72results about How to "Achieve signal amplification" patented technology

The invention discloses a biomacromolecule detection platform of a magnetic particle microarray, which is established by combining magnetic nanoparticles and biochips with microfluidics technology. The magnetic nanoparticles are taken as a biomacromolecule carrier in the magnetic particle microarray. A DNA probe or an antibody is fixed on the surface of the magnetic particles to allow the magnetic particles to cross or react with a sample to be detected, thus various samples to be detected are fixed on the surface of the magnetic particles, and then the magnetic particles are spotted in a microfluid reaction cell with a magnetic substrate to form the magnetic particle microarray. A fluorescent probe or a fluorescent labeled antibody is added to the microfluid reaction cell and reacts in the reaction cell, and an obtained mixture is washed, thus obtaining information of various samples by a fluorescent biochip scanner.

The invention relates to a dual-label rapid response nucleic acid adapter probe, which consists of a nucleic acid adaptor, the 5' end and 3' end of which are labeled by a fluorescent chromogenic grouprespectively, and a complementary probe, the 5' end and 3' end of which are labeled by a fluorescent quenching group respectively. The nucleic acid adaptor is a nucleic acid adaptor which can especially identify aflatoxin B1, namely, AFB1 nucleic acid adaptor. The nucleotide sequence of the AFB1 nucleic acid adaptor is shown as SEQ ID NO: 1 in the sequence list. The complementary probe is complementary to two ends of the AFB1 nucleic acid adaptor. The nucleotide sequence of the complementary probe is shown as SEQ ID NO: 2 in the sequence list. The method can be used for rapidly detecting aflatoxin B1. The identification process, after the aflatoxin B1 is added, can be completed in one minute, and one aflatoxin B1 molecule can trigger the recovery of two fluorescent group signals with highsensitivity. The whole reaction is carried out in a homogeneous and constant temperature solution environment, and the operation is simple.

The invention relates to a continuous spectrum light source comprising a stabilized voltage power supply, a light source, an optical fiber light source set, an optical fiber coupling lens set, and an output optical fiber. The optical fiber light source set is composed of N light spectrum channels with different wavelength coverage. Each light spectrum channel comprises orderly arranged component of a collimating lens, a band pass filter, a coupling lens, and an optical fiber. Light energies from the light source pass the collimating lens, such that parallel lights are formed; when the parallel lights pass the band pass filter, light energies with wavelengths within a range of (lambda1<(j)>, lambda2<(j)>) enter the optical fiber through the coupling lens. Optical fibers of the N light spectrum channels form an optical fiber bundle. The light energies are coupled into the output optical fiber through the optical fiber coupling lens set. Through the adjustment of light energy distribution in each light spectrum channel of the optical fiber light source set, the balance of the light energies output by the output optical fiber within an entire spectral range can be realized, such that a continuous spectrum light source is composed. Or, according to a spectrum energy distribution requirement, optical coupling efficiency of each spectrum channel of the optical fiber light source set can be adjusted, such that light energies can be arbitrarily distributed according to wavelengths.

The invention discloses an electrochemiluminescence sensor based on a functionalization metal organic frame material. The sensor utilizes Hg2+ to induce a 3(2,2'-dipyridyl) ruthenium functionalizationmetal organic frame material (RuMOFs) to be decomposed to release ECL of 3(2,2'-dipyridyl) ruthenium for detecting microRNA. Novel RuMOFs is prepared through a solvothermal method, can be selectivelyand sensitively decomposed by Hg2+ to release a large number of Ru(bpy)32+ and generate powerful ECL signals. Besides, to support a large number of RuMOFs, the target recycling process does not needthe help of nuclease, and the recycle can be achieved simply through a strand displacement process. Based on a decomposition and strand displacement process of an ion response material, a hypersensitive ECL method used for detecting microRNA is built. The method proves that in the detection range of 10 fmol / L-10 Mumol / L miRNA-155, the limit of detection is 3 fmol / L, wherein R=0.9961. The biosensorhas good analysis performance of being high in sensitivity, high in specificity, good in stability and the like, and provides a prospect for sensitivity detection of microRNA in clinical application.

The invention relates to a nicking endonuclease-based netted rolling cycle amplification system and a use thereof. Based on the existing second-generation hyperbranched rolling cycle amplification technology, the amplification system utilizes a special endonuclease which is nicking endonuclease Nb.BsrDI so that a third-generation rolling cycle amplification technology which is a netted rolling cycle amplification (NGCA) technology is produced. Intensity of fluorescence signals produced by the netted rolling cycle amplification is increased with increasing of a target DNA concentration, is obviously stronger than that of fluorescence signals produced by linear rolling cycle amplification and hyperbranched rolling cycle amplification and has a detection limit of 0.1fM. Compared with the first-generation linear rolling cycle amplification and the second-generation hyperbranched rolling cycle amplification, the nicking endonuclease-based netted rolling cycle amplification system retains the prior art advantages in operationality, use cost and amplification time, further realizes signal amplification based on the prior art thereby providing good technical conditions for ultralow-abundance nucleic acid sample analysis and detection, and has a wide application prospect.

The invention discloses a preparation method of a photoelectrochemical aptamer sensor for detecting a prostate-specific antigen. Lots of cadmium sulfide quantum dots and a signal transduction probe having one end marked with graphene quantum dots are loaded on a paper-based platinum / zinc oxide nanosheet and a co-sensitization effect is activated, so that a photocurrent signal is increased; when anaptamer of a specific recognition prostate-specific antigen with gold nanoparticles labeled and the signal transduction probe are hybridized to form three strings of helical molecular switches, the co-sensitization effect is suppressed and a signal quenching effect of the gold nanoparticle is generated, and the photocurrent signal decreases; and when the prostate-specific antigen identifies the aptamer, the conformation of the three strings of helical molecular switches changes, the co-sensitization effect is reactivated, the quenching effect is eliminated, and the photocurrent signal is enhanced. And the sensitive detection of the prostate specific antigen is realized based on the converted signal.

The invention discloses an integrated ELISA (Enzyme-Linked Immuno Sorbent Assay) chip based on distance detection targets and a detection method thereof. The integrated ELISA chip is provided with a plurality of water-phase cavities and oil-phase cavities which are alternatively arranged into a line, and front cavity bodies are communicated with rear cavity bodies; water-phase inlets are formed in the water-phase cavities; oil-phase inlets are formed in the oil-phase cavities; the water-phase cavity in the leftmost side is connected with a dye cavity which is additionally provided with a third inlet; the dye cavity is communicated with a dye gas column channel; and scales are arranged beside the dye gas column channel. The integrated ELISA chip disclosed by the invention integrates fussy steps of immunological experiment, cleaning and distance signal output onto a microfluidic pneumatic chip, and can be used for high-sensitivity quantitative instantaneous detection of multiple targets such as protein and cells and the like.

The invention discloses a magnetic composite three-dimensional vector hydrophone with a target positioning and distinguishing function and a target positioning and distinguishing method of the magnetic composite three-dimensional vector hydrophone, relates to a magnetic composite three-dimensional MEMS vector hydrophone with an automatic positioning and target distinguishing function, and belongs to the technical field of hydroacoustic sensors. The magnetic composite three-dimensional vector hydrophone with the target positioning and distinguishing function and the target positioning and distinguishing method of the magnetic composite three-dimensional vector hydrophone solve the problems that according to an existing single vector hydrophone, the space target positioning accuracy is poor, and a target can not be distinguished accurately. The magnetic composite three-dimensional vector hydrophone with the target positioning and distinguishing function comprises three MEMS acceleration sensors, two pressure hydrophones, a magnetic azimuth sensor, an orthogonal adjustment frame, a signal processing circuit and a shell made of acoustic sound-transmission encapsulating materials, wherein the three MEMS acceleration sensors, the two pressure hydrophones and the magnetic azimuth sensor are all fixed to the orthogonal adjustment frame. The magnetic composite three-dimensional vector hydrophone with the target positioning and distinguishing function and the target positioning and distinguishing method of the magnetic are suitable for detection of underwater targets.

The invention provides a signal amplification system based on bioluminescence resonance energy transfer. The system relates to an energy donor protein capable of being bound to DNA, an energy receptorprotein capable of being bound to DNA and a nucleic acid assembly system composed of three kinds of DNA probes. The energy donor protein and the energy receptor protein can be specifically bound to adouble-stranded DNA product produced by the nucleic acid assembly system to achieve signal amplification of bioluminescence resonance energy transfer. The signal amplification system can be applied to the analysis of different protein markers and improves the sensitivity and the versatility of a bioluminescence resonance energy transfer detection method.

The invention provides a method for enhancing the stability of nano gold and a biological detection method adopting the same. Mononucleotide dNMP can better stabilize the nano gold than single-stranded DNA with the same composition and the same base concentration. Various nucleases with matrix selectivity can digest nucleic acid to form the dNMP. The property of the dNMP, which enables the dNMP to better stabilize the nano gold, is integrated with specific enzyme reaction, and the change of the color of the nano gold can be used to simply and conveniently detect various analytes including enzyme and DNA. The method greatly broadens the range of detected substances biologically detected by the unmodified nano gold, and increases the sensitivity of detection. Taking DNA detection for an example, the mole ratio range of a detecting probe and a target is broadened by three orders of magnitude. The method can be applied to the detection of various types of substances including micromolecules and heavy metal ions.

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 relates to a triple-amplification-technology-based homogeneous-phase label-free method for detecting the activity of telomerase. The method is characterized in that a telomerase extension product is combined with accessory DNA to release triggering DNA, and the triggering DNA can trigger a strand displacement reaction to form a hairpin H1:H2 compound; G-quadruplexes can be formed at the two tail ends of the compound respectively, fluorescence signals of NMM are weak and are remarkably enhanced after the G-quadruplexes are embedded and inserted, and the activity of the telomerase can be sensitively detected by detecting changes of the fluorescence signals of the NMM. According to the method, the strand displacement reaction is sufficiently adopted, and signal amplification can be achieved without assisting of enzymes; meanwhile, formation of the G-quadruplexes is ingeniously adopted, the method in which the activity of the telomerase can be sensitively detected without labeling is constructed, a new concept is provided for diagnosis and treatment of tumor diseases and researching of disease mechanisms, and the method is of great significance in the telomerase-based cancer treatment and diagnosis aspect.

The invention provides a surface plasma resonance sensor for detecting miRNA-21. The surface plasma resonance sensor comprises a working chip, wherein the working chip is formed by fixing a capture probe aiming at miRNA-21 on a bare gold chip. The miRNA-21 is detected by using the sensor disclosed by the invention; a calibration curve is subjected to four-parameter fitting; a regression equation refers to Y=(A1-A2) / (1+(X / X0)P)+A2, wherein A1 is equal to -69.95+ / -7.34, A2 is equal to 2890.50+ / -18.50, X0 is equal to 5.27+ / -0.16, and P is equal to 0.47+ / -0.01; the detection range is between 0.01nM and 1000nM; the correlation coefficient is 0.9978; and the lowest detection limit is 0.009nM. Compared with the prior art, the non-enzyme and label-free sensor can realize real-time monitoring, is high in sensitivity, high in specificity, low in cost, easy and convenient to operate and short in detection period, is suitable for measuring actual samples and the like and is expected to become a sensor with actual application value.

The invention discloses a high-throughput single-cell genome 5-hydroxymethylpyrimidine single-molecule visual analysis method, belonging to the technical field of analytical chemistry. According to the invention, a microfluidic chip technology is utilized to obtain agarose gel microspheres wrapping a single-cell genome; and after single cells in the agarose gel microspheres are subjected to cracking treatment, each agarose gel microsphere wraps a single cell genome. Primers are marked on 5-hmC and 5-hmU of the single-cell genome through a specific chemical reaction; rolling circle amplification is then performed; a fluorescent probe is hybridized; and single-molecule visual analysis of modified bases 5-hmC and 5-hmU is achieved. According to the invention, a large amount of liquid drops can be formed in a short time through a microfluidic liquid drop method; the high-throughput agarose gel microspheres wrapping the single-cell genome are efficiently obtained; thus, analysis of a high-throughput single-cell target object is realized; the difference caused by cell heterogeneity is avoided; accurate detection is realized; and the reaction has the advantages of specificity, high yield,simple reaction conditions, high reaction speed and the like.

The invention belongs to the technical field of biosensing detection, and relates to a preparation method and an application of a dual-ratio adapter sensor based on electrochemistry and photoelectrochemistry. Specifically, the invention proposes a novel dual-ratio adapter sensor based on electrochemistry and photoelectrochemistry methods for specifically detecting streptomycin (STR). The preparation method comprises the following steps: step 1, preparation of gold nanoparticles (Au NPs) and design of various nucleotide chain bases in a hybrid chain reaction; step 2, construction of the dual-ratio adapter sensor based on electrochemistry and photoelectrochemistry. The dual-ratio adapter sensor based on electrochemistry and photoelectrochemistry provides an effective way for reducing external environmental influences, and accurate and wide range detection of streptomycin.

The invention discloses a preparation method of a paper-based ratio photoelectrochemical biosensor for detecting microRNA. Gold nanoparticles grow on the surfaces of paper-based dual electrodes composed of a working electrode and an internal reference electrode, then cuprous oxide is electrodeposited, graphene quantum dots and silver iodide nanoparticles are sensitized, and a photocurrent signal is enhanced; when the target microRNA exists, DNA probes output by microRNA-induced double-stranded specific nuclease reactions with different concentrations and constant concentrations are respectively incubated on the surfaces of the working electrode and the internal reference electrode; DNA bridge chains and DNA hairpins H1 and H2 on the surface of the electrode are combined to form a DNA bridge nano structure through induction; and the silver iodide nanoparticles marked at the end parts of the H1 and the H2 are far away from the surface of the electrode, so that the photocurrent signal isreduced, and the sensitive detection of the microRNA is realized based on the ratio of the working current signal to the internal reference current signal.

The invention relates to a preparation method of an electrochemical DNA biosensor for detection of LPL gene SNP (rs1801177), and belongs to the technical field of electrochemical detection. The preparation method is characterized by comprising the steps: firstly, the surface of a nitrogen-doped graphene (N-G) sheet is loaded with a large number of palladium-platinum bimetal (PdPt) nanoparticles, then polyaniline is formed on the surface of the nitrogen-doped graphene (N-G) sheet by in-situ polymerization to obtain a nano composite material, next, a single-stranded DNA signal probe is mixed with the composite material, and a redox probe is prepared; secondly, a capture probe is immobilized on the surface of a sensor by a C60 / PAMAM / Au nanocomposite material, and the electrochemical DNA biosensor for quantitative detection of rs1801177 is prepared. The biosensor is successfully applied to detection of single-base mutation of a lipoprotein lipase gene. The biosensor has the advantages of high sensitivity, strong specificity, and convenient and fast detection, provides a new method for detection of rs1801177, and provides a theoretical basis and an experimental basis for clinical diagnosis and prevention of cardiovascular diseases.

The invention relates to the technical field of chemical and biological sensing, and particularly a sensor based on hybridization chain reaction and ribozyme and a carcino-embryonic antigen detectionmethod. The sensor based on the hybridization chain reaction and ribozyme comprises a nucleic acid aptamer probe and a hairpin probe, wherein the aptamer probe comprises an aptamer sequence, an initiation chain sequence and a complementary sequence, the hairpin probes comprise a first hairpin probe and a second hairpin probe, the first hairpin probe and the second hairpin probe comprise G-quadruplex ribozyme base sequences, the nucleic acid aptamer probe specifically recognizes a carcino-embryonic antigen, the aptamer probe is subjected to conformational transformation to make the first hairpin probe and the second hairpin probe form double-stranded DNA, moreover, in the presence of hemin, the first hairpin probe and the second hairpin probe are self-assembled to form hemin / G-quadruplex ribozyme, and the hemin / G-quadruplex ribozyme catalyzes and oxidizes thiamine mediated by hydrogen peroxide and emits fluorescence, so the carcino-embryonic antigen can be quantitatively detected.

The invention discloses a nanocage probe, an application thereof and a nucleic acid detection method, the nanocage probe comprises gold / silver nanocage particles, the surfaces of the particles are modified with hairpin DNA chains, and the hairpin DNA chains are partially complementary with nucleic acid to be detected; gold / silver nano cage particles are used as a nucleic acid recognition reactionsubstrate and a scattering signal indication probe; a hairpin chain is modified on the surface of the probe as a nucleic acid recognition unit; DNA circulation and HCR amplification processes are realized by utilizing DNA base complementary pairing and strand substitution reaction rules, so that G-quadruplex-heme DNA enzyme is formed on the surface of the probe, etching of a silver component in the nanocage is realized by virtue of active oxygen generated by enzymatic catalysis of hydrogen peroxide decomposition, and a light-off response of a dark field signal is caused. The dark field signalchange with the time resolution capability shows the dependence on the concentration of the nucleic acid to be detected, and quantitative analysis is carried out in combination with a statistical analysis method.

The invention relates to a preparation method for an electrochemical immunosensor for detecting an alzheimer disease marker and an application and belongs to the field of novel nanometer functional materials, immunoassay and biosensors. Gold nano-particle functional reduced graphene oxide is prepared and served as a substrate material, so that the supporting volume of a capturing antibody of the alzheimer disease marker is increased and the electron transfer rate on the electrode surface is effectively increased; a AuCuxO@CeO2 composite nano-material is prepared and served as a signal amplification label supporting detection antibody; under a synergistic effect of Au NPs, CeO2 and CuxO, the composite material is capable of further increasing the catalytic efficiency; the prepared electrochemical immunosensor can be used for detecting the alzheimer disease related marker; the electrochemical immunosensor has high specificity, high sensitivity, low detection limit, great scientific significance and application value.

The invention discloses a voltage controlled oscillator, which comprises a bipolar voltage controlled oscillator unit and an output buffer unit, wherein the bipolar voltage controlled oscillator unit has a difference structure and comprises an LC resonant circuit module and a negative resistance circuit module; the LC resonant circuit module is used for generating first oscillation signals of the needed oscillation frequency; the negative resistance circuit module comprises a pair of first bipolar transistors; the output buffer unit comprises two second bipolar transistors; bases of the two second bipolar transistors are respectively connected with a first output port of the LC resonant circuit module; and emitters of the two second bipolar transistors serve as two second output ports of the voltage controlled oscillator and output differential pairs of second oscillation signals. Power of the oscillation signals can be improved, phase noise of the circuit can be reduced in the condition of not changing the oscillation frequency of the oscillation signals, and online test can be carried out on radio frequency parameters of the oscillation signals on a radio frequency probe table.

The invention relates to the field of electrochemical sensors, and in particular, relates to a current detection method of an ion selective electrode. A redox probe is used as an indication, and quantitative detection of to-be-detected ions is realized according to the activity (concentration) of the to-be-detected ions and the current signal change of the redox probe. The redox probe is used for indicating the potential signal of the ion selective electrode, and the relationship between the ion activity and the potential signal in the Nernst equation is converted into the relationship between the ion activity and the current signal, so that signal amplification and high-sensitivity ion measurement are realized.

The invention discloses an array fiber laser device which comprises a multi-core fiber. The multi-core fiber is a capillary tube, and multiple gain fibers and coreless fibers laid in the radial direction of the capillary tube are fixed to the inside of the multi-core fiber; two end surface and side surfaces of the capillary tube are plated with high-reflective films for pump light; film layers with high reflectivity for the pump light or photoetching gratings are applied to end surfaces of the gain fibers; the refractive index of the coreless fibers is not larger than that of an adjacent medium. The invention further discloses another array fiber laser device. The coreless fibers are used for introducing the pump light into the multi-core optical fiber, and side pumping is performed on the gain fibers in the multi-core fiber for multiple times, so that multi-wavelength signals are amplified. The invention further discloses two manufacturing methods of the multi-core fiber. The laser device or an amplifier can realize multi-wavelength laser output and signal amplification, is an all-solid-state device, and is easy to operate, simple in structure and manufacturing process and low in cost.

The invention relates to an infrared signal transmission circuit of a remote controller, which comprises an NPN type triode, wherein the collector of the NPY type triode is connected to the cathode of an infrared transmission diode; the base of the NPN type triode is connected to a carrier signal wire, while an emitter is grounded; and the anode of the infrared transmission diode is connected to a signal wire for data to be transmitted. As signal modulation and signal amplification are simultaneously realized by the NPN type triode and components are reduced, the infrared signal transmission circuit and a debugging process are simplified, and the cost is saved. In addition, the infrared signal transmission circuit generates carrier signals and signals with the data to be transmitted by the same integrated chip, so the carrier signals and the signals with the data to be transmitted are not constructed by separate elements, and the accuracy is improved.

The invention relates to the technical field of nano materials, and provides a preparation method of bifunctional microspheres, which are uniformly filled with multifunctional nano elements in a high-density manner and have good biocompatibility, uniform size and stable performance, in order to solve the problems that a traditional multifunctional nano material is uncontrollable in size, poor in chemical stability and incapable of realizing maximization of multiple functions. Mono-dispersed dendritic mesoporous silica microspheres are used as a growth template, and sequential assembly of two functional elements is realized. Firstly, ferric acetyl acetonate is used as an iron source, and Fe3O4 nano-particles grow in-situ in pore channels in the dendritic silica microspheres. Through sulfydryl-metal coordination, hydrophobic quantum dots are further assembled in pore channels of the dendritic mesoporous silica microspheres in a high-density manner, so that efficient co-assembly of the two nano-elements in a carrier is realized, and the properties do not interfere with each other. The microsphere is used as a labeling probe to be applied to a detection platform, and high-sensitivity and high-accuracy detection for measuring a target substance can be realized.

The invention discloses a method for changing the number and state of nano magnetic particles based on a biological orthogonal reaction for detecting pesticide residues. According to the method, the number and the aggregation state of the nano magnetic particles are changed simultaneously on the basis of the cascade biological orthogonal reaction of diphenyl cyclooctyne and azide, controllable adjustment of the number and the state of the magnetic nano particles is realized, and magnetic signal cascade amplification is performed by organic combination of diphenyl cyclooctyne and azide, so thatthe accuracy and the sensitivity of pesticide residue detection are improved.

The invention provides an electrochemical sensor for detecting MicroRNA-21 and a detection system comprising the electrochemical sensor. The electrochemical detection electrode system comprises a working electrode, a reference electrode and a counter electrode, wherein the working electrode is obtained by fixing a capture probe aiming at MicroRNA-21 on the surface of a gold electrode. The MicroRNA-21 is detected by using the sensor or the detection system disclosed by the invention, the concentration of the MicroRNA-21 is in a linear relation in a range from 0.001nmol / ml to 25nmol / ml, the linear equation refers to Y=1.19999E<-5>+3.63774E<-6>X, the correlation coefficient is 0.9973, and the lowest detection limit is 0.6pmol / ml. Compared with the prior art, the sensor or the detection system is high in sensitivity, high in specificity, low in cost, easy and convenient to operate and short in detection period, is suitable for measuring the MicroRNA-21 in actual samples and is expected to become a sensor or a detection system with actual application values.

The invention discloses a new method for detecting single base difference (SBD) based on magnetic separation and a solid-phase single base circular extension (SBCE) technology. The method is characterized in that: magnetic particles are used as carriers for fixing extension primers of locus to be detected; under the action of Taq enzyme, specific fluorescent labeled ddNTP is extended to 3' end of the primers and genotype signals of a template are amplified by thermal cycling reaction which comprises denaturation, annealing and extension. The method is characterized by simplicity, preciseness, low cost, high flux and high sensitivity and automated operation can be realized by the method, therefore, the method is more practical than the traditional methods.

The invention discloses a method for detecting microRNA based on a triple-helix DNA structure, and relates to the technical field of fluorescent microRNA detection. A new triple-helix DNA structure is formed through the hybridization reaction between the three probes on the surface of the microfluidic paper chip, and the triple-helix DNA structure is cut into two parts under the action of endonuclease and exonuclease, One part can circulate and participate in the reaction to achieve signal amplification, and the other part reacts with the target microRNA to generate DNA-RNA double strands, and transfers the formed DNA-RNA double strands to the surface of another paper chip modified with MnO2 nanosheets and adds DSN to detect microRNA. Compared with traditional methods, this method has higher sensitivity, simple operation, and less time-consuming, which greatly promotes the development of a simple and rapid detection system, and helps us to quantitatively analyze microRNA and understand the physiological and pathological mechanisms of organisms. And finally provide new ideas and theoretical basis for the diagnosis and treatment of diseases.

The invention belongs to the technical field of nanometer functional materials, immunization analysis and biosensing and provides a preparation method and use of a Pd / V2O5 / MWCNTs-based intestinal cancer tumor marker immunosensor. Through use of Pd / V2O5 / MWCNTs as a detection antibody marker, a sandwiched electrochemical immunosensor for detecting an intestinal cancer tumor marker is prepared. Through excellent biocompatibility and high catalytic performances of Pd / V2O5 / MWCNTs, the immunosensor has the advantages of high specificity, high sensitivity and low detecting limit.