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

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 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 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 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 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 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 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 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 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.