Self-assembled DNA Nanotechnology And Its Application In Gene Detection

DNA methylation is both an important epigenetic mechanism and an important regulator of gene expression.Extensive research has shown that there are significant differences in DNA methylation profiles between cancer cells and normal tissues.Abnormal methylation changes can lead to inappropriate gene expression and cancer.Therefore,the detection of DNA methylation has great research prospects.At present,the bisulfite-based conversion technology is still the gold standard for detecting DNA methylation.However,the existing methods for distinguishing different bases still have many problems,such as low resolution,low specificity,and the presence of false positives.DNA self-assembly technology provides the possibility to solve the above problems,the nanostructures constructed by the bottom-up self-assembly method can realize many functional applications,because it's programmable and addressable.The molecular labeling technology based on DNA origami has the characteristics of high specificity and high targeting.Taking advantage of the high resolution of the atomic force microscope,DNA nanotechnology has great potential in gene detection and methylation detection.Therefore,how to use DNA self-assembly technology to construct nanoprobes for gene detection and methylation detection is the problem that this article aims to solve.The research content of this article is mainly divided into the following three aspects:1.Design and assemble DNA origami probes using triangle,cross,and rectangle DNA origami as templates.By assembling gold nanoparticles on DNA origami,the polychromaticity of DNA origami probes was increased,and the effect of the concentration of gold nanoparticles on constructing multicolor DNA origami probes was discussed.Finally,the specificity of the constructed DNA origami probe was verified,which laid the foundation for the subsequent research.2.Use multi-color DNA origami probes to achieve gene detection for specific sequences.A program for automatically screening and outputting small satellite DNA sequences was written using Java software,and a triblock media probe was designed as a medium between the DNA origami probe and the small satellite DNA sequence on the sample template.Lambda DNA was used as an experimental template to construct a detection model,and multi-color DNA origami probes were used to label and detect small satellite DNA sequences.3.Develop specific sequence detection technology based on DNA origami probes to realize the detection of specific methylation sites.Methyltransferase was used to construct the specific methylation site of Lambda DNA as the experimental object of methylation detection.Sodium bisulfite makes sequence difference between the methylated sample and the control sample to be tested,and converts the detection of specific methylation site into the detection of specific sequence.Sequences are distinguished,and DNA origami probes are used to label specific methylation sites.