87results about How to "Reduce background fluorescence" patented technology

The invention relates to a heptamethine cyanine active fluorescent probe and a preparation method and application thereof. The structural formula of the heptamethine cyanine active fluorescent probe is as shown in the specification, wherein X=II-IX; each of R1 and R2 is (CH2)mCH3, (CH2)nOH, (CH2CH2O)pCH3 and CH2C6H5; each of R3 and R4 is H, SO3H, SO3Na and SO3K; each of a, b, c, d, e, f and g is 2-8; each of n, m and p is 1-10. The heptamethine cyanine active fluorescent probe has the advantages that the heptamethine cyanine active fluorescent probe is based on near-infrared long-wave heptamethine cyanine dye, indoline is selected as the aroma parent nucleus to increase fluorescence intensity, and methenyl chain intermediate cyclohexene rigid bridging enhances stability; nitrogen derivatives with chemical reactivity sites are used to perform nucleophilic substitution on the meso-position of the heptamethine cyanine parent dye, and accordingly Stokes shift and active chemical groups areincreased greatly to facilitate the fluorescent labeling of various substances; the fluorescent probe is of a symmetrical structure, preparation and purification processes are simplified, and cost islowered favorably; the probe can be used as the fluorescent labeling probe of biological molecules such as high-sensitivity protein, sugar and DNA and nano carriers to perform cell or living-body horizontal fluorescence imaging, and the like.

The invention discloses a fluorescence chemical sensor and a method for simultaneously detecting diversified DNA (deoxyribonucleic acid) glycosylases on single-molecular levels and application of thefluorescence chemical sensor. The fluorescence chemical sensor, the method and the application have the advantages that the fluorescence chemical sensor is based on two different molecular beacons including a molecular beacon modified by 8-hydroxyl guanine and a molecular beacon modified by deoxygenated hypoxanthine, the tail end of the molecular beacon modified by the 8-hydroxyl guanine is labeled by cyanine 3 (Cy3) and quenching groups, the tail end of the molecular beacon modified by the deoxygenated hypoxanthine is labeled by cyanine 5 (Cy5) and quenching groups, the fluorescence chemicalsensor is used for detecting 8-hydroxyl guanine DNA glycosylases and N-methylpurine DNA glycosylases and is different from the traditional molecular beacons which can be severely affected by dynamicsand thermodynamics, signal restoration of the Cy3 and the Cy5 depends on molecular beacon splitting with the DNA glycosylases used as media, the DNA glycosylases can be simultaneously sensitively detected by the aid of the method without optional signal amplification, the activity of hOGG1 and hAAG can be detected by the aid of the method in an ultra-sensitive manner without optional signal amplification, the fluorescence chemical sensor can be easily, conveniently and quickly operated, and accurate and reliable test results can be obtained.

The present invention relates to a slide having a first and a second major surface on opposite sides of the slide and one or more openings through the slide from the first major surface to the second major surface and one or more membranes mounted to one major surface of the slide over the one or more openings. The slide provides for both an ability to wash and to reduce the background fluorescence in the active membrane area. Preferably the membrane is made of nitrocellulose, nylon or PVDF. The opening(s) can be used to allow wash solutions to pass through the membrane and be removed along with the contaminants (unattached materials such as proteins or antibodies, dyes, salts, etc) from the slide thereby reducing the fluorescent background. Additionally, the one or more openings exhibit a lower fluorescence than a membrane that is laid over or attached to the slide, as neither the slide material or any adhesive is present which would otherwise increase the background fluorescence.

The invention discloses a fungus detection fluorescent dyeing liquid and a use thereof. The fungus detection fluorescent dyeing liquid comprises an independent dyeing liquid A and an independent re-dyeing liquid B. The dyeing liquid A comprises, by weight, 0.02-0.043% of a fluorescent brightener, 1-10% of potassium hydroxide, 10-20% of dimethyl sulfoxide, 0-5% of glycerin and 65-87% of water. The re-dyeing liquid B comprises, by weight, 0.1-0.5% of Evans blue and 99.50-99.90% of water. The invention discloses a use of the fungus detection fluorescent dyeing liquid. The invention provides a novel fast fungus infection detection product. The product can be used for detecting various fungi which may exist in a fresh or frozen clinical sample and paraffin and ethylene glycol methacrylate-coated tissue.

The invention provides a method, oligonucleotide and kit for detecting common high-risk HPV (human papilloma viruses). A fluorescence PCR (polymerase chain reaction) technology is adopted, HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 26, 53, 66, 73 and 82 which possibly exist in a sample are subjected to initial detection and type identification. By the method, oligonucleotide and kit for detecting the common high-risk HPV, 18 high-risk types can be detected simultaneously, and the HPV 16 and 18 can be subjected to genetic typing simultaneously. On the basis of 18 types of high-risk HPV and affinity of other types on a phylogenetic tree, a high-risk HPV primer and a probe are designed, a background fluorescence value is reduced remarkably while detection accuracy, sensitivity and specificity are guaranteed, detection flux is increased remarkably, and detection cost is greatly reduced.

The invention discloses a method for producing fluorescent/colorimetric dual-pattern paper chips for detection of cancer cell and cell surface polysaccharide. According to the method, the paper chips are produced by a wax printing technology, gold nanorods and porous silver and aptamers are grown in a fluorescent layer work area, then cancer cell capture is carried out, a multi-branched hybridization technology is used for amplification of signal molecule, and accurate measurement of the cancer cells can be realized, the produced paper chips are folded, a chromogenic solution is dropped in a reaction area, and thereby visualization pre-measurement of the cancer cells can be realized. A polysaccharide inhibitor is added, and dynamic symptom of cell surface polysaccharide is realized.

The invention discloses an adenosine determination method based on a fluorescent and colorimetric dual detection system, and belongs to the technical field of analytical chemistry. By gold-sulfur bonds, sulfydryl DNAs are connected to gold nanoparticles, and the sulfydryl DNAs can hybridize with adenosine aptamers modified by fluorescent dye; because of fluorescence quenching in high-salt solution, the detection system is free of fluorescence or very low in fluorescence intensity and the stable gold nanoparticles keep the solution in a wine red color; addition of adenosine causes changes in the structures of the aptamers, so that the adenosine aptamers modified by the fluorescent dye are dissociated from the gold nanoparticles and the fluorescence of the fluorescent dye recovers; at the moment, the gold nanoparticles cannot exist stably, the color of the solution changes from red to blue. By the adenosine determination method, through changes in fluorescence intensity and solution color of the detection system, qualitative and quantitative adenosine determination is achieved; the adenosine determination method has the advantages of high sensitivity, good selectivity and the like.

The invention discloses a coding suspension microchip and a preparation method and application thereof. The microchip comprises a transparent substrate and a non-transparent plane microstructure serving as graph identification codes, and the non-transparent plane microstructure is distributed on the surface of the transparent substrate. Preferentially, the non-transparent plane microstructure comprises a high light reflection stacking structural layer formed on the surface of the transparent substrate. The microchip can be manufactured through a semiconductor micromachining process, an application mode of the microchip is that probe molecules suspended on the microchip in a liquid phase system are used for capturing molecules of objects to be measured, then the microchip is separated from the liquid phase system and washed, and finally images of the microchip are formed in a visible light channel and a fluorescence channel respectively to determine identification of target molecules captured by the microchip and conduct quantitative analysis on the target molecules. Inexpensive manufacture of the coding suspension microchip with high throughput and good detection accuracy is achieved, and the coding suspension microchip can be applied to simultaneous detection of multiple biology/medical indexes in liquid samples.

A method of preparing cell samples for viable cell number quantification with a fluorescence digital imaging microscopy system employing digital thresholding technique. The cell sample is stained with a first, fluorescent dye and treated with a second dye that is able to quench the fluorescence of the first dye. The fluorescent dye accumulates in viable cells only and is used to stain the viable cells. The second dye is excluded from viable cells but enters non-viable cells, thereby quenching the background fluorescence in non-viable cells and the medium. Two examples of dye combinations are described: fluorescein diacetate used as the fluorescent dye with eosin Y as the quenching dye; and calcein-AM used as the fluorescent dye with trypan blue as the quenching dye. By reducing the background fluorescence, the dynamic range and accuracy of viable cell number measurements are enhanced. In low viability cultures treated with fluorescein diacetate, background fluorescence completely masked viable cells, but digital thresholding and eosin treatment dramatically reduced background fluorescence, producing a linear response over 4 logs of viable cell density.

The invention provides an AIE composite electrostatic spinning fibrous membrane and a preparation method and application thereof. The AIE composite electrostatic spinning fibrous membrane is a nanofiber membrane formed from a biocompatibility polymer and an AIE molecule, can slowly release antibacterial activity component AIE molecules in the using process, can effectively restrain and kill bacteria, is free from any side effect on generation of normal cells, can promote adhesion, growth and proliferation of the cells, has favorable bacteria resistance and air permeability, can be completely jointed to the surface of wounds to maintain stable physiological environment, and can increase the healing speed. The AIE composite electrostatic spinning fibrous membrane is prepared by an electrostatic spinning technique, is simple in preparation method, low in cost, and suitable for large-scale industrial production, and has important application value in the respects for treating chronic wounds of wounds or burns and the like.

The invention discloses preparation of a ratio-type three-dimensional metal-enhanced fluorescence Pb<2+> paper chip and application of equipment thereof in Pb<2+> detection. According to the preparation, a hydrophilic working area and a hydrophobic area of a paper chip are prepared by a wax printing technology, and further decahedral silver grows in the working area, the fluorescence intensities of two fluorescence signals are determined by means of layer-by-layer modification, the Pb<2+> is detected portably, reliably and sensitively by the relation curve of variation of two fluorescence intensity ratio over Pb<2+> concentration.

The invention discloses a fade-resistant agent used in bacteria counting by virtue of a fluorescent microscopy and a fluorescent microscopic counting method for detecting the number of bacteria in a water body and belongs to the field of environmental microbiology. The fade-resistant agent is obtained by dissolving p-phenylenediamine, sodium chloride, disodium hydrogen phosphate, Tris, glycine and glycerol in deionized water and adjusting the pH. The fluorescent microscopic counting method for detecting the number of bacteria in the water body comprises the following steps: adding a fluorescent dye into a water sample, staining, adding a fade-resistant agent working liquid for carrying out fade-resistant treatment, carrying out suction-filtration on the sample subjected to the fade-resistant treatment with a cellulose acetate filtration membrane and observing under the fluorescent microscope. The method for detecting the number of bacteria in the water body is time-saving and effort-saving, low in cost and strong in fade-resistant capability and is free of background fluorescence interference and the number of bacteria in the water sample can be quickly and accurately detected.

The invention discloses a method for identifying the production place of turmeric essential oil based on a Raman spectrum technology. The method uses qualitative and quantitative identification methods at the same time, and comprises the following specific steps: (1) collecting a calibration set verification set and processing Raman spectrum data; (2) establishing a judgment model: (2.1) establishing a PCA qualitative judgment model, and (2.2) establishing a PLS-DA quantitative judgment model; and (3) measuring the sample to be measured. The method has the characteristics of small identification error, high identification speed and no damage.

The invention discloses an arsenic induced operon gene and application thereof. The operon gene has a nucleotide sequence represented by SEQ ID NO:1 or a nucleotide sequence complementary with the nucleotide sequence represented by SEQ ID NO:1. An arsenic induced operon is a muton of a wild type arsenic induced operon and can be directly used for optimally constructing an arsenic induced biosensor and detecting the content of arsenic. An arsenic induced bacteria biological sensor constructed based on the operon has the advantages of being high in sensitivity, specific in arsenic detection and low in background fluorescence.

The invention discloses a two-photon fluorescent probe for sulfur dioxide and viscosity dual detection and a preparation method of the two-photon fluorescent probe. The compound structure of the fluorescent probe is shown as a compound PVS. The fluorescent probe realizes two-photon excitation response to viscosity by utilizing a twisted intramolecular charge transfer (TICT) mechanism between indole salt and carbazole. Meanwhile, the carbon-carbon double bond connected with the indole salt can realize response to sulfur dioxide through nucleophilic addition reaction. The PVS has the advantages that the PVS can track the fluctuation of sulfur dioxide and viscosity at the same time, and has two emissions which are easy to distinguish. The PVS can also accurately visualize the form of the mitochondria, and the real-time accurate monitoring of the sulfur dioxide and the viscosity in the mitochondria under the excitation of the two photons is successfully realized.

The invention discloses a weak background fluorescence type resin embedding method and belongs to the technical field of biological engineering. In the method, a fluorescence biological sample is permeated and embedded by using a resin solution in which Sudan black B is dissolved as a dying and embedding solution. On the premise that a biological sample obtained by adopting the method keeps the fluorescence signal intensity, the background fluorescence is greatly reduced. The method can be applicable to a large sample with a centimeter size; the obtained biological sample can be used for continuously slicing in an ultrathin manner. The method provided by the invention has the advantages of being low in cost and simple in operation steps, and is applicable to popularization and application in ordinary laboratories.

The invention relates to a preparation method of levodopa nanoparticles and biosensing application of the levodopa nanoparticles, and belongs to the technical field of nano biosensing. Levodopa (L-DA)is used as a unique precursor to synthesize levodopa nanoparticles (LNDS) at room temperature, and the formed LNDS can quickly and effectively quench a dye-labeled oligonucleotide fluorescent probe (FAM-DNA) through electrostatic interaction. Complementary deoxyribonucleic acid (cDNA) or adenosine triphosphate (ATP) is competitively combined with a fluorescent probe, so that fluorescence is recovered, and an effective sensing platform for detecting biomolecules is constructed. In addition, the sensing platform can also perform high-sensitivity and selective detection on adenosine triphosphatein a complex system (human serum). The synthetic process of the levodopa nanoparticles is simple and environmentally friendly, the toxic and side effects on cells and organisms are low, the levodopananoparticles have a very strong quenching effect on dye-labeled oligonucleotides, the background fluorescence is greatly reduced, and the signal-to-noise ratio is increased.

The invention relates to a water-soluble red fluorescence mitochondria targeting probe and application, and belongs to the field of new materials. The invention discloses a water-soluble red fluorescence mitochondria targeting probe, which has a structural general formula shown in the specification, wherein M is an aromatic ring, and N is a hydrophilic group. Compared with other commercial mitochondrial fluorescence probes, the targeting probe provided by the invention has relatively good water solubility. When the fluorescent probe disclosed by the invention is used for dyeing cells, mitochondria can be targeted; the probe has higher biocompatibility and almost has no background fluorescence, and the weak scattered light and autofluorescence of a biological sample at a red fluorescence waveband are beneficial to reducing background signals, so that the probe has a high signal-to-noise ratio. In addition, the red fluorescence has better penetration depth, has more outstanding advantages when being used for mitochondrial imaging of cells, can be used for observing the mitochondrial imaging process of the cells in situ under the rinsing-free condition, and can track the state of themitochondria of the cells for a long time.

The present invention discloses a graphene oxide-containing amplification system and an application of the system in detection of colorectal cancer markers. The amplification system comprises an isothermal amplification buffer, MgSO4, a dNTP mixture, a target-specific primer set, DNA polymerase, an amplification template, and 5-30 ng of graphene oxide. A mechanism of graphene oxide inhibiting non-specific amplification in LAMP is verified, the optimal amount of the graphene oxide in a LAMP amplification system is optimized, and the amplification system is applied in the detection of rectal cancer markers.

The present invention is generally directed to nanometric biomolecular arrays and to a novel approaches for the preparation of such nanoarrays, based on binding of biomolecules, such as avidin, to templates generated by lithographically-an-odizing biocompatible ultrathin films on silicon substrates using AFM anodization lithography. The present invention is also directed to methods of using such arrays.

The invention relates to phototherapeutic instruments, in particular to a dual-wavelength excitation type feedback phototherapeutic instrument and aims to solve technical problems of harms to normal cells, lack of a noninvasive temperature feedback function and long treatment period of an existing phototherapeutic instrument. The phototherapeutic instrument comprises a double-channel signal generator, a heating laser, a refrigerating laser, an optical fiber transmission system, an up-conversion thermotherapy probe, a spectrograph and a computer. The optical fiber transmission system comprises a coupler, an annular and a focus mirror in sequential connection through optical fibers. Two pulse laser beams in different wavelengths are used for heating and refrigerating respectively; by up-conversion fluorescence signal resolution of the probe temperature, temperature feedback in a phototherapeutic process is realized, and input laser parameters are further adjusted according to feedback temperature to realize online intervention. The dual-wavelength excitation type feedback phototherapeutic instrument is simple in operation and capable of inhibiting overheating and shortening treatment cycle.

The invention relates to a mycoplasma pneumoniae (MP) rapid detection primer group and a kit. The mycoplasma pneumoniae rapid detection primer group comprises an upper stream primer, a lower stream primer and a probe which detect a mycoplasma pneumoniae gene group P1 gene sequence. The kit comprises a lysate solution, a reconstitution fluid, an EMA reaction tube containing primer probes, a positive quality control product and a negative quality control product. The primer group can be specifically combined with the mycoplasma pneumoniae P1 gene, and cooperate with EMA (Enzymes Mediated Amplification, a multienzyme mediated nucleic acid amplification technology, namely a normal temperature nucleic acid amplification technology) to prepare the mycoplasma pneumoniae detection kit, and the mycoplasma pneumoniae rapid detection primer group and kit have the advantages of easy to operate, short in consumed time, high in sensitivity and specificity and the like.

The invention discloses a two-photon excitation delay detection fluorescence imaging analysis method and equipment for a live animal. The method is used for analyzing the time-varying kinetic propertyof distribution, fluorescence intensity or a probe concentration of nano fluorescence probes (or fluorescence nano drug carrier simulated probes) in a tissue and an organ in an animal body; the in-vivo fluorescence nano probes are subjected to two-photon excitation by red light or near infrared pulse laser, so as to perform delay detection on the fluorescence intensity and the time-varying kinetic property of an in-vivo specific part by a fluorescence imaging mode; the method has the advantages of large imaging analysis depth, high reliability, high detection sensitivity and the like.

The invention belongs to the technical field of chemical analysis and detection, and aims at solving problems that in recent years, thallium environment detection and poisoning identification and troubleshooting requirements are met. Portable detection means are lacked, a G-rich nucleic acid aptamer fragment capable of specifically capturing Tl<+> is designed, and a double-label fluorescence technology and a fluorescence resonance energy transfer principle are combined, the fluorescent probe for detecting Tl<+> based on the nucleic acid aptamer is constructed. The nucleic acid aptamer is obtained by screening and optimizing a G-rich nucleic acid aptamer by using a Poly-T extension strategy, and is named as GACT32. cyanine dyes Cy3 and Cy5 are adopted as fluorescence signal indicating groups to be modified at the 5' end and the 3' end of the nucleic acid aptamer respectively. According to the probe, background fluorescence of a traditional fluorescent probe is greatly reduced, interference of K<+>, Na<+> and other ions in a solution is eliminated, specific detection of Tl<+> is achieved, the linear range is 10 mu M-10 mM, and a portable detection method is provided for thallium ion environment detection and poisoning investigation.

The invention provides an HOCl fluorescent probe based on pyronin hydrazine, a preparation method and application. The structural formula of the probe is shown as a formula I and a formula II. According to the invention, the probe is constructed by combining a hydrazine reaction site and a pyronin fluorophore, has extremely low background fluorescence due to C=N isomerization and the PET process, provides rapid and significant fluorescence off-on response to HClO in the red light region, has extremely high sensitivity, and has been successfully used for distinguishing cancer cells/tissues from normal cells/tissues.