Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
  • B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
  • B01L3/508—Containers for the purpose of retaining a material to be analysed, e.g. test tubes rigid containers not provided for above
  • B01L3/5085—Containers for the purpose of retaining a material to be analysed, e.g. test tubes rigid containers not provided for above for multiple samples, e.g. microtitration plates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/40—Removing or ejecting moulded articles
  • B29C45/4005—Ejector constructions; Ejector operating mechanisms
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
  • B01L2300/00—Additional constructional details
  • B01L2300/08—Geometry, shape and general structure
  • B01L2300/0893—Geometry, shape and general structure having a very large number of wells, microfabricated wells
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/40—Removing or ejecting moulded articles
  • B29C2045/4063—Removing or ejecting moulded articles preventing damage to articles caused by the ejector
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/40—Removing or ejecting moulded articles
  • B29C2045/4084—Progressive ejection

Definitions

• multi-well laboratory plates have been manufactured in configurations ranging from 1 well to 96 wells.
• the wells of multi-well plates are typically used as reaction vessels for performing various tests, growing tissue cultures, screening drugs, or performing analytical and diagnostic functions.
• Industry standard multi-well plates are laid out with 96 wells in an 8 x 12 matrix (mutually perpendicular 8 and 12 w.-il rows).
• the height, length and width of the 96-well plates are standardized. This standardization has resulted in the development of a large array of auxiliary equipment specifically developed for 96-well formats.
• the equipment includes devices that load and unload precise volumes of liquid in multiples of 8, 12, or 96 wells at a time.
• equipment is available to transmit light through individual wells and to read colorimetric changes or chemiluminescence in individual wells. Some of this equipment is automated and instrumented to record, analyze and manipulate the data recorded. Recently, as sample sizes have been reduced to microliter levels and the demand for a greater number of tests per plate has increased, the number of wells on a plate have likewise increased, e.g. from 384 wells to 1536 wells and above.
• Further objects of the present invention are: to provide a multi-well plate with 1536 wells with incremental well spacing that is a fractionally based on the well spacing of "he standard 96- well plate; to equip the plate with an additional 16 control wells and 4 calibration wells; to provide a plate capable of being sealed with heat sensitive or pressure sensitive film for controlling evaporation or long term storage; to provide a multi-well plate having wells with opaque side walls and transparent bottoms; to provide a two piece assembly multi-well plate that provides advantages in storage and ease of use; and to provide a method for producing the multi-well plate of the present invention.
• the present invention relates to an improved multi-well assay plate.
• the plate has a matrix of 1536 wells, arranged in 48 columns and 32 rows.
• the plate is made of a thermoplastic material that is capable of being molded by injection molding.
• the dimensions of the plate conform to industry standards for a 96-well plate and the plate footprint is substantially identical to that of the 96-well plate.
• the plate additionally has 16 control wells and 4 calibration wells located on the periphery of the plate.
• the plate can be produced as a one piece molded assembly, or as a well matrix plate and frame comprising a two piece interlocking assembly.
• FIG. 1 is a plan view of the multi-well plate of the present invention.
• FIG. 2 is a fractional cross-sectional view of two consecutive wells of the present invention.
• FIG. 3 is a plan view of a well matrix insert of one embodiment of the present invention.
• FIG. 4 is a plan view of the support frame of one embodiment of the present invention.
• FIG. 5 is a cross-section view of a side wall of the frame of FIG. 4 taken along the section line 5-5 in FIG. 4.
• FIG. 6 is a side view of the support frame.
• FIG. 7 is a fractional cross-sectional view of a mold and ejection pins used in the molding process of the present invention.
• FIG. 1 Shown in FIG. 1 is a one-piece multi-well test plate 10 of the present invention.
• the plate includes a peripheral skirt 12, a grid system 14, and an upper surface 16 having 1536 sample wells 18, 16 control wells 20, and 4 calibration wells 22.
• the sample wells 18 are preferably arranged in 48 columns spaced a 'proximately 0.089 inches apart, measured from the center line of one column to the center line of the next consecutive column.
• Each column contains 32 wells. Sample wells in each column are likewise preferably spaced approximately 0.089 inches apart, measuring from the center of one well to the center of the next well in the column.
• a grid line 14 After every fourth column and every fourth well in each column is a grid line 14.
• the grid lines are preferably grooves recessed from the surface of the plate and, when taken as a whole, divide the plate into 96 grids, each containing 16 sample wells. The grid system helps in identifying individual wells and locations that otherwise would be difficult to discern.
• the plate 10 preferably has a chamfered corner 13 which provides clear demarcation of the orientation of the plate.
• control wells 20 Prior to the first column of sample wells and after the last column of sample wells are columns of control wells 20 having 8 wells each.
• the first control well is preferably displaced evenly between the second and third well of the nearest column of wells and approximately 0.089 inches away from the center line of the nearest column.
• the other seven consecutive control wells are preferably each displaced approximately 0.356 inches apart from the previous control well and approximately 0.089 inches away from the center line of the column.
• a known amount of a known substance is retained in the control well.
• the control is used for analytical comparison to unknowns retained in the sample wells 18.
• a calibration well 22 is located at each end of the first and last columns.
• the calibration wells are preferably displaced approximately 0.089 inches from the next well in the column and are situated directly on the center line of the column.
• calibration wells may retain a substance that is to be used in the calibration of certain analytical instrumentation. They can also be used for attaining proper alignment for particular assays.
• the matrix of 1556 total wells (1536 sample wells 18, 16 control wells 20, and 4 calibration wells 22) and surrounding area of plate surface is preferably raised approximately 0.010 inches from the surrounding skirt surface 12. This allows for coordinate lettering to be placed on the periphery or skirt 12 of the plate, while still maintaining a flat surface around the wells.
• a flat surface is important when sealing the wells with a pressure sensitive or heat sensitive film. Such sealing allows for control of evaporation and/or long term storage of compounds.
• the one-piece multi-well plate 10 of the present invention has a hole 24 and slot 26 provided at opposite ends of the plate.
• the hole 24 and slot ' are alignment features that allow the plate 10 to be positioned precisely on an analytical instrument or fluid dispenser, for example. Detents (not shown) may also be used to align the plate with a piece of instrumentation.
• Alignment pins attached to auxiliary equipment, may be used to hold the plate in place.
• a pin placed through the hole accurately locates the plate, while a pin through the slot maintains parallelism while forgiving any length tolerance issues.
• the slot is critical because it allows for some dimensional flexibility in the finished part.
• the hole and slot features also aid in fluid transfer between first and second, substantially identical, plates.
• the slot 26 and hole 24 align one plate with an inverted twin plate.
• a second plate can be inverts ! and placed upon the first plate such that the slot from the first plate aligns with the hole from the second plate on one end, and the slot from the second plate aligns with the hole from the first plate on the opposite end. Any liquid sample contained in the inverted plate will remain in the wells due to surface tension.
• a pin can then be inserted through the aligned slot and hole on both ends of the plate, essentially locking them together.
• the upper surfaces of the two plates contact and individual wells align such that, upon centrifugation, liquid in individual wells of one plate can be transferred to individual wells of a second plate.
• the fluid transfer can be accomplished by using a standard 96-well centrifuge device having two vertical pins, corresponding to the hole 24 and slot 26 of the multi-well plate, and loading a first plate and an inverted second plate onto the pins.
• the plates are clamped in place using a spring clip on two or more sides and centrifuged.
• Another interlocking embodiment (not shown) has an alignment pin situated on the surface of a first plate, capable of engaging a corresponding hole from a substantially identical and inverted second plate such that a pin from the first plate engages the hole from a second plate and the pin from the second plate engages the hole from the first plate.
• FIG. 2 shows a cross-sectional view of two consecutive sample wells 18 of the present invention.
• the wells are cylindrical recesses in the surface 16 of the plate 10.
• Each well has side walls 28 and a bottom wall 30.
• the diameter of the wells at the surface of the plate is preferably approximately 0.059 inches.
• the diameter of the wells at the bottom of the well is preferably approximately 0.047 inches.
• Each well 18 is preferably approximately 0.060 inches deep, but may be deeper in order to position the sample therein closer to a detector located beneath the plate. Positioning the sample closer to the detector has the advantage of enhancing testing accuracy and minimizing crosstalk between adjacent wells.
• the plate 10 is preferably made of a plastic such as polystyrene or polypropylene.
• the wells 18 preferably have opaque side walls 28 and a transparent bottom 30. The opaque side walls minimize crosstalk between wells.
• the clear bottom of each well allows colorimetric, fluorescent, or chemiluminescent testing to be performed from beneath the wells by standardized equipment.
• Well bottoms are preferably flat in order to enhance optical testing therethrough, but may be rounded, planted or pointed.
• FIGS. 3 and 4 are individual parts of a two piece construction that is an embodiment of the present invention.
• FIG. 3 shows a matrix well insert 32 that is used in conjunction with the frame 34 of FIG. 4 in forming a multi-well plate.
• the well matrix insert 32 preferably contains the same number of sample wells 18, control wells 20, and calibration wells 22 as the one piece construction of FIG. 1. Further, the spacing between wells is substantially identical to the spacing previously described for the one piece construction.
• a slot 26 and hole 24 are located on opposing sides of the insert in order to provide proper positioning on auxiliary equipment and to accommodate an inverted twin plate lor purposes of liquid transfer between plates as described previously.
• FIGS. 4-6 show a frame 34 capable of receiving the well matrix insert 32.
• the frame 34 is of a rectangular construction with four side walls 36 and is open through the center 38.
• the outer dimensions of the frame are approximately identxcal to the outer surface dimensions of an industry standard 96-well plate.
• At least one of the side walls 36 has an opening or insertion region 33 through which the well matrix insert 32 can be inserted.
• the well matrix insert 32 slides through the frame 34 on tracks 35 in the side walls 36 until opposing detents in the form of depressions 40 located on the top surface of the well matrix insert and dimples (not shown) on the lower portion of the upper track on the frame 34, lock the insert and frame together.
• the frame 34 and well matrix insert 32 a- ' - further locked together by slots 42 in the well matrix insert and corresponding fitted extensions 44 on the frame.
• the insert 32 may also be tracked into the frame 34 in an inverted position. By inverting the insert in the frame, and subsequently inverting the entire assembly onto an optical reader, the well bottoms can be positioned closer to an optical reader.
• a chamfered corner 46 in the well matrix insert 32 allows for physical and visual orientation of the insert and the frame.
• the resultant assay plate conforms to the industry standard and can be used with auxiliary equipment, including robots, designed for use with a standard 96-well plate.
• the two piece construction embodiment of the present invention allows the well matrix insert to be removed from the frame and stored separately. Removing the well matrix insert reduces use of storage space by 60-80% over a one piece assembly or the interlocked two piece assembly.
• Another embodiment comprises a two piece unit having an invertible well matrix insert and frame.
• the frame is constructed such that the well matrix insert can be attached to a lower surface of the frame.
• the wells in the matrix insert retain the liquid samples through surface tension.
• the inverted plate can then be aligned with optical sensors in the compatible instrumentation.
• the optical sensors that normally operate from below a multi-well plate and read color, fluorescence, or luminescence through optically transparent plastic of the well bottoms, can, in this embodiment, test the contents of each well through the well openings.
• an assembled two piece matrix plate or a one piece multi-well plate of the current invention can be inverted and placed on an optical sensing device. Surface tension will contain any sample fluid held in any well .
• the injection molding method for forming the ulti- well plate of the present invention involves a two stage ejection process.
• a plate having a plurality of wells comprising the well matrix previously disclosed, and as shown in FIG. 1, is injection molded.
• the surface of the mold 48 comprises a plurality of male well sections 50 that, when surrounded by injected plastic, create wells in the plastic. It is critical that the walls of the male well sections 50 have an inward slope of at least 3 degrees in order to ensure a molded plastic part 52 can be released from the mold.
• the mold itself has, within it, a series of knockout pins 54,56. A portion of the wells are formed on the end of a first set of knock-out pins 54.
• Such pins are preferably large enough to encompass a well or wells and m?_ come tangent to the next well edge, but do not include any part of the adjacent well. This provides for a knock out large enough to lift the molded plastic part 52 off the adjacent well molds without causing a bad steel condition in the mold, such as feather edges.
• a second set of knock out pins 56 are located on the periphery of the plate and do not contact the wells at all. After molding, the first and second set of knock out pins 54 are extended, in order to lift the molded plastic part 52 off the core of the mold 48.
• the second set of knock out pins 56 located on the periphery of the mold are further ext ⁇ ided in order to lift the molded plastic part 52 off the first set of pins 54.
• This molding technique can be used for producing either the one piece multi-well plate or the well matrix insert.
• the frame used in the two piece construction multi-well plate is molded by conventional injection molding techniques .

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• Health & Medical Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Clinical Laboratory Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Manufacturing & Machinery (AREA)
• Analytical Chemistry (AREA)
• General Health & Medical Sciences (AREA)
• Hematology (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Automatic Analysis And Handling Materials Therefor (AREA)
• Optical Measuring Cells (AREA)
• Sampling And Sample Adjustment (AREA)
• Investigating Or Analysing Biological Materials (AREA)
• Apparatus Associated With Microorganisms And Enzymes (AREA)
• Devices For Use In Laboratory Experiments (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1998
  • 1998-01-08 AU AU59594/98A patent/AU5959498A/en not_active Abandoned
  • 1998-01-08 WO PCT/US1998/000494 patent/WO1998031466A1/en not_active Application Discontinuation
  • 1998-01-08 CN CN 98801803 patent/CN1244140A/zh active Pending
  • 1998-01-08 EP EP98902786A patent/EP1017498A4/de not_active Withdrawn
  • 1998-01-08 JP JP53445498A patent/JP2001509272A/ja active Pending

Patent Citations (2)

Non-Patent Citations (1)

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