Magnetic DNA fluorescent probe and preparation method thereof

Abstract

The invention relates to a magnetic DNA fluorescent probe and a preparation method thereof. The probe adopts a magnetic core-shell quantum dot CdTe / MNs nano particle as an energy donor for emitting fluorescence, and the CdTe / MNs nano particle is connected with a single chain 3'-NH2-DNA to form CdTe / MNs-DNA; the probe adopts nano nickel oxide as an energy receptor for absorbing fluorescence, and the nano nickel oxide is connected with a single chain 5'-NH2-DNA to form nNiO-DNA; and the single chain 5'-NH2-DNA and the single chain 3'-NH2-DNA are complementary, and the CdTe / MNs-DNA and the nNiO-DNA are hybridized to form the probe. The preparation method comprises the following steps: 1, preparing the magnetic nano particle MNs; 2, preparing CdTe fluorescent quantum dot solution; 3, preparing CdTe / MNs primary solution; 4, preparing CdTe / MNs-DNA solution; 5, purifying the CdTe / MNs-DNA solution; 6, preparing nNiO; 7, preparing nNiO-DNA solution; 8, preparing the DNA fluorescent probe; and 9, purifying the DNA fluorescent probe.

Description

technical field [0001] The invention relates to bioengineering technology, in particular to a magnetic DNA fluorescent probe based on the principle of fluorescence resonance energy transfer and a preparation method thereof. The DNA probe can be used to detect certain small molecular living substances with characteristic DNA sequences in a liquid environment. Background technique [0002] In recent years, molecular biology has developed rapidly, new technologies have emerged, and their applications have become increasingly widespread. In particular, the potential application prospects of rapid, simple, and accurate detection of gene sequences in the fields of medical clinical laboratory science, immunology, and biology have become increasingly widespread. It has attracted widespread attention from the international scientific community. For the detection of living substances with specific DNA sequences, traditional methods mainly use radioactive labeling and polymerase chain...

AI Technical Summary

Problems solved by technology

However, the use of this donor-acceptor pair still has the following disadvantages: 1. Their excitation spectra are narrow, and it is difficult to excite multiple components at the same time; 2. The organic fluorescent molecules of organic dyes have a wide spectrum and asymmetric distribution, giving It is difficult to distinguish the source of organic fluorescent molecules of different probe molecules, and it is impossible to detect multiple components at the same time; 3. Specific wavelength excitation is required to emit fluorescence. If multiple diseases are detected at the same time, light excitation with different wavelengths is required.

The disadvantage is that the effective signal obtained by using DABCYL as a quencher is low, and compared with the background signal (noise signal), its energy transfer efficiency needs to be further improved; while DABCYL is still unavoidable as an organic fluorescent dye. There are the above disadvantages

[0010] In recent years, studies have shown that the quantum dot-Au sensing system still has the following shortcomings: using core-shell quantum dots such as CdTe, CdS, ZnS or CdTe / ZnS, CdTe / CdS as energy donors, in actual biological detection, often Insufficient fluorescence intensity is obtained, which seriously limits the sensitivity of the sensing system

Although the centrifugation method can partially achieve the purpose of purification, but the efficiency is very low, time-consuming and labor-intensive, to obtain a better separation effect, the shortest separation time is about 1 hour

In addition, electrophoresis can be used for separation, but the resolution is low, the practical application effect is poor, and the cost is high

The above two methods have great difficulties in industrial application.