RARE CELL ANALYSIS AFTER NEGATIVE SELECTION

1 . A method for detecting biological material from a target cell, the method comprising:

obtaining a sample suspected to contain a target cell;

conducting an assay on the sample that removes non-target cells from the sample;

extracting biological material from the remaining target and non-target cells; and

analyzing the biological material using a digital counting technique, thereby detecting the biological material from a target cell.

2 . The method according to claim 1 , wherein the assay results in the target cell being present at about or less than 1 in 1,000,000 cells.

3 . The method according to claim 1 , wherein the assay results in the target cell being present at about or less than 1 in 10,000 cells.

4 . The method according to claim 1 , wherein the biological material is nucleic acid.

5 . The method according to claim 4 , wherein the digital counting technique is selected from the group consisting of is digital PCR and sequencing.

6 . The method according to claim 5 , wherein sequencing is sequencing-by-synthesis.

7 . The method according to claim 1 , wherein the biological material is protein.

8 . The method according to claim 7 , wherein the digital counting technique is digital ELISA.

9 . The method according to claim 1 , wherein analyzing comprises:

compartmentalizing the extracted biological material into compartmentalized portions; and

conducting an assay on the biological material in each of the compartmentalized portions.

10 . The method according to claim 9 , wherein the compartmentalized portions are aqueous droplets in an immiscible fluid.

11 . The method according to claim 10 , wherein the immiscible fluid is oil.

12 . The method according to claim 11 , wherein the oil is a fluorinated oil.

13 . The method according to claim 11 , wherein the oil comprises a surfactant.

14 . The method according to claim 13 , wherein the surfactant is a fluorinated surfactant.

15 . The method according to claim 10 , wherein the droplets are flowing through a channel.

16 . The method according to claim 15 , wherein the biological material is nucleic acid and the assay comprises amplifying the nucleic acid within the compartmentalized portions.

17 . The method according to claim 16 , wherein a plurality of the droplets comprises no more than a single target nucleic acid in each droplet.

18 . The method according to claim 9 , wherein the compartmentalized portions are produced by a flow focusing technique.

19 . The method according to claim 18 , wherein the biological material is in an aqueous solution and the compartmentalized portions are produced by partitioning the aqueous fluid with an immiscible fluid.

20 . The method according to claim 19 , wherein the aqueous fluid is flowing through a channel.