183results about How to "Achieving Sensitive Detection" patented technology

The invention discloses a method for preparing an electrochemical luminescence paper chip and a method for measuring content of signal molecule hydrogen sulfide in MCF-7 by using an electrochemical luminescence sensor. The method is characterized by preparing a hydrophobic region, a semi-hydrophobic region, a hydrophilic region and a hollow channel on paper by utilizing a wax printing technology, cutting the hollow channel by virtue of a laser cutting machine, preparing proper printing ink, printing a corresponding reference electrode and a working electrode on the paper, functionalizing the working area, dripping stock solution in a pretreatment region, and fixing cancer cells; and folding the prepared paper chip, forming a three-electrode system, dropwise adding electrolyte solution in a reaction region, connecting an electrochemical workstation, thus realizing high-sensitivity detection of the low-content signal molecules in the cancer cells.

The invention relates to a method for detecting trace ochratoxin A by adopting an electrochemical aptamer sensor, and belongs to the technical field of electrochemical sensors. The method comprises the following steps: firstly, the DNA modification is performed on a gold electrode; then an aptamer is assembled through the complementary base pairing effect so as to capture labeled DNA of gold nanoparticles; the DNA rich in G is assembled on the surfaces of the gold nanoparticles so as to capture a great quantity of methylene blue (MB) to build a signal amplification strategy; finally, a series of OTA standard solutions is detected by taking differential pulse voltammetry scanning as the detection means so as to obtain the response relation between the reductive peak current of MB and the concentration of OTA, and a standard curve is drawn. The invention aims to provide a preparation method of an aptamer sensor, which is simple in operation, high in sensitivity and strong in specificity and is used for sensitivity detection of trace OTA.

The invention relates to a preparation method for a Cr2O3 or NiO porous film material using WO3 as a base material and a method for manufacturing an air-sensitive sensor. A WO3-Cr2O3 or WO3-NiO sol material is prepared by using chemical pure tungstic acid H2WO4 and analytical pure Cr(NO3)3.9H2O or Ni(NO3)2.6H2O as raw materials, 2mol/L of citric acid as a complexing agent, 30 percent of hydrogen peroxide (H2O2) as a dispersing agent and urea as a pore-forming agent. A porous film type air-sensitive sensor manufactured by a sol-gel method has the characteristics of high selectivity, high sensitivity, short response-recovery time, high stability and the like. By the methods, the sensitivity of low-concentration specific gas can be detected; and the methods are particularly suitable for the fields of breath detection, food quality detection, environment detection and the like, have obvious research and application value, have the characteristics of low energy consumption, low cost, smallvolume and the like and are easy to operate.

The invention discloses a polarization-sensitive distributed perturbation sensing method and a polarization-sensitive distributed perturbation sensing system. The better embodiment of the polarization-sensitive distributed perturbation sensing system comprises a function generator (1), a pulse laser (2), a polarization controller (3), a circulator (4), a sensing optical fiber (5), a polarization beam splitter (6), a balanced amplification photoelectric converter (7), a data acquisition unit (8) and a data processing unit (9), wherein the intensity of two paths of optical signals of which the polarization directions are vertical mutually is subjected to substraction by the balanced amplification photoelectric converter so as to obtain the intensity difference reflecting the change of the polarization state of the two paths of optical signals; and data acquired by a data acquisition module is detailedly analyzed to realize the sensitive monitoring on optical perturbation signals. The method has the advantage of improving the detection sensitivity of the sensing system greatly.

The invention discloses a method for detecting the DNA glycosylase activity by alpha-hemolysin nanopores. According to the method, a partial complementary double-chain DNA is designed and is used as aDNA glycosylase hOGG1 substrate; then, the double-chain DNA is fixed on the surface of a streptomyces affinity magnetic bead; a double-chain DNA-magnetic bead compound is formed to be used as a probe. When the DNA glycosylase hOGG1 exists, damaged basic groups 8-methoxyguanine on the double-chain DNA substrate can be specially recognized; the damaged basic groups are cut away; the DNA framework is cut away. The alpha-hemolysin nanopores are used for detecting the output DNA; the frequency of the generated blocking signals has positive correlation to the activity of the hOGG1. Therefore the method is used for detecting the DNA glycosylase activity, and has the advantages of high sensitivity, high efficiency, labeling avoidance and amplification avoidance.

The invention belongs to the field of electrochemical luminescence detection, and particularly relates to an electrochemical luminescence aptamer sensor for detecting ractopamine, a preparation methodand an application method thereof. The electrochemical luminescence aptamer sensor provided by the invention is formed by loading an aptamer on the surface of a glassy carbon electrode modified by anano composite material HKUST-1/PTC-PEI. According to the invention, the electrostatic interaction of PTC-PEI and HKUST-1 is fully utilized to jointly modify the surface of the glassy carbon electrode, so the flexibility and stability of electrochemical luminescence are obviously improved. The electrochemical luminescence aptamer sensor is obtained by loading the aptamer through the combination effect of the amido bond, so that the target molecule ractopamine can be specifically recognized, and the selectivity of ractopamine detection is improved.

The invention discloses an organic fluorescent gel compound based on naphthalimide. The compound is alkyl chain carboxylic acid 4-hydroxyl-N-caproyl-1,8-naphthalimide with 4-hydroxy naphthalimide as a chromophore, and has a structural formula as below, and a molecular formula of [6-HO-C12H5NO2-(CH2)5-COOH]. The invention uses simple fatty acids to introduce the naphthalimide group with fluorescence property, and provides a novel simple gel system; at the same time, the gelator has response function to triethylamine, addition of triethylamine results in fluorescence quenching, and addition of a certain amount of acid generates fluorescence recovery, therefore the invention uses this property, to realize sensitive detection of tri ethylamine by the gel system.

The invention relates to a selenocysteine near-infrared fluorescent probe, and a preparation method and application thereof, belonging to the field of chemical analysis and detection. The near-infrared fluorescent probe Fsec-3 for detecting selenocysteine provided by the invention has the advantages of good selectivity, high sensitivity, low detection limit (20 nM) and good biocompatibility. In aphosphate buffer, the fluorescence intensity and the concentration of selenocysteine (0-100[mu]M) are in a good linear relationship, which indicates that the probe Fsec-3 is suitable for quantitativedetection of selenocysteine. The probe Fsec-3 achieves fluorescence imaging of selenocysteine in the human breast cancer cell MCF-7; and the probe Fsec-3 also achieves sensitive detection of endogenous selenocysteine in a living body, and is fast in response and stable in fluorescence signals. Thus, the fluorescent probe Fsec-3 prepared by the invention is an effective tool for visual and quantitative detection of the content of selenocysteine in cells, living bodies and tumor tissue.

The invention discloses a photoelectric chemical analysis method for detection of 5-hydroxymethylcytosine based on black titanium dioxide. The method is characterized in that firstly, a photoelectricchemical biosensor for detecting 5hmC is constructed, including an electrode, black TiO2, probe DNA, the 5hmC, p-aminophenylboronic acid, PAMAM and amino-modified zinc oxide which are sequentially fixed on the surface of the electrode. The method is advantaged in that photoelectric properties of the black TiO2, the specific catalysis of glycosyltransferase for the 5-hydroxymethylcytosine, the amplification effect of a PAMAM signal and signal quenching of ZnO are utilized to achieve sensitivity detection of the 5-hydroxymethylcytosine. The method is advantaged in that operation is simple, miniaturization is facilitated, and detection of the 5-hydroxymethylcytosine can be realized through only modifying the surface of the ITO electrode.

The invention belongs to the technical field of immune analysis and biosensing detection, and particularly relates to a preparation method and an application of an electrochemical immunosensor based on Hemin-rGO (reduced graphene oxide). A Hemin-rGO (reduced graphene oxide) porous composite material separated by microporous carbon spheres loaded with silver nanoparticles is used as a detection antibody marker, and the constructed sandwich electrochemical immunosensor realizes detection of tumor marker carcinoembryonic antigens, has the advantages of high sensitivity, high specificity, low cost, low detection limit and the like, and has important scientific significance and application value for early diagnosis and disease monitoring of lung cancer.

The invention discloses a preparation method of a biosensor for detecting L-cysteine and an application of the biosensor in detecting yield of escherichia coli L-cysteine. Main components of the biosensor comprise a transcriptional control gene CcdR coding gene from pantoea ananatis, a promoter region and a terminator region of the transcriptional control gene CcdR coding gene, a promoter region of a gene ccdA from pantoea ananatis, a green fluorescent protein coding gene eGFP and a plasmid framework pTrc-Mob. The biosensor can have a good linear relation under the L-cysteine concentration of 0-32 mmol L<-1> and has the highest fluorescence intensity value and cysteine concentration relation under the L-cysteine concentration of 0.01-8 mmol L<-1>. Through combination with a high-throughput screening system, the biosensor performs real-time detection on the yield of escherichia coli L-cysteine, can screen out high-yield mutants of L-cysteine and mutants for key enzymes in biological synthesis of L-cysteine. Specific, quantitative and real-time detection of L-cysteine can be realized, and the sensitivity is high.

The invention discloses a method for preparing a cadmium sulfide-coated zinc oxide nano array composite material and a method for detecting multiple tumor cells and relates to a method for preparing the cadmium sulfide-coated zinc oxide nano array composite material and a method of the composite material. Preparation of a nano array material is realized according to chemical deposition, modification and assembly of a nanometer material are realized through the electrostatic interaction, and finally, the synthesized nano array material is applied to preparing a cancer cell biosensor. Moreover, the hepatoma cells are sensitively detected, and the method has the advantages of simplicity in operation, high reaction speed, good effect, high selectivity, low cost and the like. The method also can realize detection of multiple tumor cells by changing the types of the modified antibodies, can be used in aspects such as scientific research and clinical medicine and particularly has wide application prospects in the field of biological analysis and in the aspects such as tumor cell detection.

The invention provides a preparation method and application of an electrode for detecting a transgenic CaMV35S promoter. The method includes the steps of: preparation of a reduced graphene oxide / gold nanocomposite RGO / Au; preparation of a silicon @ cadmium telluride nanocomposite Si@CdTe; preparation of a probe 1 (Probe 1) on an ITO electrode; modification of a target DNA (t-DNA) CaMV 35S promoter onto the probe 1 (Probe 1); and modification of a probe 2 (Probe2) onto the target DNA (t-DNA) CaMV 35S promoter. Through dual signal amplification at both ends of rGO / Au NPs and Si@CdTe, the sensitive detection of the transgenic CaMV35S promoter is realized; and in the concentration range of 0.05-100 pM, the concentration of CaMV35S and photocurrent present good linear relationship, and the detection limit can reach 0.017 pM.

The invention relates to a photo-electrochemical sensor based on NSCQDs/Bi2S3 and preparation and application thereof. A Bi2S3 nanorod serves as a photoactive material, NSCQDs synthesized through a hydrothermal method is subjected to electrostatic adsorption through PDDA; then carboxy on the surface of the NSCQDs is activated through EDC and NHS, and through an amidation reaction, Ab is modified on the electrode surface; and in the presence of AFP, through antigen-antibody recognition, and an Ab-AFP immune complex is formed on the electrode surface, so that steric hindrance on the electrode surface is increased, transmission of electronic sacrificial agent ascorbic acid (AA) to the electrode surface is hindered, and consequently, photoelectric current signals of the sensor are changed. According to the relation between the AFP concentration and the sensor photoelectric current, the AFP concentration is detected; the photo-electrochemical sensor has good selectivity, repeatability and stability; detection operation on ATP is easy, the cost is low, high efficiency and high sensitivity are achieved, and the photo-electrochemical sensor has the low detection limit and the wide detection range and is of important significance to clinical and biological analysis of proteins.

The invention belongs to the technical field of immunoassay and biological sensing technologies and provides a preparation method and application of an interlayer type lung cancer marker electrochemical transducer. Graphene-loaded Cu2+ doped by functional nitrogen of dual-metal nanometer material Au@Pt of a core-shell structure is utilized as a catalytic material and serves as a marker after beinghatched with detected antibodies, and meanwhile nanometer gold particles functionalized by polydopamine are adopted as electrode modification materials, so that detection of lung cancer marks such asCEA, CA125 and SCCA is achieved. The interlayer type lung cancer marker electrochemical transducer has high sensitivity and specificity, low detection limitations and a significant scientific meaningand a high application value on early detection of lung cancer.

The invention discloses a microRNA detection method based on Hg<2+> assistance and a double-polymerase isothermal nucleic acid amplification technology, and belongs to the technical field of optical bio-sensing. On the basis of a combined catalytic action of a polymerase Klenow fragment and terminal deoxynucleotidyl transferase, microRNA is effectively extended into a polythymine base sequence which is relatively long; Hg<2+> is added, so that a T-Hg<2+>-T double-stranded structure is formed; an SYBR Green I fluorescent dye is interpolated into the T-Hg<2+>-T double-stranded structure, so that the fluorescence of the SYBR Green I is enhanced; and a fluorescence enhancing degree is positively related to the concentration of the microRNA; therefore, the sensitive detection of the microRNA is achieved.

The invention discloses a tungsten sulfide-black titanium dioxide heterojunction-based method for detecting 5fC via photoelectrochemical analysis. According to the method, a photoelectrochemical biosensor for detecting the 5fC is firstly constructed; and the photoelectrochemical biosensor comprises an electrode, and a thin-layer tungsten sulfide nanosheet, AuNPs, 4-amino-3-hydrazino-5-sulfydryl-1,2,4-triazole, 5fC and black titanium dioxide, which are modified on the surface of the electrode in sequence. According to the method, the good photoelectric activity of WS2, the effect of the AuNPs on accelerating the electron transfer, and the specific covalent reaction of a diamine group on 4-amino-3-hydrazino-5-sulfydryl-1,2,4-triazole and an aldehyde group on the 5fC are utilized, and the black titanium dioxide is used as a signal amplification molecule, so that the sensitive detection for 5-formylcytosine is realized. The detection method provided by the invention is high in operation stability, strong in sensitivity, low in detection limit and convenient to realize miniaturization, and is capable of realizing the rapid and sensitive detection for the 5fC through only modifying the surface of the ITO electrode.