9 results about "Fluorescence biosensor" patented technology

The invention discloses an aptamer-mediated EXPARs-molecular beacon fluorescent biosensor as well as a preparation method and application of the aptamer-mediated EXPARs-molecular beacon fluorescent biosensor. The construction and detection process of the sensor comprises three key steps: protein binding aptamer, exponential isothermal amplification (EXPAR) and molecular beacon fluorescence resonance energy transfer (FRET). Through the ingenious design of the EXPAR system, the system realizes triple signal amplification, the detection sensitivity is remarkably improved, and Abeta42 and Abeta40 amyloid proteins as low as 100fM level can be detected. Besides, based on the sequence specificity of the aptamer and the highly specific design of each nucleic acid sequence involved in the detection system, the method can be used for simultaneously detecting the Abeta42 amyloid protein and the Abeta40 amyloid protein or other substances in the same system (such as a plasma sample), so that the detection efficiency is improved.

The invention discloses a CRISPR-Cas14a1 and ERA fluorescent biosensor for rapidly detecting ichthyophthirius multifilis and application of the CRISPR-Cas14a1 and ERA fluorescent biosensor, and particularly relates to the field of molecular biological detection technologies and biosensing. Wherein the nucleotide sequence of the specific sgRNA is as shown in SEQ ID NO. 3. The biosensing system comprises an ERA amplification module which comprises at least one pair of primers capable of specifically amplifying 18S rRNA gene segments of ichthyophthirius multifilis; the CRISPR-Cas14a1 detection module comprises the CRISPR-Cas14a1 specific sgRNA (small guide ribonucleic acid) according to the claim 1 and a Cas14a1 protein of the CRISPR-Cas14a1 specific sgRNA according to the claim 1; and the signal reading module comprises a reporter molecule which can be subjected to trans-cleavage by the Cas14a1 protein and can generate a detectable signal. The biosensor has the advantages of high specificity, quick response and no complex amplification.

The invention provides a self-assembled antibody-gold nanocluster, a fluorescent biosensor, a preparation method and application, and belongs to the technical field of fluorescent biosensors. The invention provides a self-assembled antibody-gold nanocluster. The self-assembled antibody-gold nanocluster is prepared from the following raw materials: an antibody, chloroauric acid and a reducing agent, the molar ratio of the antibody to the chloroauric acid is (1: 60)-(1: 80); the antibody is combined with the gold nanoparticles in the gold nanocluster through surface sulfydryl. In the invention, under the action of a reducing agent, chloroauric acid is reduced into gold nanoparticles, and an antibody can be combined with the gold nanoparticles through surface sulfydryl to generate self-assembly, so that the self-assembled antibody-gold nanocluster is obtained. The self-assembled antibody-gold nanocluster disclosed by the invention can be synthesized by a one-step method, and a signal nanocluster (gold nanocluster) is generated in situ in a single antibody protein molecule template, so that the inherent defects that the chemical coupling efficiency is low, the biological activity is easy to damage and the like are overcome.

This invention discloses a method for detecting organophosphorus pesticides using a self-cascaded Pt@Fe-CDs nanozyme, belonging to the field of chemical analysis and detection technology. This method synthesizes Pt@Fe-CDs nanozymes using iron-doped carbon dots (Fe-CDs) as a reducing agent and template. Pt@Fe-CDs simultaneously possess ascorbic acid oxidase-like and peroxidase-like activities. Under the catalysis of alkaline phosphatase, they hydrolyze L-ascorbic acid-2-phosphate trisodium salt to AA. Based on the fact that organophosphorus pesticides can inhibit ALP activity and hinder AA2P dephosphorylation, leading to a reduction in AA and thus causing changes in fluorescence and colorimetric signals, a simple and sensitive dual-signal fluorescence / colorimetric sensing platform for organophosphorus pesticides is constructed, with a detection limit of 0.28-0.53 ng / mL. The colorimetric and fluorescence biosensors established in this invention exhibit excellent performance in terms of sensitivity, specificity, and accuracy in actual samples.

This invention proposes a capsaicin nucleic acid aptamer and its ratiometric fluorescent biosensor application. A capsaicin-specific nucleic acid aptamer with nanomolar affinity for capsaicin was obtained using the RNase-SELEX screening strategy. Furthermore, a ratiometric fluorescent biosensor was constructed using the pruned aptamer. A dual-signal response is achieved through competitive binding / conformational regulation of the aptamer by capsaicin and the nucleic acid dye SYBR Green II. Quantitative detection of capsaicin is achieved through a linear relationship between the fluorescence ratio and capsaicin concentration, exhibiting advantages such as high sensitivity and strong anti-interference capability.

The invention provides a magnetic control ratio fluorescent biosensor based on RPA-CRISPR / Cas12a as well as a preparation method and application of the magnetic control ratio fluorescent biosensor, and belongs to the technical field of fluorescent biosensors and pathogenic bacterium detection. The magnetic control ratio fluorescence biosensor comprises a fluorescence reference signal element, a fluorescence response signal element and a specific recognition element, according to the magnetic control ratio fluorescent biosensor, high-sensitivity and specific detection of staphylococcus aureus and salmonella is realized through the magnetic and fluorescent characteristics of the fluorescent reference signal element, the fluorescent characteristic of the fluorescent response signal element and the nucleic acid cleavage activity of Cas12a; the magnetic control ratio fluorescent biosensor has a built-in calibration function, can reduce interference brought by the environment and instruments, has good selectivity to staphylococcus aureus and salmonella, has good anti-interference performance to other bacteria, and can be used for rapid detection in the field of food safety.

Disclosed are leave-one-out GFP (LOO_GFP) biosensors immobilized in Ubx (Drosphila protein Ultrabithorax) that form immobilized and stabilized fluorescent protein biosensor systems (LOO_GFP-Ubx systems). These LOO_GFP-Ubx systems have an enhanced fluorescent signaling to noise ratio. Also disclosed are methods of making LOO_GFP-Ubx systems and methods of using such systems to detect analyte. In preferred embodiments, the LOO_GFP-Ubx system has the eighth β strand or eleventh f strand of OPT GFP left out.