36results about How to "Achieve high specificity detection" patented technology

The invention discloses ctDNA library construction and sequencing data analysis methods for simultaneously detecting common mutations of various liver cancers. The library construction method and thesequencing data analysis method have the following advantages: firstly, various mutation forms of liver cancers are simultaneously detected under the condition that capture is not needed; secondly, the methods are suitable for efficient capturing in an ultra-small target area; thirdly, the library can support 10 to 20 times of detection; fourthly, the DNA barcode is connected to an initial ctDNA molecule during the library construction process and the flow is analyzed by cooperating with a biological information analysis process to realize high-specificity detection of ctDNA low-frequency mutation; and fifthly, the library can be used for PCR hot spot detection and capture method sequencing at the same time, the false positive mutation can be filtered effectively by using the added DNA barcode to realize duplex-based high-specificity sequencing. The methods have the important clinical significance for early screening, disease tracking, curative effect evaluation, prognosis prediction and the like of liver cancers.

The invention relates to a biosensor for detecting kanamycin based on target-induced conformational changes of nucleic acid aptamers. The invention is prepared by sequentially modifying an electrode with a HAP2 layer, a Helper layer, and a homogeneous reaction mixture. The present invention utilizes the specific type recognition of nucleic acid aptamer, uses the aptamer of kanamycin as the recognition substance to realize the highly specific detection of the target kanamycin; uses the nucleic acid tool enzyme to realize the recycling of the target , played the role of signal amplification, thereby improving the detection sensitivity.

The invention relates to the technical field of the biosensor and in particular to a biosensor for detecting kanamycin based on nucleic acid aptamer comformational change induced by a target object. The specific preparation method comprises the following steps: pre-processing an electrode; decorating an HAP2 layer on the surface of the electrode; and decorating homogeneous reaction mixed liquid on the surface of the electrode. The biosensor is capable of using the specific recognition of the nucleic acid aptamer, using the aptamer of the kanamycin as a recognition substance for high specific detection of the target object kanamycin, using nucleic acid tool enzyme, and realizing the cyclic utilization of the target object, and has the function of amplifying the signal.

The invention discloses an electrochemical sensor and a method system for simultaneously detecting isocarbophos and acetamiprid. From the inside to the outside, there are electrodes, beacon probe layer, 6-mercaptohexa-1-alcohol (MCH) sealing layer, and homogeneous reaction product layer. Blue and ferrocene modification; the preparation method is first to polish the electrode and treat it with H2SO4 and H2O2, and then modify the beacon probe on the surface of the electrode. The sensor of the invention has simple preparation method, stable performance and good electrode repeatability, and is suitable for the detection of isocarbophos and acetamiprid in food safety and the practical application of biosensor industrialization; it can realize the detection of isocarbophos and acetamiprid in food. In the rapid online detection of acetamiprid, the detection limits of isocarbophos and acetamiprid were 0.12 and 0.37ppb, respectively.

The invention relates to the technical field of biosensors, and particularly relates to a fluorescent biosensor for detecting ochratoxin A based on a rolling ring amplification mediated catalytic hairpin self-assembly and incision enzyme feedback amplification method. According to the fluorescent biosensor, as for a detection mode, a fluorescence method is adopted for detection, and a luminoscopeis utilized; before detection, a padlock probe and a connecting probe form an annular template probe; then a target object is added to a homogeneous solution of a complex probe I, a complex probe II,HP 2 and HP 3, incubating is carried out for 120 minutes at 37 DEG C, and the target object and an aptamer sequence are bound; the multiple feedback amplification process is completed under the actionof a phi29 DNA polymerase and an endonuclease IV, so that signal amplification is realized; and then, the luminoscope is used for setting the excitation wavelength to be 399 nm, the fluorescence intensity at 610 nm is detected, and the detection range is 560-640 nm. Meanwhile, the invention further provides a preparation method for the biosensor. The preparation method has the advantages of beingmild in reaction condition and easy to operate.

The invention provides a molecularly imprinted electrochemical sensor for detecting patulin. The sensor comprises a glassy carbon electrode, a thionine-Pt nanoparticle-nitrogen-doped graphene composite nanomaterial layer and a molecularly imprinted polymer layer. The molecularly imprinted electrochemical sensor can effectively amplify the signal, has high sensitivity and has good selectivity, a high recovery rate and good reproducibility. The molecularly imprinted electrochemical sensor is free of expensive large instruments, has a simple pretreatment process, ensures the accuracy of the results, realizes fast detection, greatly saves a cost and improves detection efficiency.

The invention relates to an aptamer based salmonella typhimurium detection biosensor and a preparation method thereof. Signal amplification is realized by continuous generation and cyclic utilization of Primer, and consequently high-sensitivity detection of salmonella typhimurium is realized, and lower detection limit can be acquired. The aptamer based salmonella typhimurium detection biosensor is high in specificity and sensitivity, low in cost and quick in detection. By the detection method, a salmonella typhimurium detection limit is 5-15cfu / mL, and a detection range is 1*10-1*107cfu / mL.

The invention provides a method for detecting salmonellae. The method comprises the following steps: synthesizing a DNA silver nano cluster; and carrying out index enlargement under the combined action of Phi 29 polymerase and Nt.AlwI endonuclease and homogeneous reaction of strand displacement cycle amplification, and then carrying out fluorescence detection. The method provided by the invention has the advantages that specific recognition of an aptamer is utilized, and the aptamer is designed into a hairpin structure, so that high specificity detection on a target object salmonellae is realized; and cyclic utilization of Trigger is realized by utilizing the combined action of the Phi 29 polymerase and Nt.AlwI endonuclease as well as strand displacement reaction, signal simplifying effect is achieved, and detection sensitivity is effectively improved.

The invention provides a method for detecting benzyl penicillin. The detection of the benzyl penicillin is realized in a homogeneous solution; amplification of a signal is realized in a two-step circulating manner, so that high-sensitivity detection of the benzyl penicillin is realized, and a relatively small lower detection limit is obtained.

The invention discloses a microRNA SDA detecting method based on AgNCs / HpDNA probes. The method is characterized in that hairpin type DNA-templated silver nanoclusters are used as novel molecular beacons; in a chain-substitute isothermal amplification reaction mediated by primer dangling end rich-G sequences, single detection of gastric cancer plasma microRNA markers is achieved by the aid of rich-G fluorescence enhancement effects generated by hybridization. The method is high in specificity, short in reaction time, low in material use amount and simple in operation procedures, and a new direction for creating a fast and simple novel microRNA detecting method is developed.

The invention relates to the technical field of a biosensor, and particularly relates to a fluorescence biosensor for detecting UDG (Uracil-DNA Glycosylase) on the basis of a polymerase-assisted feedback rolling circle amplification and endonuclease amplification fluorescence method. The invention aims to solve problems of both low specificity and low sensitivity of a method for detecting UDG in the prior art. The biosensor for detecting the UDG on the basis of a feedback rolling circle amplification technology achieves a rolling circle amplification effect on matching of phi29 polymerase andendonuclease IV, implements fluorescence resonance energy transfer of a fluorophore and a Quenching group and performs a homogeneous reaction on mixed liquid. A preparation method comprises: constructing a circular template and a composite probe; feeding back a rolling circle amplification signal and carrying out fluorescence detection. Specific hydrolysis of the UDG on a basic group U is utilized, and by utilizing such specific reaction, the UDG can be accurately measured and meanwhile, interference can also be avoided; by utilizing endonuclease IV circle amplification, a signal amplificationeffect is achieved.

The present invention provides a biosensor for detecting Salmonella, including aptamer (Apt), template (T), hairpin probe 1 (H1), hairpin probe 2 (H2), heme, potassium ion (K + ), cysteine, gold nanoparticles modified with Raman dyes and buffer, can use surface Raman enhanced detection of Salmonella in food. The present invention utilizes good specificity and high detection sensitivity; mild reaction conditions and fast reaction speed; compared with other optical detection methods, the detection method is easy to operate and has a short detection cycle; the detection process is realized in a homogeneous phase, reducing the The complexity of the operation; no need for enzymes to effectively reduce the process cost of the biosensor, and is suitable for low-cost requirements in industrialization.