Preparation method of magnetic particles connected with dsDNA

[0046] The method for preparing magnetic particles linked with dsDNA has at least the following advantages:

[0047] (1) The preparation method of the above-mentioned magnetic particles connected with dsDNA is to preheat the dsDNA before the dsDNA reacts with the activated magnetic particles, so that the double helix structure of the dsDNA is opened, the reaction site is exposed, and the reactivity of the dsDNA is improved. , and 4-dimethylaminopyridine can accelerate the reaction between activated magnetic particles and dsDNA. Compared with the traditional method of first modifying the DNA structure (such as introducing active groups such as amino groups and sulfhydryl groups) or biotin labeling, and then reacting with magnetic particles to connect dsDNA to the magnetic particles, the above-mentioned magnetic particles with dsDNA attached The preparation method has low cost and good specificity.

[0048] (2) Although dsDNA can be connected to magnetic particles by physical a...

[0053] see figure 1 In Example 1, the reagents used to prepare the nano magnetic beads connected with dsDNA are shown in Table 1. The preparation method includes but is not limited to the following steps:

[0054] (1) Take 1mL carboxyl nano magnetic bead solution (the particle diameter of carboxyl nano magnetic bead is 2μm, the concentration of carboxyl nano magnetic bead is 100mg / mL, and the carboxyl content is 600nmol / mg, that is, every 1mL carboxyl nano magnetic bead solution Contains 100mg magnetic beads, each mg carboxyl nano-magnetic beads contain 600nmol carboxyl groups), treated in a magnetic separator for 3 minutes, removed the supernatant with a pipette, washed with 10mL 100mM MES buffer (pH 6) for 3 Second-rate.

[0055] (2) Add 2 mL of 50 mM MES buffer (pH 6) to the carboxyl nano-magnetic beads washed in step (1), then add 3 mL of EDC solution (concentration of EDC is 10 mg / mL) and 3 mL of Sulfo-NHS solution (Concentration of Sulfo-NHS: 8 mg / mL), and rotate (40 r...

[0060] The reagents used to prepare the nano magnetic beads connected with dsDNA in Example 2 are shown in Table 1, and the preparation method includes but is not limited to the following steps:

[0061] (1) Take 1mL carboxyl nano magnetic bead solution (the particle size of carboxyl nano magnetic bead is 0.5μm, the concentration is 100mg / mL, and the carboxyl content is 200nmol / mg, that is, every 1mL carboxyl nano magnetic bead solution contains 100mg magnetic bead , containing 200 nmol of carboxyl groups per mg of carboxyl nano-magnetic beads), treated in a magnetic separator for 3 minutes, removed the supernatant with a pipette, and washed 3 times with 10 mL of 100 mM MES buffer (pH=5.5).

[0062] (2) Add 2mL of 50mM MES buffer (pH 5.5) to the carboxyl nano-magnetic beads washed in step (1), then add 1mL of EDC solution (concentration of EDC is 10mg / mL) and 1mL of Sulfo-NHS solution (The concentration of Sulfo-NHS is 8 mg / mL), and rotate (40 rpm / min) at 20°C for 1.5 h to obt...