70 results about "Signal amplification technique" patented technology

This invention allows ultra-low levels of virtually any biological analyte to be detected and quantified rapidly, simply and inexpensively with an electrochemical biosensor using a novel electrochemical signal amplification technique. The invention amplifies detection signals from low level analytes using an innovative sandwich ELISA structure that replaces optical labels with a massive amount of electrochemically detectable guanine rich oligonucleotide tags. Selective binding is achieved with matched pairs of either commercial or custom analyte binding materials such as monoclonal antibodies or single stand DNA. The guanine tags are eluted from the sandwich structures and hybridize with complementary cytosine rich oligonucleotide recognition probes attached to the surface of a biosensor working electrode. An electrochemical technique generates a signal in proportion to the guanine level on the working electrode which is also proportional to the analyte level in the sample. Magnetic separation and a nanosensor are used to improve the signal-to-noise ratio for measuring analyte levels 1,000,000 times lower than enzyme-linked immunosorbent assay (ELISA).

The invention relates to novel molecule detection signal amplification technique, which is characterized in that the molecule detection signal amplification technique is a biomolecule detection method with high sensitivity which is formed by streptavidin, an antigen, an antibody, polypeptide and the like which are marked by quantum dots through tyramine signal amplification and silver strengthening dyeing signal amplification. The detection method comprises the following steps: the biomolecule to be detected is combined with nucleic acid, the antibody, the antigen, the polypeptide and the like which are fixed on a solid phase material, the quantum dots are introduced to molecule to be detected through biomolecule specificity combination, silver strengthening dyeing is carried out on the quantum dots by using silver dyeing reagents, and signals are amplified. Obtained signals can be scanned through common optical scanners, analyzed through common imaging instruments or observed through naked eyes. The detection method achieves high sensitivity detection of the biomolecule on one hand, and reduces application cost of biomolecule detection on the other hand.

The invention relates to a method for detecting Salmonella on the basis of the technique for amplifying nanogold-labeled and silver-enhanced signals. The method comprises the following steps: conducting the DNA (deoxyribonucleic acid) hybridization among a Salmonella specific oligonucleotide capture probe, a nanogold-labeled specific oligonucleotide display probe and the target nucleotide sequences of pathogenic bacteria, or alternatively, conducting the direct immunoaffinity among Salmonella polyclonal antibodies, nanogold-labeled polyclonal antibodies and Salmonella, so as to form sandwiched complexes; and adding silver-enhancement solution to the sandwiched complexes to accelerate the deposition of silver particles by the nanogold particles anchored onto the enzyme-labeled pores through the hybridization or immunoaffinity, so that the sensitive detection of Salmonella can be achieved by the absorbance detection. The detection limit of the method reaches 33fmol/L (DNA hybridization analysis) or 50cfu/mL (immunoaffinity analysis); and moreover, the detection limit thereof reaches 0.3fmol/L (DNA hybridization analysis) or 5cfu/mL (immunoaffinity analysis) according to the luminal-based chemiluminescence detection by further chemically dissolving out the deposited silver. The food-borne pathogenic bacteria detection technology established by the invention is accurate, sensitive and rapid, thereby attaching great significance to food safety.

The invention discloses a QCM detection method for detecting lysozyme based on multiple signal amplification technologies and application. The QCM detection method comprises the following steps that DNA hybridizes with lysozyme aptamer partially in a complementary mode, and through the specific binding reaction of the lysozyme and the lysozyme aptamer, the DNA is released; a Y-shaped structure is formed by complementary hybrid of the released DNA with hairpin DNA and assistant DNA modified on a gold leaf, and under the action of restriction enzyme, the hairpin DNA is cut and opened through specific identification sites; under the action of DNA ligase and DNA polymerase, using locking-ring-shaped DNA as a template chain, polymerization growing along the opened hairpin DNA is carried out, and a single chain with a large number of repeated sequences is formed; a signal probe marked with biotin hybridizes with the generated repeated sequences in a complementary mode, and after binding with streptavidin marked by HRP, hydrogen peroxide is catalyzed to oxidize 4-chloro naphthol, and precipitation reaction is generated; and accordingly the chip surface quality is increased, and the high-sensitivity detection of the QCM to the lysozyme is realized.

The invention discloses a molecular detecting method based on an exonuclease and a G tetramer and a detecting kit. Molecules are interacted with a nucleic acid aptamer, chain replacement reaction is started, a stem-loop structural DNA is opened, and then, an exonuclease mediated signal amplification technology is combined, so that a great number of G tetramer structures with activity can be generated. G tetramers are combined with hemin so as to have the catalytic activity of HRP and be capable of catalytically oxidizing TMB to generate blue substrates, a result can be seen by naked eyes, and the concentrations of molecules are directly related to the depth of blue. The molecular detecting method is simple in operation, capable of finishing the whole reaction at the room temperature, relatively high in sensitivity and favorable in specificity and can be used for rapidly detecting molecules on site; the detection limit for 17b-estradiol is 1 pM; and the detected result can be directly seen with naked eyes, but no detecting instruments are used.

The invention belongs to the technical field of biosensors and particularly relates to a miRNA detection fluorescent biological probe, a miRNA detection fluorescent sensor and application thereof anda miRNA detection method. In adoption of the probe for miRNA detection, steps are simple, marking is avoided, reaction is carried out in isothermal homogeneous solution, and problems of a complex separation process and high-time-consumption thermal cycle are avoided; a catalytic hairpin assembly technique and a lambda exonuclease (lambda-Exo) auxiliary signal amplification technique are ingeniously combined; by combination with DNA silver nano-clusters (DNA-AgNCs), high-sensitivity detection of biological targets is realized, the limit of detection reaches 0.89fM minimally, single base difference among miRNA family members can be distinguished, high specificity is realized, and the problem that a miRNA detection method in the prior art fails to achieve quickness, simplicity and low cost aswell as high detection sensitivity and high specificity.

The invention relates to a preparing method of a DNA determining electrochemical sensor based on a platinum nano particle catalysis electrochemistry circulation signal amplification technology and the application of the electrochemical sensor. A hairpin DNA 1 is assembled on the surface of a platinum nano particle modified gold electrode in a self-assembly mode, and when a target DNA 2 exists, due to the fact that the target DNA 2 and the hairpin DNA 1 assembled on the surface of the gold electrode are partially paired in a complementary mode, the hairpin structure of the DNA 1 is opened. Then, another hairpin DNA 3 chain replaces the target chain DNA 2 by competing pairing hybridization, the target chain DNA 2 is released, and the released target chain is continuously opened to form a new hairpin structure. The action is carried out in a cycling mode, recycling of the target chain DNA 2 is achieved, a prepared nano particle electrochemical probe is combined, signal amplification is achieved, the prepared electrochemical sensor is used for catalyzing cycling between PAP and PQI, further electrochemistry signal amplification is achieved, a cyclic voltammetry or DPV is used for determining current signal intensity, and according to the measured current signal intensity, determining on the target chain DNA2 is achieved. The sensor has high detecting sensitivity.

A method for detecting aflatoxin B1 based on hybridization chain reaction and DNAzyme signal amplification fluorescence detection, the invention relates to the construction and application of a signal amplification technology fluorescence spectrum sensor. Using the target aflatoxin B1 to trigger a change in the conformation of the aptamer DNA, promote the assembly of the hairpin probe to form a long-chain repetitive DNAzyme unit, and catalyze the enzyme-free AFB1 sensing strategy that cuts the molecular light to generate a fluorescent signal. Relying on this method, the detection limit can reach 0.5 ng/mL, which is far lower than the national standard (10 ng/mL). In addition, we tested aflatoxin B1 in the moldy rice extract and also obtained satisfactory results.

The invention belongs to the field of chemical analysis, in particular to a micro-droplet electrochemical sensor for detecting food-borne microorganisms and a preparation method thereof. Specific genefragments of the food-borne microorganisms are subjected to trace detection by a double-signal amplification system strategy to achieve signal amplification in the first step in the presence of a target gene fragment; a second DNA walker opens a third probe to form double-stranded DNA which is dissociated by a fourth probe modified with ferrocene at one end through two-strand displacement to release the DNA walker for use in the next cycle, thereby achieving signal amplification in the second step. According to the invention, the detection efficiency is improved by a double signal amplification technology, the signal stability is achieved, and the target escherichia coli O157:H7 specific gene fragment detection limit is reduced, the problems of the long period and complicated operation ofthe conventional detection of food-borne pathogens are solved; the detection accuracy is improved, and false positive detection is effectively avoided; and moreover, the electrochemical sensor has asimple production process and a wide application prospect.

The invention discloses a novel immunological detection method. A dendritic 'signal labeled detection antibody-target antigen-small molecule labeled capture antibody-target antigen-signal labeled detection antibody-target antigen-small molecule labeled capture antibody...' composition is formed and fixed to a detection area by a small molecule antibody on a solid phase, so that good signal amplification effects are achieved, and sensitivity is greatly improved. Compared with an existing signal amplification technology, the novel immunological detection method has the advantages that detectionsignals can be enhanced only under the condition of presence of target antigen, and accordingly, high detection sensitivity is ensured while specificity is ensured.

The invention relates to an electrochemical method for detecting microcystic toxins based on a nano material and Au@Pt marked antibody signal amplification technology and belongs to the technical field of analytical chemistry or water environment monitoring. The electrochemical method comprises the following steps: fixing an MoS2/AuNCs nano composite to the surface of a gold electrode through an Au-S bond, and then modifying an MC-LR antibody to the surface of the nano composite by utilizing the adsorption action; specifically combining the MC-LR antibody and an antigen, and then by combining an antibody marked by an Au@Pt core-shell material, realizing amplification of an electrochemical response signal by catalyzing H2O2; and realizing trace determination of MC-LR in a water sample according to the amplified electrochemical signal. The electrochemical method has the characteristics of high sensitivity, high specificity, simpleness, rapidness and the like. A detection method provided by the invention can also be used for detecting molecules and small molecules of algae toxins of other species in water and provides a rapid and convenient detection way for pollutants in the water.

The invention relates to a method for detecting metal ions based on a hybrid chain type reaction signal amplification technique, belonging to the technical field of analytical chemistry or environmental monitoring. The method comprises the following steps: fixing a nucleic acid chain S1 rich in C basic groups to the surfaces of gold-packaged magnetic nanoparticles through Au-S bonds by virtue of a self-assembling technique; in the presence of silver ions (Ag<+>), forming double-stranded DNA by a ferrocene labeled nucleic acid chain S2 rich in C basic groups and the nucleic acid chain S1 by virtue of a C-Ag<+>-C structure; after adding ferrocene labeled hairpin structure DNA H1 and H2, opening the hairpin structures H1 and H2 under the induction of S2, generating hybrid chain type reaction on the surfaces of the magnetic nanoparticles, and carrying out magnetic enrichment on generated compounds on the surfaces of the magnetic nanoparticles, so as to realize the amplification of electrochemical response signals. By determining the concentration of Ag<+> in a solution by virtue of the enhancement of electrochemical signals, the method has the characteristics of high sensitivity and selectivity, simplicity, rapidness and the like.

The invention discloses a preparation method and application of a food-borne pathogen immunosensor based on the gold label silver stain signal amplification technology. The preparation method is characterized by including the steps that a glass slide is silanized; a carbon nitride material is subjected to carboxylation and then mixed with a colloidal gold solution, the mixture is stirred, and a multifunctional carbon nitride solution is obtained; the multifunctional carbon nitride solution is combined with a food-borne pathogen primary antibody, and a food-borne pathogen primary antibody probe is obtained; a coupling reagent, a food-borne pathogen secondary antibody, a food-borne pathogen antigen and the food-borne pathogen primary antibody probe are sequentially dripped onto the silanized glass slide, and the food-borne pathogen immunosensor based on the gold label silver stain signal amplification technology is obtained. Quantitative detection and analysis are carried out by adding a silver stain reagent, and the preparation method and application of the food-borne pathogen immunosensor have the advantages that specificity and sensitivity are high, the result is accurate and reliable, cost is low, and operation is easy and fast.

The invention discloses a small signal amplifier for an underground engineering parameter test and belongs to signal amplification technologies. The small signal amplifier mainly solves the problem that signals are difficult to accurately test due to over strong signal interference during the underground engineering parameter test in the prior art. The small signal amplifier for the underground engineering parameter test comprises a voltage source, a preamplifier, a low-pass filter, a high-pass filter, a trapper, a post-stage amplifying circuit and an analog to digital (A/D) converter which are connected sequentially, wherein the voltage source is connected with the preamplifier through a bridge type circuit; the preamplifier is a fixed gain amplifier or a program-controlled gain amplifier; and the post-stage amplifying circuit is a gain-adjustable amplifier. The small signal amplifier has a reasonable design and stable component performance, can effectively eliminate noise interference around the signals in underground engineering and improves the accuracy of the signal parameter test.

The invention constructs a new method of high-sensitivity high-throughput electrochemical luminescence tumor marker detection based on the development of iridium complex molecule flexible array microchip electrode having high electrochemical luminescence efficiency. According to the method, massive iridium complex molecules with high electrochemical luminescence efficiency are loaded into meso-porous silicon which serves as an electrochemical luminescence signal probe; gold nano-particles are used as a carrier of a tumor marker antibody to improve electron transfer of a medium, so that electrochemical luminescence signals can be improved; and by developing the high-throughput microchip electrode and constructing a sensing interface on the surface of a multi-array microchip electrode, on the basis of specific identification between antigen and antibody and in combination of the signal amplification technology of nano-particles and excellent electron transfer property high-sensitivity, high throughput and accurate detection on the tumor marker can be realized by means of the excellent electrochemical luminescence property of a iridium complex filled meso-porous silicon/nano-gold compound signal probe of which the surface is modified by secondary antibody. The method can be used for comprehensively screening early tumor diseases of mass people by means of the advantages of simpleness, quickness, low price, no invasion and the like.

The invention belongs to the field of food safety detection, and specifically relates to a test strip based on TdT signal amplification technique and a preparation method thereof, wherein a combined release pad of the test strip is coated with dendritic gold nanocomposites that comprise a nanogold-sandwich aptamer 1-PolyN1 composite and a nanogold-PolyN2 composite; a reaction film coats the limitof detection of the sandwich aptamer 2 and coats the quality control line of a sequence probe complementary with the PolyN2. The preparation method comprises the following steps of soaking and absorbing a buffer solution containing the dendritic gold nanocomposites by the combined release pad, and drying the combined release pad; respectively coating the solution containing the sandwich aptamer 2marking streptavidin-biotin and the solution containing the sequence probe marking streptavidin-biotin and complementary with the PolyN2 on the reaction film by a film scratching instrument; and fixing the sample pad, the combined release pad, the reaction film and the absorption pad on a backing in sequence in a tomography direction. The test strip detects signals by amplification to improve thedetection sensitivity.

The invention discloses an electrochemical immunosensing method for detecting a leukemia stem cell tumor marker CD123 by a multiple signal amplification technology. The method includes the step of constructing an electrochemical immunosensing method for detecting the leukemia stem cell tumor marker CD123 by utilizing a nanogold material, an aminoterephthalic acid conductive polymer film and an enzyme catalysis multiple signal amplification technology and through detection research on the CD123. Experimental results show that under the optimal experimental condition, a good linear relation is shown between a current signal of the immunosensor and the concentration of CD123 within the concentration range of 0.02-2.5 [mu]g/mL, and the detection limit is as low as 7ng/mL. The established electrochemical immunosensor is stable, reliable, economical and convenient, has the advantages of accuracy, high sensitivity and high specificity, can be well applied to CD123 detection, provides a new detection platform for diagnosis, curative effect judgment and prognosis evaluation of leukemia patients, and has excellent potential clinical application value.

The invention discloses a method for ovarian cancer screening based on an ovarian cancer marker and a logic gate operation, and belongs to the technical field of biomedicine. The protein-nucleic acidrecognition technology, the signal amplification technology and a logic gate are combined, aptamers of CEA and CA125 are used for target recognition, signal transformation and amplification are performed through a G-quadruplex-heme complex, and a method for simultaneous detection of tumor markers is established. According to the method, an optical biosensor with high sensitivity and strong specificity is constructed for achieving the joint detection of the CEA and the CA125, and an ovarian cancer screening result is provided based on the logic gate; through the combination of optical detectionand the signal amplification technology, the detection sensitivity is improved; the universality of the detection principle makes the method also suitable for detection of different objects based ondifferent protein recognition elements.

Described herein is a method to create dendritic biocompatible polymers from pairs of complementary dendritic nucleic acid monomers in a controlled manner, using polymerization triggers. The dendriticmonomers are constituted of nucleic acids and an organic polymer capable of self-assembly. Each polymer contains approximately 200 dendrites that can be used to attach labels and constitute a biologically compatible signal amplification technology. Depending on the context this technology could be used to reveal the presence of a large variety of analytes such as specific nucleic acid molecules,small molecules, proteins, and peptides.

The invention provides a method for amplifying a corneal scattered signal based on a phononic crystal resonance technology. The corneal elastic modulus is measured by detecting a Brillouin scattered signal, phononic crystal structure signal resonance is adopted for amplifying the weak Brillouin scattered signal in the cornea, and the point lies in that the Brillouin scattered signal can be amplified by a phonon crystal to measure the corneal elastic modulus. A system device composed of a semiconductor continuous laser, a phononic crystal structure and other equipment is adopted, the Brillouinscattered signal is generated through a semiconductor continuous laser system, signal amplification in the phononic crystal is realized, the amplified signal is received by a receiving system to obtain the Brillouin scattered signal of the cornea, and corneal elastic characteristics are further analyzed. The method has the advantage that a phononic crystal signal amplification technology is adopted for amplifying the Brillouin scattered signal.