Systems, devices, and methods for ultra-sensitive detection of molecules or particles
Described are systems, devices, and methods which related to various aspects of assays for detecting and/or determining a measure of the concentration of analyte molecules or particles in a sample fluid. In some cases, the systems employ an assay consumable comprising a plurality of assay sites. The systems, devices, and/or methods, in some cases, are automated. In some cases, the systems, devices, and/or methods relate to inserting a plurality of beads into assay sites, sealing assay sites, imaging assay sites, or the like.
1. An apparatus for performing an assay, comprising:
a disc handler operatively coupled to an assay consumable disc having a surface comprising wells formed in the surface of the assay consumable disc that have a volume between about 1 femtoliter and about 1 picoliter;
a first liquid injector positioned to apply a sealing liquid to the surface of the assay consumable disc;
a second liquid injector positioned to load an assay sample into the wells of the assay consumable disc;
a fluid pump positioned to create a flow of a liquid, which contains a suspension of beads, over the surface of the assay consumable disc to insert beads into the wells;
a camera configured to acquire an image of the wells of the assay consumable containing assay sample;
a computer implemented controller configured and programmed to operate the first liquid injector, the second liquid injector, and the fluid pump, and to receive the image acquired from the camera; and
a motor operated by the computer implemented controller and configured to rotate the assay consumable disc about a central axis of the assay consumable disc.
2. The apparatus of claim 1 , wherein each well formed in the surface of the assay consumable disc has a volume between about 1 femtoliter and about 1 picoliter.
3. The apparatus of claim 1 , wherein well formed in the surface of the assay consumable disc has a volume between about 30 femtoliters and about 60 femtoliters.
4. The apparatus of claim 1 , wherein the wells are sized and/or shaped to each contain only zero or one of the beads inserted by the flow of the liquid, which contains the suspension of beads, over the surface of the assay consumable disc.
5. The apparatus of claim 4 , wherein the average diameter or average maximum cross-sectional dimension of the beads is between about 1 micrometer and about 10 micrometers.
6. The apparatus of claim 1 , wherein the assay consumable disc contains the assay sample and the assay sample comprises an unknown concentration of an analyte molecule.
7. The apparatus of claim 6 , wherein the computer implemented system is configured to determine a measure of the unknown concentration of the analyte molecule in the assay sample.
8. The apparatus of claim 1 , wherein the computer-implemented controller is configured and programmed to determine, from the image acquired from the camera, a measure indicative of a number or fraction of wells interrogated from the image that contain an analyte molecule or particle.
9. The apparatus of claim 8 , wherein the computer-implemented controller is configured and programmed to determine a measure of the unknown concentration of the analyte molecule in the assay sample based, at least in part, on the measure indicative of the number of fraction of wells interrogated from the image that contain an analyte molecule or particle.
10. The apparatus of claim 1 , wherein the assay sample contains analyte molecules or particles having an unknown concentration to be measured, and the second liquid injector is configured to load the assay sample into the at least some of the wells such that the wells into which assay sample is loaded contain either zero or a single analyte molecule or particle.
11. The apparatus of claim 1 , wherein the sealing liquid is substantially immiscible with a liquid contained in each assay site.
12. The apparatus of claim 1 , wherein the sealing liquid comprises an oil.
13. The apparatus of claim 1 , wherein the surface of the assay consumable disc is formed of cyclic olefin polymer and the sealing liquid comprises a fluorinated oil.
14. The apparatus of claim 13 , wherein cyclic olefin polymer comprises a cyclic olefin copolymer.
15. The apparatus of claim 1 , wherein camera comprises one or more of the following: a CCD camera, a charge injection device (CID), a complementary metal oxide semiconductor (CMOS) device, a scientific CMOS (sCMOS) device, a time delay integration device, a photomultiplier tube, and an avalanche photodiode.
16. The apparatus of claim 1 , further comprising a wiper configured to remove beads from the surface of the assay consumable disc that are not substantially contained in a well.
17. The apparatus of claim 1 , wherein the application of the sealing liquid from the second liquid injector can fluidically isolate individual beads in individual wells of the assay consumable disc.