A biosensor and its detection method for simultaneously detecting the total amount of specific dna and the amount of single base mutation

Abstract

The invention discloses a biosensor capable of simultaneously detecting specific DNA content and single-base mutation amount and a detecting method thereof. A sulfydryl-modified capturing chain cDNA with six pairs of complementary basic groups and a methylene-blue-modified beacon-capturing chain pcDNA are hybridized in advance, anchor type alDNA with the bottom end being double helixes and the topend being two unpaired long chains used as capturing arms is obtained and assembled to the surface of a gold electrode, and unoccupied loci without assembled alDNA on the surface of the electrode aresealed, so that a biosensor interface is obtained; and the sensor firstly captures the total amount of DNA of specific sequences and then through specific enzyme connection-chemical denaturation, thecontent of specific single-base mutation DNA can be obtained. The biosensor is simple in construction method, high in detection sensitivity, capable of achieving the purpose of simultaneously and quantitatively detecting the total amount of specific DNA and the content of mutation DNA thereof, mild in reaction condition and stable and efficient in sensing system, and compared with expensive and complex clinic gene sequencing, the biosensor has great practical significance and development potential, and can be popularized and used conveniently.

Description

technical field [0001] The invention relates to a biosensor capable of simultaneously detecting the total amount of specific DNA and a single base mutation and a detection method thereof, belonging to the technical field of biosensing. Background technique [0002] Single-base mutation refers to the mutation of a certain base on the DNA chain, which can lead to abnormal function of downstream proteins, thereby causing a series of diseases and even cancer. Mutated DNA may exist in cells or free in blood, interstitial fluid, saliva and other body fluids. Affected by external and genetic factors, gene mutations generally exist in human life, so the detection of single-base mutations has always been a research hotspot. [0003] At present, the commonly used detection methods for gene mutations mainly include next-generation sequencing (NGS), Sanger sequencing, digital PCR, etc., which can accurately identify the genome. Although the sensitivity is high, the operation is complic...

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Problems solved by technology

[0003] At present, the commonly used detection methods for gene mutations mainly include next-generation sequencing (NGS), Sanger sequencing, digital PCR, etc., which can accurately identify the genome. Although the sensitivity is high, the operation is complicated, time-consuming and expensive.

In terms of biosensors, detection methods such as fluorescence, ultraviolet, SPR, and colorimetry are often used in conjunction with reaction principles such as molecular beacons and enzymes, which greatly reduce detection costs and waiting time, but still have high detection limits, low sensitivity, and serious problems. Poor reproducibility, more actual sample interference and other shortcomings

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