MicroRNA biosensor coupling 3D DNA walking machine with catalytic hairpin assembly

Abstract

In the patent, a new and entropy-driven three-dimensional DNA walking machine is provided and is combined with a catalytic hairpin assembly (CHA) reaction for successful detection of microRNA. The walking machine uses streptavidin wrapped polystyrene microspheres as a 3-D rail matrix to ensure good repeatability. A preparation method is as follows: miRNA-21 is used as a target, the target continuously walks on a DNA functionalized polystyrene microsphere rail through an entropy-driven strand displacement reaction, so that a DNA trinucleotide composite substrate on the polystyrene microspheresis decomposed, and circulation of the miRNA-21 is realized. In addition, release of a large number of helper strands from the DNA trinucleotide composite substrate can catalyze the CHA reaction with aconcomitant increase in obtained fluorescence signals. A linear range of the composite biosensor is between 50 pM and 20 nM with a detection limit as low as 41 pM. In addition, satisfactory results are obtained in both reproducibility tests (1.05%-4.22%) and recovery tests (99.5%-104.8%). The results show that the method has potential application value in aspects of disease diagnosis.

Description

Technical field [0001] The invention relates to a biosensor, in particular to a simple and entropy-driven 3-D DNA walking machine coupled with a catalyzed hairpin self-assembly reaction for microRNA detection biosensor Background technique [0002] DNA machines are molecular machines constructed from DNA. Due to the universality and predictability of Watson Crick's base pairing rules, it can be logically designed. Various DNA machines are constructed and synthesized through highly programmable methods, including DNA tweezers, DNA motors, DNA walkers and DNA robots. Among them, DNA walkers can be precisely controlled in micro-scale or nano-scale programmed oligonucleotide tracks, and have important application potential in biosensors, biocomputing, and drug delivery. Previous studies have reported that the DNA walking machine moves along a one-dimensional (1D) track, two-dimensional (2D) origami, or three-dimensional (3D) track. Among them, the 3D DNA walker has a more powerful ...

AI Technical Summary

Problems solved by technology

This connection force is not strong enough to avoid non-specific DNA adsorption, which seriously hinders DNA hybridization and reduces colloidal stability.

On the other hand, it needs to immobilize the affinity ligand and three nucleic acid complexes on the surface of AuNPs and optimize their ratio accordingly, resulting in poor reproducibility of DNA and AuNPs conjugated products.

[0004] The ratio of the corresponding optimized, resulting in poor reproducibility of DNA and AuNPs conjugated products

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