. According to the method, by using the protective effect of an androgen receptor (AR) to an androgen receptor recognitionelement (ARE), the AR is bound to double-stranded DNA having a specific sequence (ARE) in the presence of the AR so as to protect from restriction endonuclease NspI cleavage, and a large number of G-quadruplex structures are aggregated on a DNA probe immobilized on the surface of an electrode and containing the ARE through sequence complementation by using a hybridization chain amplification reaction; and the G-quadruplex-heme complex having redox activity and bound on the surface of the electrode is positively correlated with the AR concentration, the peak current signal is determined by using a differential pulse voltammetry (DPV) method, and the quantitative analysis of the AR is achieved through the linear relationship between the current value and the AR concentration. According to the present invention, the method has advantages of high sensitivity, good specificity and the like, and is suitable for the quantitative analysis of the AR concentration in clinical samples such as human serum and the like.

The invention discloses a method for detecting transcription factors on the basis of cooperative masking effect and binding protection effect mediation cascade signal amplification strategies. The method has the advantages that masking effects are applied to biosensing, DNA (deoxyribonucleic acid) masking single strands designed and are hybridized with excessive recognition probes to obtain stable double strands, and accordingly false positive signals due to incompletely removed excessive recognition probes can be eliminated; the method is bound with binding protection effects of targets, cascade signal amplification, including SDA (strand displacement amplification) and ERCA (exponent rolling circle amplification), can be triggered, and accordingly the transcription factors and practical samples can be detected in a high-sensitivity manner.

The invention discloses a preparation method of an electrochemical biosensor for simultaneously detecting HAT and TdT and application thereof. The method comprises: step one, adding MCH dropwise ontoa hairpin DNA modified electrode surface induced by Hg<2+> and marking the processed electrode as Electrode 1; step two, taking acetyltransferase p300, polypeptide and acetylcoenzyme A respectively and mixing the acetyltransferase p300, the polypeptide and the acetylcoenzyme A fully in a phosphoric acid buffer solution (PBS, 10 mM, pH 7.0), dropping and coating the mixed solution on the surface ofthe Electrode1, and marking the obtained substance as Electrode2; step three, dropping and coating an Exo I solution on the surface of the Electrode2, carrying out incubation at a room temperature, dropping a TdT reaction solution on the electrode surface, and marking the obtained substance as Electrode3; and step four, adding Cu<2+> on the electrode surface obtained in the step three, dropping an ascorbic acid solution on the electrode surface, marking the obtained substance as Electrode 4, and detecting an electrochemical response in PBS electrolyte solution with parameters of 0.1M and pH7.0. The preparation method has the following advantages: the specificity and sensitivity are high; the detection speed is fast; the activities of two kinds of enzymes can be detected simultaneously; and the result is accurate and reliable and the cost is low.

The invention discloses a recognition probe, a regent and a method for detecting a transcription factor through a cascade signal amplification strategy on the basis of colocalization recognition and activation. By constructing new recognition mode and colocalization recognition of the transcription factor, subsequent cascade chain replacement and amplification are activated, high-sensitivity NF-kB p50 detection is achieved, and the detection sensitivity is 0.2 pM. By means of the detection method, detection of NF-kB p50 in actual samples is also achieved. Excessive fission recognition assemblies in the detection process cannot be autonomously hybridized into two-chain structures, the later cascade signal amplification process cannot be triggered, and the false positive influence caused by incomplete removal of excessive recognition probes is eliminated.