12 results about "Escherichia coli detection" patented technology

The application provides a preparation method of a functionalized phage probe and application of the functionalized phage probe in detection of escherichia coli. The functionalized phage is a recombinant phage (M13KO7@SaBP) in which streptavidin binding peptide (SaBP) is fused and expressed at the N terminal of the main capsid protein P8 protein of M13K07 phage. In the application, the gene encoding SaBP (MDVEAWLGAR) is inserted into the N terminal of the P8 protein gene of M13K07 phage by site-directed mutagenesis to prepare M13K07@SaBP. The stable signal amplification is realized by using the abundant P8 protein (about 2700) of M13 phage and the super strong binding force of biotin-streptavidin, the interference of food sample matrix is reduced by combining the magnetic separation technology, and a detection method of escherichia coli with high sensitivity and small sample matrix interference is constructed.

The invention belongs to the technical field of harmful microorganism detection, and particularly provides an electrochemical sensor for detecting escherichia coli (escherichia coli O157: H7) in food and a preparation method of the electrochemical sensor. According to the electrochemical sensor, the surface of a substrate electrode is sequentially modified with an electron transduction layer and a recognition molecular layer; wherein the electron transduction layer is formed by an infinite coordination polymer composite material of gold nanoparticles; the recognition molecular layer is a nucleic acid aptamer. The electrochemical sensor is high in sensitivity, good in selectivity and low in detection limit; compared with other detection methods, the method does not need incubation and can be directly used for in-situ and rapid detection of bacteria.

The invention discloses a preparation method of an SERS (Surface Enhanced Raman Scattering) sensor based on oversized annular DNAzyme, a product and application of the SERS sensor in escherichia coli O157: H7 detection, and relates to the technical field of nano materials and biological detection. The SERS sensor disclosed by the invention comprises an aptamer, namely a Key chain-Link chain three-chain body, an LDNAzyme-Block chain double-chain body, an rA Hairpin, an Au-H1 Hairpin probe, an H2 Hairpin probe and an AuNPs-H3 Hairpin probe, and the SERS sensor disclosed by the invention is characterized in that the SERS sensor comprises an aptamer, namely a Key chain-Link chain three-chain body, an LDNAzyme-Block chain double-chain body, an rA Hairpin probe and an AuNPs-H3 Hairpin probe; in the presence of escherichia coli O157: H7, a bimorphic gold nano assembly probe can be formed; the preparation method of the SERS sensor is simple and easy to control, the bimorphic gold nano assembly probe formed after target recognition has a Y-shaped structure with 3D space constraint, the stability is high, the detection operation on escherichia coli O157: H7 is simple and convenient, the sensitivity is high, the detection limit is low, and the specificity is high.

This invention discloses a method and application for detecting F17 Escherichia coli. Using the fimbrial virulence gene ctg_04543 or ctg_04549 of F17 E. coli as a target, a fluorescent quantitative probe is designed based on the nucleotide sequence. Using F17 E. coli genomic DNA as a template, the F17 fimbrial gene ctg_04543 or ctg_04549 is detected by fluorescent quantitative PCR. Based on the fitted standard curve, F17 E. coli in the sample can be quantitatively detected. The F17 E. coli detection method provided by this invention is simple, rapid, quantitative, highly sensitive, and highly specific. It can achieve quantitative detection of F17 E. coli within 2-3 hours, meeting the detection needs of various situations such as laboratory research and animal pathogen diagnosis, and has broad application prospects and extremely high market implementation potential.

The invention belongs to the technical field of biological detection, and particularly discloses a method for rapidly and ultrasensitively detecting escherichia coli O157: H7 based on SERS (Surface Enhanced Raman Scattering). Comprising the following steps: preparing immunomagnetic bead capture nanoparticles, preparing precious metal or precious metal composite nanoparticle sol, preparing immune precious metal or precious metal composite signal nanoparticles, preparing a sandwich structure, and detecting escherichia coli O157: H7. According to the method, the antibody serves as a specific recognition element and is specifically combined with and used for measuring escherichia coli O157: H7, on one hand, the dispersed state of a nano material in a detection system can be stabilized, on the other hand, target protein can be recognized with high specificity and high affinity, and the method is good in stability, low in preparation cost and suitable for large-scale popularization and application. The detection accuracy is improved to a great extent; the method is higher in detection speed, extremely simple in detection process, short in time consumption, suitable for field rapid detection and batch screening, low in detection limit, ultra-high in detection speed and ultra-high in detection sensitivity, and capable of accurately recognizing trace target thalli.

The present application relates to the technical field of microbial detection automation equipment, and discloses a pretreatment equipment for escherichia coli detection, which solves the problems proposed in the background art, and comprises a base, a filling station and a rotary driving assembly arranged on the base. The driving assembly drives the L-shaped workbench to rotate between the initial station and the processing station through the sleeve. The sleeve is provided with a bag opening clamping mechanism on the side, and the elastic adaptive module is used to fix the bag opening, which can effectively buffer the tension when the bag opening is folded. The horizontal part of the L-shaped workbench is provided with a bag body processing mechanism, which comprises a sealing clamp driven by a bidirectional screw and provided with a sealing convex rib and a groove, and an inertia beating assembly driven by a cylinder and capable of reciprocating. The beating assembly realizes soft beating through the inertia of the flexible beating plate. The present application simulates the "holding bag" and "beating" actions of human hands through the automatic mechanism, realizes the automatic filling, sealing and efficient beating mixing of the homogeneous bag, and improves the automation degree and processing efficiency of the pretreatment.

The invention discloses a hot spot self-assembly colorimetric-Raman sensing platform and an escherichia coli detection method, the hot spot self-assembly colorimetric-Raman sensing platform comprises an isothermal amplification system, a CRISPR-dCas9 system, GNPs-probe and SA-GNPs, a target bacterial gene is taken as a DNA template, RPA amplification is carried out through the isothermal amplification system, and a double-chain amplification product modified by terminal biotin is obtained; the CRISPR-dCas9 system is used for targeted recognition of a double-chain amplification product modified by terminal biotin to form a composite product; gNPs-probe is composed of gold nanoparticles, a Raman signal molecule and a DNA probe, and the GNPs-probe is combined with the stem-loop structure of the sgRNA of the composite product through the DNA probe; sA-GNPs is combined with the biotin of the composite product through streptavidin; gNPs-probe and SA-GNPs are assembled on the composite product, so that a colorimetric-Raman sensing platform for detecting target bacteria is formed. According to the present invention, the cross validation of the generated colorimetric, ultraviolet and Raman multi-mode signals is adopted to improve the result reliability, the isothermal amplification and the self-assembly hot spot are adopted to enhance the multiple sensibilization detection signal, and the specificity is enhanced based on the specific primer group and the CRISPR-dCas9 system mediated secondary recognition, such that the rapid and accurate detection of the bacteria in the actual sample is finally achieved.

The invention relates to the technical field of visible light absorption spectrum detection, in particular to a three-dimensional fluorescence detection method and system for identifying escherichia coli in bile, and the method comprises the following steps: generating a light source through a light source generation module; adjusting the intensity of the light source by using a light splitting module, and dividing the light source into two paths of light so as to obtain sample detection light and a reference spectrum; acquiring a background spectrum and a bile detection spectrum by utilizing a sample detection module based on the sample detection light; according to the reference spectrum, the background spectrum and the bile detection spectrum, the upper computer uses a spectrum detection model to identify escherichia coli in the bile sample. Based on the detection principle of three-dimensional fluorescence, the intelligent degree and efficiency of detection of escherichia coli in bile can be improved, and the detection cost can be reduced.

The invention discloses a preparation method of a ratio type electrochemical luminescence biosensor, the sensor and application of the sensor in detection of escherichia coli O157: H7, and relates to the technical field of nano materials and biological detection. The sensor provided by the invention comprises an Aptamer-Templet double-strand body, a phi29 polymerase, a Nb.BbvCI nicking enzyme, a probe 1 and a probe 2, wherein the probe 1 and the probe 2 are connected with each other; the method comprises the following steps: specifically recognizing surface protein of escherichia coli O157: H7, releasing a Templet chain, releasing a Trigger chain and opening a hairpin structure of a probe 1 under the assistance of polymerase and cutting enzyme, and opening a hairpin structure of a probe 2 by the opened probe 1, so that self-assembly of the probe 1 and the probe 2 is realized, and a detectable object is obtained; the detection limit of the sensor to escherichia coli O157: H7 is as low as 1 CFU / mL, and the sensor is wide in linear range, high in stability, suitable for multiple samples, high in specificity and easy and convenient to use and operate.

The application discloses a microfluidic chip and a method for detecting water quality by embedding coliform group in alginate hydrogel, and the microfluidic chip comprises a sample inlet, an oil phase inlet, an alginate aqueous solution inlet, a droplet mixing flow channel, an incubation chamber and an outlet; wherein the oil phase inlet is connected with the sample flow channel through two oil phase flow channels which are divided into two parts and meet at a cross-shaped port, the alginate aqueous solution inlet is connected with the flow channel from the cross-shaped port through a water phase flow channel and meets at a T-shaped port; a contraction section flow channel and a first serpentine flow channel are sequentially arranged between the T-shaped port and the droplet mixing flow channel, and are respectively used for extruding and fusing the bacterial liquid droplet and the alginate droplet. The application solves the problem that the detection effect is poor due to the spontaneous fusion of droplets caused by the increase of incubation temperature in the prior art by combining the alginate with the calcium salt solution to form the hydrogel through ion cross-linking, and has a good application prospect in the detection of coliform group in water samples.

The application belongs to the technical field of biological detection, and particularly relates to a RPA primer for detecting Escherichia coli, a kit and application thereof. The target sequence is a new target DNA sequence which is broad-spectrum and specific in Escherichia coli. The RPA primer designed based on the target sequence can be used in recombinase polymerase isothermal amplification reaction of Escherichia coli. On this basis, the application provides a RPA detection method for detecting Escherichia coli by using the RPA primer. Compared with the existing PCR detection technology, the isothermal amplification detection method of the application can rapidly detect Escherichia coli at room temperature or under slight heating, and the detection can be completed within 30 min, thereby significantly improving the detection efficiency. Moreover, the detection method has high specificity, and the detection sensitivity can detect Escherichia coli as low as 10 1 copies / µL, and the specificity and sensitivity are much higher than those of the traditional PCR detection technology.

This invention relates to the field of biomedicine, specifically to an antibody for detecting Escherichia coli O45 and its application method. The antibody is a monoclonal antibody or its antigen-binding fragment, comprising the heavy chain CDR sequence shown in SEQ ID NO:1-3 and the light chain CDR sequence shown in SEQ ID NO:4-6. This invention also provides the nucleic acid molecule encoding the antibody, the expression vector, the host cell, and the preparation method thereof. Specificity identification results show that the antibody specifically binds to Escherichia coli O45 and shows no cross-reactivity with other Escherichia coli serotypes such as O157, O26, O103, O111, O121, and O145, as well as closely related serotypes of O55, and also shows no cross-reactivity with common foodborne pathogens. The indirect ELISA detection method based on this antibody has a detection limit of 1×10⁻⁶ for Escherichia coli O45. 2 The detection rate is CFU / mL, and the entire testing process can be completed within 24 hours. The monoclonal antibody provided by this invention can be used to prepare detection kits, test strips, and other products, and is suitable for rapid screening of O45 Escherichia coli in imported and exported food.