(19)
(11)EP 3 148 700 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
18.03.2020 Bulletin 2020/12

(21)Application number: 15741622.3

(22)Date of filing:  02.06.2015
(51)International Patent Classification (IPC): 
B01L 9/00(2006.01)
B01L 7/02(2006.01)
B01L 3/00(2006.01)
G01N 35/00(2006.01)
(86)International application number:
PCT/US2015/033815
(87)International publication number:
WO 2015/187717 (10.12.2015 Gazette  2015/49)

(54)

SINGLE COLUMN MICROPLATE SYSTEM AND CARRIER FOR ANALYSIS OF BIOLOGICAL SAMPLES

EINSPALTIGES MIKROPLATTENSYSTEM UND TRÄGER ZUR ANALYSE BIOLOGISCHER PROBEN

SYSTÈME DE MICROPLAQUE À COLONNE UNIQUE ET PORTEUR POUR ANALYSE D'ÉCHANTILLONS BIOLOGIQUES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 02.06.2014 US 201462006593 P

(43)Date of publication of application:
05.04.2017 Bulletin 2017/14

(73)Proprietor: Agilent Technologies, Inc.
Santa Clara, CA 95051-7201 (US)

(72)Inventors:
  • BURROUGHS, Sarah
    Auburndale, MA 02466 (US)
  • MCGARR, Paul
    Longmeadow, MA 01106 (US)
  • ARMITSTEAD, Suzanne
    Bedford, NH 03110 (US)
  • TEICH, Jay, S.
    Berlin, MA 01503 (US)
  • DELL'ARCIPRETE, Jason
    Billerica, MA 01821 (US)

(74)Representative: Grünecker Patent- und Rechtsanwälte PartG mbB 
Leopoldstraße 4
80802 München
80802 München (DE)


(56)References cited: : 
EP-A1- 2 636 452
US-A1- 2008 014 571
US-A1- 2013 040 855
US-A1- 2006 051 249
US-A1- 2008 031 774
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the Invention



    [0001] This invention relates generally to devices that measure properties of fluids within vessels, and particularly to microplates for handling test fluids.

    Background



    [0002] In the field of cell analysis, cells are commonly placed in a multiwell microplate for purposes of testing multiple conditions and replicates in a single experiment. Standard microplates, such as 24- and 96-well plates, are two-dimensional arrays of wells. Such arrays include some wells that are at the border or edge of the array, i.e., in the first row, first column, last row, or last column. Border wells and non-border wells can experience different conditions; this is commonly known as an "edge effect". Because such assays are typically conducted at mammalian body temperature (37°C), and border wells are more exposed to the external environment, the environment within the border wells may be substantially different from that of the non-border wells. The evaporation of liquid from wells adjacent to the border of the plate occurs at a higher rate than that of non-border wells. This causes a temperature drop in the border wells due to evaporative cooling, resulting in an increase in the concentration of solutes in the liquid. Both the temperature differences and the concentration difference contribute to data inconsistency in these types of assays. Live-cell assays are particularly sensitive to these effects due to the dynamic nature of the assay and the sensitivity of living, metabolically active cells to the environmental conditions in which they are being measured. Examples of these types of assays include FLIPR calcium flux assays, Corning EPIC label-free assays, and certain high-content imaging assays.

    [0003] Several solutions have been proposed and applied to such standard microplates to address this problem. One workaround is to sacrifice the use of the border wells in the assay. By simply filling them with fluid to the same height as the assay wells, the border wells provide a humidity buffer. This approach has serious drawbacks in that the capacity of the microplate is significantly diminished, and in the case of a 24-well plate more than half of the wells are sacrificed. As the size of the well array in the microplate decreases, a higher fraction of wells become border wells. At the extreme, in one-dimensional arrays, every well has a high rate of evaporation.

    [0004] Another workaround is to seal the wells or plate by overlaying the assay wells with oil or wrapping the covered plate with a plastic paraffin film, such as Parafilm M® film available from Bemis Company, Inc., or similar material. One of the drawbacks to these methods is that gas exchange is reduced. Metabolically active cells require oxygen; thus restricting the supply of oxygen can be detrimental to the cells and cause changes in assay results.

    [0005] Existing solutions to this problem include modifications to the instrumentation or the cell growth vessel, i.e., microplate and cover. A few instrumentation manufacturers attempt to mitigate these effects by putting humidity control into the measuring chambers in which the microplate is placed. In general, however, these options are rare as high humidity levels can cause problems with the instrument electronics.

    [0006] Modifications to the cell growth vessel may include changes to the design of the microplate and lid. Changes to the lid include adding a moisture-holding layer to the lid. However, in the case of live-cell assays where addition of reagent during the course of the assay is required, a lid or cover cannot be used.

    [0007] The addition of perimeter or border wells to the microplate provides an environmental buffer between the assay well and the ambient laboratory conditions. For example, a plate may have large edge troughs, e.g., four troughs, surrounding the array of wells. Fluid may be placed in each trough, thus providing an environmental buffer. A potential drawback of this design is the large volume of each trough. Because well plates are shallow, there is potential sloshing of the border fluid when the plate is tilted or moved around the laboratory. In addition, the depth of the troughs, being the same depth as that of the wells, may require that a significant amount of fluid, more than 10x the volume of the assay well, be added to each trough. Therefore the operator may need to use a different tool (such as a different volume pipet) to fill the border troughs and the assay wells.

    [0008] Standard microplate designs include a lid or cover where the edge or skirt of the cover can be up to half the height of the plate itself and protrudes 1-2 millimeters ("mm") beyond the wall of the plate. This may present a problem while handling these plates, as it takes some dexterity to consistently pick up both the plate and the lid off of a surface, e.g., to avoid accidentally picking up only the lid and thus exposing the contents of the plate. When dealing with cell cultures that must be maintained under sterile conditions, current plate and cover assembly designs introduce considerable risk to the integrity of the cultures. Similar risks apply to assays where the contents of the wells must be protected from ambient light.

    [0009] Standard microplate designs have a fixed height and footprint, such that the volume of the wells varies with the number of wells arrayed in the plate. For example, a standard 384-well plate has four times as many wells as a standard 96-well plate, but each well is approximately one-fourth the volume. Likewise, as well density (i.e., wells per plate) goes down, the volume per well increases. This design, although convenient for maintaining a standard footprint, requires that the researcher use more cells and reagents per well when using a lower-density plate. In addition, the spacing between wells changes, which can be an inconvenience when adding reagents to the assay plate.

    [0010] Presently, no microplate is commercially available for performing an assay on a fewer number of wells while maintaining standard volumes and well-to-well spacing. Maintaining these features and reducing the number of wells may require reducing the footprint. However, since many standard laboratory workflows and instruments are designed to this standard, an adapter or carrier of some sort would be required. Examples of instruments that accept standard-footprint microplates include plate readers, high content imaging systems, centrifuges, and automated plate handling robots.

    [0011] Microscope slides adhere to a different standard in the lab, and some products exist that bridge the microplate and slide formats. Some commercially available slides contain assay wells fused to a glass microscope slide, providing assay wells with glass bottoms designed for high-resolution imaging on microscopes. Although they do provide wells, the dimensions of the wells vary and are not standard with respect to well-to-well spacing nor length and width dimensions.

    [0012] A commercially available carrier for microscope slides that conforms to the Society for Laboratory Automation and Screening ("SLAS") microplate footprint and height standards is designed for imaging applications, but the placement of the slides in the carrier allows for some variability in well position, which may make automated analysis challenging.

    [0013] US 2008/0031774 A1 discloses a system including a support that holds multiple sample receptacles, computational circuitry to execute a protocol script that delivers instructions for executing various steps of the procedure, and a progress sensor that advances the execution of the protocol script. Also disclosed is a system for storing and assembling a plurality or reagents comprising a frame having a plurality of differently sized or shaped cavities, the frame having a microplate footprint; and a plurality of inserts sized to be inserted into the plurality of cavities, at least one insert comprising at least one fluid receiving member.

    [0014] EP 2 636 452 A1 relates to a process for the production of a reaction chamber assembly, wherein a flat substrate and bottomless reaction chambers are provided. The substrate is first loaded with a biological agent and then the bottomless reaction chambers are bonded glue-free to the substrate for obtaining liquid-tight reaction chambers. At least two bottomless reaction chambers may be provided forming a superstructure and the reaction chamber assembly may comprise a frame with a grid supporting the at least one bottomless reaction chamber.

    [0015] US 2008/014571 A1 discloses devices and methods that measure one or more properties of a living cell culture that is contained in liquid media within a vessel, and typically analyzes plural cell cultures contained in plural vessels such as the wells of a multiwell microplate substantially in parallel. The devices incorporate a sensor that remains in equilibrium with, e.g., remains submerged within, the liquid cell media during the performance of a measurement and during addition of one or more cell affecting fluids such as solutions of potential drug compounds. One embodiment comprises a cartridge and microplate in the form of a typical multiwell microplate. The cartridge comprises a frame with a planar surface defining a plurality of reagents that correspond to i.e. register with a number of the respective openings of the plurality of wells defined in the multiwell plate. Within each of these regions, four ports which serve as test compound reservoirs and a central aperture to a sleeve having one or more sensors are defined.

    [0016] US 2013/040855 A1_discloses devices, systems and methods of using such devices in creating and handling hanging drops of fluid. Disclosed is a spheroid culture device based on a hanging drop cell culture technique, wherein each cell culture site is composed of an access hole through the substrate with a plateau surface, which cell culture sites are arranged with a multiwell footprint, herewith general 384-well plates. To alleviate the commonly encountered evaporation problems due to small volumes of hanging drops, a water reservoir was constructed around the peripheral of the culture sites.

    [0017] US 2006/0051249 A1 relates to a container with a base body, comprising a base plate and side walls standing out therefrom in an at least approximately perpendicular arrangement, and with wells disposed in the base body. The wells are provided in the form of a recess in the base plate and the side walls of the base plate are disposed in at least the approximately opposite direction from the recesses in order to accommodate a volume.

    Summary



    [0018] In an aspect, an embodiment of the invention may include a multiwell microplate for holding liquid samples as defined in claim 1. The multiwell microplate includes a frame defining a plurality of wells disposed in a single column, each well having an opening with a length l1; a moat disposed about the plurality of wells; and a plurality of walls traversing the moat. The walls define a plurality of compartments, each compartment having a length l2 selected from a range of greater than l1 and less than 6l1. Two compartments of the moat are disposed on opposing sides of the single column of wells.

    [0019] One or more of the following features may be included. The well length l1 may be selected from a range of 1 mm to 9 mm (0.04 to 0.35 in). The plurality of wells may include eight wells. The moat may include eight compartments.

    [0020] Two compartments disposed on opposing sides of the single column of wells may be in fluidic communication via an equalizer channel. A depth of the two compartments in communication via the equalizer channel may be less than a depth of compartments adjacent thereto.

    [0021] A depth of at least one compartment may be less than a depth of one of the wells, e.g., the depth of the at least one compartment may be up to 50% of the depth of one of the wells. A depth of a compartment proximate an end portion of the frame may be less than a depth of a compartment disposed at a center portion of the frame. All of the compartments may have a substantially equal length.

    [0022] A lifting tab may be defined on an end portion of the frame. At least one well may be opaque white or opaque black. The frame may define an indent on a lower edge.

    [0023] Also disclosed is a multiwell microplate carrier including a body defining a plurality of regions configured to hold a plurality of multiwell microplates in parallel, each multiwell microplate defining a single column of wells, and each of the regions defining a plurality of openings adapted to mate with the single columns of wells.

    [0024] One or more of the following features may be included in the disclosed carrier. The body may have a base footprint with outside dimensions of approximately 5 inches (12,7 cm) by 3,4 inches (8,6 cm). Each region may define eight openings. The body may define three or four regions configured to hold three or four multiwell microplates, respectively.

    [0025] Further disclosed is a cartridge for mating with the multiwell microplate described herein. The cartridge includes a substantially planar surface having a plurality of regions corresponding to a number of respective openings of the wells in the multiwall microplate. Also located in plural respective regions of the cartridge is a sensor or a portion of a sensor adapted to analyze a constituent in a well and/or an aperture adapted to receive a sensor. At least one port may be formed in the cartridge, the port being adapted to deliver a test fluid to a respective well of the plate. The multiwell microplate may include eight wells and the cartridge may include eight regions.

    [0026] In another aspect, embodiments of the invention include a method for preparing a liquid analytical sample. The method includes delivering the analytical sample to a well defined by a frame of a multiwell microplate. A fluid is delivered to a moat defined by the frame. The frame defines a plurality of wells disposed in a single column, each well having an opening with a length l1. The moat is disposed about the plurality of wells. A plurality of walls traverses the moat, the walls defining a plurality of compartments, each compartment having a length l2 selected from a range of greater than l1 and less than 6l1. Two compartments of the moat are disposed on opposing sides of the single column of wells.

    [0027] One or more of the following features may be included. Delivering the analytical sample to the well may include using a pipettor. Delivering the fluid to the moat may include using a pipettor.

    Brief Description of Figures



    [0028] 

    Figures 1a and 1b are upright and inverted (respectively) perspective views of a multiwell microplate in accordance with one embodiment of the invention;

    Figure 1c are mechanical drawings of a top view and an end view of a multiwell microplate in accordance with an embodiment of the invention, in which Figure 1c1 is a top view and Figure 1c2 is an end view;

    Figure 1d are mechanical drawings of various views of a multiwell microplate in accordance with one embodiment of the invention, in which Figures 1d1-1d2 are top views of shallow and deep moats, respectively, Figure 1d3 is a top view of a multiwell microplate, Figure 1d4-1d6 are cross-sectional views of the multiwell microplate of Figure 1d3, Figure 1d7 is a perspective view of a multiwell microplate, and Figures 1d8-1d9 are cross-sectional views of the multiwell microplate of Figure 1d7;

    Figures 2a and 2b are upright and inverted (respectively) perspective views of a cartridge adapted to mate with the multiwell microplate of Figures 1a and 1b;

    Figure 2c are mechanical drawings of top and end views of a cartridge, in which Figure 2c1 is a top view and Figure 2c2 is an end view;

    Figure 3 is a perspective view of a cartridge mated with a multiwell microplate;

    Figure 4 is a perspective view of a cover for the multiwell microplate and cartridge of Figure 3;

    Figure 5a is a perspective view of a carrier tray;

    Figure 5b is a perspective view of a carrier tray in combination with three multiwell microplates and covers;

    Figure 6 is a bar chart illustrating the impact on fluid loss with a microwell plate having a moatin accordance with an embodiment of the invention;

    Figure 7 is a table illustrating sensitivity of measurement to temperature variations that may be due to varying rates of evaporation in assay wells not protect by fluid-filled moats in accordance with an embodiment of the invention;

    Figures 8a - 8d are bar charts of baseline metabolic rates (OCR and ECAR) of C2C12 cells measured under several conditions to test the effect of the moat of a microplate being filled or empty in accordance with an embodiment of the invention; and

    Figures 9a and 9b are graphs illustrating inter- and intra-well variability of the background OCR signal over time in multiwell microplates in accordance with embodiments of the invention.


    Detailed Description



    [0029] Evaporation from peripheral wells of a multiwell microplate may have a negative impact on various analytical steps, including cell seeding, cell plate incubation and running assays. In particular, cell-based assays ("CBA") with adherent cells are susceptible to edge effects from cell seeding and cell plate incubation. Live-cells assays such as label-free and extracellular flux ("XF") measurements are also susceptible to edge effects during the running of the assays. Multiwell plate designs having moats with compartments to hold hydration fluid, e.g., water or cell media, at and/or near the edges of the multiwell plate, in accordance with embodiments of the invention, help reduce such edge effects, reducing the evaporation of fluid from the wells by providing a humidified buffer between the air above the wells and the drier air outside a perimeter of the plate.

    [0030] Referring to Figures 1a and 1b, a multiwell microplate 100 in accordance with an embodiment of the invention is formed from a frame 110 defining a single column of wells 120. The number of wells 120 in a plate may vary from two to thousands, preferably a maximum of 128 (corresponding to an industry standard of wellplates with 1536 wells, with 128 wells in a single column). In some embodiments, the multiwell microplate may have a column of four, six, or twelve wells. In a particular embodiment, the multiwell microplate has eight wells 120. A configuration with eight wells may be especially advantageous, as it allows up to four replicates of two conditions such as disease/normal, drug treated/native, or genetic knock-out vs. wild type, while maintaining a small footprint. Moreover, many analytical instruments are configured to handle well plates having columns of eight wells, such as 96 well plates (8 x 12).

    [0031] In one embodiment, the multiwell microplate 100 includes a one-dimensional pattern of wells complying, in relevant part, with the pattern and dimensions of a microplate, as described by the American National Standards Institute and Society for Laboratory Automation and Screening standards, including Height Dimensions for Microplates (ANSI/SLAS 2-2005, 10/13/2011); Well Positions for Microplates (ANSI/SLAS 4/2004, 10/13/2011); and Footprint Dimensions for Microplates (ANSI/SLAS 1-2004, 10/12/2011).

    [0032] The multiwell microplate may be formed from a molded plastic, such as polystyrene, polypropylene, polycarbonate, or other suitable material. The bottoms of the wells may be transparent and the sides colored black to reduce optical cross-talk from one well to another. In some embodiments, e.g., for use with luminescence measurements, the wells may be white. In some embodiments, e.g., for use in high-resolution imaging applications, the plate may be formed with glass as the bottom of the wells and plastic polymer forming the sides of the plate and walls of the wells.

    [0033] Each of the wells has a top portion with an opening having a length l1 as well as may have a bottom portion that may be cylindrical or square, and may have a tapered sidewall. A seating surface may be provided to act as a positive stop for sensors disposed on barriers (see discussion of cartridge with respect to Figures 2a and 2b). This seating surface enables the creation of a localized reduced volume of medium, as discussed in U.S. Patent No. 7,276,351. In an embodiment, the seating surface may be defined by a plurality of raised dots, e.g., three dots, on a bottom surface of a well. The well length l1 can be any dimension and may be preferably selected from a range of 1 to 9 mm, e.g., 6 mm. Preferably, the wells are spaced equally from each other, e.g., 3 - 18 mm, more preferably 9 mm as measured center to center of the wells. Each of the wells in the microwell plate can have substantially the same dimensions, including the same well length l1 as well as a width equal to the length. In some embodiments, however, the wells may have varying dimensions, including different well lengths l1. A depth of the wells may range from 1 to 16 mm or more, preferably about 15 mm.

    [0034] A moat 130 extends about an external perimeter of the wells. A plurality of walls 140 traverse the moat, the walls 140 defining a plurality of compartments 150. The walls 140 are preferably thick enough to provide rigidity to the microplate, while being thin enough to be injection molded without distortion. Accordingly, a thickness of the walls may range from 0.5 to 1.5 mm, preferably about 1 mm. The compartments each have a length l2 that is greater than l1, preferably a multiple of l1, and less than 6l1, preferably about 2l1, and not less than 6 mm. For example, if a well opening has a length l1 of 9 mm, an abutting compartment may have a length of 2l1 of 18 mm. A length of less than 6 mm (9 mm well-to-well spacing) could make filling the compartments challenging. All of the compartments may have substantially equal longitudinal lengths, i.e., the length from one end wall to an opposing end wall varying no more than 25%.

    [0035] In a preferred embodiment, the moat has eight compartments and eight wells, with one or more compartments having a length approximately equal to the sum of the lengths of approximately two well openings, plus a thickness of one or more walls defining the well openings.

    [0036] Two compartments disposed on opposing sides of the single column of wells may be in fluidic communication via an equalizer channel 160. The moat may include two equalizer channels 160, one at each end of the multiwell microplate. To equalize the volumes of the compartments of the moat, a depth of two compartments in communication via the equalizer channel may be less than a depth of compartments adjacent thereto. In one preferred embodiment, the equalizer channel is disposed at an end of the multiwell microplate, and is 0.08 inches (0,2 cm) wide and 0.25 inches (0,6 cm) deep. The dimensions of the equalizer channel are preferably small enough to reduce the contribution of the channel width to the overall plate size but are wide enough to overcome surface tension and allow the chosen fluid to fill the channel. In a preferred embodiment, the channel has a feature 165 (e.g., surface tension breaker 165 as illustrated in figure 1d) that breaks the surface tension of the fluid allowing it to self-fill at a lower volume. Since sharp corners break the surface tension of the fluid, to stimlate fluid flow through the narrow opening of the equalizer channel, one or more sharp edges may be included.

    [0037] A depth of at least one compartment may be less than a depth of one of the wells, e.g., the depth of the at least one compartment may be 50% or less than the depth of one of the wells.

    [0038] A depth of a compartment proximate an end portion of the frame may be less than a depth of a compartment disposed closer to a center portion of the frame. In one preferred embodiment, to maintain a constant fluid height across all compartments with 800 µl in end compartments connected by an equalizer channel and 400 µl of fluid in the inner compartments, the inner compartments may be 0.055 inches (0,14 cm) deeper than the outer compartments.

    [0039] The moat may have a width of at least 0.2 inches (0,5 cm) and no more than 0.5 inches (1,3 cm), preferably approximately 0.265 inches (0,673 cm). A moat that is too narrow could minimize the benefit of having a hydrating barrier between the wells and the dry outside air; whereas, a moat that is too wide could introduce the risk of sloshing and contamination of the assay wells.

    [0040] All of the compartments may be of substantially equal length, e.g., varying no more than 25%.

    [0041] Various features of the moat facilitate its filling with a multi-channel pipettor design for Society for Biomolecular Screening ("SBS") standard microplates. Suitable multi-channel pipettors include Eppendorf 3122000051 and Mettler-Toledo L8-200XLS+, available from Eppendorf AG and Mettler-Toledor International Inc., respectively. The walls defining compartments are positioned so as to not interfere with pipette tips on the multi-channel pipettor. Such multi-channel pipettors have a standard tip-to-tip spacing of 9 mm, so compartments of a moat preferably allow access of an equal number of pipet tips into each compartment. Equalizer channels at the ends allow fluid to be drawn from the side compartments, thereby enabling hydration fluids to surround the end wells. The compartments are more than one well and less than six wells in length to reduce splashing of liquid out of the microwell plate or contamination of assay wells with hydration liquid. Finally, the moat depth is preferably 50% or less than the well depth to reduce the required volume of hydration liquid and to allow the use of a pipettor the same size as a cell pipettor.

    [0042] A lifting tab 170 may defined on one or both end portions of the frame. The lifting tab may have a length l3 of 0.3 to 0.55 inches (0,76 to 1,40 cm), e.g., 0.435 inches (1,105 cm). The lifting tab facilitates lifting of the multiwell microplate and a cover or a microplate and a cartridge, without removing the cover or cartridge.

    [0043] The lower edge of the frame may define one or more indents 180. The indents may be positioned at the ends and/or the sides of the frame. The incorporation of one or more indents provides stability for the frame when positioned in a carrier tray. Moreover, without the indents, the frame would sit higher in the carrier, which may prevent its use in different instrumentation. The height of one multiwell microplate is preferably about 0.5 to 0.9 inches (1,27 to 2,29 cm), more preferably 0.685 inches (17.4 mm) without the carrier. Side-loading plate readers, for example, have plate access heights of 16 mm to 28 mm. The indent allows placement of the plates in the carrier with minimal added height (0 to 0.05 inches, i.e., 0 to 1 mm). In one preferred embodiment, the carrier adds less than 0.001 inches (0,025 mm) to the height of the plate.

    [0044] The relative surface areas of fluids in the compartments and the wells are relevant for the impact of the moat on reducing evaporation in the wells. If the surface area of the fluid in the compartments is too small, the reduction of evaporation in the wells may be negligible. If the surface area of the fluid in the compartments is larger than necessary for the desired impact, the multiwell microplate may be less compact than necessary, and may present a challenge in filling the compartments with the same pipettes that are used for filling the wells.

    [0045] Preferred embodiments may provide the surface areas and volumes when fluid is introduced into the wells and compartments indicated in Table 1. Embodiments of the invention include ranges of the preferred values of at least ±25% and greater; preferably the ratios of volumes and surface areas of the wells and compartments are substantially equal to the indicated values, i.e., ±50%. In one preferred embodiment, the difference between the two bottom-up measurements in the compartments for the cell culture and assay conditions is 0.055 inches (0,14 cm). This difference in depth results in the fluid height of all compartments being at a constant depth relative to the top surface of the plate (i.e., 0.180 inches or 0,457 cm). This difference compensates for the equalizer channel.
    Table 1
     Maximum capacityCell cultureAssay
    Depth of fluid in well (from bottom of well) 0 inches 0.200 inches 0.340 inches
    Depth of fluid in well (from top of plate) 0.610 inches 0.410 inches 0.270 inches
    Depth of fluid in inner compartment (from bottom of compartment) 0.40 inches 0.220 inches 0.220 inches
    Depth of fluid in inner compartment (from top of plate) 0 inches 0.180 inches 0.180 inches
    Depth of fluid in end compartment (from bottom of compartment) 0.345 inches 0.165 inches 0.165 inches
    Depth of fluid in end compartment (from top of plate) 0 inches 0.180 inches 0.180 inches
    Surface area of fluid in a well 0.1014 in2 0.0333 in2 0.0825 in2
    Total surface area of fluid in 8 wells 0.8112 in2 0.2664 in2 0.6600 in2
    Surface area in end (shallow) compartment 0.4387 in2 0.4272 in2 0.4272 in2
    Surface area in inner compartment 0.1768 in2 0.1723 in2 0.1723 in2
    Total surface area of compartments 1.5846 in2 1.5436 in2 1.5436 in2
    in2 of compartment surface area per in2 of well surface area 1.9534 5.7942 2.3387
    Ratio of compartment surface area to well surface area ∼2:1 ∼6:1 ∼5:2
    Volume of fluid in well 639 microliters ("µl") 200 µl 200 µl
    Total volume of fluid in 8 wells 5112 µl 1600 µl 1600 µl
    Volume in compartments at each end (shallow), including equalizer channel 2113 µl 800 µl 800 µl
    Volume in inner compartment 926 µl 400 µl 400 µl
    Total volume in compartments 7930 µl 3200 µl 3200 µl
    µl of compartment volume per µl of well volume 1.551 2 2
    Ratio of compartment volume to well volume ∼3:2 2:1 2:1

    Cartridge



    [0046] Referring to Figures 2a and 2b, a cartridge 200 is configured to mate with the multiwell microplate 100. The cartridge 200 has a generally planar surface 205 including a cartridge frame made, e.g., from molded plastic, such as polystyrene, polypropylene, polycarbonate, or other suitable material. Planar surface 205 defines a plurality of regions 210 that correspond to, i.e., register or mate with, a number of the respective openings of a plurality of wells 120 defined in the multiwell microplate 100. Within each of these regions 210, the planar surface defines first, second, third, and fourth ports 230, which serve as test compound reservoirs, and a central aperture 215 to a sleeve 240. Each of the ports is adapted to hold and to release on demand a test fluid to the respective well 120 beneath it. The ports 230 are sized and positioned so that groups of four ports may be positioned over each well 120 and test fluid from any one of the four ports may be delivered to a respective well 120. The number of ports in each region may be less than four or greater than four. The ports 230 and sleeves 240 may be compliantly mounted relative to the multiwell microplate 100 so as to permit them to nest within the microplate by accommodating lateral movement. The construction of the cartridge to include compliant regions permits its manufacture to looser tolerances, and permits the cartridge to be used with slightly differently dimensioned microplates. Compliance can be achieved, for example, by using an elastomeric polymer to form planar element 205, so as to permit relative movement between the frame 200 and the sleeves and ports in each region.

    [0047] Each of the ports 230 may have a cylindrical, conic or cubic shape, open at planar surface 205 at the top and closed at the bottom except for a small hole, i.e., a capillary aperture, typically centered within the bottom surface. The capillary aperture is adapted to retain test fluid in the port, e.g., by surface tension, absent an external force, such as a positive pressure differential force, a negative pressure differential force, or alternatively a centrifugal force. Each port may be fabricated from a polymer material that is impervious to test compounds, or from any other suitable solid material, e.g., aluminum. When configured for use with a multiwell microplate 100, the liquid volume contained by each port may range from 500 µl to as little as 2 µl, although volumes outside this range can be utilized.

    [0048] Referring to Figure 2b, in each region of the cartridge 200, disposed between and associated with one or more ports 230, is the submersible sensor sleeve 240 or barrier, adapted to be disposed in the corresponding well 120. Sensor sleeve 240 may have one or more sensors 250 disposed on a lower surface 255 thereof for insertion into media in a well 120. One example of a sensor for this purpose is a fluorescent indicator, such as an oxygen-quenched fluorophore, embedded in an oxygen permeable substance, such as silicone rubber. The fluorophore has fluorescent properties dependent on the presence and/or concentration of a constituent in the well 120. Other types of known sensors may be used, such as electrochemical sensors, Clark electrodes, etc. Sensor sleeve 240 may define an aperture and an internal volume adapted to receive a sensor.

    [0049] The cartridge 200 may be attached to the sensor sleeve, or may be located proximal to the sleeve without attachment, to allow independent movement. The cartridge 200 may include an array of compound storage and delivery ports assembled into a single unit and associated with a similar array of sensor sleeves.

    [0050] Referring to Figure 3, the cartridge 200 is sized and shaped to mate with multiwell microplate 100. Accordingly, in an embodiment in which the microplate has eight wells, the cartridge has eight sleeves.

    Cover



    [0051] Referring to Figure 4, the apparatus may also feature a removable cover 400 for the cartridge 200 and/or for the multiwell microplate 100. The cover 400 may be configured to fit over the cartridge 200, thereby to reduce possible contamination or evaporation of fluids disposed in the ports 230 of the cartridge. The cover 400 may also be configured to fit directly over the multiwell microplate 100, to help protect the contents of the wells and compartments when the microplate 100 is not in contact or mated with the cartridge 200.

    Carrier tray



    [0052] Referring to Figures 5a and 5b, a multiwell microplate carrier tray 500 allows several, e.g., three or four, single-column multiwell microplates to be placed and measured in an instrument designed for 96 well standard microplates that comply with standard ANSI/SLAS 1-2004. Accordingly, the carrier tray may have outer dimensions of 5.0299 inches ± 0.0098 inches by 3.3654 inches ± 0.0098 inches, i.e., about 5 by 3 inches or about 127 mm x 84 mm. The outer dimensions of the carrier tray may be scaled, depending upon the number of wells in the single-column microplates and the instrument in which measurements may be carried out.

    [0053] The carrier has three regions 510 defining a plurality of openings 520 configured to align and mate with the wells of each multiwell microplate 100. In use, the columns of wells of the multiwell microplates are disposed at positions that correspond to columns 3, 7, and 11 of a 96-well microplate. Since the wells of the disclosed multiwell microplates are located at positions defined by the ANSI/SLAS standard, no modification of the plate readers is required. A collar 530 surrounds the bottom region of each microplate well when installed in the cartridge. Each collar forms a circular opening that provides positioning as well as light blockage. The collar may be colored black to shield crosstalk light from fluorescent signaling molecules in wells, or may be white to amplify emitted light from luminescent markers. The carrier may include slots 540 that correspond to indents on the multiwell microplate. The skirts of two adjacent microplates may fit into each slot. Scalloped edges 550 enable a user to easily remove the microplates as necessary, while providing rigidity to the carrier.

    [0054] The carrier openings allow the microplate to sit in the carrier at the same height as if the plate was not in the carrier, i.e., the height of the plate is equal to the height of the plate and carrier assembly.

    [0055] Cartridges 200 and covers 400 may be placed over the microplates 100, as discussed above. The multiwell microplates and cartridges may generally be used as described in U.S. Patent Nos. 7,276,351 and 8,658,349. Moreover, the individual wells, barriers, and ports may have any of the characteristics and features of the wells, barriers, and ports described in these patents.

    [0056] In use, a liquid analytical sample may be prepared by delivering the analytical sample to a well defined by a frame of a multiwell microplate 100, and delivering a fluid to a moat 130 defined by the frame. The analytical sample may be, for example, cells in a media. The fluid may be the same media, or another liquid, such as water. Both the analytical sample and the fluid may be delivered by a pipettor; in some embodiments, the sample and the fluid may be delivered by the same pipettor.

    Examples


    Example 1



    [0057] Incubator evaporation experiments were run to compare evaporation in covered multiwell microplates with hydration fluid in moats and without such fluid. For each of six plates, 80 microliters of liquid was placed in each well, and for three of those plates, 400 microliters of liquid was placed in each compartment of the moat. Three multiwell microplates with covers but with no liquid in moats ("dry") and three multiwell microplates with covers and with liquid in moats were incubated overnight in a humidified incubator at 37°C in a 10%CO2 atmosphere. The volume of liquid remaining in each well was measured, and the following values determined:
    10% CO2 Incubator Testing
     With MoatWithout Moat
    Average Volume Remaining (microliters) 76.4 74.0
    Average Volume Lost (microliters) 3.6 6.0
    % Lost 4.5% 7.5%

    Example 2



    [0058] Evaporation of liquid from wells in uncovered microwell plates was measured after conducting a mock assay (∼90 minutes) within an extracellular flux analyzer instrument. Referring to Figure 6, the average % of fluid lost in a microwell plate with a filled moat was 3.75%, whereas about 15.8% of fluid was lost in a microwell plate with an empty moat. Evaporation is preferably reduced, as it causes variations in assay data due to changes in temperature as well as the ionic strength of the cell media.

    Example 3



    [0059] Referring to Figure 7, cells disposed in media were observed with hydration fluid in moats and without hydration fluid. Key metabolic parameters of oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were monitored in each well. The well-to-well variability in plates with dry moats (CV 60-95%) was considerably higher than the variability observed for assay wells in plates with filled moats (20-65%). Low well-to-well variability of both the OCR and ECAR signals is required for good assay performance. The OCR measurement is particularly sensitive to temperature variations which can be caused by varying rates of evaporation in assay wells not protect by fluid-filled moats.

    Example 4



    [0060] Referring to Figures 8a - 8d, baseline metabolic rates (OCR and ECAR) of C2C12 cells seeded at equal densities were measured under several conditions to test the effect of the moat being filled or empty. In Figures 8a and 8b, the moat was filled as prescribed (400 µl per compartment) at the time of cell seeding. For plates represented by hashed bars, the moats were emptied prior to performing the assay in the XF instrument. In Figures 8c and 8d, the cells were seeded and incubated overnight without placing fluid in the moats. In C and D plates represented by solid bars had fluid added to the moats prior to running the experiment. Both OCR and ECAR were measured for all plates. To assess the effect of the presence of fluid in the moats at the time of seeding on the OCR measurement, Figure 8a is compared to Figure 8c. Cells seeded in plates with fluid in the moats had OCR values in the range of 80-120, whereas cells seeded in plates with dry moats had OCR values in the range of 0-60. OCR is a measure of the metabolic health of the cells. Low OCR values indicate that the cells were not metabolically active. Similar results are seen when comparing Figures 8b and 8d for the ECAR measurement. When cells are seeded in plates and the moat is not filled, the metabolic rate as measured by ECAR is also very low, indicating poor cell health. Thus, it is shown that the presence of fluid in the moats at the time of cells seeding and overnight incubation is an important requirement for good cell health in the single-column microplate.

    Example 5



    [0061] Referring to Figures 9a and 9b, inter- and intra-well variability of the background OCR signal over time was compared in a plate without fluid in the moat to a plate with fluid in the moat. For each plate tested, media was placed in each well, the plate was allowed to equilibrate in the instrument for 15 minutes, then measurements were made over 30 minutes. In the plate without fluid in the moat, the background OCR signal varied significantly from well to well, ranging from -37 to +5 (range of 42) and rising 10-20 units over the 30 minute period. When the moat was filled, the signal was much more stable with an overall range of -14 to +7 (range of 21) and rising about 7 units over the time period. Thus it is shown that the presence of fluid in the moats is required for stable background levels in this assay.

    [0062] The foregoing embodiments are to be considered in all respects illustrative of the invention described herein. Various features and elements of the different embodiments can be used in different combinations and permutations, as will be apparent to those skilled in the art. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description.


    Claims

    1. A multiwell microplate (100) for holding liquid samples, the multiwell microplate (100) comprising:
    a frame (110) defining

    a plurality of wells (120) disposed in a single column, each well (120) having an opening with a length l1;

    a moat (130) disposed about the plurality of wells (120); and a plurality of walls (140) traversing the moat (130), the walls (140) defining a plurality of compartments (150), each compartment (150) having a length l2 selected from a range of greater than l1 and less than 6l1, wherein two compartments (150) of the moat (130) are disposed on opposing sides of the single column of wells (120).


     
    2. The multiwell microplate (100) of claim 1, wherein the well length l1 is selected from a range of 1 mm to 9 mm.
     
    3. The multiwell microplate (100) of claim 1 or 2, wherein the plurality of wells (120) comprises eight wells, and/or wherein the moat (130) comprises eight compartments (150).
     
    4. The multiwell microplate (100) of any one of claims 1 to 3, wherein two compartments (150) disposed on opposing sides of the single column of wells (120) are in fluidic communication via an equalizer channel (160), wherein a depth of the two compartments (150) in communication via the equalizer channel (160) is preferably less than a depth of compartments (150) adjacent thereto.
     
    5. The multiwell microplate (100) of any one of claims 1 to 4, wherein (a) a depth of at least one compartment (150) is less than a depth of one of the wells (120), wherein the depth of the at least one compartment (150) is preferably up to 50% of the depth of one of the wells; and/or (b) wherein a depth of a compartment (150) proximate an end portion of the frame (110) is less than a depth of a compartment (150) disposed at a center portion of the frame (110).
     
    6. The multiwell microplate (100) of any one of claims 1 to 5, wherein all of the compartments (150) have a substantially equal length.
     
    7. The multiwell microplate (100) of any one of claims 1 to 6, wherein at least one well (120) is opaque white, and/or wherein at least one well (120) is opaque black.
     
    8. The multiwell microplate (100) of any one of claims 1 to 7, the frame (110) further comprising an indent (180) on a lower edge thereof, and/or the multiwell microplate (100) further comprising a lifting tab (170) defined on an end portion of the frame (110).
     
    9. A method for preparing a liquid analytical sample, the method comprising:

    delivering the analytical sample to a well (120) defined by a frame (110) of a multiwall microplate (100); and delivering a fluid to a moat (130) defined by the frame (110),

    wherein (i) the frame (110) defines a plurality of wells (120) disposed in a single column, each well (120) having an opening with a length l1; (ii) the moat (130) is disposed about the plurality of wells (120); and (iii) a plurality of walls (140) traverses the moat (130), the walls (140) defining a plurality of compartments (150), each compartment (150) having a length 12 selected from a range of greater than l1 and less than 6l1, wherein two compartments (150) of the moat (130) are disposed on opposing sides of the single column of wells (120).


     
    10. The method of claim 9, wherein delivering the analytical sample to the well (120) comprises using a pipettor, and/or wherein delivering the fluid to the moat (130) comprises using a pipettor.
     
    11. The method of claim 9 or 10, wherein the multiwell microplate (100) is a multiwall microplate (100) according to any one of claims 2 to 8.
     
    12. The method of any one of claims 9 to 11, wherein the two compartments (150) disposed on opposing sides of the single column of wells (120) are in fluidic communication via an equalizer channel (160).
     


    Ansprüche

    1. Multiwell-Mikroplatte (100) zur Aufnahme von flüssigen Proben, wobei die Multiwell-Mikroplatte (100) umfasst:
    einen Rahmen (110), welcher umgrenzt:

    eine Vielzahl von Vertiefungen (120), die in einer einzigen Säule angeordnet sind, wobei jede Vertiefung (120) eine Öffnung mit einer Länge l1 aufweist,

    eine Ringmulde (130), die um die Vielzahl von Vertiefungen (120) herum angeordnet ist und eine Vielzahl von Wänden (140), welche die Rungmulde (130) durchqueren, wobei die Wände (140) eine Vielzahl von Kammern (150) definieren, wobei jede Kammer (150) eine Länge l2 aufweist, die aus einem Bereich von mehr als l1 und weniger als 6l1 ausgewählt ist, wobei zwei Kammern (150) der Ringmulde (130) auf gegenüberliegenden Seiten der einzelnen Säule von Vertiefungen (120) angeordnet sind.


     
    2. Multiwell-Mikroplatte (100) nach Anspruch 1, wobei die Vertiefungslänge l1 aus einem Bereich von 1 mm bis 9 mm ausgewählt ist.
     
    3. Multiwell-Mikroplatte (100) nach Anspruch 1 oder 2, wobei Vielzahl von Vertiefungen (120) acht Vertiefungen umfasst und/oder wobei die Ringmulde (130) acht Kammern (150) umfasst.
     
    4. Multiwell-Mikroplatte (100) nach einem der Ansprüche 1 bis 3, wobei zwei Kammern (150), die auf gegenüberliegenden Seiten der einzelnen Säule von Vertiefungen (120) angeordnet sind, über einen Ausgleichskanal (160) in Fluidverbindung stehen, wobei eine Tiefe der beiden Kammern (150), die über den Ausgleichskanal (160) in Verbindung stehen, vorzugsweise geringer ist als eine Tiefe der Kammern (150), die daran angrenzen.
     
    5. Multiwell-Mikroplatte (100) nach einem der Ansprüche 1 bis 4, wobei (a) die Tiefe mindestens einer Kammer (150) geringer ist als die Tiefe einer der Vertiefungen (120), wobei die Tiefe der mindestens einen Kammer (150) vorzugsweise bis zu 50 % der Tiefe einer der Vertiefungen beträgt, und/oder (b) wobei die Tiefe einer Kammer (150) in der Nähe eines Endabschnitts des Rahmens (110) geringer ist als die Tiefe einer Kammer (150), die in einem Mittelabschnitt des Rahmens (110) angeordnet ist.
     
    6. Multiwell-Mikroplatte (100) nach einem der Ansprüche 1 bis 5, wobei alle Kammern (150) eine im Wesentlichen gleiche Länge haben.
     
    7. Multiwell-Mikroplatte (100) nach einem der Ansprüche 1 bis 6, wobei mindestens eine Vertiefung (120) opak weiß ist und/oder wobei mindestens eine Vertiefung (120) opak schwarz ist.
     
    8. Multiwell-Mikroplatte (100) nach einem der Ansprüche 1 bis 7, wobei der Rahmen (110) weiterhin eine Einkerbung (180) an einem unteren Rand davon umfasst und/oder die Multiwell-Mikroplatte (100) weiterhin eine Hublasche (170) umfasst, die an einem Endabschnitt des Rahmens (110) abgegrenzt ist.
     
    9. Verfahren zum Herstellen einer flüssigen analytischen Probe, wobei das Verfahren umfasst:

    Zuführen der analytischen Probe zu einer Vertiefung (120), die durch einen Rahmen (110) einer Multiwell-Mikroplatte (100) abgegrenzt ist und Zuführen eines Fluids zu einer Ringmulde (130), die durch den Rahmen (110) abgegrenzt ist,

    wobei (i) der Rahmen (110) eine Vielzahl von Vertiefungen (120), die in einer einzigen Säule angeordnet sind, abgrenzt, wobei jede Vertiefung (120) eine Öffnung mit einer Länge von l1 aufweist, (ii) die Ringmulde (130) um die Vielzahl von Vertiefungen (120) herum angeordnet ist und (iii) eine Vielzahl von Wänden (140) die Ringmulde (130) durchquert, wobei die Wände (140) eine Vielzahl von Kammern (150) definieren, wobei jede Kammer (150) eine Länge l2 aufweist, die aus einem Bereich von mehr als l1 und weniger als 6l1 ausgewählt ist, wobei zwei Kammern (150) der Ringmulde (130) auf gegenüberliegenden Seiten der einzelnen Säule von Vertiefungen (120) angeordnet sind.


     
    10. Verfahren nach Anspruch 9, wobei die Abgabe der analytischen Probe an die Vertiefung (120) die Verwendung einer Pipette umfasst, und/oder wobei die Abgabe de Fluids an den Graben (130) die Verwendung einer Pipette umfasst.
     
    11. Verfahren nach Anspruch 9 oder 10, wobei die Multiwell-Mikroplatte (100) eine Multiwell-Mikroplatte (100) gemäß einem der Ansprüche 2 bis 8 ist.
     
    12. Verfahren nach einem der Ansprüche 9 bis 11, wobei die beiden Kammern (150), die auf gegenüberliegenden Seiten der einzelnen Säule von Vertiefungen (120) angeordnet sind, über einen Ausgleichskanal (160) in Fluidverbindung stehen.
     


    Revendications

    1. Microplaque à alvéoles multiples (100) destinée à retenir des échantillons liquides, la microplaque à alvéoles multiples (100) comprenant :
    un châssis (110) définissant :

    une pluralité d'alvéoles (120) disposées en une colonne unique, chaque alvéole (120) comportant une ouverture de longueur I1,

    une cavité (130) disposée autour de la pluralité d'alvéoles (120), ainsi qu'une pluralité de parois (140) traversant la cavité (130), les parois (140) définissant une pluralité de compartiments (150), chaque compartiment (150) présentant une longueur I2 sélectionnée dans une plage supérieure à I1 et inférieure à 6 I1, où deux compartiments (150) de la cavité (130) sont disposés sur des côtés opposés d'une colonne unique d'alvéoles (120).


     
    2. Microplaque à alvéoles multiples (100) selon la revendication 1, dans laquelle la longueur d'alvéole I1 est sélectionnée dans une plage allant de 1 mm à 9 mm.
     
    3. Microplaque à alvéoles multiples (100) selon la revendication 1 ou la revendication 2, dans laquelle la pluralité d'alvéoles (120) comprend huit alvéoles, et/ou dans laquelle la cavité (130) comprend huit compartiments (150) .
     
    4. Microplaque à alvéoles multiples (100) selon l'une quelconque des revendications 1 à 3, dans laquelle deux compartiments (150) disposés sur des côtés opposés dans la colonne unique d'alvéoles (120) sont en communication par fluide au travers d'un canal d'égalisation (160), la profondeur des deux compartiments (150) en communication au travers du canal d'égalisation (160) est de préférence inférieure à la profondeur des compartiments (150) adjacents à ceux-ci.
     
    5. Microplaque à alvéoles multiples (100) selon l'une quelconque des revendications 1 à 4, dans laquelle (a) la profondeur d'au moins un compartiment (150) est inférieure à la profondeur de l'une des alvéoles (120), la profondeur du ou des compartiments (150) étant de préférence supérieure à 50 % de la profondeur de l'une des alvéoles ; et/ou dans laquelle (b) la profondeur d'un compartiment (150) proche de la partie terminale du châssis (110) est inférieure à la profondeur d'un compartiment (150) disposé au centre du châssis (110).
     
    6. Microplaque à alvéoles multiples (100) selon l'une quelconque des revendications 1 à 5, dans laquelle tous les compartiments (150) présentent une longueur pratiquement égale.
     
    7. Microplaque à alvéoles multiples (100) selon l'une quelconque des revendications 1 à 6, dans laquelle au moins une alvéole (120) est blanche opaque, et/ou dans laquelle au moins une alvéole (120) est noire opaque.
     
    8. Microplaque à alvéoles multiples (100) selon l'une quelconque des revendications 1 à 7, où le châssis (110) comprend en outre une indentation (180) sur son bord inférieur, et/ou la microplaque à alvéoles multiples (100) comprend en outre une patte d'élévation (170) définie sur la partie terminale du châssis (110).
     
    9. Procédé permettant de préparer un échantillon analytique liquide, le procédé comprenant :

    la délivrance de l'échantillon analytique à une alvéole (120) définie par un châssis (110) de microplaque à alvéoles multiples (100), et la délivrance d'un fluide à une cavité (130) définie par le châssis (110),

    dans lequel (i) le châssis (110) définit une pluralité d'alvéoles (120) disposées en une colonne unique, chaque alvéole (120) comportant une ouverture de longueur I1 ; (ii) la cavité (130) étant disposée autour de la pluralité d'alvéoles (120) ; et (iii) une pluralité de parois (140) traversant la cavité (130), les parois (140) définissant une pluralité de compartiments (150), chaque compartiment (150) présentant une longueur I2 sélectionnée dans une plage supérieure à I1 et inférieure à 6 I1, où deux compartiments (150) de la cavité (130) sont disposés sur des côtés opposés d'une colonne unique d'alvéoles (120).


     
    10. Procédé selon la revendication 9, dans lequel la délivrance de l'échantillon analytique à l'alvéole (120) comprend l'utilisation d'un dispositif de pipetage, et/ou dans lequel la délivrance du fluide à la cavité (130) comprend l'utilisation d'un dispositif de pipetage.
     
    11. Procédé selon la revendication 9 ou la revendication 10, dans lequel la microplaque à alvéoles multiples (100) est une microplaque à alvéoles multiples (100) conforme à l'une quelconque des revendications 2 à 8.
     
    12. Procédé selon l'une quelconque des revendications 9 à 11, dans lequel les deux compartiments (150) disposés sur des côtés opposés de la colonne unique d'alvéoles (120) sont en communication par fluide au travers d'un canal d'égalisation (160).
     




    Drawing
























































    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description