37 results about "Fluorescence biosensor" patented technology

The invention belongs to the technical field of biosensors, and provides a cadmium telluride quantum dot-based fluorescent biosensor for detecting tetracycline, which comprises a CdTe quantum dot, an Apt-T composite probe, M-2P, a C chain and an Ag-HP chain, the Apt-T composite probe is obtained by hybridizing Apt and a T chain; the M-2P is obtained by hybridizing an M chain and a P chain according to a molar ratio of 1: 2; the nucleotide sequences of Apt, T, M, P, C and HP are as shown in SEQ ID NO: 1-6. The sensor disclosed by the invention has the advantages of high detection speed, simplicity in operation, low price, low detection limit, high specificity and the like, can make up for the defects and deficiencies of the existing tetracycline detection method, and realizes rapid and accurate quantitative detection of tetracycline.

The present invention belongs to the field of biological detection technology, and in particular relates to a rapid and accurate detection method for pathogens based on lanthanide MOF and paper needles. The present invention constructs a fluorescent biosensor by combining LnMOF with an aptamer (Apt-LnMOF) that specifically captures target pathogens. A needle-shaped paper-based device (paper needle) is used as a visual signal output carrier, and qualitative or quantitative analysis is performed by the diffusion distance and red fluorescence intensity (R value) of Apt-LnMOF at the paper-based interface. Apt-LnMOF is used as a signal label for a visualization detection strategy to improve the sensitivity and response speed of the visualization detection method for pathogens; the dual signal coupled with the diffusion distance and R value of Apt-LnMOF at the paper-based interface is used to visualize the result output, thereby improving the accuracy of the detection method. The present invention uses paper needles as signal output carriers, which improves the convenience of operation for non-professionals.

The invention discloses an LAMP (Loop-Mediated Isothermal Amplification) visual biosensor for diagnosing coagulase negative staphylococcus. The LAMP visual biosensor comprises (1) a coagulase negative staphylococcus aptamer sequence; (2) optimizing reaction conditions of the coagulase negative staphylococcus aptamer molecular beacon fluorescent biosensor; and (3) detecting coagulase negative staphylococcus. And coupling the aptamer and the magnetic bead modified with the complementary chain through complementary base pairing to form a magnetic bead-complementary chain-aptamer compound. When the target exists, the aptamer identifies the target and dissociates from the complementary chain, and signal normalization is completed through magnetic separation. And performing amplification by using the magnetically separated supernatant as an LAMP template to realize signal amplification. In the LAMP amplification process, pyrophosphoric acid generated by decomposition of the dNTP is combined with Mg < 2 + >, and the concentration of Mg < 2 + > is reduced, so that hydroxynaphthol blue is triggered to develop, and visual output of signals is realized. The Ct value is generated based on LAMP amplification, and quantitative detection can be achieved.

The invention discloses a kind of miRNA detection composition based on infinite zipper type hybridization chain reaction (ZHCR), fluorescent biosensor and its construction method and application.HCR is combined with PER by the present invention, and the single-stranded DNA product generated by PER is used as the track for fixing hairpin, and is reacted and combined with the leg hairpin H1-1, H2-1 of HCR to generate ZH1 and ZH2 respectively;Target recognition unit is also designed according to miRNA sequence, and after target miRNA is combined with it, closed chain falls off, exposes initiation sequence, causes ZH2 and ZH1 to occur ZHCR, produces fluorescent signal.Reaction substrate preparation and sequence design of the present invention are simple, and free hairpin can be positioned on long track, so as to improve reaction rate, realize isothermal, rapid, sensitive amplification to miRNA in vitro, can provide a promising new platform for miRNA efficient imaging and in vitro detection in living cells.

The invention belongs to the technical field of detection of pests in food, and particularly relates to a rapid staphylococcus aureus detection method based on a nano double-fluorescent probe. The method comprises the following steps: synthesizing carbon dots, preparing silicon nanoparticles, carrying out surface functional modification (introducing vancomycin and an antibody), and constructing a ratio-type fluorescent biosensor. The prepared sensor has double emission fluorescence peaks (492 nm and 529 nm), is good in repeatability and high in sensitivity, and quantitatively analyzes the content of staphylococcus aureus by measuring the ratio (F492 / F529) of the two fluorescence peaks. The detection linear range is wide, and the correlation regression coefficient can reach 0.98. The standard recovery rate in actual sample detection is 94-102.9%, and the relative standard deviation is less than 5%. The method is high in specificity and excellent in anti-interference capability, can be widely applied to rapid, accurate and quantitative detection of staphylococcus aureus in complex matrixes such as dairy products and the like, and has a wide application prospect.

The invention discloses an aptamer-mediated EXPARs-molecular beacon fluorescent biosensor as well as a preparation method and application of the aptamer-mediated EXPARs-molecular beacon fluorescent biosensor. The construction and detection process of the sensor comprises three key steps: protein binding aptamer, exponential isothermal amplification (EXPAR) and molecular beacon fluorescence resonance energy transfer (FRET). Through the ingenious design of the EXPAR system, the system realizes triple signal amplification, the detection sensitivity is remarkably improved, and Abeta42 and Abeta40 amyloid proteins as low as 100fM level can be detected. Besides, based on the sequence specificity of the aptamer and the highly specific design of each nucleic acid sequence involved in the detection system, the method can be used for simultaneously detecting the Abeta42 amyloid protein and the Abeta40 amyloid protein or other substances in the same system (such as a plasma sample), so that the detection efficiency is improved.

The invention discloses a polypeptide probe fluorescent biosensor for detecting an ERRgamma active substance, which adopts a polypeptide probe containing an ERRgamma co-activator conserved sequence as an element for identifying an activated state ERRgamma, and realizes high-sensitivity detection of the ERRgamma active substance by virtue of a signal of a fluorescence labeled molecule. In the operation process, the activated state ERRgamma recruits and is combined with the polypeptide probe marked with the fluorescent molecules, and after a chemical substance to be detected is added, the inhibited state ERRgamma is separated from the polypeptide probe marked with the fluorescent molecules. By detecting and comparing the fluorescence polarization values of the system before and after the chemical substance to be detected is added, the detection of the ERRgamma active substance is realized. The fluorescent biosensor disclosed by the patent can simulate a biological action process, and can quickly detect and evaluate known and unknown ERRgamma active substances. The sensor has the remarkable advantages of low cost, high sensitivity, good selectivity, simplicity and convenience in operation, high response speed, convenience in on-site instant detection and the like, is expected to promote technical development in the field of pollutant sensing detection, and has important significance in commercialization and practical application.

The invention belongs to the technical field of biosensors, and provides a rolling circle amplification-based DNA / AgNCs detection ATP fluorescent biosensor, which comprises: a PL chain complementarily combined with AgNCs-L1 and L2 chains; the PL chain is a product obtained by rolling circle amplification of an annular template with a nucleotide sequence as shown in SEQ ID NO: 1 and a P chain with a nucleotide sequence as shown in SEQ ID NO: 2 as a primer; the nucleotide sequence of the L2 chain is shown as SEQ ID NO.4, and the 5'end of the L2 chain is modified with BHQ1. The sensor has the advantages of being high in detection speed, easy to operate, low in price, low in detection limit, high in specificity and the like, the defects of an existing ATP detection method can be overcome, and rapid and accurate quantitative detection of ATP is achieved.

The invention relates to the technical field of photochemical biosensing detection, and discloses a fluorescent biosensor, system and method for detecting tumor markers, commercialized filter paper is used as a substrate, a silica-based sensitive layer is constructed on the surface of the substrate by a sol-gel method to obtain a nanopore membrane, and specific capture of target molecules is realized by introducing click chemistry. The stability and the tolerance of a sensing system are improved. The method is simple and convenient to operate, high in result visualization degree, capable of greatly shortening the detection time, high in specificity, high in sensitivity, high in precision, good in reproducibility and low in cost, and can be widely applied to tumor marker detection.

The invention belongs to the technical field of biosensors, and provides a vibrio parahaemolyticus fluorescent biosensor based on a DNA (deoxyribonucleic acid) reticular nanostructure, which comprises DNF (at) AuNCs, DNA-H, Apt-T, H6 and Mg < 2 + >. The sensor disclosed by the invention has the advantages of high detection speed, simplicity in operation, low price, low detection limit, high specificity and the like, can make up the defects and deficiencies of the existing detection method of the vibrio parahaemolyticus, and realizes rapid and accurate quantitative detection of the vibrio parahaemolyticus.

The invention relates to the technical field of biosensors, in particular to a transgenic corn CP4-EPSPS protein aptamer molecular beacon fluorescent biosensor. According to the invention, a systematic aptamer rational cutting and conformation adaptation strategy is constructed, the strategy obtains an initial aptamer through magnetic bead-SELEX screening, and the CP4-EPSPS protein aptamer is precisely cut and optimized by adopting the steps of loop region active core positioning, stem region structure optimization and base binding domain identification, so that the binding performance and the structural stability are remarkably improved. Subsequently, on the basis of stable conformational characteristics, a complementary chain competition sensing mechanism is designed, and a transgenic corn CP4-EPSPS protein aptamer molecular beacon fluorescent biosensor is successfully constructed, so that amplification-free high-sensitivity rapid detection of CP4-EPSPS protein is realized, and a solution is provided for supervision of transgenic crops.

The invention discloses a hybridization chain reaction fluorescent biosensor and a preparation method and application thereof, red cell membrane coated gold nanoparticles are used as a reaction substrate, the surface of the gold nanoparticles is covalently connected with a sulfydryl modification initiation probe aiming at target miRNA through an Au-S bond, and the red cell membrane coated gold nanoparticles are treated by Fe < 3 + >. According to the method, the red cell membrane completely coats the gold nanoparticles, so that common false positive signals in a complex body fluid environment are remarkably reduced; the hybridization chain reaction is limited on the surface of the cell membrane, so that the local concentration of the hairpin probe is improved, the chain amplification process is accelerated, and the detection time is shortened; sufficient sites are provided for probe fixation and HCR polymerization by utilizing the large specific surface area of the gold nanoparticles, and the signal amplification factor is further enhanced; fe < 3 + > is introduced to perform surface modification on the red cell membrane coated gold nanoparticles, so that non-specific binding is effectively inhibited, blank background fluorescence is remarkably reduced, and the signal-to-noise ratio is increased.

The present invention relates to the production of a protease-based protein biosensor capable of specifically quantifying methionine sulfoxide present in a target protein and use thereof, and more specifically, to: a recombinant protein for a fluorescent biosensor for quantifying methionine sulfoxide present in a target protein, the recombinant protein comprising a fluorescent protein, a methionine sulfoxide reductase (Msr) protein, an enterokinase cleavage site, a thioredoxin protein, and protein G; a biosensor comprising same; and a method for quantifying methionine sulfoxide in a target protein using same. The biosensor according to the present invention can accurately measure in a quantitative manner the degree of oxidation of methionine residues in a specific protein rather than all proteins through the detection of specific fluorescence changes, and thus can be used as a fluorescent biosensor for diagnosing oxidative stress diseases. Moreover, the biosensor can recognize the degree of aging through the measurement of the degree of oxidation, and thus can be effectively used for diagnosing aging and related diseases.

The present invention relates to a phenylalanine fluorescent biosensor and its use in detecting phenylalanine in blood. The phenylalanine fluorescent biosensor of the present invention can accurately and rapidly detect the phenylalanine concentration in a sample. Compared with existing phenylalanine detection methods, the phenylalanine fluorescent biosensor of the present invention has the advantages of simple operation, short detection cycle, high sensitivity, strong specificity, low cost, no need for expensive and complex equipment, and amenability to high-throughput, real-time, rapid detection.

The application relates to the field of biotechnology, in particular to a fluorescent biosensor, a preparation method thereof, an miRNA21 detection kit and application. The fluorescent biosensor comprises a Cas12a protein, a crRNA sequence of the Cas12a, a blocking chain, an activating chain and an ssDNA report probe modified with a fluorescent report group and a fluorescent quenching group, and the nucleotide sequence of the crRNA sequence is shown in SEQ ID NO. 1. The application combines cascade chain displacement isothermal amplification and Cas nucleases, and realizes one-step rapid detection of miRNA21 through fluorescent signal output; the application only needs DNA and RNA sequence design and Cas12a protein, and the cutting of the Cas protein is used to release the fluorescent signal, so that miRNA21 can be quickly, efficiently and accurately detected, the detection difficulty and cost are greatly reduced, and the application is suitable for resource-limited environments and on-site rapid detection.

The invention discloses a CRISPR-Cas14a1 and ERA fluorescent biosensor for rapidly detecting ichthyophthirius multifilis and application of the CRISPR-Cas14a1 and ERA fluorescent biosensor, and particularly relates to the field of molecular biological detection technologies and biosensing. Wherein the nucleotide sequence of the specific sgRNA is as shown in SEQ ID NO. 3. The biosensing system comprises an ERA amplification module which comprises at least one pair of primers capable of specifically amplifying 18S rRNA gene segments of ichthyophthirius multifilis; the CRISPR-Cas14a1 detection module comprises the CRISPR-Cas14a1 specific sgRNA (small guide ribonucleic acid) according to the claim 1 and a Cas14a1 protein of the CRISPR-Cas14a1 specific sgRNA according to the claim 1; and the signal reading module comprises a reporter molecule which can be subjected to trans-cleavage by the Cas14a1 protein and can generate a detectable signal. The biosensor has the advantages of high specificity, quick response and no complex amplification.

The invention belongs to the technical field of biosensors, and provides a fluorescent biosensor based on a DNA (deoxyribonucleic acid) functionalized nanomaterial for detecting tetracycline, which comprises an Apt-T composite probe, a self-locking DNAzyme chain S and a Helper chain H, the Apt-T composite probe is obtained by hybridizing an aptamer Apt and a T chain; the nucleotide sequences of the Apt, the T chain, the S chain and the H chain are as shown in SEQ ID NO: 1-4. The sensor disclosed by the invention has the advantages of high detection speed, simplicity in operation, low detection limit, high specificity and the like, can make up for the defects and deficiencies of the existing tetracycline detection method, realizes rapid and accurate quantitative detection of tetracycline, and has potential application prospects in food safety and environment detection.

The invention relates to the technical field of food safety detection, in particular to an aptamer biosensor and a method for determining ochratoxin A based on an aggregation-induced emission effect. According to the present invention, the nucleic acid aptamer capable of specifically binding with the ochratoxin A is adopted as the recognition element, and the fluorescence biosensor based on the aggregation-induced emission effect is constructed to detect the ochratoxin A, such that the ochratoxin A detection sensitivity is improved, the ochratoxin A with the minimum of 1.37 ng / mL can be detected, and the detection time is shortened. The cost of detecting the target toxin is greatly reduced, the specificity is good, and the operation is simple and convenient; the invention also solves the problems of high ochratoxin A detection cost, complex detection scheme and overlong detection time. Therefore, the invention provides an effective method for measuring and detecting the ochratoxin A and other harmful substances.

The invention discloses a coagulase-negative staphylococcus aptamer molecular beacon fluorescent biosensor. The coagulase-negative staphylococcus aptamer molecular beacon fluorescent biosensor comprises: (1) a coagulase-negative staphylococcus aptamer sequence; (2) optimizing reaction conditions of the coagulase negative staphylococcus aptamer molecular beacon fluorescent biosensor; and (3) detecting coagulase negative staphylococcus. The detection principle of the sensor is as follows: a ThT-nucleic acid aptamer compound formed by an FAM fluorophore-labeled aptamer and thioflavin T (ThT) has high fluorescence intensity, when target coagulase-negative staphylococcus exists in a system, the target coagulase-negative staphylococcus is combined with the FAM-labeled aptamer to cause reduction of the fluorescence intensity of the system, and the higher the concentration of the coagulase-negative staphylococcus is, the higher the concentration of the coagulase-negative staphylococcus is, the higher the concentration of the coagulase-negative staphylococcus is, the higher the concentration of the coagulase-negative staphylococcus is, the higher the concentration of the coagulase-negative staphylococcus is, the higher the concentration of the coagulase-negative staphylococcus is. The fluorescence intensity of the system is lower, so that simple, convenient, rapid, low-cost and high-sensitivity detection of the coagulase negative staphylococcus is realized.

The invention belongs to the technical field of detection, and particularly relates to a fluorescent biosensor for lead ion detection and a preparation method and application thereof. The preparation method comprises the following steps: carrying out sulfydryl activation treatment on sulfo-GR-5S and sulfo-Poly-T by using TCEP, then taking sulfo-GR-5S and sulfo-Poly-T and gold nanoparticles as reactants, and constructing a primary gold-labeled probe through a halide ion auxiliary modification strategy; taking the primary gold-labeled probe and biotin-labeled GR-5E as reactants, and performing hybridization annealing treatment to obtain a bifunctional gold-labeled probe; and by taking the bifunctional gold-labeled probe and streptavidin magnetic beads as reactants, carrying out biotin-streptavidin binding reaction, so as to obtain the AuNP-coated MB probe. The probe is used for lead ion detection, the linear detection range is 1-500 nM, the detection limit is 0.34 nM, the probe shows excellent performance in actual sample analysis, and the recovery rate reaches 91.6-117%.

The invention provides a self-assembled antibody-gold nanocluster, a fluorescent biosensor, a preparation method and application, and belongs to the technical field of fluorescent biosensors. The invention provides a self-assembled antibody-gold nanocluster. The self-assembled antibody-gold nanocluster is prepared from the following raw materials: an antibody, chloroauric acid and a reducing agent, the molar ratio of the antibody to the chloroauric acid is (1: 60)-(1: 80); the antibody is combined with the gold nanoparticles in the gold nanocluster through surface sulfydryl. In the invention, under the action of a reducing agent, chloroauric acid is reduced into gold nanoparticles, and an antibody can be combined with the gold nanoparticles through surface sulfydryl to generate self-assembly, so that the self-assembled antibody-gold nanocluster is obtained. The self-assembled antibody-gold nanocluster disclosed by the invention can be synthesized by a one-step method, and a signal nanocluster (gold nanocluster) is generated in situ in a single antibody protein molecule template, so that the inherent defects that the chemical coupling efficiency is low, the biological activity is easy to damage and the like are overcome.

The application belongs to the field of biosensors and detection technologies, and relates to a preparation method of an RCA-GO aptamer fluorescent biosensor, which comprises the following steps: first, preparing a quantum dot coupled fluorescent probe; then, preparing a circular DNA template CDT; and finally, preparing a rolling circle amplification product RCAP, which is hybridized with the quantum dot coupled fluorescent probe at a volume ratio of 1:1, and GO solution is added to prepare the RCA-GO aptamer fluorescent biosensor after incubation at 37 DEG C. The prepared RCA-GO aptamer fluorescent biosensor is applied to fluorescent detection of aflatoxin B1 (AFB1) and ochratoxin A (OTA). The quantum dots have low preparation cost, high coupling activity, and a mature and stable preparation method. The aptamer that is not combined with the target substance is combined with Padlock to form CDT, and a rolling circle amplification reaction is performed, so that the fluorescent signal is greatly enhanced, the detection of AFB1 and OTA is realized, the theoretical basis is mature, and the reliability is good. The fluorescent probe coupled with the quantum dots has stable signal and high sensitivity, and the double-stranded structure (RCAP / QDs-cDNA) formed has good stability and is not prone to false positive signals.

The invention discloses a multivalent aptamer fluorescent biosensor for detecting pseudomonas aeruginosa and a preparation method of the multivalent aptamer fluorescent biosensor, sequence template design is carried out based on an aptamer (F23), a long multivalent ligand with repeated aptamer units is synthesized through RCA rolling circle amplification, and through the synergistic effect between the aptamer units and a formed'capture net ', the fluorescent biosensor is used for detecting the pseudomonas aeruginosa. The binding efficiency with the target pseudomonas aeruginosa is remarkably improved, and the sensitivity of a detection system is enhanced.

The present invention provides a fluorescent biosensor for detecting deoxynivalenol, which is composed of streptavidin magnetic beads, a substrate strand ssDNA, a cDNA-FAM, and an aptamer strand DON-Apt. The fluorescent biosensor provided by the present invention can effectively and rapidly determine the content of deoxynivalenol in grain samples with high sensitivity, high recovery rate, and good selectivity. It does not require reliance on expensive large-scale instruments, and pretreatment is simple. While ensuring the accuracy of the results, it achieves rapid detection, greatly saving costs and improving detection efficiency.

The invention provides a chlorogenic acid nucleic acid aptamer sequence and a fluorescent biosensor and in-vitro anti-oxidation application thereof. A specific nucleic acid aptamer with high affinity to chlorogenic acid is screened and obtained through an SELEX (systematic evolution of ligands by exponential enrichment) technology, and a signal closing type fluorescent biosensor is constructed based on the specific nucleic acid aptamer. According to the sensor, target chlorogenic acid is used for inducing an aptamer hairpin structure to be closed, an FRET effect is triggered to cause end-labeled Cy5 fluorescence signals to be quenched, so that ultra-sensitive detection of chlorogenic acid is realized, the detection limit is as low as 1.85 nM, and the sensor has the advantages of high specificity and simplicity and convenience in operation. In addition, it is found for the first time that a compound formed by combining the aptamer and chlorogenic acid can significantly enhance the in-vitro antioxidant activity of the aptamer, and a new direction is provided for application of the aptamer in the fields of functional food and drug synergy.

This invention discloses a method for detecting organophosphorus pesticides using a self-cascaded Pt@Fe-CDs nanozyme, belonging to the field of chemical analysis and detection technology. This method synthesizes Pt@Fe-CDs nanozymes using iron-doped carbon dots (Fe-CDs) as a reducing agent and template. Pt@Fe-CDs simultaneously possess ascorbic acid oxidase-like and peroxidase-like activities. Under the catalysis of alkaline phosphatase, they hydrolyze L-ascorbic acid-2-phosphate trisodium salt to AA. Based on the fact that organophosphorus pesticides can inhibit ALP activity and hinder AA2P dephosphorylation, leading to a reduction in AA and thus causing changes in fluorescence and colorimetric signals, a simple and sensitive dual-signal fluorescence / colorimetric sensing platform for organophosphorus pesticides is constructed, with a detection limit of 0.28-0.53 ng / mL. The colorimetric and fluorescence biosensors established in this invention exhibit excellent performance in terms of sensitivity, specificity, and accuracy in actual samples.

The invention discloses a method for detecting uranyl ions in a biological sample based on DNAzyme, and relates to the technical field of biosensing. The invention provides a detection method and application. The fluorescent biosensor is constructed by taking DNAzym for specifically recognizing uranyl ions as a molecular recognition element and modifying a fluorophore and a quenching group at two ends of the molecular recognition element respectively. When the DNAzyme is combined with the uranyl ions, a specific cleavage reaction is carried out, a fluorescence signal is generated, and quantitative detection of the uranyl ions is realized. In particular, for a biological sample with complex components, the pretreatment process is optimized, including digestion, drying, resuspension, pH adjustment and reducing agent addition, and impurity interference is effectively removed. The method has the characteristics of simplicity and convenience in detection operation, rapidness in detection, high specificity and the like, can be used for detecting uranyl ions with lower concentration, is suitable for uranium exposure personnel monitoring and environmental pollution evaluation, and provides an efficient detection means for nuclear safety and medical diagnosis.

This invention proposes a capsaicin nucleic acid aptamer and its ratiometric fluorescent biosensor application. A capsaicin-specific nucleic acid aptamer with nanomolar affinity for capsaicin was obtained using the RNase-SELEX screening strategy. Furthermore, a ratiometric fluorescent biosensor was constructed using the pruned aptamer. A dual-signal response is achieved through competitive binding / conformational regulation of the aptamer by capsaicin and the nucleic acid dye SYBR Green II. Quantitative detection of capsaicin is achieved through a linear relationship between the fluorescence ratio and capsaicin concentration, exhibiting advantages such as high sensitivity and strong anti-interference capability.

The application belongs to the technical field of nucleic acid detection, and specifically discloses a lanthanide metal organic framework DNA sensor as well as a preparation method and application thereof. The lanthanide metal organic framework (LaMOF) surface is not fully coordinated with metal sites, and the chemical coordination reaction activity of the oligonucleotide phosphate group is utilized. A capture DNA strand complementary to a target DNA is coupled to the LaMOF surface to construct a fluorescence biosensor based on the LaMOF. The synthesis steps are simple, complex synthesis reactions are avoided, the solvent is non-toxic and environmentally friendly, the operation is simple, and the time cost and reagent cost are low. Then, the luminescent metal organic framework and the in-situ fluorescence quenching reaction are combined to detect nucleic acids, the amount of the target DNA is specifically converted into a fluorescence signal, and quantitative analysis of free nucleic acid cfDNA is realized. The method has a good linear correlation in a concentration range of 25-250 nM, is high in precision, and is good in reproducibility.