A cap having a core structure dimensioned to receive a pipette therethrough. The cap includes two axially aligned frangible seals that are affixed to the core structure in a spaced-apart relationship. The frangible seals include a foil layer and are constructed so that air passageways are formed between the frangible seals and a pipette tip when the pipette tip penetrates the frangible seals. The cap optionally includes a filter interposed between the first and second frangible seals.
1. A penetrable cap comprising:
a generally cylindrical core structure configured to be screwed onto an open-ended vessel, the core structure being a molded plastic formed to have an opening extending therethrough; and
first and second frangible seals affixed to the core structure, the second seal being axially aligned with and positioned below the first seal,
wherein the second seal comprises a foil and is constructed and arranged to provide a barrier to the passage of a fluid through the opening formed in the core structure,
wherein the cap is capable of being penetrated by a plastic pipette tip, and
wherein the seals are constructed and arranged so that air passageways are formed when the seals are pierced by a plastic pipette tip, thereby permitting air to be vented through the cap.
2. The cap of claim 1 , wherein the core structure comprises an inwardly extending ledge, and wherein the second seal is affixed to a surface of the ledge.
3. The cap of claim 2 , wherein the ledge comprises a depending skirt.
4. The cap of claim 3 , wherein the second seal is affixed to a bottom surface of the skirt.
5. The cap of claim 2 , wherein the first seal is affixed to a top surface of the core structure.
6. The cap of claim 1 , wherein each of the seals is welded to the core structure or affixed to the core structure with an adhesive.
7. The cap of claim 1 , wherein the foil is an aluminum foil.
8. The cap of claim 1 , wherein the second seal further comprises a heat seal layer and a brittle layer.
9. The cap of claim 1 , wherein the first seal comprises a plastic film.
10. The cap of claim 1 , wherein the first seal comprises a foil.
11. The cap of claim of claim 10 , wherein the foil of each of the seals is an aluminum foil.
12. The cap of claim 1 , wherein the first seal comprises one or more series of perforations that facilitate penetration of the first seal by a plastic pipette tip.
13. The cap of claim 1 , wherein the first seal comprises score lines.
14. The cap of claim 1 , further comprising a filter interposed between the seals.
15. The cap of claim 14 , wherein the filter is comprised of a resilient material.
16. The cap of claim 14 , wherein the filter is gas permeable.
17. The cap of claim 16 , wherein the filter is constructed and arranged to trap an aerosol and/or bubbles.
18. The cap of claim 1 , wherein the cap does not include a filter interposed between the seals.
19. The cap of claim 1 , wherein the seals tear when pierced by a plastic pipette tip.
20. A collection device comprising the cap of claim 1 screwed onto an open end of a fluid-holding vessel, thereby providing a substantially leak-proof seal between the cap and the vessel.
21. A method for removing a fluid substance from the collection device of claim 20 , the method comprising the steps of:
(a) piercing the seals with a plastic pipette tip, thereby forming air passageways that aid in venting air from the collection device;
(b) drawing a fluid substance contained in the vessel into the pipette tip; and
(c) removing the pipette tip from the collection device.
22. The method of claim 21 , wherein the core structure comprises an inwardly extending ledge, and wherein the second seal is affixed to a surface of the ledge.
23. The method of claim 22 , wherein the ledge comprises a depending skirt.
24. The method of claim 23 , wherein the second seal is affixed to a bottom surface of the skirt.
25. The method of claim 22 , wherein the first seal is affixed to a top surface of the core structure.
26. The method of claim 21 , wherein each of the seals is welded to the core structure or affixed to the core structure with an adhesive.
27. The method of claim 21 , wherein the foil is an aluminum foil.
28. The method of claim 21 , wherein the second seal further comprises a heat seal layer and a brittle layer.
29. The method of claim 21 , wherein the first seal comprises a plastic film.
30. The method of claim 21 , wherein the first seal comprises a foil.
31. The method of claim of claim 30 , wherein the foil of each of the seals is an aluminum foil.
32. The method of claim 21 , wherein the first seal comprises one or more series of perforations that facilitate penetration of the first seal by the pipette tip.
33. The method of claim 21 , wherein the first seal comprises score lines.
34. The method of claim 21 , further comprising a filter interposed between the seals.
35. The method of claim 34 , wherein the filter is comprised of a resilient material.
36. The method of claim 34 , wherein the filter is gas permeable.
37. The method of claim 36 , wherein the filter is constructed and arranged to trap an aerosol and/or bubbles.
38. The method of claim 21 , wherein the cap does not include a filter interposed between the seals.
39. The method of claim 21 , wherein the seals are torn in step (a).
40. The method of claim 21 further comprising the step of amplifying a target nucleic acid sequence present in the fluid substance removed from the collection device in step (c).