Method for preparing specimen in use for researching DNA through microscope in atomic force

Abstract

The invention relates to a preparation method of a sample used in the study of DNA by an atomic force microscope. First, DNA is mixed with an appropriate amount of divalent metal ions. The basic ratio of the two is, 1ng / μl DNA: 1mM Mg 2+ , heated at 37-40°C for 30-60 minutes, took 20μl of its solution and dropped it on 1.5cm 2 On the newly dissociated mica surface, adsorb for 5-8 minutes at 25°C. Then diffuse the inorganic salt ions in ultrapure water at 4-25° C., and the diffusion time is 10-30 minutes. The samples were taken out of the water and placed in absolute ethanol for 10-40 seconds. Finally, the samples were dried at 25° C. under nitrogen protection for 2 hours. The DNA sample prepared by this diffusion method avoids the disadvantage of washing with water, maintains the conformation of the DNA molecule and prepares a clean sample. The success rate of preparing samples is as high as 95%.

Description

technical field [0001] The invention belongs to a method for preparing a sample by using a diffusion method in ultrapure water, in particular to a method for preparing a sample used in the study of DNA by an atomic force microscope. Background technique [0002] Atomic force microscope is one of the third generation of new microscopes developed after optical microscope and electron microscope. It relies on tiny probes to detect the shape of the measured object and its properties such as electricity, magnetism, viscoelasticity, and hardness. Due to its ultra-high resolution, the need for no conductive substrate, and the ability to operate in liquid and atmospheric environments, atomic force microscopy has been widely used to image DNA and study the interaction of DNA with other molecules. In these studies, mica has become a widely used substrate due to its atomic-level flatness, super-large single-crystal facets, and easy dissociation to prepare new surfaces. Therefore, the...

AI Technical Summary

Problems solved by technology

Due to the uncontrollability of this treatment method in the process of washing with water, the success rate of the prepared DNA sample is very low (destruction of the DNA conformation adsorbed to the substrate and partial clustering of the DNA, etc.)

Furthermore, short-term washing cannot effectively remove the salt ions adsorbed on the DNA molecules, so that they precipitate on the surface and DNA molecules during the drying process to form salt crystals that seriously interfere with DNA imaging.

In addition, washing with water also removes a large number of DNA molecules, so that the DNA molecules adsorbed to the surface of the substrate become very small, resulting in the waste of DNA samples.