Sample holder with a well having a wicking promoter

1. A device for holding a sample, comprising:

a holder including an upper member attached to a lower member to form a well having a side wall region and a floor, the side wall region extending from a top border to the floor and widening toward the floor at a position intermediate the top border and the floor to create a distinct edge that conceptually divides the well into an upper portion and a lower portion, the well including a side wall protrusion defined by the upper member and adapted to promote wicking of an aqueous sample into the lower portion from the upper portion, the holder defining a channel communicating with the lower portion of the well and with a channel junction that provides a droplet generator;

wherein the side wall protrusion is contiguous with the edge.

2. The device of claim 1 , wherein a top of the side wall protrusion is disposed at a same elevation as the edge.

3. The device of claim 1 , wherein the side wall protrusion abuts the lower member.

4. The device of claim 1 , wherein the side wall protrusion is spaced from the lower member to form a gap between the protrusion and the lower member.

5. The device of claim 1 , wherein the side wall protrusion projects at least generally toward a central vertical axis of the well from the side wall region.

6. The device of claim 1 , wherein the holder includes a plurality of wells each having a protrusion that promotes wicking, and wherein the holder provides a plurality of emulsion production units each including at least one of the plurality of wells.

7. A device for holding a sample, comprising:

a holder including an upper member attached to a lower member to form a well having a side wall region and a floor, the side wall region extending from a top border to the floor and widening toward the floor at a position intermediate the top border and the floor to create a distinct edge that conceptually divides the well into an upper portion and a lower portion, the floor defining a protrusion projecting upwardly in the well, the holder defining a channel communicating with the lower portion of the well;

wherein the lower member defines a recess under the protrusion.

8. The device of claim 7 , wherein the lower member is a sheet member having a top surface and a bottom surface, and wherein the sheet member is deformed such that the top surface defines the protrusion and the bottom surface defines the recess.

9. A method of making a device for holding a sample, the method comprising:

providing an upper member defining at least one through-hole bounded by a side wall region, the side wall region extending from a top border to a bottom border and widening toward the bottom border at a position intermediate the top border and the bottom border to create a distinct edge that conceptually divides the through-hole into an upper portion and a lower portion;

attaching a lower member to an underside of the upper member to create a well bounded laterally by the side wall region and having a floor formed by the lower member; and

deforming the lower member to define a protrusion adapted to promote wicking of an aqueous sample into the lower portion from the upper portion.

10. The method of claim 9 , wherein the step of attaching creates a plurality of wells, and wherein the step of deforming creates a plurality of recesses in a bottom surface of the lower member, with each recess being aligned with a different well.

11. The method of claim 9 , wherein the step of deforming includes a step of heating the lower member and a step of applying pressure to the lower member, and wherein the step of heating and the step of applying pressure are performed with a same tool.

12. A device for holding a sample, comprising:

a holder including an upper member attached to a lower member to form a well having a side wall region and a floor, the side wall region extending from a top border to the floor and widening toward the floor at a position intermediate the top border and the floor to create a distinct edge that conceptually divides the well into an upper portion and a lower portion, the floor defining a protrusion projecting upwardly into the upper portion of the well, the holder defining a channel communicating with the lower portion of the well.

13. The device of claim 12 , wherein a bottom surface region of the lower member under the protrusion is flat.

14. The device of claim 12 , wherein the channel communicates with at least one other well of the holder.