106 results about "Fluorescence ratio" patented technology

The invention discloses an MOF-CQD enzyme-sensitive FRET hydrogel diagnosis and treatment probe as well as a preparation method and application thereof, and belongs to the technical field of biomedical detection and treatment. The probe takes a carboxyl carbon quantum dot (CQD) as a donor and a metal organic framework (MOF) as an acceptor, and the donor and the acceptor are connected through a replaceable enzyme response polypeptide bridge; when the fluorescence is complete, FRET is generated to quench the CQD fluorescence, the FRET is interrupted after the target enzyme cuts off the peptide bridge, and the blue / red fluorescence ratio is changed to realize nanomole-level quantitative detection and has self-correction capability. The probe is packaged in a four-arm PEG transparent hydrogel which does not need a photoinitiator and can be quickly self-crosslinked, and can be prepared into a film, a tooth socket and the like for POCT (point-of-care testing) of parts such as an oral cavity / skin and the like. After detection, the MOF is activated by illumination of 630-660 nm to generate active singlet oxygen, so that local antibacterial or anti-tumor treatment is realized, and a diagnosis and treatment integrated scheme is constructed.

The invention discloses a fluorescence ratio type carbon dot hydrogel sensor, a preparation method thereof and application of the fluorescence ratio type carbon dot hydrogel sensor in rapid detection of doxorubicin hydrochloride. The invention discloses a fluorescence ratio type carbon dot hydrogel sensor which is characterized in that 3-aminophenol is used as a carbon source, absolute ethyl alcohol is used as a solvent, carbon dots are prepared through a one-step solvent method, the carbon dots have green fluorescence, agarose is dissolved in a mixed solution of deionized water and a phosphate buffer solution to be fully dissolved, and then the carbon dots are prepared into the fluorescence ratio type carbon dot hydrogel sensor. And adding the carbon dots into the mixed solution, fully dispersing, and cooling to obtain the fluorescence ratio type carbon dot hydrogel sensor. The sensor disclosed by the invention has the characteristics of high selectivity and high sensitivity when being used for detecting doxorubicin hydrochloride, and also has the characteristics of convenience, visibility, rapidness, portability, easiness in operation and the like.

The invention discloses a fluorescent colorimetric sensor for detecting circulating tumor cells and a preparation method of the fluorescent colorimetric sensor. The preparation method comprises the following steps: S4, adding a prepared detection antibody modified with horse radish peroxidase and used for detecting the circulating tumor cells, and incubating; s5, adding a Tris buffer solution and a H2O2 solution, and incubating; s6, preparing an EuMOF nanoflower solution; and S7, adding the EuMOF nanoflower solution and 3, 3 ', 5, 5'-tetramethyl benzidine to react, detecting the fluorescence intensity in the presence of circulating tumor cells with different concentrations by using a luminoscope, detecting the ultraviolet absorbance value in the presence of circulating tumor cells with different concentrations by using a multifunctional microplate reader, and constructing a fluorescence intensity-concentration working curve and an ultraviolet absorbance value-concentration working curve. The method is used for qualitative and quantitative analysis and detection of the circulating tumor cells, realizes bimodal signal response to the circulating tumor cells, and has high sensitivity and simplicity and convenience in operation.

The invention relates to the technical field of analytical chemistry, and particularly discloses a double-signal ratio type up-conversion luminescent probe, a preparation method thereof and application of the double-signal ratio type up-conversion luminescent probe in oxalate detection, and the double-signal ratio type up-conversion luminescent probe comprises up-conversion nanoparticles UCNPs and an iron-chromium cyanine R compound. The upconversion nanoparticles UCNPs are combined with the iron-chromium cyanine R compound to construct a double-emission-peak regulation and control system, when the system is used for oxalate detection, oxalate can be chelated with Fe < 3 + > in the iron-chromium cyanine R compound, blue shift of an induced absorption spectrum is achieved, green and red emission peaks of the UCNPs are synchronously regulated and controlled, and the detection sensitivity is high. The fluorescent-colorimetric bimodal high-sensitivity detection of the oxalate is realized.

The invention discloses a fluorescent / colorimetric dual-mode paper-based sensor for detecting cadmium ions in rhizoma polygonati as well as a preparation method and application of the fluorescent / colorimetric dual-mode paper-based sensor, and belongs to the technical field of detection of heavy metal residues in food with homology of medicine and food. PEI-UCNPs and PtNPs are loaded on a paper base and are mixed and reacted with Apt-AMNPs (at) TMB, H2O2, a PBS buffer solution and a solution containing Cd < 2 + >. The Aptamer specifically recognizes and captures Cd < 2 + >, so that the Apt-AMNPs (at) TMB is dissociated, and the TMB is released from holes of the AMNPs; the PtNPs on the paper base catalyzes colorless TMB (Tetramethylbenzidine) to generate blue oxide (oxTMB) under the action of H2O2, and the oxTMB can quench up-conversion fluorescence of PEI-UCNPs through fluorescence inner filtration. When the fluorescence / colorimetric dual-mode paper-based sensor is used for detecting the content of cadmium ions in rhizoma polygonati, the fluorescence / colorimetric dual-mode paper-based sensor has the characteristics of simplicity and convenience in operation, low detection cost, rapidness, specificity, sensitivity, portability and the like, and the fluorescence / colorimetric dual-mode paper-based sensor can be applied to on-site detection of the cadmium ions in rhizoma polygonati.

The invention relates to a method for detecting miRNA (micro Ribonucleic Acid) by using a ratio-type CRISPR / Cas12a (Clustered Regularly Interspaced Short Palindromic Repeats / CRISPR / Cas12a) system. The method is characterized by being realized by applying a multifunctional probe in the CRISPR / Cas12a system. Wherein the multifunctional probe is a single-stranded DNA (deoxyribonucleic acid) with a hairpin structure and comprises two functional areas, namely a neck part and a loop part; wherein the neck part of the probe is used for identifying a target miRNA; wherein the probe ring part has various different functions of lightening a fluorescent dye, activating a CRISPR / Cas12a system, serving as a Cas12a trans-cracking substrate, triggering a self-driven cascade reaction and the like; the working principle of the method is as follows: when no target exists, the ring part of the probe cannot activate the CRISPR / Cas12a system, the G quadruplex structure of the ring part of the probe can be combined with a fluorescent dye to emit fluorescence, and the neck part of the probe is opened by combining the sticky end with the target when the target exists, so that the G quadruplex structure of the ring part of the probe disappears and releases an activator to activate the CRISPR / Cas12a system; the activated Cas12a simultaneously reversely cuts the reporter probe and the multifunctional probe around the Cas12a, so that the fluorescence of the reporter probe is enhanced and the fluorescence of the multifunctional probe is reduced, and the multifunctional probe releases more activators to trigger a self-driven cascade reaction, so that the fluorescence of the reporter probe is further enhanced and the fluorescence of the multifunctional probe is further reduced; quantitative detection of the target miRNA can be realized through the mathematical relationship between the fluorescence ratio of the report probe and the multifunctional probe and the target concentration. The ratio-type CRISPR / Cas12a system is designed according to the structure activity of DNA, the property of the fluorescent dye and the characteristics of the CRISPR / Cas12a system, sensitive detection of miRNA is achieved, and the ratio-type CRISPR / Cas12a system can be used for scientific research analysis and clinical detection and has wide market prospects.

The present invention discloses a ratiometric fluorescent smart label for visually detecting the freshness of meat, and its preparation method and application. The smart label preparation method is specifically as follows: first, a ratiometric fluorescent indicator of gold-copper bimetallic nanoclusters (indicator) with red fluorescence and dual-ligand gold nanoclusters (internal standard) with green fluorescence is prepared; then, by a solution doping method, the ratiometric fluorescent indicator is added to a polyvinyl alcohol / polyethylene glycol solution to prepare a ratiometric fluorescent smart label; finally, a fluorescent colorimetric card is made based on the ratiometric fluorescent smart label, and the smart label is applied to the prediction of meat freshness grade and total volatile basic nitrogen content in combination with a smart phone. The ratiometric fluorescent smart label prepared by the present invention has higher accuracy and sensitivity than a colorimetric sensing indicator film; and the smart label is safe, biocompatible, biodegradable, and has strong mechanical properties, and has the function of real-time monitoring of the freshness of fresh meat and aquatic products.

The invention relates to a cellulose membrane-based fluorescence colorimetric sensor based on nano-copper and MOF (Metal Organic Framework), a preparation method of the cellulose membrane-based fluorescence colorimetric sensor and application of the cellulose membrane-based fluorescence colorimetric sensor in tetracycline detection The sensor comprises a cellulose membrane, nano-copper clusters and MOF-5, the nano-copper clusters are fixed on the surface of the porous cellulose membrane through hydrogen bonds to form CCM, and then the MOF-5 is further loaded on the surface of the cellulose membrane to obtain the CCMM. When tetracycline exists in a sample to be detected, Zn (II) in the sensor and tetracycline form a luminous complex, so that the color of the trigger fluorescence is changed from orange red to green. The sensor provided by the invention has the advantages of high sensitivity (the detection limit is 0.5 mu M), quick response (qualitative treatment within 5 seconds), excellent selectivity (resistance to influences of various metal ions and interferents), good long-term stability (the performance is not changed after the sensor is stored for 60 days) and the like, and can be used for carrying out real-time visual detection on TC in drinking water, environmental water, milk and other samples.

The application discloses a kind of fluorescence colorimetric double-mode detection streptococcus agalactiae without aerosol pollution method, comprising the following steps: (1) strain culture and DNA extraction;(2) the combination of UDG and LAMP;(3) UDG-LAMP-CRISPR fluorescence mode detection system;(4) colorimetric mode detection system: read image RGB value in G value, G value significantly increases, and it is positive result.This patent innovatively combines UDG, LAMP, CRISPR and G4, introduces connection probe to realize "fluorescence-colorimetric" single system double-mode detection.The two detection modes of the detection platform can be freely split or combined, and can meet the needs of different detection environments.By combining UDG system and LAMP technology, aerosol pollution possibly carried in amplification process is avoided.Connection probe is introduced, CRISPR fluorescence detection is combined with G4 colorimetric detection, a detection system with "fluorescence-colorimetric" two detection modes is established, which is used for quantitative identification and cross verification of streptococcus agalactiae.

The application discloses an aggregation-induced emission metal organic framework, a preparation method thereof and fluorescent / colorimetric dual-mode intelligent detection for trace HCl. 2+ The aggregation-induced emission metal organic framework is prepared by providing Zn(NO3)3.6H2O as Zn 2+ , imidazole-2-formaldehyde and an AIE molecule HDBB as organic ligands, and through a solvothermal method to obtain ZIF-90-HDBB, which can change the aggregation state fluorescence from yellow green to orange red after being contacted with HCl gas; the ZIF-90-HDBB is uniformly loaded on cellulose filter paper to obtain a paper-based sensor for portable detection of HCl, and through combination with a color recognition APP of a smart phone, the HCl can be rapidly and sensitively detected on site in a fluorescent / colorimetric dual mode. Since the HDBB molecule is prone to protonation under acidic conditions, the fluorescence color changes, and therefore the material can be accurately and efficiently used for detection of acidic gas, and the material can be recycled.

The invention discloses a double-emission carbon dot hydrogel film as well as a preparation method and application thereof, and relates to the technical field of analysis detection and functional materials. The double-emission carbon dot hydrogel film takes polyvinyl alcohol hydrogel as a carrier, and double-emission carbon dots (O-CDs) synthesized by taking L-glutamic acid and o-phenylenediamine as precursors are uniformly dispersed in the polyvinyl alcohol hydrogel. The O-CDs have double emission peaks of 400 nm and 530 nm under the excitation of 375 nm. The dual-emission carbon dot hydrogel film is applied to portable visual detection of Cu < 2 + > and Ag < + >, and the portable visual detection is dual-mode measurement based on RGB and comprises fluorescence colorimetric measurement in a solution and visual detection of the film assisted by a smart phone. According to the dual-mode strategy, precise instruments are not needed, rapid, reliable and synchronous detection of Cu < 2 + > and Ag < + > can be achieved within 10 min, the limitation of traditional single-mode detection is broken through, and a stable platform is provided for on-site metal ion monitoring.

The application discloses a fluorescent / colorimetric dual-mode sensor for hydrogen sulfide detection and a preparation method thereof. The method comprises the following steps: synthesizing gold nanoclusters and metal-organic framework materials in situ to obtain a gold nanocluster / metal-organic framework composite material, uniformly mixing the composite material and sodium alginate to obtain a casting solution, and then dropping the casting solution on a substrate to perform scraping, molding and cleaning to obtain a gold nanocluster / metal-organic framework hydrogel membrane sensor. The sensor not only has a significant improvement in the fluorescence performance, but also can respond to hydrogen sulfide in the fluorescence and colorimetric channels respectively, and has the advantages of high sensitivity and high selectivity.

The invention discloses a method for jointly detecting creatinine and human serum albumin based on fluorescence colorimetric double signals, in the method, creatinine and molybdenum diselenide are used as cocatalysts and Cu < 2 + > are used for co-catalyzing hydrogen peroxide to decompose and etch Au (at) Ag NRs, and solutions present different colors. Free-state silver ions generated by etching the silver shell layer are reduced by taking the human serum albumin as a template in the presence of a reducing agent to generate Ag NCs with fluorescence, so that creatinine and human serum albumin are sequentially detected through colorimetric fluorescence double signals, cross interference is avoided, and the advantages of multi-target detection, high sensitivity, simple operation, low cost and the like are achieved.

The present invention discloses a ratiometric fluorescent probe for detecting SO2 derivatives and its synthesis method and application. The fluorescent probe has the molecular formula C 41 H 44 ClN5O8. The fluorescent probe provided by the present invention can specifically recognize SO2 derivatives and undergo nucleophilic addition reaction, thereby blocking the ICT effect inside the oxonium structure, and then blocking the FRET effect, showing a transition from red fluorescence to green fluorescence. The optical properties of the probe are excellent: it has a 191nm emission band gap, which can effectively avoid the occurrence of fluorescence overlap; high specificity to avoid interference from other substances; and excellent sensitivity, with a detection limit of 64μM. In addition, when the Na2SO3 concentration is in the range of 0-50μM, it is proportional to the fluorescence ratio of the probe, R 2 >0.99, which means that the Na2SO3 concentration can be quantitatively calculated based on the fluorescence ratio within this range.

The application provides a nucleic acid test strip and a detection method for detecting smut genes, and belongs to the technical field of detection. The application comprises a bottom plate, a sample pad and a water absorption pad; an NC film is attached to the bottom plate, the NC film is provided with a T line and a C line, the T line is sprayed with a coupling agent of a capture probe and streptavidin; the C line is sprayed with a coupling agent of a quality control probe and streptavidin; the quality control probe is complementary to a DNA sequence of a DNA1-AgInS2 / ZnS fluorescent probe. The application utilizes the advantages of AgInS2 / ZnS quantum dots (AgInS2 / ZnS QDs), such as good biocompatibility, high fluorescence intensity and wide spectral range. The test strip based on AgInS2 / ZnS quantum dots has higher sensitivity and stronger quantitative capacity than traditional test strips. The fluorescence ratio of the T line and the C line is detected by using a fluorescence immunoassay instrument for quantitative detection, the fluorescence immunoassay instrument can quickly read out the value, and has the advantages of rapidness, simple operation, low sensitivity, good selectivity and the like.

The application discloses a fluorescent colorimetric ionic liquid, a composite ionic probe and application in detection of phoxim, and the functionalized composite ionic probe is successfully synthesized by electrostatic self-assembly of the fluorescent colorimetric ionic liquid and a surfactant, the sensitivity and selectivity of the composite ionic probe in detection of phoxim are effectively improved, and the detection limit is reduced, and the detection limit of the fluorescent method in detection of phoxim can reach 3.0*10 ‑8 M, which is lower than the minimum maximum allowable concentration specified in the national standard. The composite ionic probe can visually and conveniently detect phoxim.

The present application relates to the field of nanomaterials and analytical detection technology, in particular to a reagent for rapid detection of aureomycin and a rapid detection method of aureomycin. After adding 3-mercaptopropionic acid modified AgInS2 quantum dots to aureomycin, the fluorescence intensity and color of AgInS2 QDs change due to electrostatic interaction and band gap transition, thereby constructing a fluorescence colorimetric sensor to realize the ultra-sensitive detection of aureomycin. In order to realize the on-site detection of aureomycin, a portable device equipped with a smartphone and integrated with the AgInS2 QDs sensor is also designed. The cloud server data analysis system based on machine learning algorithm is integrated into the smartphone, which is convenient for color data collection, correction, interpretation and display. The present application utilizes the function of modern smartphones to capture and process fluorescence color signals, thereby providing a user-friendly on-site detection solution for aureomycin detection.

Systems and methods for multiplex detection through measurement of localized fluorescence ratios are disclosed herein. This can include creating a plurality of capture structures that each include a detection portion that can couple with a target analyte and a stem that can include a capture structure code uniquely identifying a type of the capture structure. The capture structures can be attached to a sample surface and mixed with a sample containing a plurality of target analytes. A location and the capture structure code of each of the capture structures can be determined. A location at which a target analyte is bound to one of the capture structures can be identified, and the target analyte can be determined based on the capture structure code of the capture structure at the location at which the target analyte is bound to one of the capture structures.

The invention discloses a nano-signal amplification paper-based sensor for fluorescence / colorimetric bimodal detection of Hg and a preparation method and application of the nano-signal amplification paper-based sensor for fluorescence / colorimetric bimodal detection of Hg. A composite nano-micelle HTPP-PAM-PCL is formed through modular self-assembly of a porphyrin micromolecular probe 4-((5Z, 9E, 10Z, 14Z, 16E, 19Z)-5, 15, 20-triphenyl-1H, 4H-porphyrin-10-yl) phenol HTPP and an amphiphilic polymer PAM-PCL, and the paper-based sensor is used for detecting Hg in a fluorescence / colorimetric bimodal manner. The fluorescence / colorimetric bimodal detection of Hg < 2 + > is realized. Meanwhile, the HTPP-PAM-PCL composite nano-micelle is fixed on filter paper through an impregnation method to prepare a portable paper-based sensor, and fluorescence quenching and color development change are synchronously output; and in combination with a color recognition color picker APP of a smart phone, the change of the RGB value of the test paper is captured to realize real-time quantitative analysis of the concentration of Hg < 2 + > in an actual water sample.

The invention relates to the technical field of fluorescence sensing and colorimetric detection, in particular to a concentration-gated three-emission fluorescence-colorimetric dual-mode visual sensing probe as well as a preparation method and application thereof. A three-emission fluorescence system is combined with a colorimetric signal, multiple reading channels are provided, the lower detection limit is remarkably lower than that of a traditional single-signal sensor, and good linear response is kept in a wide concentration range. Fluorescence and colorimetric modes are based on different mechanisms and are mutually independent and complemented, so that false positive / negative is effectively avoided, and the reliability of a detection result is remarkably improved. The continuous change of the fluorescence color from blue to red to orange to yellow to green can be identified by naked eyes or a smart phone, and the method is suitable for on-site rapid detection and semi-quantitative analysis. A concentration gating mechanism enables the sensor to present a switching type response behavior in a low / high concentration interval, a saturation phenomenon is avoided, a detection dynamic range is expanded, and the sensor is especially suitable for synchronous monitoring of trace and excessive residues of TC.

The invention discloses an endoplasmic reticulum targeted lipid peroxidation fluorescent indicator and application thereof, and the indicator introduces a conjugated diolefin structure as a lipid peroxidation recognition unit to obtain a series of BODIPY derivatives with the maximum emission wavelength of 620 nm. A conjugated diene part of the fluorescent probe can be subjected to oxidative cracking under the action of reactive oxygen species, and a conjugated system of the fluorescent probe becomes smaller due to breakage of double bonds, which shows that absorption and emission wavelengths are obviously shortened. Therefore, the LPO process can be monitored through the change of the fluorescence ratio. Meanwhile, hydrophilic succinimide ester sulfonic acid group NHS is introduced as a group reacting with protein, the oil-water coefficient of the compound is moderate, the compound easily penetrates through a cell membrane and reacts with adjacent protein free amino in a short time, the probe can be fixed on the protein of an endoplasmic reticulum through a chemical bond, and the probe can be used for long-time fluorescence imaging research. And long-time real-time tracking is carried out on the movement and form change of the endoplasmic reticulum.

The invention discloses a fluorescent material with alpha-cyano diarylethene as a skeleton structure, a synthesis method and application of the fluorescent material in determination of the water content of an organic solvent. The chemical name of the fluorescent material is 2-hydroxy-1, 3-bis [2-(4-pyridine-4-yl phenyl) vinyl nitrile] benzene, the structural formula of the fluorescent material is shown in the specification, and the fluorescent material is prepared from self-made 2-(4-pyridine-4-yl phenyl) acetonitrile and m-hydroxyphthalaldehyde through a Knoevenagel condensation reaction. The fluorescent material has the characteristics of aggregation-induced fluorescence enhancement and adjustable fluorescence in the isomerization process. The fluorescent material can be used for performing fluorescence-colorimetric dual-mode high-sensitivity quantitative detection on the water content in the organic solvent, and the specific performance is as follows: within a certain range, along with the increase of the water content in the organic solvent, the maximum fluorescence emission peak and the maximum ultraviolet absorption peak of the fluorescent material present regular blue shift, and both have a good linear relationship. The fluorescent material is a novel fluorescent-colorimetric dual-mode sensor capable of performing high-sensitivity quantitative detection on the water content in an organic solvent.

This invention provides a method for constructing a donor-acceptor type perylene diimide-based porous conjugated polymer probe and detecting methamphetamine and amphetamine solutions. The method synthesizes donor-acceptor type perylene diimide-based porous conjugated polymer probes with different topologies by combining an electron acceptor perylene diimide derivative and an electron donor aggregation-induced emission fluorophore via a succinate coupling reaction. When used for the detection of methamphetamine and amphetamine, this system exhibits a clear ratiometric fluorescence response, with the fluorescence color gradually changing from yellow-green to orange and orange-red, demonstrating a significant ratiometric fluorescence response. It features fast response speed, high detection sensitivity, good selectivity, and no interference from other common structurally and property-similar substances, enabling the differentiation and identification of methamphetamine and amphetamine.

The present invention provides a FRET-based fluorescent probe comprising the structure shown in Formula 1: R is selected from one of H, a sulfonic acid group, and a sulfonate salt. The present invention also provides a method for preparing the fluorescent probe and its use in detecting sialic acid. This fluorescent probe is simple to prepare and exhibits excellent single-excitation dual-emission performance. Used as a probe, it enables fluorescence ratiometric detection of sialic acid, avoiding the vulnerability of single-wavelength fluorescence detection to probe concentration, environmental factors, and other factors. The detection limit reaches 1.83 μM.

One embodiment of the present invention provides a peptide-based real-time proportional fluorescence sensor with excellent selectivity for methylmercury ions and mercury ions, and a method for detecting methylmercury and mercury ions using the same. According to one embodiment of the present invention, the peptide-based real-time proportional fluorescence sensor with excellent selectivity for methylmercury ions and mercury ions dissolves well in a pure aqueous solution (1% DMSO), is excited by visible light, and can recognize Hg(II) and methylmercury with high sensitivity through proportional fluorescence behavior. In particular, it exhibits a fast detection speed for methylmercury and has high water solubility, but this fluorescence sensor penetrates well into cells and can sensitize Hg(II) and methylmercury inside the cell through a change in the ratio of red and green fluorescence.

The application relates to a Me 2+ The method for detecting tetracycline antibiotics by using the MA-IPA@SA hydrogel film comprises the following steps: S1, in-situ synthesis of a MA-IPA@SA hydrogel by using melamine MA and isophthalic acid IPA as hydrogen bond active ligands and sodium alginate SA as a carrier; Me 2+ Crosslinking SA forms a porous structure hydrogel film to obtain the Me 2+ MA-IPA@SA hydrogel film; S2, reaction of the Me 2+ MA-IPA@SA hydrogel film with a TCs standard solution for more than 6 min; S3, placing the Me 2+ MA-IPA@SA hydrogel film into a UV analyzer, and analyzing the RGB value of the fluorescence color by using software; a standard working curve is established by using the fluorescence ratio as a TCs solution concentration response signal; and S4, the same method is used to process a sample to be detected, and the TCs concentration in the solution is quantified by combining the standard working curve.

The invention discloses a fluorescence-colorimetric dual-mode probe. The chemical structural formula of the probe is as follows: # imgabs0 #. The fluorescent-colorimetric dual-mode probe is connected with 7-nitrobenzoxadiazole (NBD) and a benzothiazole fluorophore through an ether bond, the ether bond can be selectively broken by hydrogen sulfide to generate a chromophore (NBD-SH) and a free benzothiazole fluorophore, and the fluorescent-colorimetric dual-mode probe is output along with fluorescent light (lambda ex = 380 nm and lambda em = 595 nm) and colorimetric dual-mode signals. The probe has the advantages of high selectivity, high response speed, good sensitivity, large Stokes shift (215 nm), obvious colorimetric phenomenon and the like, and has huge application prospects in the technical fields of analytical chemistry, life science, biomedical treatment and the like.

The present invention provides a zinc porphyrin-based nanofiber material, a preparation method, a visual dual-modal fluorescence / colorimetric ratio biosensor and applications, belonging to the technical fields of electrochemiluminescence and colorimetry. The present invention synthesizes an Al-ZnTCPP@PAN nanofiber material by a solvothermal method. ZnTCPP has both fluorescence and colorimetric properties. After being compounded with PAN, the PO4 3‑ attacking the Al nodes can cause ZnTCPP to fall off, generating fluorescence / colorimetric signal changes for highly sensitive sensing of ALP. By calculating the ratio of the FL signal to the colorimetric signal, the detection limit of the material for ALP can be reduced and the sensing accuracy can be improved. At the same time, the visual dual-modal ratio sensing of ALP is realized by means of mobile phone photography and color recognition of the mobile phone APP.

The application discloses a kind of enzyme-free, entropy-driven combination DNA-AgNCs detection microRNA-21 fluorescence ratio type biosensor.The analysis method is composed of two parts, the first part is the target cycle design without enzyme, L-DNA, S, Trigger chain is mixed and annealed to form stable three-strand DNA substrate in PB and CH3COONa hybridization buffer according to 1:1:1 molar ratio, when target exists, Trigger is released in the triggered entropy-driven cycle amplification system;The second part is the ratio fluorescence signal probe part, Y2-DNA or Y3-DNA is mixed in PB buffer according to DNA:AgNO3:NaBH4=1:6:6 molar ratio, obtain Y2-AgNCs and Y3-AgNCs.Y2-AgNCs, Y3-AgNCs and equal concentration Y1-DNA are mixed with equal volume, form Y type ratio fluorescence signal probe.When target microRNA-21 exists, trigger entropy-driven reaction to cause strand displacement and release Trigger chain, it is hybridized with Y1 chain in Y type structure, open Y type structure, Y2-AgNCs, Y3-AgNCs chain dimer separates, realize the controllable change of fluorescence emission from red fluorescence to yellow fluorescence, through the change of the ratio of two fluorescence intensities, realize the high sensitivity detection of target microRNA-21.