FIELD OF THE INVENTION [0002] This invention pertains to multiple well devices, and methods of using the devices.

BACKGROUND OF THE INVENTION [0003] Multiple well plates are used in a variety of protocols, particularly cell culturing, microtitration and/or microfiltration protocols. Typically, the plates have a standard number of wells, e. g. , 96 wells, or 384 wells (arranged in four blocks of 96 wells each), and in some plates the wells include a filter arranged therein such that application of a vacuum or air pressure to one side of the plate causes the fluid in each well to pass through the filter and from the well.

[0004] It has been found that fluid can drip from the wells over time and/or drops of fluid can drip from the underside of a multiple well plate after filtration. This can lead to cross contamination and/or create a biohazard as the drops migrate when the wells are handled, e. g. , during an automated or manual handling protocol. Tapping the plates to remove the handing drops is labor intensive, and, for those protocols wherein a portion of fluid is to remain in the well for a period of time (e. g. , in some cell culturing applications), the tapping can cause fluid flow to start again.

[0005] The present invention provides for ameliorating at least some of the disadvantages of the prior art. These and other advantages of the present invention will be apparent from the description as set forth below.

BRIEF SUMMARY OF THE INVENTION [0006] In an embodiment of the invention, a multiple well device comprises a plurality of wells for receiving fluid to be processed, each well having an upper end and a lower end; each lower end comprising a bottom wall and a fluid flow port; and, a valve in fluid communication with each fluid flow port, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the port and the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0007] A multiple well device according to another embodiment of the invention comprises a plurality of wells for receiving fluid to be processed, each well having an upper end and a lower end; each lower end comprising a bottom wall and a valve, the valve comprising an elastomeric material and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0008] In accordance with another embodiment of the present invention, a multiple well device is provided, comprising a plurality of wells for receiving fluid to be processed, each well having an upper end and a lower end; each lower end comprising a bottom wall; and a valve disposed in the well, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0009] In accordance with an embodiment of the invention, a method for processing fluid in a multiple well device comprises passing a plurality of fluid samples into separate wells for receiving the fluid samples; each well of the multiple well device having an upper end and a lower end, each lower end comprising a bottom wall and a valve, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the port and the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position; applying sufficient pressure to open the valve and flow at least a portion of fluid from the well and through the valve; and removing the applied pressure to sealingly close the valve and prevent further. fluid flow through the valve.

[0010] Another embodiment for processing fluid in a multiple well device comprises passing a plurality of fluid samples into separate wells for receiving the fluid samples; each well of the multiple well device having an upper end and a lower end, each lower end comprising a bottom wall; and a valve disposed in the well; the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position; applying sufficient pressure to open the valve and flow at least a portion of fluid from the well and through the valve; and removing the applied pressure to sealingly close the valve and prevent further fluid flow through the valve.

[0011] A method for processing fluid in a multiple well device according to another embodiment of the invention comprises passing a plurality of fluid samples into separate wells for receiving the fluid samples; each well of the multiple well device having an upper end and a lower end, each lower end comprising a bottom wall and a fluid flow port; the multiple well device further comprising a valve in fluid communication with each fluid flow port, the valve comprising an elastomeric material, the valve including a sealing portion movable between an open position permitting fluid flow through the port and the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position; applying sufficient pressure to open the valve and flow at least a portion of fluid from the well and through the valve; and removing the applied pressure to sealingly close the valve and prevent further fluid flow through the valve.

BRIEF DESCRIPTION OF THE DRAWINGS [0012] Figure 1 is a bottom plan view of a multiple well device including a valve communicating each well according to an embodiment of the present invention.

[0013] Figure 2 is a side view of a multiple well device including a conduit associated with each well and valves pressed on to some of the conduits according to another embodiment of the invention.

[0014] Figure 3 is a perspective view of an illustrative duckbill valve suitable for use in accordance with an embodiment of the invention.

[0015] Figures 4a and 4b show cross-sectional views of an illustrative duckbill valve.

[0016] Figure 5 is a perspective view of the tip of a duckbill valve according to an embodiment of the invention.

[0017] Figure 6 shows an embodiment of a valve array suitable for use in accordance with the invention.

[0018] Figure 7 shows another embodiment of a valve array suitable for use in accordance with the invention.

[0019] Figure 8 shows perspective and cross-sectional views of another illustrative duckbill valve suitable for use in accordance with an embodiment of the invention, wherein the valve includes a collar.

(0020] Figures 9a and 9b show cross-sectional views of the duckbill valve illustrated in Figure 8.

[0021] Figure 10 is a side view of a multiple well device and valves pressed on to a plate including wells according to another embodiment of the invention.

[0022] Figures 1 la and 1 lb show embodiments of diaphragm valves suitable for use in accordance with the invention.

[0023] Figure 12 shows a cross-sectional exploded view of a well including a filter, wherein the well communicates with a valve in accordance with an embodiment of the invention.

[0024] Figure 13 shows cross-sectional exploded and partially assembled views of wells including filters, wherein the wells each communicate with a valve in accordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION [0025] In accordance with an embodiment of a multiple well device according to the invention, the device comprises a plurality of wells for receiving fluid to be processed, each well having an upper end and a lower end; each lower end comprising a bottom wall and a fluid flow port; and, a valve in fluid communication with each fluid flow port, the valve comprising an elastomeric material, the valve including a sealing portion movable between an open position permitting fluid flow through the port and the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position. In accordance with embodiments of the invention, the valve can be disposed upstream of the fluid flow port or downstream of the fluid flow port.

[0026] In accordance with another embodiment of the present invention, the multiple well device comprises a plurality of wells for receiving fluid to be processed, each well having an upper end and a lower end; each lower end comprising a bottom wall and a valve, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0027] In accordance with another embodiment of the present invention, a multiple well device comprises a plurality of wells for receiving fluid to be processed, each well having an upper end and a lower end; each lower end comprising a bottom wall; and a valve disposed in the well, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0028] In yet another embodiment, a well device comprises a well for receiving fluid to be processed, the well having an upper end and a lower end; the lower end comprising a bottom wall and a fluid flow port; and, a valve in fluid communication with the fluid flow port, the valve comprising an elastomeric material, the valve including a sealing portion movable between an open position permitting fluid flow through the port and the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0029] A well device according to another embodiment of the invention comprises a well for receiving fluid to be processed, the well having an upper end and a lower end; the lower end comprising a bottom wall and a valve, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position.

[0030] In preferred embodiments of well devices, more preferably, multiple well devices, the valve comprises a duckbill valve. In some embodiments, the duckbill valve includes two opposing walls, each wall having a tip and a slit between the tips, wherein the valve further comprises a collar spaced from the slit, more preferably, spaced from the walls. Alternatively, or additionally, in some embodiments, the duckbill valve has two opposing walls, each wall having a tip, wherein each tip includes at least one indentation.

[0031] In more preferred embodiments of multiple well devices according to the invention, the devices include a filter comprising at least one filter element, and in some embodiments, each well includes, sealed therein, the filter comprising at least one filter element.

[0032] In accordance with another embodiment, a method for processing fluid in a multiple well device comprises passing a plurality of fluid samples into separate wells for receiving the fluid samples; each well of the multiple well device having an upper end and a lower end, each lower end comprising a bottom wall and a valve, the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position; applying sufficient pressure to open the valve and flow at least a portion of fluid from the well and through the valve; and removing the applied pressure to sealingly close the valve and prevent further fluid flow through the valve.

[0033] Another embodiment for processing fluid in a multiple well device comprises passing a plurality of fluid samples into separate wells for receiving the fluid samples; each well of the multiple well device having an upper end and a lower end, each lower end comprising a bottom wall; and a valve disposed in the well; the valve comprising an elastomeric material, and including a sealing portion movable between an open position permitting fluid flow through the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position; applying sufficient pressure to open the valve and flow at least a portion of fluid from the well and through the valve; and removing the applied pressure to sealingly close the valve and prevent further fluid flow through the valve.

[0034] In accordance with another embodiment of a method for processing fluid in a multiple well device, the method comprises passing a plurality of fluid samples into separate wells for receiving the fluid samples; each well of the multiple well device having an upper end and a lower end, each lower end comprising a bottom wall and a fluid flow port; the multiple well device further comprising a valve in fluid communication with each fluid flow port, the valve comprising an elastomeric material, the valve including a sealing portion movable between an open position permitting fluid flow through the port and the valve, and a closed position preventing fluid flow through the valve, wherein the sealing portion is resiliently biased toward its closed position; applying sufficient pressure to open the valve and flow at least a portion fluid from the well and through the valve; and removing the applied pressure to sealingly close the valve and prevent further fluid flow through the valve.

[0035] In yet another embodiment, a duckbill valve is provided, comprising a tubular body having a first end, a second end, and a collar; the second end having first and second opposing oblique walls, each oblique wall having an end contacting the end of the opposing oblique wall when the duckbill valve is in a closed position; a slit between the contacting ends of the opposing oblique walls and a collar spaced from the slit, wherein the slit is opened and allows fluid flow therethrough when the duckbill valve is in the open position; the duckbill valve comprising an elasteromeric material and being resiliently biased in the closed position and preventing fluid flow therethrough when in the closed position. In a more preferred embodiment, the collar is disposed laterally to the oblique walls.

[0036] A duckbill valve according to another embodiment of the invention comprises a tubular body having a first end and a second end; the second end having first and second opposing oblique walls, each oblique wall having an end contacting the end of the opposing oblique wall when the duckbill valve is in a closed position, wherein the contacting ends of the first and second opposing oblique walls each have a tip having at least one indentation; a slit between the contacting ends of the opposing oblique walls, wherein the slit is opened and allows fluid flow therethrough when the duckbill valve is in the open position; the duckbill valve comprising an elasteromeric material and being resiliently biased in the closed position and preventing fluid flow therethrough when in the closed position. In some embodiments, each tip of the duckbill valve includes at least two depressions.

Alternatively, or additionally, in some embodiments, the duckbill valve further comprises a collar, e. g. , spaced from the opposing oblique walls.

[0037] In accordance with the invention, at least one of preventing the formation of hanging drops, minimizing dripping of hanging drops, and preventing dripping under static pressure, is especially desirable as it can reduce the potential for cross-contamination with other multiple well devices and reduce the potential for undesirable migration of fluids (that can be biohazards) when the devices are handled and/or when the devices contain fluid for various periods of time (e. g. , one or more days) before further handling. Fluid processing in accordance with the invention can be carried out with multiple well devices without requiring tapping the devices, which can be labor-and/or time-intensive. Of course, tapping can be carried out if desired, e. g. , if an automated handling protocol includes tapping, the protocol can still be utilized without modification. Preventing the formation of hanging drops, minimizing dripping of hanging drops and/or preventing dripping under static pressure can provide at least some of the following advantages: allowing handling to be carried out without requiring a drip tray; maintaining consistent well volumes; eliminating the risk of contamination associated with replacing lost fluid in the wells; reducing operator time since there is no need to replace lost fluid; and reducing experimental variation, e. g., due to different volumes of fluid and/or refilling.

[0038] A variety of valves are suitable for use in accordance with the invention. In accordance with typical embodiments of the invention, the valve comprises a normally closed valve that allows forward flow and prevents or minimizes backflow. Typically, a normally closed comprises an elastomeric material providing a sealing element that, upon applied stress (e. g. , pressure), opens and allows forward flow, and, upon the release of the stress, returns or rebounds to the original closed position. Exemplary valves (including one-way valves) comprising elastomeric material include duckbill valves, e. g. , including<BR> elastomeric lips in the shape of a duckbill; diaphragm valves, e. g. , a diaphragm including<BR> slits providing two or more elastomeric flaps; and umbrella valves, e. g. , including an elastomeric diaphragm-shaped sealing disk or umbrella shape, typically wherein the sealing disk has a preloaded convex shape to create the sealing force against the port, or valve seat.

[00391 In accordance with the valved devices of the invention, when pressure (negative or positive) is applied to the well device as is known in the art, the valve opens, allowing fluid flow from the well through the valve. When the pressure is removed or released, the <BR> <BR> valve returns to a sealingly closed position, without hanging drips forming, e. g. , on the tip and/or the bottom surface of the valve, or, if drips form, they remain associated with the valve without falling or dripping therefrom.

[0040] Embodiments of the invention can be used with a variety of fluids, including those with low surface tensions. The cracking pressure of the valves can be controlled precisely, and thus, the wells and devices will not drip or weep over time under static pressure. The cracking pressure can be selected based upon, for example, the processing protocol and fluid (s) used. Typically, the cracking pressure is in the range of at least about 2 inches of water to about 28 inches of water (about 0.15 to about 2 inches of mercury; about 0.07 to about 1 psi; about 0.5 kPa to about 7 kPa), more typically, in the range of from about 4 to about 20 inches of water (about 0.29 to about 1.46 inches of mercury; about 0.15 to about 0.72 psi; about 1 to about 5 kPa), preferably, in the range of from about 9 to about 17 inches of water (about 0.66 to about 1.25 inches of mercury; about 0.33 to about 0.63 psi; about 2.3 to about 4.2 kPa).

[0041] The valves can be associated with well devicesand/or multiple well devices in accordance with a variety of techniques and arrangements. For example, separate valves <BR> <BR> can be attached (e. g. , pressed on) individually to the individual tips of the wells and/or to<BR> conduits communicating with the wells (e. g. , as illustrated in Figure 2 showing individual<BR> valves 100) and/or separate valves can be attached to the plates, e. g. , via flanges on the<BR> plates. Alternatively, an array of valves (e. g. , a valve array 200 wherein two or more valves 100 are connected as a strip or layer, as shown in, for example, Figures 1,6 (showing 3 arrays), 7 and 10) can be attached to, for example, at least one of the plate, the tips of the wells, and the conduits communicating with the wells. In some embodiments, for example, an injection molded well plate can be overmolded with the valves (e. g. , the plates can be overmolded with the valve array 200 shown in Figure 6). In yet another embodiment, for example, wherein the valve comprises a diaphragm valve (e. g. , valve 100 as shown in Figures 1 la and 1 lb), preferably including slits providing at least two elastomeric flaps (in one embodiment wherein x-shaped slits provide four elastomeric flaps), the bottom wall of the well can include the valve, or the valve can be disposed in the well. For example, a disc comprising the valve can be inserted in the well, wherein the side wall of the disc frictionally and sealingly contacts the inner surface of the side wall of the well.

[0042] In some embodiments wherein the valve comprises a duckbill valve, the multiple well device (e. g. , a multiple well plate) includes, associated with each well, and communicating with the port and bottom end of each well, conduits extending from the bottom surface of the device (e. g. , conduits 150 communicating with valves 100 as shown in Figure 2), preferably wherein the inside diameter of the tubular body of the duckbill valve is smaller than the outside diameter of the conduit. Such an arrangement is especially desirable for providing a fluid tight seal between the outside surface of the conduit and the inside surface of the valve.

[0043] Figures 3-5 illustrate some embodiments of duckbill valves 100, comprising a hollow tubular body 50, having one end 1 (and an optional flange 10 at the end 1), and a tapered construction with two oblique walls or flaps Sa, Sb at the other end 2. A slit 25 is present between the ends or lips of the oblique walls, that are biased in the closed position to prevent fluid flow through the slit. When pressure (negative or positive) is applied to the appropriate side of the well device, the ends of the walls separate, opening the slit and allowing fluid flow from the well, through the port, and through the valve. When the pressure is removed, the slit is closed, stopping liquid flow without hanging drops forming on the end of the valve or on the bottom surface of the valve.

[0044] In the embodiment shown in Figure 5, the tips of the ends of the walls of the valve include one or more indentions 75 such as grooves, slots, serrations, recesses or cut-outs that do not penetrate all the way through the tips or walls. The indentations can be any desired shape, e. g. , with straight and/or rounded sides or walls. Without being bound to any particular mechanism, it is believed these configurations allow air to enter the indentions, further minimizing the ability of a drop to form and hang on the tip.

[0045] Figures 8-10 illustrate another embodiment of a duckbill valve 100, comprising a hollow tubular body 50, having one end 1 (and an optional flange 10 at the end 1), and a tapered construction with two oblique walls or flaps Sa, Sb at the other end 2, a slit 25 present between the ends or lips of the oblique walls, and a band or collar 30 spaced from the slit, preferably spaced from the oblique walls. The oblique walls are biased in the closed position to prevent fluid flow through the slit. When pressure (negative or positive) is applied to the appropriate side of the well device, the ends of the walls separate, opening the slit and allowing fluid flow from the well, through the port, and through the valve.

When the pressure is removed, the slit is closed, stopping liquid flow. Without being bound to any particular mechanism, it is believed including a collar spaced from the slit further minimizes the ability of a drop to fall from the valve, e. g. , by providing an increase in surface area allowing the liquid to remain associated with the valve without falling. <BR> <BR> <P>[0046] In a preferred embodiment, e. g. , as illustrated in Figures 8,9a and 9b, the collar 30 is disposed laterally to the oblique walls, and extends in the direction of fluid flow beyond the lips of the valve, and the lips of the walls are disposed toward the center of the open area of the collar. The illustrated collar is annular, although other shapes and configurations are also suitable.

[0047] Figures 11 a and l lb show illustrative embodiments of a diaphragm valve 100 including two slits 25 crossing to form an x-shaped configuration between flaps 6a, 6b, 6c and 6d, that are biased in the closed position. As noted above, in accordance with embodiments of the invention, the bottom wall of the well can comprise a diaphragm valve, or a diaphragm valve can be can be inserted into the well. When pressure (negative or positive) is applied to the appropriate side of the multiple well device, the flaps move, opening the slits and allowing fluid flow through the valve. When the pressure is removed, the flaps return to their original position, closing the slits, and stopping liquid flow without hanging drops forming on the bottom surface of the valve.

[0048] A variety of materials compatible with the fluids and/or reagents in the wells are suitable for use in valves according to the invention. If desired, the multiple well device is chemically resistant, and can be used with harsh solvents and/or harsh chemicals. <BR> <BR> <P>Accordingly, in some embodiments, e. g. , wherein solvents such as, for example,<BR> trifluoroacetic acid (TFA) and/or acetonitrile (ACN) are utilized in the wells (e. g. , in protein precipitation), elastomeric materials such as ethylene propylene diene (EPDM, including, but not limited to, injection moldable grades of EPDM, e. g., SANTAPRENETM) rubber <BR> <BR> and/or fluorocarbon rubber, e. g. , ASTM D1418 designation FKM (FPM in Europe), such as VITON8, FLUORELS, TECHNOFLONS, and DAI-ELQ3), are especially suitable.

[0049] Other suitable materials for some applications include, for example (with ASTM D1418 abbreviations listed in parentheses), ethylene propylene (EPM), nitrile (NBR), hydrogenated nitrile (HNBR), fluorosilicone (FVMQ), silicone (VMG, MQ, PVMQ), butyl (IIR), polyisoprene (IR, NR), epichlorohydrin (CO, ECO), chloroprene (CR), polyurethane (AU, EU), styrene-butadiene (SBR), and polyacrylate acrylic (ACM, AEM, ANM).

[0050] In accordance with embodiments of the invention, duckbill valves can be produced with a collar and/or depressions in the tips. Also in accordance with embodiments of the invention, inserts comprising diaphragm valves can be produced. However, in other embodiments, e. g. , without a duckbill valve or utilizing a duckbill valve without a collar and/or without depressions in the tips, a variety of valves are suitable for use in accordance with the invention, including, but not limited to, those commercially available from, for example, Vemay Laboratories, Inc. (Yellow Springs, OH), MiniValve International (Yellow Springs, OH), and A. C. Hoffinan Engineering, Inc. (Riverside, CA).

[0051] In accordance with embodiments of the invention, the valves can be used with a wide variety of individual well and multiple well devices, including commercially available multiple well devices, particularly multiple well plates or trays. Multiple well devices can include wells connected together in the form of, for example, a strip, disc, or tray. Multiple <BR> <BR> well devices can include integrally formed wells (e. g. , formed by injection or blow<BR> molding), or the wells can be formed from a plurality of components, e. g. , an upper plate, tray or insert defining the upper portion of the wells, and a bottom plate, tray or insert defining at least the bottom wall of the wells.

[0052] In accordance with any of these embodiments, the valves can be placed in fluid communication with the lower ends of the wells, wherein the valves are attached to, for example, the tips of the wells and/or the inserts, the conduits communicating with the wells, and/or the plates. In some embodiments, the bottom walls of the wells comprise the valves, or the valves are disposed in the wells, e. g., the valves are inserted into the wells adjacent the bottom walls of the wells.

[0053] The multiple well devices can have any suitable configuration. For example, in some embodiments, e. g. , as shown in Figures 1, 2, 10, and 12, a single plate 101 provides the upper end and a lower end of each well (Figure 2 shows a partial cut away of illustrative wells; Figure 12 shows a cross-sectional view of an illustrative well in more detail), wherein each lower end comprises a bottom wall and a fluid flow port, and each fluid flow port communicates with a valve.

[0054] Alternatively, for example, a multiple well comprises at least one plate or tray defining at least a part of the upper portion of the wells or at least a part of the lower portion of the wells, and a plurality of separate components (for example, inserts) defining at least a <BR> <BR> part of another portion of the well (e. g. , a part of the lower portion wherein the plate or tray defines at least a part of the upper portion of the wells). In accordance with other configurations of multiple well devices, the device comprises at least a top plate and a bottom plate. For example, the device can comprise an upper plate or tray defining the upper portion of the wells, and a bottom plate or tray defining at least the bottom wall of the wells.

[0055] If desired, particularly in some embodiments wherein a filter is arranged in each well, the device can include a rib arrangement, e. g. , wherein bottom wall of each well further comprises a rib arrangement projecting upwardly from the bottom wall.

Alternatively, or additionally, in some embodiments, the device can include a drainage grid <BR> <BR> arrangement, e. g. , projecting upwardly from the bottom wall (illustrative embodiments of a rib arrangement and a drainage grid arrangement are described below with respect to Figure 12).

[0056] In some embodiments wherein an insert such as a disc comprising the valve <BR> <BR> (e. g. , a diaphragm valve including one or more slits) is disposed within the well adjacent to the bottom wall of the well, the disc and/or bottom wall of the well can further comprise a rib arrangement and/or a drainage grid arrangement (wherein a rib arrangement and/or a drainage grid arrangement projects upwardly from the bottom wall of the well and/or projects downwardly from the inserted disc). For example, the disc and/or bottom wall of the well can comprise a rib arrangement and/or drainage grid arrangement to allow space for the elastomeric flaps of the diaphragm valve to move downwardly to open the valve, allowing fluid to flow through the valve and then through the port in the bottom wall of the well. The disc can also comprise a rib arrangement and/or drainage grid arrangement projecting upwardly to contact the bottom surface of the filter, preferably, to support the filter during filtration.

[0057] Alternatively, in another embodiment, an insert such as a disc comprising the valve (e. g. , a diaphragm valve including one or more slits) is disposed within the well wherein a filter is interposed between disc and the bottom wall of the well. Illustratively, in a fluid processing embodiment including protein precipitation, protein can be precipitated before contacting the filter. In some embodiments, the disc can comprise a rib arrangement and/or drainage grid arrangement facing downwardly toward the upstream surface of the filter to allow space for the elastomeric flaps of the diaphragm valve to move downwardly to open the valve, allowing fluid to flow through the valve and then through the filter.

[0058) In yet another embodiment, wherein the bottom wall of the well comprises a diaphragm valve, the bottom wall can further comprise a rib arrangement and/or drainage grid arrangement, e. g. , projecting upwardly from the bottom wall.

[0059] In typical embodiments of multiple well devices, the plates and/or separate components are snap-fit or press-fit together. In some embodiments, the plates and/or separate components are snap-fit or press-fit together and subsequently additionally bonded, e. g. , via welding (such as ultrasonic welding), adhesives and/or solvents.

[0060] The present invention is useful in a variety of applications including microtitration, microchromatography, radiography, microfiltration, ultrafiltration, nanofiltration, washing processes, polymerase chain reaction (PCR) analysis, high throughput, especially high throughput screening (HTS), combinatorial chemistry, nucleic acid and protein processing (including synthesis, sequencing, separation and/or purification) and microculture of cell suspensions and tissues. The invention can be used in any suitable setting, including, but not limited to, hospitals and laboratories. Embodiments of the invention are suitable for a variety of protocols, including sample preparation, clinical diagnostic assays, and screening specimens, e. g. , drugs in pharmaceutical research. If<BR> desired, materials (e. g. , ligands, nucleic acids) can be bound to solid phase particles such as beads and collected in the wells, and the materials can be cleaved from the particles such that the materials are collected in the filtrate. In some embodiments, the cleaved materials (e. g. , ligands and synthesized nucleic acids) can be further processed (e. g. , screened) using<BR> another well, e. g. , the filtrate can be passed into one or more multiple well devices.

Alternatively, or additionally, the invention can be compatible with other subsequent processes including, but not limited to, at least one of dot blotting, immunoblotting, receptor binding assays, ELISA, and RIA.

[0061] The wells and multiple well devices according to the invention can have any suitable overall dimension and capacity, although preferred embodiments have substantially the same overall dimension and capacity of standard wells and devices. Such embodiments are preferred as being more easily utilized with devices and instruments, such as liquid handling systems and readers, that are commonly available for use with conventional wells and devices. In those applications wherein a signal is generated, e. g. , in the course of a<BR> microtitration assay, the signal can be read by any suitable means, e. g. , by visual analysis, or the detection of a fluorometric, spectrophotometric, radiometric, or chemiluminescent signal.

[0062] Typically, each well is suitable for receiving at least about 200 microliters (fol), more typically, at least about 350 AL, of fluid to be processed. In some embodiments, each well is suitable for receiving at least about 800, aL of fluid, or at least about 1 mL, or at least about 2 mL of fluid, or more.

[0063] In a preferred embodiment, the multiple well device includes a filter, more preferably, wherein individual filters are disposed in each well. However, in other embodiments, the multiple device can include a single filter, e. g. , wherein the filter is placed between components that are snap-fit or press-fit together, for example, to allow separate portions of the filter to be utilized in the separate wells.

[0064] In those embodiments wherein filters are disposed in the wells, a variety of arrangements are suitable for sealing the filters in the wells. For example, the filters can be sealed in the well via welding, adhesives and/or solvents. In some embodiments, the multiple well device includes sealing rings to seal the filters (via compression) in each well, including, for example, the multiple well devices with sealing rings as described in International Application No. PCT/US02/16686, filed on May 29,2002, and published as Publication No. WO 02/09653.

[0065] Figure 12 shows a partial cross-sectional exploded view of an illustrative multiple well device including a well 60, having an upper end 12 and a lower end 13, a filter 20 to be sealed in the well via a sealing ring 40 pressing against the upper surface of the filter (the sealing ring also pressing against the inner surface of the side wall 18 of the well), and a valve 100 in fluid communication with the well via a fluid flow port 7. In this illustrated embodiment, the lower end 13 of the well comprises a bottom wall 4 and a fluid flow port 7, and an optional rib arrangement 15 projecting upwardly from the bottom wall, wherein the raised portion has a top surface 16 (that is preferably a non-planar surface, e. g., a rounded surface) disposed to contact the lower surface of the filter 20.

[0066] In the embodiment illustrated in Figure 12, the lower end 13 further comprises an optional drainage grid comprising plurality of drainage grid spacers projecting upwardly from the bottom wall, with drainage channels between the grid spacers (and a drainage grid wall forming the bottom of the drainage channels), wherein the drainage channels communicate with fluid flow port 7, and the fluid flow port communicates with the valve 100. The drainage grid can have a variety of configurations so long as the filter can be supported and sufficient space is allowed for the passage of filtrate.

[0067] As noted above, in some embodiments, wherein the valve comprises a <BR> <BR> diaphragm valve (e. g. , valve 100 as shown in Figures 1 la and 1 lb), the bottom wall of the well can include the valve (for example, the bottom wall includes elastomeric flaps), or the valve can be inserted in the well. In accordance with such embodiments the bottom wall and/or inserted valve can comprise a rib arrangement and/or a drainage grid arrangement.

In accordance with the embodiment of a diaphragm valve illustrated in Figure 1 lb, the valve includes a drainage grid arrangement. As noted above, the inserted valve can include a drainage grid arrangement facing upwardly to contact the bottom surface of the filter and/or can include a drainage grid arrangement facing downwardly to provide space for the elastomeric lips to open.

[0068] In some embodiments of multiple well devices according to the invention including filters and sealing rings, the device comprises at least one plate or tray defining at least a part of the upper portion of the wells or at least a part of the lower portion of the wells (and the plate or tray can comprise the sealing ring); a plurality of separate <BR> <BR> components (e. g. , inserts) defining at least a part of another portion of the well (e. g. , a part of the lower portion wherein the plate or tray defines at least a part of the upper portion of the wells; and the separate insert can further comprise a sealing ring), and a filter compressed by the sealing ring. For example, Figure 13 illustrates cross-sectional exploded and assembled views an embodiment of a multiple well device comprising a plate 101 defining the upper portion of the wells, and separate inserts 102 defining the lower portion of the wells, wherein the inserts also comprise sealing rings (each sealing ring compressing against one surface of the filter 20), and wherein valves 100 attached to the inserts 102 communicate with each well. Figure 13 also illustrates a downwardly facing rib arrangement 15, extending from the side wall of the well, and compressing against the other surface of the filter 20.

[0069] In other embodiments of multiple well devices, the device comprises at least a top plate and a bottom plate, and a filter. For example, the device can comprise an upper plate or tray defining the upper portion of the wells and/or a sealing ring, a bottom plate or tray defining at least the bottom wall of the wells, and a filter between the sealing ring and the bottom wall.

[0070] The multiple well devices are suitable for use with a variety of other components such as a chamber, plenum, manifold, manifold cover, or the like, e. g., for applying pressure or vacuum to the wells. The multiple well devices are also suitable for use with a variety of other components such as a tray and/or receiving plate (e. g. , having a plurality of chambers with a chamber associated with each well) for collecting filtrate. Accordingly, some embodiments of the multiple well devices further comprise, for example, a manifold cover and/or a receiving plate.

[0071) A variety of materials are suitable for producing inserts, chambers, plates, and sealing rings according to the invention. Illustrative materials include, for example, polyvinyl chloride with or without copolymers, polyethylenes, polystyrenes, polystyrene-acrylonitrile, polypropylene, polyvinylidine chloride, and the like.

[0072] Embodiments of the invention are especially suitable for removing particulates from a fluid, e. g. , to provide a filtered sample for analysis, for example, by high pressure liquid chromatography (HPLC), gas chromatography (GC), mass spectrometry (MS), infra red (IR), nuclear magnetic resonance (NMR), and solid-phase extraction.

[0073] Accordingly, a variety of filters and filter elements (as used herein, the terms "filter"and"filter element"refer to porous media used in these various applications) are suitable for use in the invention, and those skilled in the art will recognize that the choice of filter (s) and filter element (s) will depend on the intended use of the well. The filter can comprise a depth filter and/or a sieve filter. The filter can include fibrous and/or membrane filter elements. The filter element can be, for example, a nanofiltration element, an ultrafiltration element, or a microfiltration element. The filter can include additional elements and/or components such as, for example, at least one of a drainage, cushion, and prefilter layer. Typical filter elements include membranes, especially polymeric membranes. For some applications, the filter elements are chemically resistant, and can be used with harsh solvents and/or harsh chemicals. In some embodiments, the filter comprises a plurality of filter elements, and the elements can have, if desired, different characteristics, e. g. , at least one of pore size, chemistry (for example, at least one of critical wetting surface tension, surface charge, polarity, hydrophilicity, and attached functional groups), and can include different reagents and assay components.

[0074] Filters and filter elements of suitable shape for use in the invention are typically stamped or otherwise cut out of sheets of suitable material (s), e. g. , membrane sheets.

[0075] A filter element such as a porous membrane or a fibrous element can have any suitable pore structure such as a pore size, or a pore rating or a pore diameter. Thus, e. g. , a filter element comprising a membrane typically has an average pore size of about 100, um or less, preferably from about 0. 01 um to about 100, um. In some embodiments, the membrane has an average pore size of about 0.1 Am or less, or from about 0.1 Am to about 10, um.

Preferably, the membrane has an average pore size of about 5 Am or less.

[0076] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0077] The use of the terms"a"and"an"and"the"and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e. g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0078] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations of those preferred embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.