A Positive Feedback Amplified Electrochemical Sensor Based on Exonuclease Ⅲ

Abstract

The invention discloses a positive feedback amplification electrochemical sensor based on exonuclease (Exo) III. The positive feedback amplification electrochemical sensor comprises a gold electrode and Hybrid DNA fixed to the gold electrode; the Hybrid DNA sequentially comprises a sulfur-hydrogen bond, a double-stranded DNA structure and a single-stranded DNA structure from the 5' end to the 3' end; the double-stranded DNA structure is prepared from C-DNA and A-DNA as well as G4-DNA which are hybridized; the basic group sequence of the single-stranded DNA structure is complementary with the basic group sequence of T-DNA; and the Hybrid DNA is fixed to the gold electrode through an S-Au key. Through Hairpin DNA and the Hybrid DNA which are ingeniously designed, and target object circular amplification based on the Exo III, a positive feedback amplification strategy combining a homogeneous phase reaction with a heterogeneous phase reaction is achieved; and the strategy shows ultra-highsensitivity, the detection limit is as low as 0.12 aM T-DNA, and high selectivity for the T-DNA and other base group mismatch DNA is achieved.

Description

technical field [0001] The invention belongs to the technical field of electrochemical sensors, in particular to a positive feedback amplification electrochemical sensor based on exonuclease III and its preparation method and application. Background technique [0002] Acquired immune syndrome, also known as AIDS, is an acquired infectious disease. When the human immunodeficiency virus (HIV) was first identified in the United States in 1983, it was accompanied by one of the world's deadliest diseases, acquired immunodeficiency syndrome (AIDS). The genes of this HIV group are two identical strands of RNA that, through reverse transcription, can be transcribed into DNA for further gene expression in the host cell. It attacks the host's immune system and causes the destruction of T4 lymphocytes, causing the body's immune system to collapse, making the body unable to defend against many diseases and resulting in death. Therefore, detection of HIV biomarkers or genes is very imp...

AI Technical Summary

Problems solved by technology

However, the nicking enzyme has a special recognition site, so it puts forward higher requirements on the DNA sequence, resulting in increased design complexity

Not only that, but it often requires polymerase-assisted recycling, which adds to the cost

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