Methods for determining the concentration of an analyte in solution
Disclosed is a method for measuring the concentration of an analyte or analytes in a solution. Although the methods can be conducted using a number of different assay formats, in one embodiment, the assays are conducted in reaction vessels defined, at least in part, by the distal ends of fiber optic strands.
1. A method of determining the concentration of an analyte in a fluid sample to be tested, the method comprising the steps of:
(a) partitioning at least a portion of the analyte molecules in the fluid sample across a plurality of reaction vessels so that more than 20% but less than 95% of the reaction vessels contain at least one molecule, wherein the analyte is attached to a nanoparticle or microparticle by a capture component;
(b) determining the presence or absence of the analyte in each reaction vessel to identify the number of reaction vessels that contain analyte and/or to identify the number of reaction vessels that contain no analyte; and
(c) determining the concentration of the analyte in the fluid sample by a Gaussian distribution analysis of the number of reaction vessels that contain the analyte.
2. The method of claim 1 , wherein, in step (a), more than 20% but less than 60% of the reaction vessels contain at least one molecule.
3. The method of claim 1 , wherein, in step (a), more than 60% but less than 95% of the reaction vessels contain at least one molecule.
4. The method of claim 1 , wherein, in step (a), the sample to be tested is partitioned into at least 1,000 reaction vessels.
5. The method of claim 1 , wherein, in step (a), the sample to be tested is partitioned into from 10,000 to 200,000 reaction vessels.
6. The method of claim 5 , wherein the sample to be tested is partitioned into from 50,000 to 100,000 reaction vessels.
7. The method of claim 1 , wherein the analyte is a biomolecule.
8. The method of claim 7 , wherein the biomolecule is selected from the group consisting of a protein, a nucleic acid, a lipid, and a carbohydrate.
9. The method of claim 1 , wherein the reaction vessels have a volume of from 10 attoliters to 50 picoliters.
10. The method of claim 1 , wherein at least a portion of the reaction vessel is defined by a distal end of an optical fiber.