38 results about "Dna hairpin" patented technology

The invention discloses a microRNA trace detection method based on an exponential order non-enzymatic amplification and electrochemical luminescence principle. A non-enzymatic amplification and hybrid chain type reaction system is adopted, and the specific sequences of DNA hairpin probes H1, H2, H3 and H4 are designed based on a detection target microRNA sequence; when an amplification system contains to-be-detected microRNA, the subsequent hybrid chain type reaction process is triggered by virtue of an H1+H2 double-chain composite structure, and is finished by H3 and H4 together; and moreover, an amplification product is captured by virtue of streptavidin magnetic bead capture, and an electrochemical luminescence signal is generated and detected by virtue of an electrochemical detection system. According to the method, an enzyme is not involved in the whole process, the principle is simple, and the detection cost is low; and the method has the advantages of constant temperature amplification, high sensitivity, simple operation, simplicity in popularization and the like. The method is applied to nucleic acid detection and can be combined with a protein aptamer related technology to be used for protein detection.

The invention belongs to the technical field of molecular circuit-based design and particularly relates to a DNA strand self-assembly principle-based and local DNA hairpin strand displacement reaction-based XOR gate and a complementing circuit constructed by utilizing the same. The XOR gate is constructed by adopting double-rail logic and comprises a single-stranded DNA input, a fuel hairpin and a DNA hairpin fixed to a fold paper substrate. The complementing circuit belongs to a three binary input complementing circuit and is composed of two parallel XOR gates. According to the provided XOR gate, the occurrence probability of wrong strand displacement reactions is relatively low and the DNA strand displacement reaction efficiency is improved. According to the provided complementing circuit, parallel computing can be realized without mutual interference; and a simulation result for Visual DSD of the complementing circuit shows that the complementing circuit is reasonable to construct, has good performance and has the advantages of high construction speed, high precision, high expandability and the like in construction of a large complex molecular system.

The invention relates to a surface-enhanced Raman technology based on signal-off and used for detecting intracellular telomerase activity. According to the technology, graphene, carbon nitride, MoS2, SiO2 and the like are taken as carriers, nano-gole or nano-silver with controllable dimension and morphology or a composite magnetic nano-particle with a core-shell structure is supported by the carriers, and then a hairpin probe containing a telomerase primer and a Raman molecule beacon is fixedly disposed on the nano=particle surface, so that the high-sensitivity high-selectivity SERS detection method based on signal-off is established. When a target exists, the primer extends and generates a DNA chain with a repeat sequence under the effect of telomerase, and the DNA chain is hybridized with the probe molecule, then the DNA hairpin structure is opened, a Raman signal molecule with the single-chain labeled end is far away from a Raman substrate, the Raman signal is reduced, and high-sensitivity detection on telomerase is realized. The probe prepared by taking Hela cervical carcinoma cell as a model realizes intracellular telomerase activity detection and dynamic detection on intracellular telomerase activity variation under effect of a telomerase inhibiting medicament. By using multiple cells for imaging, the probe is confirmed to be capable of distinguishing tumor cells and normal cells.

The invention discloses preparation of a fixation-free biological sensing electrode and the application of the fixation-free biological sensing electrode to label-free homogeneous photo-electrochemical pesticide residue detection and cancer diagnosis. An electroreduction way is adopted to co-modify a phenyldiazonium salt which contains a negative group and the phenyldiazonium salt which does not contain the negative group on the surface of a base electrode. The electrode only adsorbs a single-stranded DNA (deoxyribonucleic acid) and does not adsorb a double-stranded DNA and is high in stability and reproducibility. The electrode can be applied to a label-free homogeneous photo-electrochemical biosensing method. The method comprises a biochemical reaction loop triggered by a target molecule, wherein the biochemical reaction loop contains a label-free DNA hairpin (DNA-1) and a single strand (DNA-2). When the target molecule does not exist, the DNA-1 and the DNA-2 can be both adsorbed onto the surface of the electrode, porphyrin can be adsorbed onto the surface of the electrode by means of the DNA-1 and the DNA-2, and photo-electrochemical signal response is generated; when the target molecule exists, the DNA-1 and the DNA-2 are hybridized with each other, under the action of a polymerase, a large number of DNA-1s and DNA-2s are changed into long double-stranded DNAs, the adsorbing capacity of the DNA-1 and the DNA-2 on the surface of the electrode is reduced, and the porphyrin photo-electrochemical response is reduced.

The invention discloses a DNA and polymer hybrid nucleic acid drug carrier and its preparation method and application. Firstly, acrylamide-modified DNA with initiator chain I and acrylamide are used to construct an acrylamide polymer by free radical polymerization / DNA hybrid nanogel, design DNA hairpin structure H1 and H2, the ends of H1 and H2 can be complementary base pairing or covalently linked nucleic acid drug sequence. The prepared polymer / DNA hybrid nanogel is dispersed in the solution containing the corresponding hairpin structures H1 and H2, and the efficient assembly of nucleic acid drugs in the nanogel can be realized through in situ DNA hybridization chain reaction, thereby preparing stable Targeted nucleic acid nanomedicine with high specificity and high loading efficiency. As a unique biopolymer, DNA has precise and adjustable structure, efficient and controllable assembly, and can endow nanogel with stimuli responsiveness and controllable drug release performance; acrylamide polymers have high stability and are easy to functionalize, which can improve nanogel The in vivo stability and tumor targeting ability of the gel enable efficient transfection and expression of nucleic acid drugs at tumor sites.

The invention provides a suturing Toehold activation method used for controlling a DNA strand displacement reaction and a toolkit. A novel Toehold activation method is developed based on hairpin reconstruction caused by mutual action of a DNA hairpin structure and different environmental irritants (Hg2+ or ATP). The invention develops a novel Toehold activation method. The extra level of the DNA strand displacement reaction can be accurately controlled by changing the concentration of the environmental irritants.

The invention discloses a highly sensitive and decomposable quantum dot nanosphere probe and a preparation method thereof. Through a fulcrum-mediated strand displacement reaction, a DNA hairpin probe modified by three desulfated biotins is self-assembled into a Y-type DNA nanostructure; and the Y-type DNA structure and quantum dots coupled to streptavidin are self-assembled to form the quantum dot nanosphere probe. The prepared quantum dot nanosphere probe and an immunomagnetic separation technology are combined to be applied to quick detection of a target analyte. Because of a binding force between biotin and streptavidin stronger thana binding force of desulfurized biotin, the quantum dot nanosphere probe is decomposed, and thus quantum dots are released; the target analyte concentration is determined by detecting the fluorescence value of a quantum dot solution, and a shielding effect of immunomagnetic beads on the quantum dots is overcome. The method has high sensitivity and the detection limit of microorganisms is 1.37 cfu / mL. This method is good in specificity, and common other microorganisms do not affect the detection.

The present invention relates to an AND gate molecular circuit, a NOT gate molecular circuit, an XOR molecular circuit and a half-subtracter molecular circuit based on a DNA hairpin structure, belonging to the biocomputer technology field. The principles of the DNA single hairpin structure, the double hairpin structure and the two-way strand displacement reaction are employed to design a strand displacement reaction structure taking a conventional small fulcrum as an identification area to realize the construction of AND gate, NOT gate and XOR gate basic logic operation structures and perform globality simulation argumentation. A basic logic circuit is employed to perform combination design of the half-subtracter molecular circuit and perform argumentation simulation of the circuit feasibility.

The invention relates to the technical field of nanoprobes, in particular to a h-BN / MoS capable of realizing targeted photothermal and chemical synergistic therapy 2 Nanoprobe and preparation method and application thereof, the preparation method includes: h-BN nanosheet dispersion and FA-PEI modified MoS 2 Equal volume mixing of quantum dot dispersion to obtain h‑BN / MoS 2 Composite materials; preparation of DNA hairpins, h‑BN / MoS 2 The composites adsorb DNA strands to obtain h‑BN / MoS 2 Nanoprobe; h‑BN / MoS 2 Nanoprobes can be used for miRNA fluorescence and Raman dual-mode detection and / or fluorescence in situ imaging and preparation of nanoformulations. The invention broadens the application of 2D nanosheets, realizes photothermal and chemical therapy, and also lays a foundation for further developing a diagnosis and treatment integrated platform for cancer marker detection and synergistic therapy.