69 results about "Fluorescence biosensor" patented technology

The invention provides a fluorescent biosensor for detecting N-terminal B-type pro-natriuretic peptide as well as a preparation method and application of the fluorescent biosensor. The fluorescent biosensor is mainly composed of a palladium nanosheet and a fluorescent dye modified nucleic acid aptamer of N-terminal B-type pro-natriuretic peptide. Fluorescence resonance energy transfer and an inner filtering effect can be generated between the palladium nanosheet and the fluorescent dye modified nucleic acid aptamer of the N-terminal B-type pro-natriuretic peptide, so that fluorescence of a system is quenched, a fluorescence signal is closed, and the fluorescent dye modified nucleic acid aptamer can be used for specifically recognizing the N-terminal B-type pro-natriuretic peptide, so that the sensitivity of the system is greatly improved. The fluorescent dye modified nucleic acid aptamer is far away from the palladium nanosheet, the system fluorescence signal is open, the fluorescence recovery efficiency and the logarithm of the N-terminal B-type pronatriuretic peptide have a good linear relationship in the concentration range of 0.8-30 pg / mL, and the detection limit is 0.21 pg / mL. The sensitive, rapid and specific detection of the N-terminal B-type pro-natriuretic peptide in a short time is realized through the change of the fluorescence intensity of the system.

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 invention provides a ratiometric fluorescent biosensor as well as a preparation method and application thereof, and belongs to the technical field of fluorescent biosensors and pathogenic bacterium detection. According to the invention, an Eu-MOF fluorescent material is combined with RPA-CRISPR / Cas12a, high-sensitivity and specific detection of staphylococcus aureus is realized through fluorescence characteristics of Eu-MOF and nucleic acid cleavage activity of Cas12a, and along with recognition and cleavage of target DNA, fluorescence signal change of the ratiometric fluorescent biosensor can be observed; the ratiometric fluorescent biosensor has a built-in calibration function, can reduce interference brought by the environment and instruments, has good selectivity to staphylococcus aureus and good anti-interference performance to other bacteria, and can be used for rapid detection in the field of food safety.

The invention provides a microRNA fluorescent biosensor for quantitative detection of colorectal cancer. The microRNA fluorescent biosensor comprises a microRNA padlock probe for colorectal cancer, diethyl pyrocarbonate treatment water, T4DNA ligase, T7RNA polymerase, an rNTPs mixture, DNA endonuclease, a signal probe, a biological buffer solution and a Simply P total RNA extraction kit. According to the invention, simultaneous detection of a plurality of miRNAs (miR-21, miR-17, miR-31 and miR-92a) related to colorectal cancer can be realized; the adopted fluorescent probe has universal capability and can be applied to other gene detection by changing a target object recognition domain; a promoter is not needed to start transcription, so that the experimental design and operation are simplified.

The invention belongs to the technical field of biology, and particularly discloses a system for detecting HIV RNA, a fluorescent biosensor and preparation and application of the fluorescent biosensor. The system comprises red blood cells, a first report chain, a second report chain, crRNA, Cas12a and a DNA hairpin probe H1. On the basis of the system, a fluid membrane-red blood cell confinement Cas12a can be constructed, and a simple, sensitive and specific fluorescence detection sensing strategy of virus RNA such as HIV RNA is developed, so that the problems of low reaction efficiency, complex reaction steps and the like of an HIV RNA detection method based on CRISPR-Cas12a in the prior art are solved.

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.

This invention provides the nucleic acid molecules encoding novel small monomeric near-infrared fluorescent protein miRFP670nano, variants and derivatives thereof as well as proteins and peptides encoded by these nucleic acids. The invention also relates to derivatives, homologues, or mutants of the specific proteins referenced above as well as fragments of the nucleic acids and the peptides encoded thereby. The invention further relates to host-cells, stable cell lines and transgenic organisms comprising above-referenced nucleic acid molecules. The present invention also refers to methods of making and using small monomeric near-infrared fluorescent proteins derived from cyanobacteriochromes. The presented protein and its derivatives find use in a variety of applications and approaches, including labeling of biomolecules, cells or cell organelles, detecting protein-protein interactions, and generation of genetically encoded fluorescent biosensor.

The present invention belongs to the technical field of biological detection, and provides a fluorescence biosensor for jointly detecting glutathione and ATP, comprising: a ligation probe L with nucleotide sequences shown in SEQ ID NO: 1-4, a padlock probe M, an ATP block strand, a reporter probe S, and Mg<supgt;2+< / supgt;, phi29 DNA polymerase, T4 DNA ligase, dNTP; the 5'-end of the padlock probe M is phosphorylated; the 8th and 9th positions of the ATP block strand are modified with disulfide bonds, and the 3'-end is modified with Inverted dT; the 13th and 14th positions of the reporter probe S are ribonucleotides; a fluorescence quenching group is modified before the 13th position, and a fluorescence reporting group is modified after the 14th position. The sensor of the present invention has the advantages of fast detection speed, low detection limit, high specificity, etc., realizes the joint detection of two target substances by one method, can make up for the defects and deficiencies of the existing detection methods, and realizes fast and accurate quantitative detection.

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 a fluorescent biosensor for one-step detection of miRNA based on CRISPR / Cas13a and primer exchange reaction, which comprises a CRISPR / Cas13a reaction system consisting of Cas13a protein, crRNA corresponding to the Cas13a protein and a hairpin H1, and a primer exchange reaction system consisting of Bst3.0 DNA polymerase, a buffer solution of the Bst3.0 DNA polymerase, a hairpin H2, dNTP and a molecular beacon MB, and realizes one-step detection of target nucleic acid. And the instability of the detection process and the complexity of operation are remarkably reduced, and great clinical application potential and value are shown.

The invention designs a preparation method of a hydrogel-based fluorescent biosensor for rapidly detecting the specific content of Hg < 2 + >. An RCA / G quadruplex product is synthesized in the rolling circle amplification process, the RCA / G quadruplex product is combined with ThT fluorescent dye, an RCA-ThT fluorescent probe material with excellent performance is obtained, and Hg < 2 + > can be efficiently and sensitively recognized. In addition, in order to realize on-site rapid detection, a designed RCA / G quadruplex product is introduced into the hydrogel for physical combination, and the product is packaged on a centrifugal tube cover to serve as a real-time detection sample. The hydrogel fluorescent biosensor packaged by the centrifugal tube can be used at any time, and is convenient to carry and low in cost. Meanwhile, a smart phone WeChat applet is developed, and the quantitative result of Hg < 2 + > can be obtained in real time through mobile phone photographing. The detection limit of the hydrogel-based fluorescent biosensor on Hg < 2 + > is 0.044 [mu] M, and the detection range is 0-100 [mu] M. Experimental results show that the sensor has good stability and instant detection capability, and has application prospects in food safety monitoring.

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 discloses a composition for miRNA detection based on an infinite zipper hybridization chain reaction (ZHCR), a fluorescent biosensor as well as a construction method and application of the fluorescent biosensor. According to the invention, HCR and PER are combined, a single-stranded DNA product generated by PER is used as a track for fixing hairpins, and ZH1 and ZH2 are generated by respectively reacting and combining with legged hairpins H1-l and H2-l of HCR; a target recognition unit is further designed according to the miRNA sequence, after the target miRNA is combined with the target recognition unit, a closed chain falls off, an initiation sequence is exposed, ZH2 and ZH1 are initiated to generate ZHCR, and a fluorescence signal is generated. The preparation of the reaction substrate and the sequence design are simple, and the free hairpin can be positioned on a long track, so that the reaction rate is improved, isothermal, rapid and sensitive amplification of miRNA in vitro is realized, and a new platform with a prospect can be provided for efficient imaging and in-vitro detection of miRNA in living cells.

The utility model discloses an air microorganism detection system, which relates to the field of microorganism detection and comprises a device shell, a plurality of preformed holes are formed in one end of the device shell, a central controller is fixed at the top of the inner side of the device shell, and a fluorescent biosensor is fixedly and electrically connected to the bottom of the central controller. A mounting block is fixed to one end of the inner side of the device shell, a protection assembly is arranged on the top of the mounting block, a glass tube is arranged on the inner side of the protection assembly, a protection block is mounted on the top of the glass tube, and the fluorescent biosensor and the glass tube are arranged in an up-down corresponding mode. According to the clamping device, a stable clamping function can be provided for the glass tube for microorganism storage and detection, so that the detection equipment provides good protection for the internal glass tube in the moving process, and the clamping assembly can be quickly disassembled, so that the glass tube is convenient to replace or disassemble.

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 provides a ratio fluorescence biosensor based on photonic crystal signal amplification and application thereof. The biosensor comprises a fluorescent magnetic bead modified by a capture antibody, a detection antibody modified by biotin, avidin modified by fluorescein and a substrate layer, wherein a photonic crystal layer is deposited on the substrate layer. The detection method provided by the invention has the advantages of small sample dosage, convenience in detection, rapidness, high efficiency, high sensitivity and low cost, and has the potential to be applied to various scenes requiring detection of low-abundance markers, such as drug research and development, early diagnosis of nerve diseases, tumor recurrence monitoring, discovery and confirmation of disease markers and the like.

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.

Disclosed herein are a polypeptide biosensor and compositions comprising the polypeptide biosensor that detects acetyl coenzyme A (acetyl-CoA). The polypeptide comprises an acetyl-CoA binding protein and a fluorescent protein. Further described herein are methods of using the biosensor to detect acetyl-CoA and expression vectors comprising the biosensor.

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 relates to the technical field of biology, in particular to a fluorescent biosensor, a preparation method of the fluorescent biosensor, a miRNA21 detection kit and application. The fluorescent biosensor comprises a Cas12a protein, a crRNA sequence of Cas12a, a closed chain, an activated chain and an ssDNA reporter probe modified with a fluorescence reporter group and a fluorescence quenching group, wherein the nucleotide sequence of the crRNA sequence is as shown in SEQ ID NO. 1. According to the application, cascade strand displacement isothermal amplification is combined with Cas nuclease, and one-step rapid detection of miRNA21 can be realized through fluorescence signal output; the miRNA21 can be rapidly, efficiently and accurately detected only by DNA and RNA sequence design and Cas12a protein and by utilizing the cleavage of the Cas protein to release a fluorescence signal, so that the detection difficulty and the detection cost are greatly reduced, and the miRNA21 detection kit is suitable for an environment with limited resources and on-site rapid detection.

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 invention provides a fluorescent biosensor detection technology for up-conversion nanoparticles and magnetic nanoparticles. In combination with the inherent optical characteristic of the upconversion nanoparticles and the advantage that the magnetic nanoparticles can be rapidly enriched, an aptamer and a complementary chain are used as biological recognition elements to respectively modify the magnetic nanoparticles and the upconversion nanoparticles to obtain a capture probe and a signal probe, and the capture probe and the signal probe are combined through a base complementary effect to form a biological sensing system. The fluorescence in the system is the strongest. The target detection object can be preferentially combined with the capture probe, so that the fluorescence intensity in the system is reduced. Quantitative detection can be achieved through the linear relation between the change value of the fluorescence intensity and the concentration of a target detection object. The invention realizes quantitative detection application in thiamethoxam residue, and has the advantages of strong specificity, high sensitivity, simple, rapid and accurate detection, low cost, wide application range and easy popularization and application.

The invention relates to an ssDNA aptamer capable of specifically recognizing 2 '-fucosyllactose and a construction method and application of the ssDNA aptamer. The nucleotide sequence of the ssDNA aptamer is shown as SEQ ID NO.1 or 5. The ssDNA aptamer is used for preparing a fluorescent biosensor for detecting coupling of the ssDNA aptamer of the 2'-fucosyllactose and CRISPR / Cas12a. The sensing part comprises a magnetic bead, short-chain ssDNA and an ssDNA aptamer-dsDNA hybrid chain, the short-chain ssDNA is complementarily paired with the end part of an ssDNA aptamer and is provided with a marker, and the dsDNA is complementarily paired with the end part of the ssDNA aptamer; and the detection part comprises crRNA, a Cas12a protein and a fluorescent probe. Compared with the prior art, the ssDNA aptamer has high affinity with 2 '-fucosyllactose, and the fluorescent biosensor has the characteristics of high efficiency, rapidness and high throughput detection.

The present invention discloses a quenching-competitive fluorescence biosensor and a detection method based on the ARGET-ATRP signal amplification strategy. The sensor is mainly prepared from the following raw materials: carboxylated Fe3O4 magnetic beads, EDC, NHS, PBS buffer solution, Apt, BPAA, cDNA, Me6TREN, CuBr2, FA, AA. In the present invention, the Apt sequence is immobilized on the surface of carboxylated magnetic beads through an amide reaction. Meanwhile, BPAA is linked to cDNA through an amide reaction. Then, Apt and cDNA are combined through base complementary pairing. Subsequently, an ARGET-ATRP reaction occurs, enabling a large number of FA monomers to graft and polymerize at the active sites of BPAA, thereby significantly amplifying the fluorescence signal. Finally, the target substance OTA competes with cDNA for Apt, causing the cDNA with fluorescence signal to fall off. The sensor of the present invention has the advantages of high sensitivity, good selectivity, simple operation, low cost, environmental friendliness, etc., and the detection limit can be as low as 7.6 fg / mL.

The invention relates to a buffer solution for a CRISPR (clustered regularly interspaced short palindromic repeats) / Cas12a fluorescent biosensor, which comprises Tris-HCl, calcium ions and magnesium ions and does not comprise any one or more of DTT (dithiothreitol), BSA (bovine serum albumin) and recombinant albumin. The buffer solution provided by the invention removes DTT, BSA, recombinant albumin and the like, reduces the cost, improves the detection efficiency and accuracy, has the characteristics of cross-bacterial source universality, economy, practicability and the like, and is suitable for the fields of environmental monitoring, disease diagnosis, food safety and the like.

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.