WO2009006457A2

WO2009006457A2 - Microplate sealing cover and apparatus

Info

Publication number: WO2009006457A2
Application number: PCT/US2008/068874
Authority: WO
Inventors: Quentin Polosky; Kirk Hirano; James Nurse
Original assignee: Applera Corporation
Priority date: 2007-06-29
Filing date: 2008-06-30
Publication date: 2009-01-08

Abstract

The present teachings describe a sealing cover or film for sealing microplates and film-plate combinations that prevent warpage and leaking. The sealing cover or film for covering and sealing a microplate includes at least one polymeric layer and an adhesive. Changes in temperature do not cause substantial changes in film dimensions relative to the microplate. The film can include an compliant layer and can function as a cover seal and compression pad in microplate clamping systems. Films and microplates with no warpage or substantially no warpage can be used in high-throughput applications and can be more easily accommodated by microplate handling robots.

Description

MICROPLATE SEALING COVER AND APPARATUS

INTRODUCTION

[001] Microplates are used in various ways to screen, analyze, and process many individual samples, reactions, and assays. Common microplates include a 96-well format that can be adapted for use with various types of laboratory instrumentation including optical plate readers and thermal cyclers. Microplates are often constructed from a polymeric substrate, such as polypropylene. In some cases, microplates can be frosted to minimize interfering fluorescence from a cycling block and the polymeric substrate can be screened to eliminate auto-fluorescent plates for use in applications that employ an optical plate reader and where the well contents include fluorescent dyes, for example. Microplates can also provide a barrier to ambient air to help insure well-to-well temperature uniformity throughout the plate. Each microplate can be labeled with a unique serialized, character and/or number label, such as a bar code, that is user- readable and machine-readable to facilitate tracking in high-throughput applications.

[002] A sealing cover or film is used to cover and seal a microplate, reducing the chance of well-to-well contamination and sample evaporation. Sealing covers or films can include a pressure-sensitive adhesive to provide a tight seal over every well. In some cases, the adhesive can be selected to be optically clear so that it will not interfere with an optical plate reader. A compression pad and various clamping systems are used in some applications to support a proper thermal seal between the thermal cycler and microplate when using an adhesive film. Film applicators can also be used to assist in forming a tight seal between a microplate and the adhesive film and can help minimize air bubbles.

SUMMARY

[003] The present teachings relate to various embodiments of sealing covers or films used to seal microplates, film-plate combinations, and methods of making the same.

[004] In various embodiments, a sealing cover may comprise a film assembly for covering and sealing a microplate includes at least one polymeric layer that does not substantially change in length or width relative to the microplate upon experiencing a temperature change. The temperature change may include any changes in temperature within in the range of about 4°C to about 104°C. In various embodiments, the sealing cover or film may also comprise an adhesive on the polymeric layer for affixing the film to the microplate. According to various embodiments, a sealing cover or film may comprise a polymeric layer that changes less than 2 mm in length or width relative to the microplate upon a temperature change from about 4°C to about 104°C

[005] In various embodiments, a sealing cover or film for covering and sealing a microplate includes an elastic layer having a thickness to perform a compression pad function, and to provide a tight seal for each well of a microplate. The elastic layer may be a silicone material, such as polydimethylsiloxane. In various sealing cover or film embodiments, the polymeric base stock layer may comprise a layer of about 50 microns (about 2 mil) of polypropylene and the elastic layer may comprises a layer of about 3 mm of polydimethylsiloxane.

DRAWINGS

[006] The skilled artisan will understand that the drawings, described herein, are for illustration purposes only. It is to be understood that the figures are not drawn to scale, nor are the objects in the figures necessarily drawn to scale in relationship to one another. The figures are depictions that are intended to bring clarity and understanding to various embodiments of apparatuses and methods disclosed herein. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. The drawings are not intended to limit the scope of the present teachings in any way.

[007] FIG. 1A is a top view of a sealing cover according to various embodiments used for sealing embodiments of microplates in accordance with the present teachings. FIG. 1 B is a cross- sectional view of a sealing cover of FIG. 1A. FIG. 1C is a perspective view a sealing cover of FIG. 1A in relationship to an embodiment of a microplate.

[008] FIG. 2A is a section view of an assembly comprising an embodiment of a microplate placed in a thermocycler heating block, with a sealing cover according to various embodiments of the present teachings placed in position for sealing a microplate. Figure 2B is a section view showing the assembly of FIG. 2A, comprising a platen according to various embodiments on top of the sealing cover.

[009] FIG. 3 and FIG. 4 are partial cross-sections of various embodiments of a sealing cover affixed on a microplate.

[0010] FIG. 5A and FIG. 5B are cross-sectional views of various embodiments of a sealing cover having multiple layers. [0011] FIG. 6A and FIG. 6B illustrates how various embodiments of a sealing cover may be assembled in various embodiments of a pressure clamp system.

[0012] FIG. 7 is a cross-sectional view of a multilayer sealing cover according to various embodiments.

[0013] FIG. 8 illustrates a perspective view of a sealing cover roll.

DESCRIPTION

[0014] The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the present teachings, applications, or uses. Although the present teachings will be discussed in various embodiments as relating to microplates used in optical plate readers, thermal cyclers, or for applications such as real-time PCR, such discussion should not be regarded as limiting the present teachings to only such instrumentation and applications.

[0015] All literature and similar materials cited in this application, including but not limited to, patents, patent applications, articles, books, treatises-, and internet web pages, regardless of the format of such literature and similar materials, are expressly incorporated by reference in their entirety for any purpose. In the event that one or more of the incorporated literature and similar materials differs from or contradicts this application, including but not limited to defined terms, term usage, described techniques, or the like, this application controls.

[0016] "A" and "an" as used herein indicate "at least one" of the item is present; a plurality of such items may be present, when possible. "About" when applied to values indicates that the calculation or the measurement allows some slight imprecision in the value (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If, for some reason, the imprecision provided by "about" is not otherwise understood in the art with this ordinary meaning, then "about" as used herein indicates at least variations that may arise from ordinary methods of measuring or using such parameters. In addition, disclosure of ranges includes disclosure of all distinct values and further divided ranges within the entire range.

[0017] In various embodiments, the present teachings provide a sealing cover or film for sealing microplates, such as polymerase chain reaction (PCR) plates, where the sealing cover or film has little or no shrinkage and is relatively warp-free when exposed to changing temperatures, such as those experienced during PCR. The sealing cover or film may reduce or substantially eliminate warpage of the microplate to which it is applied, as well as providing a tight seal. Microplate warpage may occur due to exposure of the microplate and film to changing temperatures, where for example, temperatures may range from about 4°C to about 104⁰C. The present sealing covers or films can overcome problems associated with post-PCR microplates by preventing significant microplate warpage.

[0018] In some cases, instrumentation and high-throughput systems, such as microplate handling robots, cannot accommodate or manipulate warped microplates. As a result, warped microplates can consequently interrupt laboratory workflow. Embodiments of the present sealing covers or films overcome warpage problems by maintaining integrity and uniformity of the microplate dimensions. The present sealing covers or film, as well as film and microplate combinations, may exhibit no warpage or substantially no warpage following exposure to changing temperatures, thereby facilitating high-throughput processes.

[0019] In various embodiments, the adhesive film used to seal the top of the microplate can have the greatest effect on microplate warpage, rather than the microplate itself. Films may include one or more polymeric or metallized layers. Films including polyethylene terephthalate (PET) (non-oriented) may reduce warpage of the microplate. In some cases, the microplate warpage is almost nonexistent when using the present sealing cover or film.

[0020] In various embodiments, sealing covers or films include optical adhesive covers and non-optical adhesive covers. A typical optical adhesive cover may shrink about 15 times more than a typical non-optical adhesive cover when heated at about 100⁰C for about 1 hour. Typical sealing cover or film may experience a total shrinkage of about 2 mm in its length and width. Thus, when the typical optical adhesive cover is adhered to a microplate, it pulls the microplate into the warped shape. The present teachings provide sealing covers or films that do not experience the dimension changes seen in typical film as a result of temperature changes, and consequently do not pull the microplate into a warped shape. Additionally, various embodiments of a sealing cover or film of the present teachings has a compliant layer than conforms to the wells of a microplate, as well as sealing at the surface of microplate interface.

[0021] According to various embodiments of a sealing cover of film, a non-adhesive film layer may have an adhesive layer applied to it or the film itself may have inherent adhesive properties. In either case, the sealing cover or film may exhibit very little or no shrinkage when exposed to temperatures in the range of those used by the PCR process, where the thermal cycler block may reach about 96°C and the heated cover for the microplate may reach about 104⁰C. The adhesive film may possess optical properties if needed by the application; that is, the film may allow transmission and emission of light used by optical readers. Various embodiments of a sealing cover or film may include a warp-free film that is optical or non-optical. Various embodiments of an optical warp-free film may be non-autofluorescent or have substantially no autofluorescence in order to prevent background or false signals.

[0022] In various embodiments of a sealing cover, embodiments of a film layer used as a base stock material may be a polymeric film designed to resist changes in shape or prevent shrinking based on the process used in manufacture of the polymeric film. According to various embodiments, sealing covers or films formed using a biaxial-orientation (BO) process, like biaxially-oriented polypropylene (BOPP), may shrink or warp more than a film made by a casting process. Sealing covers or films including amorphous polymers, such as polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copolymer (COC), or cyclic olefin polymer (COP), among others, may be more thermally-stable than semi-crystalline ones, such as polypropylene (PP) and polyethylene terephthalate (PET), among others. The relaxation temperature and amount of shrinkage of the polymeric films may be tested by ASTM D1204-94el, ISO/DIS 11501, Standard Test Method for Linear Dimensional Changes of Nonrigid Thermoplastic Sheeting or STM D2732-03 Standard Test Method for Unrestrained Linear Thermal Shrinkage of Plastic Film and Sheeting.

[0023] In various embodiments, the sealing cover or film may include several different materials that comprise a laminate or multi-layer cover approach, as will be discussed subsequently.

[0024] As depicted in FIG. 1A and FIG. 1 B, various embodiments of a sealing cover or film 80 may be comprised of two layers including a shrink-resistant base stock layer 84, and a compliant layer 86. In various embodiments of a sealing cover or film 80, the shrink-resistant film 84 may be about a 50 micron (about 2-mil) layer of, for example, but not limited by, polypropylene and compliant layer 86 may be about a 3 mm layer of a material, such as, for example, but not limited by, a silicone material such as polydimethylsiloxane (PDMS). A sealing cover or film may include an assembly or laminate structure, or a single layer made with a casting process which is then combined with a cover film layer placed on top of it. The sealing cover or film 80 may include perforations 85 that delimit end areas for handling the sealing cover or film, which may later be removed after the sealing cover is applied to a microplate.

[0025] According to various embodiments as depicted in FIG. 1 B and FIG. 1B, the sealing cover or film may be comprised of three layers that include a base stock layer of a shrink- resistant base stock layer, such as, for example, but not limited by, polypropylene, a compliant layer, such as for example, but not limited by, polydimethylsiloxane (PDMS), and optionally an adhesive layer (not shown), such as, but not limited by, a silicone-based pressure sensitive adhesive (PSA). The film may be constructed as an optical adhesive cover that includes about a 50 micron (about 2-mil) layer of polypropylene combined with about a 50 micron layer (about 2 mil) of a PSA. The adhesive side of the film may also have a protective liner or backing that can be easily removed or peeled off for application to a microplate. The film may include one or more compliant layers, such as, for example, but not limited by PDMS, or similar compliant material to provide an optically clear layer that is flexible and can serve the dual purpose of a compression pad and cover seal.

[0026] FIG. 1C is a perspective view that depicts the orientation of sealing cover 80 over an embodiment of a microplate 20, and in position for mounting and sealing. Microplate 20 may have a plurality of wells. The overall positioning of the plurality of wells 26 as shown in FIG. 1C can be referred to as a well array. Microplate 20 generally comprises a main body or substrate 28. According to various embodiments, main body 28 is substantially planar. According to various embodiments, microplate 20 comprises an optional skirt or flange portion 30 disposed about a periphery of main body 28. Skirt portion 30 can form a lip around main body 28 and can vary in height. Skirt portion 30 can facilitate alignment of microplate 20 on a thermocycler block, as will be discussed subsequently. Additionally, skirt portion 30 can provide additional rigidity to microplate 20 such that during handling, filling, testing, and the like, microplate 20 remains rigid, thereby ensuring that the contents disposed in each of the plurality of wells 26 does not contaminate adjacent wells. However, in various embodiments, microplate 20 may be skirtless depending upon user preference. In various embodiments, as depicted in FIG. 1C, each of the plurality of wells 26 may comprise a generally circular rim portion 32. As will be discussed subsequently (see FIG. 3 and Fig. 4) the wells may comprise a downwardly-extending, generally- continuous sidewall that terminates at a bottom wall interconnected to sidewall having a radius. As one of ordinary skill in the art is apprised, though wells with circular rims are shown as an example in FIG. 1C, many well shapes and aspect ratios are possible for a variety of microplate designs.

[0027] Though sealing covers or films or the present teachings may be used with any configuration of microplate, various embodiments of sealing covers or films may be used in high density microplates and methods and systems that use such microplates. Embodiments of microplates and sealing covers include those described in U.S. Patent Application Publication No. 2005/0233472 to Kao et al., incorporated herein by reference. [0028] In FIG. 2A and FIG. 2B, an assembly according to various embodiments using a sealing cover according to the present teachings is depicted. In FIG. 2A, a sealing cover according to various embodiments is positioned over a microplate 20, which is mounted in a thermocycler heating block 102. According to various embodiments, at least one thermocycler block 102 provides heat transfer to microplate 20 during analysis to vary the temperature of a sample to be processed, which sample is contained in wells 26. It should be appreciated that in some embodiments thermocycler block 102 can also provide thermal uniformity across microplate 20 to facilitate accurate and precise quantification of an amplification reaction.

[0029] According to various embodiments of an assembly using embodiments of sealing cover 80, as depicted in FIG. 2B, such an assembly may include a pressure clamp system that can comprise a platen 112 used to apply pressure over the sealing cover 80 to provide a tight seal thereby. For example, and as will be discussed in more detail subsequently, the platen 112 may comprise an inflatable transparent bag positioned between and in engaging contact with a transparent window and sealing cover 80. In various embodiments, a platen 112 may be comprised of a transparent window material in direct contact with sealing cover 80. A downward force on platen 112 can be exerted upon microplate 20 to maintain a proper thermal engagement between microplate 20 and thermocycler block 102. Additionally, such downward force can further facilitate sealing engagement of sealing cover 80 and microplate 20, as well as a generally uniform force upon sealing cover 80 and sealing interface 92. Such a force can press compliant material into the rims of the wells 26, creating a tight seal thereby, as shown in FIG. 2B. Such generally uniform force can provide a reliable and consistent sealing engagement between sealing cover 80 and microplate 20. This sealing engagement can reduce water evaporation or contamination of assay 1000 during thermocycling.

[0030] The present teachings of various embodiments of sealing covers include a film used as an optical adhesive cover for high-density microplates. For example, the present sealing cover or film may be used in applications that use the MicroAmp™ Optical Adhesive Film AB P/N 4311971 (Applied Biosystems, Foster City, CA, USA). The sealing cover or film may be used to seal the reaction wells in a variety of open well microplate formats that are used in Real Time Sequence Detection Systems. Often as the density of wells in these reaction microplates increases it may become more difficult to provide uniform sealing for all wells. Embodiments of the present sealing covers or films can overcome this problem, as they not only address the issue of plate warpage, but also the effective sealing of wells in a microplate. [0031] In various embodiments, such as illustrated in FIGS. 3 and 4, sealing cover 80 can be generally disposed across microplate 20 to seal assay 1000 within each of the plurality of wells 26 of microplate 20 along a sealing interface 92. That is, sealing cover 80 can seal (isolate) each of the plurality of wells 26 and its contents (i.e. assay 1000) from adjacent wells 26, thus maintaining sample integrity between each of the plurality of wells 26 and reducing the likelihood of cross contamination between wells. Each of the plurality of wells 26 is sized to receive assay 1000. As illustrated in FIGS. 3 and 4, assay 1000 is disposed in at least one of the plurality of wells 26 and sealing cover 80 is disposed thereon. In some embodiments, one or more of the plurality of wells 26 may not be completely filled with assay 1000, thereby defining a headspace 1006, which can define an air gap or other gas gap. As shown in FIGS. 3 and 4, the sealing cover 80 may permit transmission of light 202 using excitation energy from a source 200 and the resultant emission may be detected using detector 300.

[0032] In some embodiments, assay 1000 can be a homogenous polynucleotide amplification assay, for coupled amplification and detection, wherein the process of amplification generates a detectable signal and the need for subsequent sample handling and manipulation to detect the amplified product is minimized or eliminated. Homogeneous assays can provide for amplification that is detectable without opening a sealed well or further processing steps once amplification is initiated. Such homogeneous assays 1000 can be suitable for use in conjunction with detection probes. For example, in some embodiments, the use of an oligonucleotide detection probe, specific for detecting a particular target DNA can be included in an amplification reaction in addition to a DNA binding agent of the present teachings. Homogenous assays among those useful herein are described, for example, in commonly assigned U.S. Pat. No. 6,814,934, which is incorporated by reference herein.

[0033] Turning now to FIG. 5A and FIG. 5B, in various embodiments, sealing cover 80 can comprise multiple layers. In FIG. 5A, various embodiments of a multilayer sealing cover may comprise layers such as a friction reduction film 82, a base stock 84, a compliant layer 86, a pressure sensitive adhesive 88, and a release liner 90. In FIG. 5B, various embodiments of a multilayer sealing cover may comprise layers such as a friction reduction film 82, a base stock 84, a compliant layer 86, and a release liner 90.

[0034] Referring to FIG. 5A and 5B, friction reduction film 82 can be a fluorocarbon material, such as Teflon®, or a similar friction reduction material that can be peeled off and removed after sealing cover 80 is applied to microplate 20 and before microplate 20 is placed in high-density sequence detection system 10. In various embodiments of a sealing cover, base stock 84 can be a scuff resistant and water impermeable layer with low to no fluorescence. In various embodiments of a sealing cover, base stock layer 84 may be comprised of materials, for example, but not limited by, polypropylene, COC, polyethylene (PE), PS, PC, PMMA, and combinations thereof, including any transparent non-fluorescent material that will not stick or melt to the heated cover in thermal cycling applications, for example. In various embodiments of a sealing cover, such as depicted in FIG. 5A, compliant layer 86 can be a soft silicone elastomer or other material known in the art that is deformable to allow pressure sensitive adhesive 88 to conform to irregular surfaces of microplate 20, increase bond area, and resist delamination of sealing cover 80. Compliant layer 86 materials may include PDMS, polyurethane, silicone, thermoplastic elastomer, and combinations thereof. In various embodiments of a sealing cover, pressure sensitive adhesive 88 and compliant layer 86 can be a single layer, if the pressure sensitive adhesive exhibit sufficient compliancy. The adhesive layer 88 of FIG. 5A may include pressure sensitive adhesive (PSA), UV sensitive (curable) adhesive, epoxy adhesive, and combinations thereof. In various embodiments, such sealing material can comprise one or more compliant coatings and/or one or more adhesives, such as pressure sensitive adhesive (PSA) or hot melt adhesive. According to various embodiments, a pressure sensitive adhesive can be readily applied at low temperatures. In various embodiments, the pressure sensitive adhesive can be softened to facilitate the spreading thereof during installation of sealing cover 80. According to various embodiments, such sealing maintains sample integrity between each of plurality of wells 26 and prevents wells cross-contamination of contents between wells 26. In various embodiments, adhesive 88 of FIG. 5A exhibits low fluorescence. In various embodiments of a sealing cover, such as shown in FIG. 5B, adhesive layer may be absent. Release liner 90 is removed prior to coupling pressure sensitive adhesive 88 to microplate 20.

[0035] As previously mentioned, films of the present teachings that function as a cover seal and compression pad can also be used to provide robust sealing of many microplate formats such as 96- and 384-well microplates, and a microplates having a high-density of wells. The present film that functions as a cover seal and compression pad can alleviate the negative effects of uneven well tops and can allow for looser tolerances in microplate mounting and clamping systems. In various embodiments, the film that may function as a cover seal and compression pad may obviate the need to use a separate compression pad in a clamping system. According to various embodiments, the film can be applied as a cover for high-density microplates such as for 1536- well microplates. The film may be adapted to work with higher density microplates. The present films may also provide more robust sealing of typical 96- and 384-well microplates used on instrumentation such as the 7300 and 7500 real-time PCR systems (Applied Biosystems, Foster City, CA, USA).

[0036] In various embodiments, sealing cover 80 can be made of any material conducive to the particular processing to be done. According to various embodiments, sealing cover 80 can comprise a durable, generally optically transparent material, such as an optically clear film exhibiting abrasion resistance and low fluorescence when exposed to an excitation light. In various embodiments, sealing cover 80 can comprise glass, silicon, quartz, nylon, polystyrene, polyethylene, polycarbonate, copolymer cyclic olefin, polycyclic olefin, cellulose acetate, polypropylene, polytetrafluoroethylene, metal, and combinations thereof.

[0037] In various embodiments, sealing cover 80 comprises an optical element, such as a lens, lenslet, and/or a holographic feature. According to various embodiments, sealing cover 80 comprises features or textures operable to interact with (e.g., by interlocking engagement) circular rim portion 32 or square-shaped rim portion 38 of the plurality of wells 26. In various embodiments, sealing cover 80 can provide resistance to distortion, cracking, and/or stretching during installation. In some embodiments, sealing cover 80 can comprise water impermeable- moisture vapor transmission values below 0.5 (cc-mm)/(m2-24 hr-atm). According to various embodiments, sealing cover 80 can maintain its physical properties in a temperature range of 4°C to 99°C and can be generally free of inclusions (e.g. light blocking specks) greater than 50 μm, scratches, and/or striations.

[0038] In various embodiments, the sealing cover material can provide sufficient adhesion between sealing cover 80 and microplate 20 to withstand about 2.0 lbf per inch or at least about 0.9 lbf per inch at 95°C. In various embodiments, the sealing cover material can provide sufficient adhesion at room temperature to contain assay 1000 within each of the plurality of wells 26. This adhesion can inhibit sample vapor from escaping each of the plurality of wells 26 by either direct evaporation or permeation of water and/or assay 1000 through sealing cover 80. According to various embodiments, the sealing material maintains adhesion between sealing cover 80 and microplate 20 in cold storage at 2°C to 8⁰C range (non-freezing conditions) for 48 hours.

[0039] In various embodiments, in order to improve sealing of the plurality of wells 26 of microplate 20, various treatments to microplate 20 can be used to enhance the coupling of sealing cover 80 to microplate 20. In various embodiments, microplate 20 can be made of a hydrophobic material or can be treated with a hydrophobic coating, such as, but not limited to, a fluorocarbon, PTFE, or the like. The hydrophobic material or coating can reduce the number of water molecules that compete with the sealing material on sealing cover 80. As discussed above, grooves 52, 54 can be used to provide seal adhesion support on the outer edges of sealing cover 80. In these embodiments, for example, a pressure chamber gasket can be sealed against grooves 52, 54 for improved sealing.

[0040] As depicted in FIG. 6A and FIG. 6B, in various embodiments, the sealing cover or film can be used in a microplate clamping assembly that comprises various embodiments of a platen for applying force to a sealing cover 80, and ensuring a tight seal over a microplate 20 thereby. The clamping mechanism may include a direct contact clamping system, using various embodiments of a platen, and a pressure clamp system, using an air platen, and as previously described. According to various embodiments, sealing cover 80 can be positioned within an optional depression 94, as shown in FIG. 6A and FIG. 6B, which optical depression 94 is formed in main body 28 of microplate 20 to promote proper positioning of sealing cover 80 relative to the plurality of wells 26. As previously described, the assembly may include an excitation source 200, as well as a detector 300, and include a thermal cycler system 100, having a thermocycler block 102.

[0041] As shown in FIG. 6A, various embodiments of a pressure clamp system may include a direct contact clamping system. According to various embodiments, a direct clamping system may comprise platen 112, which may be a transparent window material in order to provide for excitation by source 200 and detection of emitted light from samples in the plurality of wells 26 of microplate 20 by detector 300. Such a transparent window material may be a silicon dioxide material, such as a glass or quartz material, or an aluminum oxide material, such as sapphire, or a transparent, heat resistant polymeric material, or combinations of such materials. According to various embodiments, the platen 112 may comprise a heated lid. According to various embodiments, the heated lid may be transparent, as described in published application US 20050237528, which is incorporated herein by reference. As previously described, force may be applied to platen 112 in order to engage sealing cover 80 to provide a tight seal for microplate 20.

[0042] As shown in FIG. 6B, in various embodiments, pressure clamp system 110 can comprise an inflatable transparent bag 116 positioned between and in engaging contact with a transparent window 112 and sealing cover 80. In the embodiment illustrated in FIG. 6B, transparent window 112 and thermocycler block 102 are fixed in position against relative movement. Inflatable transparent bag 116 comprises an inflation/deflation port 118 that can be fluidly coupled to a pressure source 122, such as an air cylinder, which can be controllable in response to a control input from a user or control system 1010. It should be understood that in some embodiments inflatable transparent bag 116 can comprise a plurality of inflation/deflation ports to facilitate inflation/deflation thereof. In various embodiments, the pressure clamp system may comprise the air platen assembly (116, 188, 122, and 1010) alone.

[0043] As can be seen in FIGS. 7and 8, according to various embodiments, sealing cover 80 can be configured as a roll 512. The use of sealing cover roll 512 can provide, in various embodiments, and circumstances, improved ease in storage and application of sealing cover 80 on various embodiments of microplates when used in conjunction with a manual or automated sealing cover application device. According to various embodiments, sealing cover roll 512 can be manufactured using a laminate comprising a protective liner 514, a base stock 516, a compliant layer or adhesive layer 518, and a carrier liner 520. During manufacturing, protective liner 514 can be removed and discarded. Base stock 516 and compliant layer or adhesive layer 518 can then be kiss-cut, such that base stock 516 and compliant layer or adhesive layer 518 are cut to a desired shape of sealing cover 80, yet carrier liner 520 is not cut. As previously discussed for FIG. 5A and FIG. 5B, a multilayer sealing cover may include a compliant layer, an adhesive layer, and a single layer that functions as a compliant layer and an adhesive layer. Excess portions of base stock 516 and compliant or adhesive layer 518 can then be removed and discarded. In various embodiments, base stock 516 can be a scuff resistant and water impermeable layer with low to no fluorescence.

[0044] According to various embodiments, carrier liner 520 can then be punched or otherwise cut to a desired shape and finally the combination of carrier liner 520, base stock 516, and compliant layer or adhesive layer 518 can be rolled about a roll core 522 (see FIG. 8). Roll core 522 can be sized so as not to exceed the elastic limitations of base stock 516, compliant layer 518, and carrier liner 520. In various embodiments, compliant layer or adhesive layer 518 is sufficient to retain base stock 516 to carrier liner 520, yet permit base stock 516 and compliant layer or adhesive layer 518 to be released from carrier liner 520 when desired. According to various embodiments, base stock 516, compliant layer or adhesive layer 518, and carrier liner 520 are rolled upon roll core 522 such that base stock 516 and compliant layer or adhesive layer 518 face toward roll core 522 to protect base stock 516 and compliant layer or adhesive layer 518 from contamination and reduce the possibility of premature release.

[0045] As can be seen in FIG. 8, in various embodiments, such a desired shape of carrier liner 520 can comprise a plurality of drive notches 524 formed along and slightly inboard of at least one of the elongated edges 526. The plurality of drive notches 524 can be shaped, sized, and spaced to permit cooperative engagement with a drive member to positively drive sealing cover roll 512 and aid in the proper positioning of sealing cover 80 relative to various embodiments of a microplate. In various embodiments, the desired shape of carrier liner 520 can further comprise a plurality of staging notches 528 to be used to permit reliable positioning of sealing cover 80. According to various embodiments, the plurality of staging notches 528 can be formed along at least one elongated edge 526. In various embodiments, the plurality of staging notches 528 can be shaped and sized to permit detection by a detector, such as an optical detector, mechanical detector, or the like. An end/start of roll notch or other feature 530 can further be used in various embodiments to provide notification of a first and/or last sealing cover 80 on sealing cover roll 512. Similar to the plurality of staging notches 528, end/start of roll notch 530 can be shaped and sized to permit detection by a detector, such as an optical detector, mechanical detector, or the like. It should be appreciated that the foregoing notches and features can have other shapes than those set forth herein or illustrated in the attached figures. It should also be appreciated that other features, such as magnetic markers, non-destructive markers (e.g. optical and/or readable markers), or any other indicia may be used on carrier liner 520. To facilitate such detection with an optical detector to avoid physical contact, in various embodiments, carrier liner 520 can be opaque. However, in some embodiments, carrier liner 520 can be generally opaque only near elongated edges 526 with generally clear center sections 532 to aid in in-process adhesive inspection.

Claims

What is claimed is:

1. An assembly for covering and sealing a microplate comprising:

a sealing cover disposed over a microplate having a plurality of wells, each well having a rim, the sealing cover comprising:

at least one polymeric layer that does not substantially change in length or width relative to the microplate upon a temperature change, the temperature change occurring within the range of about 4⁰C to about 104⁰C; and

a compliant layer for sealing the plurality of wells; and

a platen disposed over the sealing cover, wherein force exerted on the platen presses the compliant layer into each well rim, sealing the plurality of wells thereby.

2. The assembly according to Claim 1 , wherein the polymeric layer comprises about a 50 micron layer of polypropylene and the compliant layer comprises about a 3 mm layer of polydimethylsiloxane.

3. The assembly according to Claim 1 , wherein said polymeric layer changes less than 2 mm in length or width relative to the microplate upon a temperature change.

4. The assembly according to Claim 1 , wherein said polymeric layer does not substantially shrink relative to the microplate when heated to about 100⁰C and subsequently cooled to room temperature.

5. The assembly according to Claim 1 , wherein said polymeric layer is metallized.

6. The assembly according to Claim 1 , wherein said polymeric layer is optically clear.

7. The assembly according to Claim 1 , wherein the sealing cover is a multilayer film.

8. The assembly according to Claim 6, wherein the multilayer film has an adhesive layer.

9. The assembly according to Claim 7, wherein the adhesive layer is optically clear.

10. The assembly according to Claim 7, further comprising a peelable backing layer covering said adhesive.