BIOCHIP STORAGE WELLS

Abstract

The present invention is directed to a cap for a biochip storage well. The cap comprises a resilient sealant layer capable, under the application of pressure, of forming a vapour-proof seal with a line contact interface formation extending around the perimeter of a biochip storage well.

An assay assembly comprising the cap of the invention and a biochip storage is disclosed. Methods of sealing a biochip storage well using a cap of the invention are also disclosed.

Claims

1-11. (canceled)

12. An assay assembly comprising a biochip storage well having a base and one or more side walls, adapted to receive a biochip, with a line contact interface formation facing away from the base and extending along an upwardly facing perimeter of the wall(s) and a cap comprising a resilient sealant layer, wherein a vapour-proof seal can be formed between the resilient sealant layer of the cap and the line contact interface formation of the biochip storage well, when the resilient sealant layer of the cap is applied, under pressure, against the line contact interface formation.

13. The assay assembly according to claim 12, wherein the line contact interface formation is in the form of a knife-edge.

14. The assay assembly according to claim 12, wherein the pressure applied is in the range of 10-50 N.

15-16. (canceled)

17. A method of sealing the assay assembly of claim 12, comprising the steps of: placing the cap onto the biochip storage well wall so that the resilient sealant layer is above the line contact interface formation; applying external force onto the cap so that the cap closes the biochip storage well and the resilient sealant layer is pressed into the line contact interface formation, forming a vapour-proof seal.

18. The method of claim 17, wherein the biochip storage well has a corresponding flange extending along the perimeter of the biochip storage well and wherein the cap slides onto the corresponding flange extending along the perimeter of the biochip storage well so as to form a vapour-proof seal with the line contact interface formation of the biochip storage well.

19. The method according to claim 17, wherein the pressure applied is in the range of 10-50 N

20. The method according to claim 17, wherein the vapour-proof seal provides less than 6% evaporation of the fluid within.

21. The method according to claim 17, wherein the line contact interface formation is in the form of a knife-edge.

22. The assay assembly according to claim 12, wherein the cap further comprises two opposing slide members, each defining a groove to enable the cap to slide onto a corresponding flange extending along the perimeter of the biochip storage well and thereby forming the vapour-proof seal with the line contact interface formation extending around the perimeter of the biochip storage well.

23. The assay assembly according to claim 22, further comprising a support member having a recess in which the biochip well sits, wherein the corresponding flange extending along the perimeter of the biochip storage well is formed by the support member.

24. The assay assembly according to claim 12, wherein the cap further includes a component extending away from the sealant layer to allow the cap to be manipulated.

25. The assay assembly according to claim 24, wherein the component extending away from the sealant layer is a hollow tube through which a pipette can be inserted.

26. The assay assembly according to claim 25, further comprising a pierceable membrane at the base of the hollow tube.

27. The assay assembly according to claim 12, wherein the resilient sealant layer is a polymer sealant.

28. The assay assembly according to claim 27 wherein the resilient sealant layer is polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) or polyethylene (PE).

29. The assay assembly according to claim 27, wherein the resilient sealant layer is a nitrile layer.

30. The assay assembly according to claim 29, wherein the nitrile sealant layer is 0.1 to 10 mm in thickness.

31. The assay assembly according to claim 12, further comprising a hydrophobic layer, coated onto the resilient sealant layer.

32. The assay assembly according to claim 12, wherein the cap is made from injection moulding.

33. The assay assembly according to claim 12, wherein the cap comprises a plastic flat top section.

Description

[0037] Preferred embodiments of the invention will now be explained with reference to the accompanying drawings, in which;

[0038] FIGS. 1a and 1b are perspective views of a first embodiment of a biochip well cap according to the invention.

[0039] FIG. 2 is a perspective view of biochip storage well to be used in conjunction with the biochip well cap.

[0040] FIG. 3 illustrates a method of sealing the biochip storage well with the biochip well cap

[0041] FIG. 4 is a graph showing the percentage evaporation of liquid for assay assemblies according to the invention, when the resilient sealant layer is 1 mm thick nitrile

[0042] FIG. 5 is a graph showing the average percentage evaporation of liquid per resilient sealant layer tested.

[0043] FIG. 6 illustrates a biochip well cap according to the second embodiment of the present invention.

[0044] FIG. 7 illustrates a biochip well cap according to the second embodiment of the present invention viewed from below.

[0045] FIG. 8 illustrates a support member.

[0046] FIG. 9 illustrates a biochip storage well and a support member.

[0047] FIG. 10 illustrates an assay assembly device comprising the cap of the second embodiment, biochip storage well and a support member.

[0048] FIGS. 1a and 1b illustrate a preferred embodiment of the cap according to the present invention, comprising a flat top section 2 and a resilient sealant layer 3.

[0049] The flat top section 2 is made of a plastic material and is bonded to the resilient sealant layer 3 by adhesive. Optionally, a component 1 extending away from the resilient sealant layer is present. This component 1 is cylindrical in shape. Component 1 is in the shape of a hollow tube, and is made of a plastic material and could be integrally formed by injection moulding, with the flat top section 2. The hollow tube of component 1 may contain a pierceable membrane at its base aligning with a hole in the flat top section 2 and the resilient sealant layer 3 (not shown).

[0050] The cylindrical component 1 is typically 12 mm in height and is hollow with an internal diameter of 5 mm, and is joined to the flat top section 2. The flat top section 2 covers an area of 225 mm.sup.2 and is composed of a square area with an adjoining triangular area, with all corners rounded to 3 mm radii, and is preferably 2 mm thick. The sealant layer 3 covers the same area and dimension as the flat top section 2 and is preferably 1 mm thick.

[0051] FIG. 2 illustrates a biochip storage well or receptacle which can be used to form a vapour-proof seal with the cap as shown in FIGS. 1a and 1b. The biochip storage well has a base 5 and side wall 6, and is adapted to receive a biochip (not shown). A rimmed section 7 is formed on top of the side wall 6. The rimmed section 7 projects laterally outwards from the side wall 6 in the form of a flange, and includes a tab 8, allowing the storage well to be handled. Most importantly, the biochip storage well has a line contact interface in the form of a knife-edge formation 4 which projects from, extends around the perimeter of and is integrally formed with the rimmed section 7. The cap of FIGS. 1a and 1b extends across the entire biochip storage well of FIG. 2, forming under pressure a tight vapour-proof seal between the resilient layer 3 and the knife-edge interface 4 and thus closing the storage well.

[0052] FIG. 3 illustrates the method of sealing the biochip storage well shown in FIG. 2, with the cap shown in FIGS. 1a and 1b. The flat top section of the cap 2, bonded to the resilient sealant layer 3 is the same shape as the top face of the biochip storage well. The resilient sealant layer 3 is placed onto the knife-edge interface 4, extending around the perimeter of the rimmed section 7. Force typically of 10-50 N, preferably 10-30 N, most preferably 15 N is applied on the top flat section 2 of the cap, pressing the raised knife-edge interface 4 into the resilient sealant layer 3, forming a vapour-proof seal. In use, the biochip storage well cap is placed onto the biochip storage well. This can be achieved using a simple robotics system or a manual pipette (not shown). For example, a robotic arm can grasp the cylindrical component 1 of the cap in order to move the cap onto the biochip storage well, so that the resilient sealant layer 3 covers the knife-edge 4. The robotic arm can then push down onto the flat section 2 of the cap, applying the required force to achieve sealing. A pipette can be inserted, either manually or robotically, into the hollow tube 1 to pierce the pierceable membrane aligning with a hole in the flat top section 2 and the resilient sealant layer 3. The pipette can dispense or aspirate fluid into the sealed biochip storage well, which is under sustained pressure. An assay can then be performed, for example at 60° C. for 60 minutes, to the sealed storage well. After this time, the seal is released and the cap is removed, by the simple robotics system.

[0053] FIG. 6 illustrates the biochip well cap of the second embodiment 10. It comprises a flat top section 20 and a resilient sealant layer 30. Preferably the flat top section 20 and resilient sealant layer 30 are integrally formed, however they can form separate layers. Preferably the flat top section 20 and resilient sealant layer 30 are made of polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE) or polyethylene (PE). A component 40 extending away from the resilient sealant layer is present and allows the cap to be manipulated. The cap comprises two opposing slide members 50, each defining a groove 60, to enable the cap 10 to slide onto a corresponding flange extending along the perimeter of the biochip storage well. FIG. 7 illustrates the cap of the second embodiment when viewed from below.

[0054] FIG. 8 illustrates an elongate support member 80, which can be used in the assay assembly of the present invention. The support member 80 comprises a recess 90 in which the biochip storage well sits. A cut away section 100 extends around the perimeter of the recess 90. The support member also comprises a raised member 110, which prevents the cap from sliding beyond a desired point.

[0055] FIG. 9 illustrates the biochip well 120 sitting in the recess of the support member 80. The biochip storage well 120 comprises a knife-edge interface 130 extending around the perimeter of the biochip storage well 120. The biochip storage well 120 is supported in the support member 80 as the rimmed section 140 sits in the cut away section 100 of the support member 80. In this embodiment, the corresponding flange extending along the perimeter of the biochip well is formed by the edges 150 of the support member.

[0056] FIG. 10 illustrates the assay assembly device 160 comprising the cap of the second embodiment 10, the biochip storage well 120 and the support member 80. The biochip storage well 120 sits in the recess 90 of the support member 80 as shown in FIG. 9. The cap 10 slides along the edges 150 of the support member until the leading end of the cap 170 engages the raised member 110 which prevents the cap 10 sliding further. The slide members 50 are a tight fit on the support member 80 so that the resilient sealant layer 30 is forced under pressure onto the knife-edge interface 130. The resilient layer 30 of the cap 10 thus forms a vapour-proof seal with the knife-edge interface 130 extending along the perimeter of the biochip storage well 120. In this case no extra pressure is required to achieve the seal.

EXAMPLES

[0057] The invention will now be described in relation to the following non-limiting examples. The amount of evaporation occurring in an assay assembly comprising a cap according to the first embodiment of the present invention and biochip storage well as illustrated in FIG. 2 was determined, in order to investigate the vapour-proof seal between the resilient sealant layer and knife-edge interface. A force of 50 N was applied to the cap to act as the clamping force.

[0058] The test method used to determine the % of evaporation was as follows; [0059] Heat wells to 60° C. for 1 hour [0060] Place 550 μl of deionised water into the wells [0061] Weigh the wells before and after test [0062] Well caps should be clamped at 50 N

[0063] Table 1 shows the results for the above method when testing a nitrile sealant layer of 1 mm. The cap according to the present invention, comprising a 1 mm nitrile sealant layer was placed onto the storage well of FIG. 2 containing 550 μl of deionised water. A force of 50 N was applied, and the assembly heated to 60° C. for 1 hour. The weight of the sample and storage well/cap was measured at various stages, as shown in Table 1 below. The percentage difference was calculated using the results from the test. The difference in weight of the wells before and after the test was attributed to a small amount of vapour condensing on the surface of the cap exposed to the vapour during the test. A small degree of experimental error is also expected. FIG. 4 shows the results in bar chart form.

TABLE-US-00001 TABLE 1 Weight Weight of Weight Weight Weight without well with of of well of Sample sample Sample after sample Difference before test before test prior test after test Percentage Run (g) (g) (g) (g) (g) (%) 1 2.7735 3.3219 0.5483 3.3021 0.5286 3.59 2 2.6696 3.2700 0.6004 3.2568 0.5872 2.20 3 2.7569 3.3267 0.5698 3.3119 0.5550 2.59 4 2.6716 3.1275 0.4559 3.1151 0.4435 2.72 5 2.7255 3.2823 0.5568 3.2561 0.5306 4.71 6 2.7589 3.3127 0.5538 3.2975 0.5386 2.75 7 2.7849 3.4232 0.6383 3.3719 0.5870 8.01 8 2.8199 3.3003 0.4804 3.2864 0.4665 2.89

[0064] The test method as described above was then repeated for various different polymer sealants, specifically, 0.8 mm thick neoprene, 1 mm thick neoprene, 1.5 mm thick EPDM, 1.5 mm thick natural rubber and 1 mm thick nitrile. FIG. 5 shows the average percentage evaporation for each sealant.

CONCLUSION

[0065] Analysis of FIG. 5, a graph displaying the average evaporation percentages for the different gasket materials upon which the evaporation tests were completed, clearly shows that 1 mm thick Nitrile has performed the best compared to the other materials.