Abstract:
A multi-well plate and plate holder assembly comprising a multi-well assay plate clamped between an upper plate holder and a lower plate holder to facilitate handling of the plate, and to prevent the plate from warping when liquid samples placed within wells of the multi-well assay plate are stored, analyzed and/or subjected to a reaction or other process, particularly when the samples are subjected to high temperatures. The upper plate holder is releasably engageable with the lower plate holder. Preferably, at least one detent positions and holds the upper plate holder in relation to the lower plate holder.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to multi-well containers, such as microtitration plates, for multi-sample fluid handling systems. 
     BACKGROUND OF THE INVENTION 
     Patient health care and biological research have made dramatic improvements in recent years, in part due to the utilization of assay techniques. Laboratory and clinical procedures involving biospecific affinity reactions are commonly employed in testing biological samples, such as blood or urine, for the identification and/or quantification of a wide range of target substances, such as particular chemical substances that have been correlated or associated with various disease conditions. The efficiency with which various tests, reactions, assays and the like can be performed in biology, clinical diagnostics, and other areas, has been greatly increased by adoption of parallel sample handling techniques. Specific examples include polymerase chain reaction (PCR) techniques, enzyme-linked immunosorbent assay (ELISA), enzyme immune assay (EIA), radioimmune assay (RIA), membrane capture assays, cell washing, enzyme assays, receptor binding assays, other molecular biological reactions and washes, and the like. In most of these procedures, samples are processed in multi-well or multi-well assay plates. 
     One of the most common plate formats is a 96-well assay plate, wherein the wells are arranged in a matrix having 8 lettered rows and 12 numbered columns. Multi-well assay plates may be manually handled or handled by automated systems. Known automated systems include robotic devices for use in various procedures including thermal cycling of PCR reactions, luminometers, plate readers and the like. Fluids may be transferred between selected wells, and the plates may be manipulated for storing, reacting and/or analyzing the samples. 
     During certain processing steps, the samples (and the plates holding the samples) may be heated. Under extreme temperatures, it is not uncommon for the multi-well assay plates to warp. A warped multi-well assay plate is difficult to effectively utilize and handle. 
     SUMMARY OF THE INVENTION 
     Accordingly, there is a need for an assembly that prevents or reduces the likelihood of a multi-well assay plate from warping as a result of exposure to extreme heating conditions. There is also a need for an assembly that facilitates and improves the handling of a multi-well assay plate. Thus, it is desirable to provide an assembly which includes a multi-well assay plate, which is of relatively simple, yet dependable, construction and operation, which improves the handling of the multi-well assay plate, and which is of practical utility for use in various laboratory and clinical procedures. 
     Briefly, the present invention includes a multi-well assay plate and plate holder and a method of assembling the same. The plate holder engages a top side and a bottom side of the multi-well assay plate. The plate holder holds the multi-well assay plate to prevent or substantially inhibit the ability of the multi-well assay plate to warp when the multi-well assay plate is subjected to changing temperatures. The plate holder enhances the ease in which the multi-well assay plate can be manually or mechanically handled. In one embodiment, the plate holder includes an upper portion designed to be positioned above the multi-well assay plate, and a lower portion designed to be positioned under the multiwell assay plate. The upper portion is releasably engaged to the lower portion to sandwich and hold the multi-well assay plate therebetween. Preferably, the plate holder includes at least one detent for positioning and holding the upper portion in relation to the lower portion. 
    
    
     Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims and drawings in which like numerals are used to designate like features. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is perspective view of a multi-well assay plate and plate holder assembly according to the present invention. 
     FIG. 2 is an exploded perspective view of the multi-well assay plate and plate holder assembly of FIG.  1 . 
     FIG. 3 is a cross-sectional view taken along line III—III of FIG.  1 . 
     FIG. 4 is an enlarged perspective view of a portion of a modified plate holder illustrating a different embodiment of the present invention. 
    
    
     Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a multi-well assay plate and plate holder assembly  10  including a multi-well assay plate  14  and a plate holder  18 . As will be further explained below, the plate  14  is held by the plate holder  18  in such a way so as to prevent the plate  14  from warping when the plate  14  is subjected to extreme temperature. Before explaining in detail the features of the assembly  10 , the elements of the plate  14  and the plate holder  18  are identified for the sake of clarity. 
     With reference to FIG. 2, the illustrated plate  14  is shown as having a common  96 -well format arranged in an eight by twelve array. Labels in the form of letters and numbers  20  can be used to identify the individual wells. The invention may, of course, be used with other multi-well formats. The wells  22  are shown as being integrally formed with the plate  14  to create a single, one-piece plate  14 , but the invention is capable of use with plate assemblies where the wells are not integrally formed with a plate. The plate  14  is preferably made of plastic, but can be made of other suitable material. The plate  14  is substantially rectangular having a first side  26 , a second side  30 , a third side  34  and a fourth side  38 , all of which extend between a top side  42  and a bottom side  46 . The wells  22  extend through the top side  42  and the bottom side  46 . Each well  22  includes an upper portion  50  which extends from the top side  42  of the plate  14  and a lower portion  54  which extends from the bottom side  46  of the plate  14  (see also FIG.  3 ). The upper portion  50  includes an opening  58  for receiving a fluid sample which is stored, analyzed or subjected to a reaction, in accordance with the desired procedure. 
     With continued reference to FIG. 2, the plate holder  18  includes an upper plate holder  62  and a lower plate holder  66 . The illustrated upper plate holder  62  and the illustrated lower plate holder  66  are substantially rectangular and flat. Preferably, the upper plate holder  62  and the lower plate holder  66  are made of a non-warping material, such as aluminum or a heat resistant plastic material, but may be made of other suitable material. Preferably the material of the plate holders is stiffer than the material of the plate. The upper plate holder  62  has a plurality of openings  70 , one for each well  22 , a first side  74 , a second side  78 , a third side  82  and a fourth side  86 , all of which extend between a top side  90  and a bottom side  94 . The top side  90  includes labels in the form of letters and numbers  96  in order to facilitate identification of the individual wells. The upper plate holder  62  further has a first L-shaped notch  98  extending between the first side  74  and the second side  78 , a second L-shaped notch  102  extending between the second side  78  and the third side  82 , a third L-shaped notch  106  extending between the third side  82  and the fourth side  86 , and a fourth L-shaped notch  110  extending between the first side  74  and the fourth side  86 . The lower plate holder  66  has a plurality of openings  114 , one for each well  22 , a first side  118 , a second side  122 , a third side  126  and a fourth side  130 , all of which extend between a top side  134  and a bottom side  138 . The lower plate holder  66  further has a first substantially rectangular projection  142 , a second substantially rectangular projection  146 , a third substantially rectangular projection  150  and a fourth substantially rectangular projection  154 , all of which extend from the top side  134 . 
     Although not clearly shown in FIG. 2, for reasons which will be further explained below, each notch  98 ,  102 ,  106  and  110  of the upper plate holder  62  includes a detent  158  and each projection  142 ,  146 ,  150  and  154  of the lower plate holder  66  includes a detent receiving hole or bore  162 . FIG. 3 is representative of the cooperation between the detents  158  and the detent receiving holes  162 . FIG. 3 best shows the combination of the detent  158  of notch  106  (FIG. 2) and the detent receiving hole  162  of the projection  150  (FIG.  2 ). It should be understood that the invention can include any number of detents. 
     Having described in detail the components of the plate  14  and plate holder  18 , the overall assembly of the multi-well plate and plate holder  10  will now be explained in greater detail taking into account FIGS. 1-3. 
     The upper plate holder  62  is releasably engaged with the lower plate holder  66  to sandwich and hold the multi-well assay plate  14  therebetween. The plurality of openings  70  of the upper plate holder  62  align with and receive the upper portions  50  of the wells  22 , and the plurality of openings  114  of the lower plate holder  66  align with and receive the lower portions  54  of the wells  22 . So as to allow for the proper use of the wells  22  during certain laboratory and clinical procedures, the upper portions  50  of the wells  22  extend beyond the top side  90  of the upper plate holder  62  and the bottom portions  54  extend beyond the bottom side  138  of the lower plate holder  66 . The bottom side  94  of the upper plate holder  62  engages the top side  42  of the plate  14  and the top side  134  of the lower plate holder  66  engages the bottom side  46  of the plate  14 . Notches  98 ,  102 ,  106  and  110  of the upper plate holder  62  receive the projection members  142 ,  146 ,  150  and  154  of the lower plate holder  66 , respectively. The detents  158  of the upper plate holder  62  are received by the associated detent receiving holes  162  of the lower plate holder  66  to hold the upper plate holder  62  to the lower plate holder  66 . So assembled, the multi-well assay plate  14  is more easily handled, as compared to a plate standing by itself. Moreover, because the upper plate holder  62  and the lower plate holder  66  are made of a non-warping or stiff material and are generally flat, the plate holder  18  will prevent the multi-well assay plate  14  from warping when, for example, the plate  14  is subjected to high temperatures, thereby eliminating the problems associated therewith. To release the upper plate holder  62  from the lower plate holder  66 , a force is simply applied to the tops of each projection member  142 ,  146 ,  150  and  154  to separate the detents  158  from the detent receiving holes  162 . 
     Variations and modifications are within the scope of the present invention. For example, the lower plate holder  66  could include a diagonal corner  151  (FIG. 4) so that a PCR machine or the like can detect the corner  151  to determine the position of the multiwell assay plate relative to the machine. As another example, the upper plate holder  62  and the lower plate holder  66  need not be separable from each other and could be hinged or otherwise coupled to each other. It is understood that the invention disclosed and defined herein extends to alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention. The claims are to be construed to include alternative embodiments to the extent permitted by the prior art. 
     Various features of the invention are set forth in the following claims.