Magnetic bead suspension reagent, method for purifying nucleic acid and method for sorting nucleic acid

1 . A magnetic bead suspension reagent comprising:

magnetic beads; and

a mixed surfactant,

wherein the mixed surfactant comprises a nonionic surfactant, an anionic surfactant, and a cationic surfactant, the nonionic surfactant, the anionic surfactant, and the cationic surfactant are present in the magnetic bead suspension reagent.

2 . The magnetic bead suspension reagent according to claim 1 ,

wherein a side chain of both the anionic surfactant and the cationic surfactant comprises a carbon chain, and a length of the carbon chain is greater than or equal to 10 carbon atoms and less than or equal to 20 carbon atoms.

3 . The magnetic bead suspension reagent according to claim 2 ,

wherein the mixed surfactant is selected from a group consisting of Tween 20, polyethylene glycol octyl phenyl ether, sodium dodecyl sulfate, octadecyl diester quaternary ammonium salt.

4 . The magnetic bead suspension reagent according to claim 2 , wherein the mixed surfactant comprises Tween 20, sodium dodecyl sulfate and octadecyl diester quaternary ammonium salt.

5 . The magnetic bead suspension reagent according to claim 1 , further comprising:

a dehydrating agent; and

an ionic salt,

wherein a volume of the mixed surfactant accounts for 0.5%~5% of a volume of the magnetic bead suspension reagent, a mass of the dehydrating agent accounts for 20%~30% of a mass of the magnetic bead suspension reagent, and a molarity of the ionic salt in the magnetic bead suspension reagent is 1 mol/L~5 mol/L.

6 . The magnetic bead suspension reagent according to claim 5 ,

wherein the volume of the mixed surfactant accounts for 0.5% of the volume of the magnetic bead suspension reagent, the mass of the dehydrating agent accounts for 30% of the mass of the magnetic bead suspension reagent, and the molarity of the ionic salt in the magnetic bead suspension reagent is 1.5 mol/L.

7 . The magnetic bead suspension reagent according to claim 5 ,

wherein the dehydrating agent comprises polyethylene glycol with at least one relative molecular mass, and the relative molecular mass of the polyethylene glycol is in a range of 8000~15000.

8 . The magnetic bead suspension reagent according to claim 5 ,

wherein the ionic salt is selected from a group consisting of NaCl and MgCl 2 .

9 . The magnetic bead suspension reagent according to claim 1 , further comprising:

a buffer solution,

wherein the buffer solution comprises tris(hydroxymethyl)aminomethane hydrochloride, and a molarity of the buffer solution is 0.1 mmol/L~10 mmol/L, and a pH value of the buffer solution is 7.5~8.5.

10 . The magnetic bead suspension reagent according to claim 1 , further comprising:

a stabilizing solution,

wherein the stabilizing solution comprises ethylene diamine tetraacetic acid, and a molarity of the stabilizing solution is 0.5 mmol/L~20 mmol/L.

11 . The magnetic bead suspension reagent according to claim 1 ,

wherein each of the magnetic beads is a superparamagnetic magnetic bead, and the superparamagnetic magnetic bead has a three-layer structure, an innermost layer of the three-layer structure is polystyrene, an intermediate layer of the three-layer structure is Fe 3 O 4 , and an outermost layer of the three-layer structure is a modified layer with carboxyl and/or silanol functional groups.

12 . The magnetic bead suspension reagent according to claim 11 ,

wherein a ratio of a mass of the intermediate layer of the superparamagnetic magnetic bead to a mass of the superparamagnetic magnetic bead is greater than 70%, and a particle size of the magnetic bead is 50 nm~4.5 μm, and a concentration of the magnetic beads in the magnetic bead suspension reagent is 1~10 mg/mL.