Method for sealing substances, method for detecting target molecule, array, kit, and target molecule detection device

1. A method for sealing a bead in a receptacle, the method comprising:

(i) a step of introducing a first solvent containing beads and a surfactant on a substrate,

wherein

the substrate has a hydrophilic surface,

a plurality of receptacles capable of storing the beads are formed, separated from each other by a side wall having a height, on the hydrophilic surface of the substrate,

the side wall is made of a hydrophilic structure,

a hydrophobic layer is formed on an upper surface of the side wall,

the height of the side wall is equal to or greater than an average particle diameter of the beads, and equal to or smaller than 1.5 times the average particle diameter of the beads, and

the plurality of receptacles each have a width that is 1 to 2 times larger than the average particle diameter of the beads; and

(ii) a step of introducing a second solvent having a greater specific gravity than that of the first solvent onto the first solvent so that the second solvent laminated onto the first solvent moves down below the first solvent due to its greater specific gravity than that of the first solvent and thereby the first solvent is substituted by the second solvent, thereby to form droplets of the first solvent within the plurality of receptacles covered with the second solvent, the step (ii) being carried out after the step (i);

wherein

at least one of the droplets of the first solvent formed within the plurality of receptacles covered with the second solvent contains one of the beads.

2. The method as set forth in claim 1 , wherein the surfactant is polyoxyethylene sorbitan monolaurate or polyethylene glycol mono-4-octylphenyl ether.

3. The method as set forth in claim 1 , wherein the surfactant has a concentration of 0.001% by weight to 1% by weight.

4. The method as set forth in claim 1 , wherein the surfactant has a concentration of 0.01% by weight to 0.1% by weight.

5. The method as set forth in claim 1 , wherein the surfactant has a concentration of 0.01% by weight to 0.05% by weight.

6. The method as set forth in claim 1 , wherein the second solvent is at least one selected from the group consisting of saturated hydrocarbon, unsaturated hydrocarbon, aromatic hydrocarbon, silicone oil, hexafluoropropylene epoxide polymer, a polymer having a hydrofluoroether structure, perfluoropolyether, chlorotrifluoroethylene polymer, and a polymer having a perfluorocarbon structure, or is a mixed solvent that includes at least one of these solvents.

7. The method as set forth in claim 1 , wherein the first solvent is at least one selected from the group consisting of water, hydrophilic alcohol, hydrophilic ether, ketone, nitrile solvents, dimethyl sulfoxide, and N,N-dimethylformamide, or is a mixed solvent that includes at least one of these solvents.

8. A method for detecting a target molecule selected from the group consisting of a protein, a nucleic acid, a sugar, and a virus particle, the method comprising:

(i) a step of reacting with target molecules, beads specifically capturing the target molecules by target-capturing molecules bound to the beads, the target-capturing molecule selected from the group consisting of a protein, an antibody, and a nucleic acid;

(ii) a step of introducing a first solvent containing the beads of the step (i) and a surfactant on a substrate,

wherein

the substrate has a hydrophilic surface,

a plurality of receptacles capable of storing the beads are formed, separated from each other by a side wall having a height, on the hydrophilic surface of the substrate,

the side wall is made of a hydrophilic structure,

a hydrophobic layer is formed on an upper surface of the side wall,

the height of the side wall is equal to or greater than an average particle diameter of the beads, and equal to or smaller than 1.5 times the average particle diameter of the beads, and

the plurality of receptacles each have a width that is 1 to 2 times larger than the average particle diameter of the beads,

the step (ii) being carried out after the step (i);

(iii) a step of introducing a second solvent having a greater specific gravity than that of the first solvent onto the first solvent so that the second solvent laminated onto the first solvent moves down below the first solvent due to its greater specific gravity than that of the first solvent and thereby the first solvent is substituted by the second solvent, thereby to form droplets of the first solvent within the plurality of receptacles covered with the second solvent, the step (iii) being carried out after the step (ii); and

(iv) a step of detecting the target molecule to determine whether or not any one of beads having captured the target molecule is stored in each of the plurality of the receptacles by use of a fluorescence microscope or an image sensor, the step (iv) being carried out after the step (iii).

9. The method as set forth in claim 8 , wherein the step (i) is preceded by a step of binding to the beads, the target-capturing molecules.

10. The method as set forth in claim 8 , wherein the second solvent is at least one selected from the group consisting of saturated hydrocarbon, unsaturated hydrocarbon, aromatic hydrocarbon, silicone oil, hexafluoropropylene epoxide polymer, a polymer having a hydrofluoroether structure, perfluoropolyether, chlorotrifluoroethylene polymer, and a polymer having a perfluorocarbon structure, or is a mixed solvent that includes at least one of these solvents.

11. The method as set forth in claim 8 , wherein the first solvent is at least one selected from the group consisting of water, hydrophilic alcohol, hydrophilic ether, ketone, nitrile solvents, dimethyl sulfoxide, and N,N-dimethylformamide, or is a mixed solvent that includes at least one of these solvents.