Patent Application
20050163637
Pursuant to 37 C.F.R. § 1.71(e), Applicants note that a portion of this disclosure contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
The invention generally provides material conveying systems and related methods for accurately conveying selected quantities of material to and/or from material sites.
Rotary peristaltic pumps are utilized to convey material in a wide variety of applications including in the production of pharmaceuticals, chemicals, foods, and beverages. In a typical rotary peristaltic pump system, a series of rollers or shoes are rotated in a circular path into contact with one or more material conduits, e.g., flexible tubes or hoses, such that the conduits are compressed against a compression surface, such as a curved wall. This generates moving regions of compression along a length of the conduit, which pull material in the conduit that is upstream from the moving regions and pushes material in the conduit that is downstream from the moving regions to effect conveyance of the material through the conduit. One advantage of peristaltic pumps is the ability to convey material through conduits in the absence of contact between internal pump components and the material being conveyed. For example, this tends to reduce the risk of contaminating the conveyed material.
Periodic variations in the quantity of material conveyed by a rotary peristaltic pump are typically observed and can lead to inaccurately conveyed quantities of material, especially when multiple uniform quantities are sought to be conveyed. More specifically, there is generally a substantially linear relationship between angular displacement and the quantity of material conveyed during a displacement cycle when the lead roller (i.e., the roller whose contact with a material conduit is furthest advanced in a particular displacement cycle) applies constant pressure on the material conduit. However, this relationship tends to become non-linear as the lead roller undergoes a disengagement event during which the pressure applied by the lead roller on the material conduit decreases to zero. This produces a repeatable aberration or periodic variation in the function relating displaced quantity of material with angular displacement of the pump, which when unaccounted for can lead to inaccurately dispensed quantities of material.
Accordingly, it is apparent that systems that account for periodic variations in the quantities of material conveyed by rotary peristaltic pumps are desirable. These and a variety of additional features of the present invention will become evident upon complete review of the following disclosure.
The invention generally relates to material conveying systems and methods that reliably convey selected quantities of material using peristaltic pumps, including microliter volumes of fluidic material. The approaches to reproducibly conveying desired quantities of material described herein readily account for periodic variations that are commonly observed in quantities of material conveyed with peristaltic pumps, and are typically less complex to implement than many pre-existing conveyance techniques. According to certain embodiments, for example, the systems of the invention are configured to effect substantially identical roller disengagement events for each quantity of material conveyed to minimize roller disengagement as a source of variation among conveyed quantities. In certain embodiments, the systems and methods of the invention further provide for the synchronous and accurate conveyance of multiple quantities of material to achieve elevated levels of throughput. Embodiments of the invention also include methods to minimize the carryover of material between material sites, such as between wells disposed in a multi-well container, to reduce, e.g., the risk of cross-contaminating those sites or conveying inaccurate amounts of material. The invention also provides related computer program products that can be used to implement the methods and systems described herein.
In one aspect, the invention provides a material conveying system. The system includes at least one peristaltic pump having a rotatable roller support that supports at least two rollers (e.g., fixed rollers, rotatable rollers, or combinations thereof), and at least one motor that is operably connected to the peristaltic pump to rotate the roller support. The system also includes at least one controller that is operably connected to the motor. The controller is configured to effect rotation of at least the roller support in at least one rotational increment that substantially corresponds to an integral multiple of an angular distance disposed between adjacent rollers supported by the roller support such that when one or more material conduits are operably connected to the peristaltic pump and the peristaltic pump conveys material through the material conduits, quantities of material that correspond to the rotational increment are conveyed to or from at least one material site (e.g., a material container, a substrate surface, etc.). Identical rotational increments generally convey substantially uniform quantities of material to or from the material site. Moreover, the rotational increment is typically uncompensated for flow rate characteristics of the system. In some embodiments, the system further includes at least one material conduit that is operably connected to the peristaltic pump. Typically, the controller is configured to effect substantially identical roller disengagements from the material conduit for each conveyed quantity of material to minimize periodic variation among the conveyed quantities of material. Optionally, the system also includes at least one detector operably connected to the controller. The detector is configured to detect detectable signals produced at one or more material sites.
In certain embodiments, the system further includes at least one positioning component that is operably connected to the controller. The positioning component is structured to moveably position at least one material conduit and/or one or more material sites relative to one another. The positioning component typically comprises at least one object holder that is structured to support the material sites. In some embodiments, the system further includes the material conduit operably connected to the positioning component and to the peristaltic pump. Optionally, the system further includes at least one cleaning component operably connected to the controller. The cleaning component is structured to clean the material conduit when the material conduit is operably connected at least to the positioning component, and the positioning component moves the material conduit at least proximal to the cleaning component. In certain embodiments, the system further includes at least one mounting component that mounts at least the peristaltic pump, the motor, and the positioning component relative to one another.
In another aspect, the invention provides a material conveying system that includes at least one material conduit and at least one peristaltic pump that is operably connected to the material conduit. The peristaltic pump includes a rotatable roller support that supports at least two rollers. The material conveying system is typically automated. The system also includes at least one feedback component that is operably connected to the peristaltic pump. The feedback component comprises at least one motor that rotates the roller support. In addition, the system also includes at least one controller that is operably connected to the feedback component, which controller is configured to effect rotation of at least the roller support in at least one rotational increment that substantially corresponds to an integral multiple of an angular distance disposed between adjacent rollers supported by the roller support such that quantities of material conveyed through the material conduit to or from at least one material site correspond to the rotational increment. The rotational increment generally corresponds to at least a 0.1 μl material volume. Further, identical rotational increments generally convey substantially uniform material volumes to or from the material site. Typically, the rotational increment is uncompensated for flow rate characteristics of the system. In some embodiments, the material conveying system further comprises at least one detector operably connected to the controller. The detector is configured to detect detectable signals produced at one or more material sites.
The peristaltic pumps that are included in the material conveying systems of the invention include various embodiments. In some embodiments, for example, the peristaltic pump comprises a multi-channel peristaltic pump. Typically, the peristaltic pump is configured to reversibly convey the quantities of material to or from the material site. In addition, the peristaltic pump typically generates sufficient material flow rates at least proximal to a terminus of the material conduit to effect non-contact material dispensing from the terminus. Further, the roller support typically supports, e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 30, or more rollers. The moment of inertia of the roller support is generally minimized to prevent a quantity of material from adhering to an external portion of the material conduit when the peristaltic pump conveys material through the material conduit. Moreover, angular distances disposed between pairs of adjacent rollers supported by the roller support are typically substantially equal to one another. For example, adjacent rollers supported by the roller support are generally disposed at most 180° apart from one another. In some embodiments, the roller support is interchangeable with at least one other roller support. In embodiments where the rollers are rotatable, the peristaltic pump optionally includes a gear mechanism that effects rotation of the rotatable rollers when the motor rotates the roller support, e.g., to minimize material conduit wear.
In some embodiments, the feedback component comprises at least one drive mechanism that is operably connected to the motor. The drive mechanism typically includes at least one control component that effects position feedback control of the motor. The motor generally includes at least one position encoder and at least one gear reduction component. For example, the motor typically comprises a servo motor or a stepper motor. In certain embodiments, the feedback component further comprises one or more weight scales that are operably connected to the controller. The weight scales detect weights of materials disposed at one or more material sites.
The controller is generally configured to effect substantially identical roller disengagements from the material conduit for each conveyed quantity of material to minimize periodic variation among the conveyed quantities of material. In embodiments where the rollers are rotatable, the controller is optionally further configured to effect rotation of at least one of the rollers supported by the roller support. In these embodiments, the rollers typically rotate in a direction that is opposite from a direction of rotation of the roller support to minimize material conduit wear. For example, the rollers and the roller support typically rotate at velocities that have substantially equal absolute values. In certain embodiments, the controller effects at least one negative pressure pulse at least proximal to a terminus of the material conduit after effecting rotation of the roller support in the rotational increment to prevent a quantity of material from adhering to an external portion of the material conduit. The moment of inertia of the roller support is generally minimized to further prevent the quantity of material from adhering to the external portion of the material conduit.
The material conduits included in the systems of the invention also include various embodiments. In some embodiments, for example, a cavity disposed through the material conduit includes a cross-sectional dimension of between 1 mm and 105 μm. Typically, the material conveying system comprises a plurality of material conduits in which termini of at least two of the material conduits are spaced at a distance from one another to simultaneously communicate with different wells disposed in at least one multi-well container. In some embodiments, the material conveying system comprises a plurality of material conduits in which two or more of the material conduits communicate with different material sources.
In some embodiments, at least one terminus of the material conduit comprises at least one tip. In these embodiments, the tip is optionally integral with the terminus. In certain embodiments, a cavity disposed through the tip comprises at least two different cross-sectional dimensions. Typically, at least a portion of the tip is tapered. In some embodiments, at least a portion of the material conduit proximal to the terminus is substantially linear. The substantially linear portion of the material conduit comprises a length of at least 60 mm. In some embodiments, the terminus of the material conduit and the tip are connected by an insert, e.g., such that the conduit and tip communicate with one another. In some of these embodiments, portions of the insert are inserted into portions of the terminus and the tip, whereas in other embodiments, portions of the terminus and the tip are inserted into portions of the insert. The insert is generally fabricated from a less flexible material than at least the material conduit.
In certain embodiments, the material conveying system further includes at least one positioning component that is operably connected to the controller. The positioning component is generally structured to moveably position the material conduit and/or the material site relative to one another. For example, the positioning component optionally includes at least one object holder that is structured to support the material site. In addition, the controller is typically configured to simultaneously effect rotation of the roller support and moveably position the material conduit and/or the material site relative to one another such that the quantities of material are conveyed to or from the material site synchronous with the relative movement of the material conduit and/or the material site.
In some embodiments, the positioning component comprises at least one X/Y-axis linear motion table operably connected to at least one position feedback control drive that controls movement of the X/Y-axis linear motion table along an X-axis and a Y-axis. Typically, the positioning component comprises at least one object holder operably connected to the X/Y-axis linear motion table, which object holder is structured to support the material site. In certain embodiments, the positioning component includes at least one Z-axis linear motion component comprising at least one material conduit support head that supports at least a portion of the material conduit and that moves along a Z-axis. The Z-axis linear motion component generally comprises at least one solenoid. The positioning component is typically configured to move the material conduit support head with sufficient velocity to eject adherent material that adheres to an external portion of the material conduit.
In certain embodiments, the material conveying system further includes at least one cleaning component operably connected to the controller, which cleaning component is structured to clean the material conduit when the positioning component moves the material conduit at least proximal to the cleaning component. In some of these embodiments, for example, the cleaning component comprises a vacuum chamber comprising at least one orifice into or proximal to which the positioning component moves the material conduit such that an applied vacuum removes adherent material from an external surface of the material conduit. An outer cross-sectional dimension of the material conduit is typically smaller than a cross-sectional dimension of the orifice.
In some embodiments, the material conveying system further includes at least one mounting component that mounts at least the peristaltic pump, the feedback component, and the positioning component relative to one another. The mounting component is typically substantially rigid.
In another aspect, the invention provides a computer program product comprising a computer readable medium having one or more logic instructions for receiving one or more input parameters selected from the group consisting of: (i) a rotational increment that substantially corresponds to an integral multiple of an angular distance disposed between adjacent rollers supported by a roller support of a peristaltic pump; (ii) a cross-sectional dimension of a material conduit; (iii) a quantity of material to be conveyed to or from a material site; and (iv) an angular distance disposed between adjacent rollers supported by a roller support of a peristaltic pump. The computer program product also includes one or more logic instructions for rotating a roller support of a peristaltic pump in rotational increments that substantially correspond to integral multiples of an angular distance disposed between adjacent rollers supported by the roller support of the peristaltic pump such that when one or more material conduits are operably connected to the peristaltic pump and the peristaltic pump conveys material through the material conduits, quantities of material that correspond to the rotational increments are conveyed to or from at least one material site. In certain embodiments, the computer program product further includes at least one logic instruction for moving an X/Y-axis linear motion table and a Z-axis motion component synchronous with rotating the roller support.
In another aspect, the invention relates to a method of conveying material. The method includes providing a material conveying system comprising at least one controller that is operably connected to at least one motor that is operably connected to at least one peristaltic pump. The peristaltic pump comprises a rotatable roller support that supports at least two rollers and is operably connected to at least one material conduit. The system is typically automated. The method also includes conveying the material (e.g., a cell suspension, a reagent, a buffer, a solid support suspension, etc.) through the material conduit in which the controller effects rotation of the roller support in at least one rotational increment that substantially corresponds to an integral multiple of an angular distance disposed between adjacent rollers supported by the roller support such that quantities of material conveyed to or from at least one material site correspond to the rotational increment. The controller typically effects rotation of the roller support such that shearing effects on material (e.g., cells or the like) conveyed in the material are minimized. Typically, the material is conveyed to the material site without the material conduit contacting the material site. The quantities of material generally comprise at least 0.1 μl of the material. In some embodiments, the system further comprises at least one feedback component that is operably connected to the motor, which feedback component effects position feedback control of the peristaltic pump. The controller generally effects substantially identical roller disengagements from the material conduit for each conveyed quantity of material to minimize periodic variation among the conveyed quantities of material. The rotational increment is generally uncompensated for flow rate characteristics of the system. Identical rotational increments typically convey substantially uniform quantities of material to or from the material site. In certain embodiments, the method further includes effecting at least one negative pressure pulse at least proximal to a terminus of the material conduit with the controller after effecting rotation of the roller support in the rotational increment to prevent a quantity of material from adhering to an external portion of the material conduit.
In some embodiments, the system further comprises at least one positioning component that is operably connected to the controller, which positioning component is structured to moveably position the material conduit and/or the material site relative to one another. The positioning component typically moves the material conduit with sufficient velocity to eject adherent material, if any, that adheres to an external portion of the material conduit. Typically, the method includes moving the material conduit with sufficient velocity to eject adherent material, if any, that adheres to an external portion of the material conduit. In some embodiments, the positioning component moves the material conduit such that adherent material, if any, that adheres to an external portion of the material conduit contacts at least one other object to remove the adherent material from the external portion of the material conduit. For example, the other object optionally comprises a portion of a well of a multi-well container.
In certain embodiments, the material site comprises at least one multi-well container and the method comprises conveying at least a first quantity of material into at least a first well of the multi-well container, moving the material conduit and/or the material site relative to one another, e.g., with the positioning component such that the material conduit is in communication with at least a second well of the multi-well container, and conveying at least a second quantity of material into the second well of the multi-well container. The moving step and at least one conveying step are typically substantially simultaneous with one another. Typically, the moving step comprises positioning a portion of the material conduit above or in the second well.
In some embodiments, the system includes a plurality of material conduits that are operably connected to the peristaltic pump and the method comprises conveying multiple quantities of material to or from the material site through the material conduits. In these embodiments, two or more of the material conduits generally materially communicate with different material sources. Typically, the multiple quantities of material are conveyed substantially simultaneously. In some embodiments, the material site comprises at least one multi-well container and termini of at least two of the material conduits are spaced at a distance that corresponds to a distance between at least two wells disposed in the multi-well container. In these embodiments, the method generally comprises simultaneously conveying the material through the two material conduits to or from the two wells. The material site generally comprises at least one material container and/or at least one substrate surface. The material container typically comprises a multi-well material container having, e.g., 6, 12, 24, 48, 96, 192, 384, 768, 1536, or more wells. The substrate surface optionally comprises a membrane surface.
In another aspect, the invention provides a method of conveying material to a material site. The method includes providing a material conveying system comprising at least one material conduit, and at least one pump that is operably connected to the material conduit, which pump conveys the material through the material conduit. The material conveying system also includes at least one positioning component that is operably connected to the material conduit, which positioning component moves the material conduit. In addition, the material conveying system also includes at least one controller that is operably connected to the pump and the positioning component. The controller effects the pump to convey the material through the material conduit and the positioning component to move the material conduit. The method also includes conveying the material (e.g., fluidic material, etc.) through the material conduit such that a quantity of the material adheres to a terminal portion of the material conduit, thereby forming an adherent material quantity. In addition, the method also includes accelerating at least the terminal portion of the material conduit towards the material site with the positioning component, and decelerating the terminal portion of the material conduit with the positioning component such that the adherent material quantity is conveyed from the terminal portion of the material conduit to the material site. The material site generally comprises at least one well of a multi-well container. The decelerating step typically comprises ejecting the adherent material quantity from the terminal portion of the material conduit. Typically, the adherent material quantity is conveyed to the material site without contacting the terminal portion of the material conduit and the material site. In some embodiments, the material comprises a cell suspension and the method minimizes shearing effects on conveyed cells.
FIGS. 2A-C schematically illustrate various exemplary angular distances.
FIGS. 16A-D schematically illustrate various material conduit tips according to certain embodiments of the invention.
I. Definitions
Before describing the present invention in detail, it is to be understood that this invention is not limited to particular systems or methods, which naturally can vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. Further, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In describing and claiming the present invention, the following terminology and grammatical variants will be used in accordance with the definitions set out below.
The term “material” refers to matter in essentially any physical state. For example, material can be in the form of gases, liquids, semi-liquids, pastes, powders, and combinations thereof. To further illustrate, material comprises cell and/or reagent suspensions in certain embodiments of the invention.
The term “angular distance” or “angular displacement” refers to an angle that a rotating body rotates through. In some embodiments of the present invention, for example, a rotatable roller support of a peristaltic pump rotates in rotational increments that substantially correspond to integral multiples of angular distances disposed between adjacent rollers supported by the roller support.
The term “moment of inertia” refers to a measure of the resistance of a body to angular acceleration about a given axis that is equal to the sum of the products of each element of mass in the body and the square of the element's distance from the axis.
The term “reversibly convey” refers to a process of conveying material in which the material or portions thereof are capable of being, e.g., removed from a material site after being dispensed at the site, dispensed at one material site after being removed from another material site, and/or the like. In certain embodiments of the invention, for example, fluidic materials are aspirated from material sites (e.g., wells of a micro-well plate or other fluidic material source) and dispensed at other sites (e.g., wells of a micro-well plate, surfaces of substrates, fluidic material waste containers, etc.). Reversible material conveyance is typically effected by rotating the peristaltic pump roller support in a direction that is opposite from the direction the roller support is rotated to convey the material to the particular material site from which the material is removed.
The term “non-contact material dispensing” refers to a process of material dispensing in which material conduits of a material conveying system do not contact material sites or material disposed at material sites when the material is dispensed from the conduits.
The term “feedback component” refers to a component of a system that provides information about one or more other components of the system. In certain embodiments, for example, the material conveying systems of the invention include feedback components comprising motors that rotate roller supports of peristaltic pumps. In these embodiments, the feedback components generally provide, e.g., information relating to roller support position to controllers to which the feedback components are typically operably connected such that the controllers can effect rotation of the roller supports in selected rotational increments. In some embodiments, feedback components provide information such as the weight of material present at a particular material site. Additional details relating to these types of feedback components, which are optionally adapted for use in the material conveying systems of the invention, are described further in, e.g., U.S. patent application Ser. No. 10/350,905, entitled “FLUID HANDLING METHODS AND SYSTEMS,” filed Jan. 24, 2003 by Micklash II et al., which is incorporated by reference.
The term “rotational increment” refers to an angular displacement of a roller support. For example, controllers of the systems of the invention are typically configured to effect rotation of roller supports in rotational increments that substantially correspond to integral multiples of angular distances disposed between adjacent rollers supported by the roller supports, e.g., such that substantially identical roller disengagements are effected for each quantity of material conveyed. In certain embodiments, for example, a user directly selects the rotational increment in which a roller support rotates, whereas in other embodiments, a system controller is configured to select an appropriate rotational increment, e.g., based upon an input quantity of material that a user desires to be conveyed.
The term “roller disengagement” or “disengagement event” refers to a process in which a roller of a roller support is removed from contact with a material conduit during operation of a peristaltic pump. The disengagement event typically corresponds to a change in pressure applied by the roller undergoing the disengagement from approximately a maximum to substantially zero.
The phrase “integral multiple of an angular distance disposed between adjacent rollers” refers to the product of the angular distance disposed between adjacent rollers supported by a roller support of a peristaltic pump by an integer, that is, any of the natural numbers, the negatives of these numbers, or zero. The controllers of the systems described herein are typically configured to effect rotation of roller supports in rotational increments that substantially correspond to integral multiples of angular distances disposed between adjacent rollers supported by the roller supports. To illustrate, if a roller support includes three rollers disposed 120° apart from one another and the selected integer is +2, then the rotational increment of the roller support will be 240°, whereas if the selected integer is +4 for the same roller support, then the rotational increment of the roller support will be 480°, and so forth. Positive and negative signs before the selected integer generally refer to the relative direction of rotation of the roller support, e.g., forward or reverse.
A material conduit “communicates” with a material site when material can be translocated to and/or from the material site through the conduit, e.g., under an applied pressure a peristaltic pump.
The term “periodic variation” refers to a recurrent change in output or other characteristic of a given device or system. To illustrate, there is typically a periodic variation in the quantity of material conveyed by a rotary peristaltic pump, e.g., when a roller disengages from a material conduit during a displacement cycle. More specifically, there is generally a substantially linear relationship between angular displacement and the quantity of material conveyed during a displacement cycle when the lead roller (i.e., the roller whose contact with a material conduit is furthest advanced in a particular displacement cycle) applies constant pressure on the material conduit. However, this relationship tends to become non-linear as the lead roller undergoes a disengagement event during which the pressure applied by the lead roller on the material conduit decreases to zero. This produces a repeatable aberration or periodic variation in the function relating displaced quantity of material with angular displacement of the pump.
The term “top” refers to the highest point, level, surface, or part of a device or system, or device or system component, when oriented for typical designed or intended operational use, such as conveying material from a source to a destination. In contrast, the term “bottom” refers to the lowest point, level, surface, or part of a device or system, or device or system component, when oriented for typical designed or intended operational use.
II. Introduction
While the present invention will be described with reference to a few specific embodiments, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications can be made to the embodiments of the invention described herein by those skilled in the art without departing from the true scope of the invention as defined by the appended claims. For example, although the conveyance of relatively small quantities or volumes of material (e.g., on the scale of milliliters, microliters, etc.) is emphasized herein primarily for clarity of illustration, it will be appreciated that the systems and methods of the invention can be adapted to accurately convey essentially any quantity of material. It is also noted here that for a better understanding, certain like components are designated by like reference letters and/or numerals throughout the various figures.
The systems and methods of conveying materials of the present invention generally include rotating peristaltic pumps with precisely regulated accelerations, velocities, and decelerations to effect accurate angular displacements. Moreover, the systems and methods described herein typically account for periodic variations produced, e.g., by roller disengagement events such that accurate and repeatable conveyance of material is achieved using rotary peristaltic pumps. In certain embodiments, for example, material conveying systems are configured such that substantially identical roller disengagement events occur for each conveyed quantity of material, thereby minimizing roller disengagement as a source of variation among conveyed quantities of material.
To illustrate, there is generally a substantially linear relationship between angular displacement of a pump roller support and the quantity (e.g., volume) of material conveyed when the lead pump roller begins and ends a displacement cycle applying constant pressure to a material conduit. Further, as the lead roller begins to disengage from the material conduit, e.g., while another roller begins to engage the conduit (e.g., tubing or the like), there is typically a period where the conveyed quantity becomes at least partially negative as a function of angular displacement as at least some material in the conduit is sucked backwards to fill the gap left by the lead roller coming out of contact with the conduit. This is further illustrated in
Accordingly, aspects of the invention disclosed herein relate to systems and methodologies that readily account for this periodic variation such that selected quantities of material (e.g., fluidic material, etc.) are accurately conveyed using rotary peristaltic pumps. In certain embodiments, for example, the invention provides a control system configured to convey quantities of material (e.g., fluid volumes) that correspond to an angular pump rotation or rotational increment that is equal to an integral multiple of the angular distance disposed between adjacent rollers. Various exemplary angular distances are schematically illustrated in FIGS. 2A-C. More specifically,
θ=S/r
where S is the distance along the circumference of the circular path disposed between the axes of rotation of adjacent rollers 202 (i.e., the arc length subtended by the angle θ) and r is the distance from the axis of rotation of roller support 200 to the axis of rotation of roller 202. In this manner, the methods and systems described herein ensure that the same roller disengagement events occur for each dispense/aspiration, thereby eliminating the roller disengagement as a source of variation in dispense/aspiration quantities between dispenses/aspirations.
To further illustrate aspects of the invention,
Material conduits 308 are disposed between the compression surfaces and rollers of peristaltic pump 302. In addition, one set of termini of material conduits 308 communicate with the same or different material sources (not within view), while the other set of termini are operably connected to material conduit support head 310 via tips 311. Material conduit support head 310 is attached to arm 318 via Z-axis linear motion component 312 (e.g., a compact, high speed, short travel Z-axis motion component or system). Arm 318 suspends material conduit support head 310 above object holder 314. A motor (not shown), such as a solenoid motor or the like, is typically operably connected to Z-axis linear motion component 312 to effect Z-axis translation of material conduit support head 310 relative to material sites (e.g., multi-well plates, membranes, etc.) disposed on object holder 314. Object holder 314 is operably connected to X/Y-axis linear motion tables 320, which move object holder 314 relative to material conduit support head 310 along the X- and Y-axes. X/Y-axis linear motion tables 320 are also mounted on mounting component 304. One or more motors (e.g., solenoid motors, etc.) are generally operably connected to the material conveying systems of the invention to effect motion of object holders on X/Y-axis linear motion tables. For example, solenoid motor 316 effects motion of object holder 314 in material conveying system 300. Although not within view in
III. Peristaltic Pumps
Among the advantages of the systems and methods described herein is that identical rotational increments convey substantially (i.e., approximately or exactly) uniform quantities of material (e.g., material volumes, etc.) to or from the material site. Moreover, rotational increments are typically uncompensated for flow rate characteristics of the particular system utilized unlike certain pre-existing systems, such as the apparatus alleged in, e.g., U.S. Pat. No. 6,393,338, entitled “APPARATUS AND CONTROL METHOD FOR ACCURATE ROTARY PERISTALTIC PUMP FILLING,” issued May 12, 2002 to Kemnitz, which is incorporated by reference. Accordingly, the systems and methods of the present invention are typically easier or less complex to implement than many of these pre-existing methods and systems.
Essentially any rotary peristaltic pump can be used in the systems of the present invention. Peristaltic pumps typically use a turning mechanism to move material through a tube or other conduit that is compressed at a number of points in contact with, e.g., rollers, shoes, etc. of the pump such that the material is moved through the tube with each rotating motion. Typically, peristaltic pumps are configured to reversibly convey quantities of material to or from selected material sites (e.g., microtiter plates, surfaces of substrates, or the like). Peristaltic pumps generally include rotatable roller carriers or supports that support at least two rollers (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 30, or more rollers). In certain embodiments, roller supports may be interchanged with one another, e.g., roller supports having different numbers of rollers. To further illustrate, roller supports typically support between about 2 and about 50 rollers, more typically between about 3 and about 40 rollers, and still more typically between about 4 and about 30 rollers. Generally, the greater the number of rollers supported on a given roller support, the smaller the quantity of material the peristaltic pump will be capable of conveying, since the controllers of the invention are typically configured to rotate roller supports in rotational increments that substantially correspond to integral multiples of angular distances disposed between adjacent rollers supported on the roller supports.
Adjacent rollers supported by a roller support are generally disposed at most 180° apart from one another. Moreover, angular distances disposed between pairs of adjacent rollers supported by roller supports are typically substantially (i.e., approximately or exactly) equal to one another. For example, adjacent rollers supported by a roller support are optionally positioned such that rotational increments substantially correspond to angular displacements selected from, e.g., about 12° (e.g., corresponding to 30 substantially equally spaced rollers), about 18° (e.g., corresponding to 20 substantially equally spaced rollers), about 22.5° (e.g., corresponding to 16 substantially equally spaced rollers), about 24° (e.g., corresponding to 15 substantially equally spaced rollers), about 25.7° (e.g., corresponding to 14 substantially equally spaced rollers), about 27.7° (e.g., corresponding to 13 substantially equally spaced rollers), about 30° (e.g., corresponding to 12 substantially equally spaced rollers), about 32.7° (e.g., corresponding to 11 substantially equally spaced rollers), about 36° (e.g., corresponding to 10 substantially equally spaced rollers), about 40° (e.g., corresponding to 9 substantially equally spaced rollers), about 45° (e.g., corresponding to 8 substantially equally spaced rollers), about 51.4° (e.g., corresponding to 7 substantially equally spaced rollers), about 60° (e.g., corresponding to 6 substantially equally spaced rollers), about 72° (e.g., corresponding to 5 substantially equally spaced rollers), about 90° (e.g., corresponding to 4 substantially equally spaced rollers), about 120° (e.g., corresponding to 3 substantially equally spaced rollers), about 180° (e.g., corresponding to 2 substantially equally spaced rollers), or the like. Optionally, angular distances disposed between pairs of adjacent rollers supported by a given roller support are not equal to one another.
Although other fluidic material volumes may be conveyed using the systems described herein, rotational increments generally correspond to at least about a 0.1 μl volume of fluidic material. Microliter volumes are generally desirable, e.g., when conveying fluidic materials to and/or from high-density multi-well plates, such as 1536-well plates having total volume capacities that are typically between about 10 to about 15 μl/well, with the systems of the present invention. Larger volumes of fluidic material (e.g., milliliter volumes, liter volumes, etc.) are also optionally conveyed using the systems of the present invention. A user can typically select the desired quantities of material (e.g., volumes or aliquots of fluidic material) conveyed with the systems of the invention by varying such parameters as the number of rollers supported by a roller support of the peristaltic pump, the rotational increments selected, the inner cross-sectional dimensions (e.g., diameter, etc.) of the material conduits utilized, the depth or extent of contact between rollers and material conduits when the rollers compress the materials conduits against the compression surface of the peristaltic pump, and the like.
In some embodiments, for example, the peristaltic pump comprises a multi-channel peristaltic pump such that multiple quantities of material can be conveyed simultaneously. To illustrate,
Although rotatable rollers (e.g., passively or actively rotatable) that rotate relative to roller supports are typically utilized in the systems of the invention, non-rotatable functionally equivalent components, such as fixed rollers or shoes are also optionally used. However, rotatable rollers generally produce less wear on material conduits (e.g., flexible tubing or the like) than non-rotatable equivalents for comparable amounts of usage. Conduit wear is typically initially observed primarily at or near the regions of initial contact between the rollers and conduits. To illustrate this type of wear,
VR=−VC sin φ
φ=180°−90°−θ or 90°−θ, so
VR=−VC sin(90°−θ)
VR=−VC(sin 90° cos θ−cos 90° sin θ)
sin 90°=1 and cos 90°=θ, so
VR=−VC cos θ
and cos θ is 1 when the conduit wrapped around the rollers. Accordingly, to minimize this type of conduit wear, rollers are optionally actively rotated such that they have initial velocities that are substantially equal to −VC in certain embodiments of the invention. In some of these embodiments, for example, a planetary gear transmission produces this rotation of the rollers, which rotation is in a direction opposite from or counter to the rotation of the roller support. In particular, a spur gear or the like is attached coaxially to each roller. The pitch curve of the gears is substantially equal to the radius of the rollers. In addition, a fixed ring gear or the like surrounds the spur gears. The transmission is driven by spinning the roller support or carrier. To illustrate,
More gradual wear is also generally observed over time at all points of contact along the particular conduit. As described further below, the rollers are typically accelerated and decelerated at rates that are sufficient to achieve clean conveyances of material from material conduits, e.g., without significant adherence or carryover of fluidic materials to material conduit surfaces proximal to dispense termini (e.g., dispense tips, nozzles, etc.) of the material conduits. If the force from the acceleration is greater than the frictional force between the rollers and the conduit, the surfaces of the rollers and the conduit will slide across one another causing the material conduit to wear. This more gradual wear can also be minimized by giving the rollers an initial velocity that equals −VC by, e.g., the gear transmission mechanism described above.
A peristaltic pump utilized in a system of the present invention typically generates sufficient material conveyance or flow rates at least proximal to a terminus a material conduit to effect non-contact material dispensing from the terminus. Non-contact dispensing minimizes the risk of cross-contaminating material sites, such as the wells disposed in multi-well plates. Moreover, non-contact material dispensing also typically enhances system throughput as material can be conveyed from material conduits “on-the-fly”, such as when materials are dispensed as material conduits and material sites are moved relative to one another.
To convey uniformly sized quantities of material (e.g., uniform volumes of fluidic material in the range of about 0.1 to about 10 μl, etc.), carryover, adherence, or wicking of material on outer surfaces of material conduits, e.g., proximal to dispense termini should avoided. For example,
Peristaltic pumps that can be adapted for use in the systems of the invention are available from a wide variety of commercial suppliers including, e.g., ABO Industries Inc. (San Diego, Calif., USA), Analox Instruments Ltd. (London, UK), ASF Thomas Industries GmbH (Puchheim, Germany), Barnant Co. (Barrington, Ill., USA), Cole-Parmer Instrument Company (Vernon Hills, Ill., USA), Fluid Metering Inc. (Syosset, N.Y., USA), Gorman-Rupp Industries (Bellville, Ohio, USA), I & J Fisnar Inc. (Fair Lawn, N.J., USA), Möller Feinmechanik GmbH & Co. (Fulda, Germany), PerkinElmer Instruments (Shelton, Conn., USA), Terra Universal Inc. (Anaheim, Calif., USA), and the like. Additional details relating to rotary pumps are described in, e.g., Karassik et al. (Eds.), Pump Handbook, The McGraw-Hill Companies (2000) and Nelik, Centrifugal and Rotary Pumps: Fundamentals with Applications, CRC Press (1999), which are both incorporated by reference.
IV. Motion Control
The motion control systems of the invention typically include matched components such as controllers, motor drives, motors, encoders and resolvers, user interfaces and software. Controllers, user interfaces, and software are described in greater detail below. Peristaltic pump drive motors generally include at least one position encoder and at least one gear reduction component. Exemplary motors utilized in the systems of the invention typically include, e.g., servo motors, stepper motors, or the like. In some embodiments, feedback components of the systems of the invention include at least one drive mechanism that is operably connected to the motor. The drive mechanism typically includes at least one control component that effects position feedback control of the motor.
As referred to above, the movement of peristaltic pump roller supports is typically effected by a motor operably connected to the pump. Exemplary motors that are optionally utilized in the systems of the invention include, e.g., DC servomotors (e.g., brushless or gear motor types), AC servomotors (e.g., induction or gearmotor types), stepper motors, linear motors, or the like. Servomotors typically have an output shaft that can be positioned by sending a coded signal to the motor. As the input to the motor changes, the angular position of the output shaft changes as well. Stepper motors generally use a magnetic field to move a rotor. Stepping can typically be performed in full step, half step, or other fractional step increments. Voltage is applied to poles around the rotor. The voltage changes the polarity of each pole, and the resulting magnetic interaction between the poles and the rotor causes the rotor to move. To further illustrate,
The systems of the invention also generally include motor drives (e.g., AC motor drives, DC motor drives, servo drives, stepper drives, etc.), which act as interfaces between controllers and motors. In certain embodiments, motor drives include integrated motion control features. For example, servo drives typically provide electrical drive output to servo motors in closed-loop motion control systems, where position feedback and corrective signals optimize position and speed accuracy. Servo drives with integrated motion control circuitry and/or software that accept feedback, provide compensation and corrective signals, and optimizes position, velocity, and acceleration.
Suitable motors and motor drives are generally available from many different commercial suppliers including, e.g., Yaskawa Electric America, Inc. (Waukegan, Ill., USA), AMK Drives & Controls, Inc. (Richmond, Va., USA), Enprotech Automation Services (Ann Arbor, Mich., USA), Aerotech, Inc. (Pittsburgh, Pa., USA), Quicksilver Controls, Inc. (Covina, Calif., USA), NC Servo Technology Corp. (Westland, Mich., USA), HD Systems Inc. (Hauppauge, N.Y., USA), ISL Products International, Ltd. (Syosset, N.Y., USA), and the like. Additional detail relating to motors and motor drives are described in, e.g., Polka, Motors and Drives, ISA (2002) and Hendershot et al., Design of Brushless Permanent-Magnet Motors, Magna Physics Publishing (1994), which are both incorporated by reference.
V. Positioning and Mounting Components
In some embodiments, the material conveying systems of the invention further include a positioning component that is operably connected to a controller. Controllers are described in greater detail below. The positioning component is generally structured to moveably position material conduits and/or material sites relative to one another. Positioning components typically include at least one object holder that is structured to support the material site (e.g., a multi-well plate, a substrate, etc.). In addition, the controller is typically configured to simultaneously effect rotation of the roller support and moveably position the material conduits and/or material sites relative to one another such that the material volumes are conveyed to or from the material site synchronous with the relative movement of the material conduits and/or the material sites, e.g., to effect high throughput “on-the-fly” material dispensing.
For positioning along two different axes, the object holders of the invention generally have one or more alignment members positioned to receive, e.g., each of the two axes of a multi-well container. For example,
The alignment members can be, for example, locating pins, tabs, ridges, recesses, or a wall surface, and the like. In preferred embodiments, an alignment member includes a curved surface that contacts a properly positioned multi-well container. The use of a curved surface minimizes the effect of, for example, roughness of the container surface that contacts the alignment member. The use of two alignment members along one axis and one alignment member along the second axis, as shown in
Certain embodiments of the invention apply specifically to the positioning of microtiter plates when used as the material sites. To illustrate, microtiter plate 1400 is shown in FIGS. 14A-C. As shown, microtiter plate 1400 comprises well area 1402 which has many individual sample wells for holding samples and reagents. Microtiter plates are available in a wide variety of sample well configurations, including commonly available plates with 6, 12, 24, 48, 96, 192, 384, 768, 1536, or more wells. It will be appreciated that microtiter plates are available from a various manufacturers including, e.g., Greiner America Corp. (Lake Mary, Fla., USA), Nalge Nunc International (Rochester, N.Y., USA), and the like. Microtiter plate 1400 has outer wall 1404 having registration edge 1406 at its bottom. In addition, microtiter plate 1400 includes bottom surface 1408 below the well area on the plate's bottom side. Bottom surface 1408 is separated from outer wall 1404 by alignment member receiving area 1410. Alignment member receiving area 1410 is bounded by a surface of outer wall 1404 and by inner wall 1412 at the edge of bottom surface 1408. Although there may be some lateral supports 1414 in alignment member receiving area 1410, these areas are generally open between inner wall 1412 and an inner surface of the outer wall 1404.
According to the invention, to position a microtiter plate the alignment members of the container station are optionally arranged to cooperate with inner wall 1412 of the microtiter plate. Inner wall 1412 is advantageously used, as inner wall 1412 is typically more accurately formed and is more closely associated with the perimeter of the sample well area, as compared to an outer wall of plate 1400, such as wall 1404. Accordingly, aligning an inner wall (e.g., inner wall 1412) of a microtiter plate relative to alignment members is generally preferred to aligning with an outer wall, such as wall 1404. The increased positioning precision that is obtained by using an inner wall as the alignment surface makes possible the use of high-density microtiter plates, such as 1536-well plates. Further, by having the alignment members (e.g., alignment protrusions 1306 and 1308) cooperate with an inner wall 1412 of plate 1400, minimal structures are needed adjacent the outside of the plate. In such a manner, a robotic arm or other transport device is able to readily access plate 1400. Having the protrusions positioned adjacent inner wall 1412 thereby facilitates translocating plate 1400. However, it will be appreciated that the alignment members or protrusions can be placed in alternative positions and still facilitate the precise positioning of the plate.
The object holders of the invention generally include one or more movable members. The movable members function to move a container against one or more alignment members. For example, once a multi-well container is placed in the general location of the alignment members, the movable members (termed “pushers” herein) move the container so that an alignment surface of the container is in contact with one or more of the alignment members of the positioning device. The positioning device can have pushers for positioning of the container along one or more axes. For example, a positioning device will often have one or more pushers that position a container along an x-axis, and one or more additional pushers that position the container along a y-axis. The pushers can be moved by means known to those of skill in the art. For example, air cylinders, springs, pistons, elastic members, electromagnets or other magnets, gear drives, and the like, or combinations thereof, are suitable for moving the pushers so as to move containers into a desired position.
One embodiment of a container station of an object holder having pushers for positioning a microtiter plate along both the x-axis and the y-axis is shown in
As referred to above, the object holder embodiment shown in
In certain embodiments, positioning components also include X/Y-axis linear motion tables operably connected to position feedback control drives that control movement of the X/Y-axis linear motion tables along X- and Y-axes. In certain embodiments, linear motion tables are configured to move only along a single axis, such as an X-axis or a Y-axis. Typically, object holders are mounted on, e.g., X/Y-axis linear motion tables. As an example,
Various other positioning components or portions thereof can be utilized in the systems of the invention. In certain embodiments, for example, detectable signals produced at material sites (e.g., multi-well plates, substrate surfaces, etc.) disposed on the object holders of the systems described herein are detected. In some of these embodiments, orifices are disposed through object holders to facilitate such detection. To further illustrate, object holders optionally comprise nests in which multi-well plates or other material sites can be positioned in some embodiments of the invention. These or other types of object holders that can be utilized in the systems of the present invention are described in, e.g., International Publication No. WO 01/96880, entitled “AUTOMATED PRECISION OBJECT HOLDER,” filed Jun. 15, 2001 by Mainquist et al., U.S. Provisional Pat. Appl. No. 60/492,586, entitled “MULTI-WELL CONTAINER POSITIONING DEVICES AND RELATED SYSTEMS AND METHODS,” filed Aug. 4, 2003 by Evans, and U.S. Provisional Pat. Appl. No. 60/492,629, entitled “NON-PRESSURE BASED FLUID TRANSFER IN ASSAY DETECTION SYSTEMS AND RELATED METHODS,” filed Aug. 4, 2003 by Evans et al., which are each incorporated by reference.
In some embodiments, the material conveying system further includes at least one mounting component that mounts at least the peristaltic pump, the feedback component, and the positioning component relative to one another. The mounting component is typically substantially rigid, e.g., fabricated from steel or other materials that can adequately support the other system components during operation of the system.
VI. Cleaning Components
The material conveying systems of the invention optionally also include cleaning components that are structured to clean material conduits (e.g., tips thereof), e.g., when positioning components move the material conduits at least proximal to the cleaning components. As described above, for example, as fluidic materials are dispensed, some fluid typically wicks up the outer surface of material conduit tips. This generally leads to additional wicking if the adherent fluid is not removed from the tips, because as the surface finish of a tip becomes coated with fluid it tends to attracts more fluid, e.g., during subsequent dispensing steps. Moreover, this also typically leads to inaccurate quantities of material being dispensed, since wicked materials are not dispensed at the selected material sites and/or are dispensed at non-selected sites. This inaccuracy may be compounded when multiple quantities of material are simultaneously dispensed from multiple material conduits, because material wicking tends to occur at different rates at the material conduit tips. Accordingly, wicked material is generally cleaned from material conduit tips, e.g., between dispensing steps using a cleaning component in certain embodiments of the invention.
In some embodiments, for example, cleaning components include vacuum chambers that comprise at least one orifice into or proximal to which the positioning component moves the material conduits such that an applied vacuum removes wicked or otherwise adherent material from external surfaces of the material conduits. Typically, outer cross-sectional dimensions of the material conduits are smaller than cross-sectional dimensions of the orifices. To illustrate,
As cross-sectional dimensions of vacuum chamber orifices decrease, the risk of contacting vacuum chambers and thereby damaging material conduit tips as the tips are lowered into the orifices increases. Accordingly, compliant materials, such as certain tapes, are optionally disposed over the orifices of vacuum chambers having orifice cross-sectional dimensions that are too large to otherwise produce sufficiently high VA to remove adherent materials from material conduit tips when those tips are disposed in the orifices. The tape acts to seal the orifices. In these embodiments, as the tips are lowered, they puncture the tape creating holes that are typically slightly larger than that cross-sectional dimensions of the tips. Sufficiently high VA can typically be achieved through the gaps between the tips and edges of the holes in the tape to effect removal of adherent materials from the outer surfaces of the tips.
VII. Material Conduits
The material conduits used in the systems of the invention include various embodiments. In some embodiments, for example, a terminus of a material conduit includes a tip (e.g., a tapered tip, such as a nozzle or the like) that is fabricated integral with the conduit or is connected to the conduit, e.g., via an insert. The size (e.g., internal cross-sectional dimension) of the material conduit (e.g., pump tubing, etc.) and/or tip utilized is typically dependent, at least in part, on, e.g., the desired dispense volume, the viscosity of the material being conveyed, and the like. Although larger sizes are optionally utilized, cavities disposed through material conduits and/or tips typically include, e.g., cross-sectional dimensions of between about 100 μm and about 105 mm, more typically between about 500 μm and about 104 mm, and still more typically between about 1 mm and about 103 mm. Optionally, cavities disposed through material conduits or tips include at least two different cross-sectional dimensions. In certain embodiments, cavities disposed through material conduits and/or tips include cross-sectional dimensions that differ from one another. Generally, the optimum tubing size (e.g., internal diameter) is such that it is large enough to allow the dispense volume to be delivered rapid enough to generate high velocities at the dispense tips, but small enough so that the angular displacement of the pump is sufficiently large to make hysteresis and other mechanical/hydraulic variations nebulous. As described herein, when significantly high tip velocities are attained, the fluid or other material can be ejected at a distance great enough to allow dispensing without entering, e.g., the target well of a multi-well container with the dispenser tip. Moving the target material site or tip along the x- and y-axes synchronous with the pump delivery timing produces an automated system for rapidly and accurately dispensing fluids at material sites. Pumps and X/Y-axis linear motion tables are described in greater detail above. Moreover, increasing the number of pump channels and delivery tips to 2, 4, 8, 16, etc. correspondingly reduces the delivery times by ½, ¼, ⅛, {fraction (1/16)}, etc., respectively.
To further illustrate, there are many instances where delicate living cells are dispensed into micro-well plates or other material sites. These cells can be damaged by the shear forces associated with being forced through delivery tips with very small inside diameters (e.g., less than 200 μm). If the internal tip diameter utilized for dispensing these cells is so large that high tip velocities cannot be attained, the fluid may form a drop on the tip during the dispense cycle rather than forming a stream. Material wicking is also described above. In some embodiments of the invention, accurate dispensing is further achieved by moving the tips down into the selected wells along the Z-axis far enough such that after the fluid is dispensed, the fluid level in the well will be slightly above the end of the delivery tips. This also allows the fluid to be dispensed into wells with smaller cross-sectional areas than fluid drops that would form on the tips during, e.g., a non-contact dispense condition. When the dispensing is complete, the tips are raised and/or the material site is lowered along the Z-axis such that a wet touch off condition is created which eliminates any residual drops from forming on the delivery tips. Optionally, the tips are contacted with, e.g., dry sides of the wells to wick-off the droplets.
In certain embodiments, the systems of the invention are configured to propel droplets, which are formed on the ends of dispense tips, off using mechanical inertia principals. In this configuration, the fluid is dispensed to form a droplet on the end of the dispense tip. At this point, the pump typically stops flowing material through the material conduits and the dispense tips are typically accelerated at a sufficient rate downward along the Z-axis to accelerate the drops without moving or significantly deforming them. Once an adequate velocity is reached, dispense tips are rapidly decelerated to propel the droplets off the end of the dispense tips. The shapes of the moving droplets are typically more columnar, and with smaller diameters, than the original droplets formed on the tips. This allows the droplets to enter, e.g., wells with small cross-sectional areas. This approach provides another method for non-contact dispensing.
In some embodiments, the systems of the invention generate initial positive pressure pulses followed by negative pressure pulses as described herein. The negative pressure pulses are produced by large negative flow rate changes that occur at the end of a given dispense cycle to prevent droplets from forming on the tip. More specifically, at the start of a particular dispense cycle a high flow rate is typically achieved in a small amount of time, because the dispense volumes are generally small and the volume dispensed at low velocity is typically minimized. A large negative flow rate change typically occurs when the high flow rate is abruptly stopped. These abrupt flow rate changes, or pressure pulses, are transmitted from the pump to the dispense tip outlet as efficiently as possible to prevent the dispensing performance from being compromised. The flow path downstream of the pump roller support generally should not have any features that add accumulator or flow restricting properties to the fluid system. In some embodiments, for example, flow paths have the following attributes:
To illustrate, FIGS. 16A-D schematically illustrate various material conduit tips according to certain embodiment of the invention. More specifically,
Material conduits, tips, and inserts are optionally fabricated from a wide variety of materials. Exemplary materials used to fabricated material conduits include fluorinated ethylene propylene (FEP), polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), autoprene, C-FLEX® (a styrene-ethylene-butylene (SEBS) modified block copolymer with silicone oil), NORPRENE® (a polypropylene-based material), PHARMED® (a polypropylene-based material), silicon, TYGON®, VITON® (includes a range of fluoropolymer elastomers), and the like. Material conduit tips and inserts can be fabricated from, e.g., various polymeric materials such as, polytetrafluoroethylene (TEFLON™), polypropylene, polystyrene, polysulfone, polyethylene, polymethylpentene, polydimethylsiloxane (PDMS), polycarbonate, polyvinylchloride (PVC), polymethylmethacrylate (PMMA), and the like. Material conduit tips and inserts are also optionally fabricated from other materials including glass and various metals. Materials for fabricating material conduits, tips, and inserts are typically readily available from many different commercial suppliers including, e.g., Saint-Gobain Performance Plastics (Garden Grove, Calif., USA), DuPont Dow Elastomers L.L.C. (Wilmington, Del., USA), and the like.
VIII. Material Sites
The systems and methods of the present invention can be adapted for use with essentially any type of material site. Typical material sites used in the systems of the invention include material containers, substrate surfaces, and the like. Exemplary material containers include multi-well material containers, such as micro-well plates, reaction blocks, and other containers used, e.g., to perform multiple assays, synthesis reactions, or other processes in parallel. Multi-well material containers such as these typically include, e.g., 6, 12, 24, 48, 96, 192, 384, 768, 1536, or more wells, and are generally available from various commercial suppliers including, e.g., Greiner America Corp. (Lake Mary, Fla., USA), Nalge Nunc International (Rochester, N.Y., USA), H+P Labortechnik AG (Oberschleiheim, Germany), and the like. Additional details relating to reaction blocks that are suitable for use in the systems of the invention are provided in, e.g., International Publication No. WO 03/020426, entitled “PARALLEL REACTION DEVICES,” filed Sep. 5, 2002 by Micklash II, et al., which is incorporated by reference.
To further illustrate, the systems of the invention are also optionally configured to dispense material on substrate surfaces. For example, the systems described herein can be utilized to produce dot arrays or the like on substrate surfaces at various different densities. Arrayed materials are commonly used in, e.g., clinical testing (e.g., blood cholesterol tests, blood glucose tests, pregnancy tests, ovulation tests, etc.) in addition to many other applications known in the art. Essentially any substrate material is optionally adapted for use with the systems of the invention. In certain embodiments, for example, substrates are fabricated from silicon, glass, or polymeric materials (e.g., glass or polymeric microscope slides, silicon wafers, etc.). Suitable glass or polymeric substrates, including microscope slides, are available from various commercial suppliers, such as Fisher Scientific (Pittsburgh, Pa., USA) or the like. Optionally, substrates utilized in the systems of the invention are membranes. Suitable membrane materials are optionally selected from, e.g. polyaramide membranes, polycarbonate membranes, porous plastic matrix membranes (e.g., POREX® Porous Plastic, etc.), porous metal matrix membranes, polyethylene membranes, poly(vinylidene difluoride) membranes, polyamide membranes, nylon membranes, ceramic membranes, polyester membranes, polytetrafluoroethylene (TEFLON™) membranes, woven mesh membranes, microfiltration membranes, nanofiltration membranes, ultrafiltration membranes, dialysis membranes, composite membranes, hydrophilic membranes, hydrophobic membranes, polymer-based membranes, a non-polymer-based membranes, powdered activated carbon membranes, polypropylene membranes, glass fiber membranes, glass membranes, nitrocellulose membranes, cellulose membranes, cellulose nitrate membranes, cellulose acetate membranes, polysulfone membranes, polyethersulfone membranes, polyolefin membranes, or the like. Many of these membranous materials are widely available from various commercial suppliers, such as, P.J. Cobert Associates, Inc. (St. Louis, Mo., USA), Millipore Corporation (Bedford, Mass., USA), or the like.
IX. Controllers, Computer Program Products, and Additional System Components
The controllers of the automated systems of the present invention are generally configured to effect substantially identical roller disengagements from material conduits for each conveyed quantity of material to minimize periodic variation among the conveyed quantities of material. Controllers are typically operably connected to one or more system components, such as motors (e.g., via motor drives), positioning components (e.g., X/Y-axis linear motion tables, Z-axis motion components, etc.), cleaning components, detectors, fluid sensors, robotic translocation devices, or the like, to control operation of these components. More specifically, controllers are generally included either as separate or integral system components that are utilized, e.g., to effect roller support rotation in selected rotational increments, the movement of positioning components, the detection and/or analysis of detectable signals received from sample containers by detectors, etc. Controllers and/or other system components is/are optionally coupled to an appropriately programmed processor, computer, digital device, or other logic device or information appliance (e.g., including an analog to digital or digital to analog converter as needed), which functions to instruct the operation of these instruments in accordance with preprogrammed or user input instructions (e.g., material conduit cross-sectional dimensions, rotational increments, volumes to be conveyed, etc.), receive data and information from these instruments, and interpret, manipulate and report this information to the user.
A controller or computer optionally includes a monitor which is often a cathode ray tube (“CRT”) display, a flat panel display (e.g., active matrix liquid crystal display, liquid crystal display, etc.), or others. Computer circuitry is often placed in a box, which includes numerous integrated circuit chips, such as a microprocessor, memory, interface circuits, and others. The box also optionally includes a hard disk drive, a floppy disk drive, a high capacity removable drive such as a writeable CD-ROM, and other common peripheral elements. Inputting devices such as a keyboard or mouse optionally provide for input from a user. An exemplary system comprising a computer is schematically illustrated in
The computer typically includes appropriate software for receiving user instructions, either in the form of user input into a set of parameter fields, e.g., in a GUI, or in the form of preprogrammed instructions, e.g., preprogrammed for a variety of different specific operations. The software then converts these instructions to appropriate language for instructing the operation of one or more controllers to carry out the desired operation, e.g., varying or selecting the rate or mode of movement of various system components, directing translation of positioning components, or the like. The computer then receives the data from, e.g., sensors/detectors included within the system, and interprets the data, either provides it in a user understood format, or uses that data to initiate further controller instructions, in accordance with the programming, e.g., such as in monitoring detectable signal intensity, multi-well container positioning, or the like.
More specifically, the software utilized to control the operation of the systems of the invention typically includes logic instructions that direct, e.g., the system to convey material (e.g., fluidic material) to material sites, the pushers of an object holder of a positioning component to push containers into contact with alignment members when the containers are positioned on the object holder, a robotic handling device to translocate containers, and/or the like. To further illustrate, the invention provides control software, or computer program products that include computer readable media, having one or more logic instructions for receiving one or more input parameters selected from the group consisting of: (i) a rotational increment that substantially corresponds to an integral multiple of an angular distance disposed between adjacent rollers supported by a roller support of a peristaltic pump; (ii) a cross-sectional dimension of a material conduit; (iii) a quantity of material to be conveyed to or from a material site; and (iv) an angular distance disposed between adjacent rollers supported by a roller support of a peristaltic pump. The software or computer program product also includes one or more logic instructions for rotating a roller support of a peristaltic pump in rotational increments that substantially correspond to integral multiples of an angular distance disposed between adjacent rollers supported by the roller support of the peristaltic pump such that when one or more material conduits are operably connected to the peristaltic pump and the peristaltic pump conveys material through the material conduits, quantities of material that correspond to the rotational increments are conveyed to or from material sites. In certain embodiments, the software or computer program product further includes at least one logic instruction for moving an X/Y-axis linear motion table and a Z-axis motion component synchronous with rotating the roller support. The computer readable medium of, e.g., the computer program product optionally includes one or more of: a CD-ROM, a floppy disk, a tape, a flash memory device or component, a system memory device or component, a hard drive, a data signal embodied in a carrier wave, or the like.
The computer can be, e.g., a PC (Intel x86 or Pentium chip-compatible DOS™, OS2™, WINDOWS™, WINDOWS NT™, WINDOWS95™, WINDOWS98™, WINDOWS2000™, WINDOWS XP™, LINUX-based machine, a MACINTOSH™, Power PC, or a UNIX-based (e.g., SUN™ work station) machine) or other common commercially available computer which is known to one of skill. Standard desktop applications such as word processing software (e.g., Microsoft Word™ or Corel WordPerfect™) and database software (e.g., spreadsheet software such as Microsoft Excel™, Corel Quattro Pro™, or database programs such as Microsoft Access™ or Paradox™) can be adapted to the present invention. Software for performing, e.g., material conveyance to selected wells of a multi-well plate, assay detection, and data deconvolution is optionally constructed by one of skill using a standard programming language such as Visual basic, C, C++, Fortran, Basic, Java, or the like.
The automated systems of the invention are optionally further configured to detect and quantify absorbance, transmission, and/or emission (e.g., luminescence, fluorescence, etc.) of light, and/or changes in those properties in samples that are arrayed in the wells of a multi-well container, on a substrate surface, or at other material sites. Alternatively, or simultaneously, detectors can quantify any of a variety of other signals from multi-well containers or other material sites including chemical signals (e.g., pH, ionic conditions, or the like), heat (e.g., for monitoring endothermic or exothermic reactions, e.g., using thermal sensors) or any other suitable physical phenomenon. In addition to other system components described herein, the material conveying systems of the invention optionally also include illumination or electromagnetic radiation sources, optical systems, and detectors. Because the systems and methods of the invention are flexible and allow essentially any chemistry to be assayed, they can be used for all phases of assay development, including prototyping and mass screening.
In some embodiments, the systems of the invention are configured for area imaging, but can also be configured for other formats including as a scanning imager or as a nonimaging counting system. An area imaging system typically places an entire multi-well container or other specimen onto the detector plane at one time. Accordingly, there is typically no need to move photomultiplier tubes (PMTs), to scan a laser, or the like, because the detector images the entire container onto many small detector elements (e.g., charge-coupled devices (CCDs), etc.) in parallel. This parallel acquisition phase is typically followed by a serial process of reading out the entire image from the detector. Scanning imagers typically pass a laser or other light beam over the specimen, to excite fluorescence, reflectance, or the like in a point-by-point or line-by-line fashion. In certain cases, confocal-optics are used to minimize out of focus fluorescence. The image is constructed over time by accumulating the points or lines in series. Nonimaging counting systems typically use PMTs or light sensing diodes to detect alterations in the transmission or emission of light, e.g., within wells of a multi-well container. These systems then typically integrate the light output from each well into a single data point.
A wide variety of illumination or electromagnetic sources and optical systems can be adapted for use in the systems of the present invention. Accordingly, no attempt is made herein to describe all of the possible variations that can be utilized in the systems of the invention and which will be apparent to one skilled in the art. Exemplary electromagnetic radiation sources that are optionally utilized in the systems of the invention include, e.g., lasers, laser diodes, electroluminescence devices, light-emitting diodes, incandescent lamps, arc lamps, flash lamps, fluorescent lamps, and the like. One preferred type of laser used in the assaying systems of the invention are argon-ion lasers. Exemplary optical systems that conduct electromagnetic radiation from electromagnetic radiation sources to sample containers and/or from multi-well containers to detectors typically include one or more lenses and/or mirrors to focus and/or direct the electromagnetic radiation as desired. Many optical systems also include fiber optic bundles, optical couplers, filters (e.g., filter wheels, etc.), and the like.
Suitable signal detectors that are optionally utilized in these systems detect, e.g., emission, luminescence, transmission, fluorescence, phosphorescence, absorbance, or the like. In some embodiments, the detector monitors a plurality of optical signals, which correspond in position to “real time” results. Example detectors or sensors include PMTs, CCDs, intensified CCDs, photodiodes, avalanche photodiodes, optical sensors, scanning detectors, or the like. Each of these as well as other types of sensors is optionally readily incorporated into the systems described herein. The detector optionally moves relative to material sites, such as multi-well plates or other assay components, or alternatively, multi-well plates or other assay components move relative to the detector. In certain embodiments, for example, detection components are coupled to translation components that move the detection components relative to material sites positioned on container positioning devices of the systems described herein. Optionally, the systems of the present invention include multiple detectors. In these systems, such detectors are typically placed either in or adjacent to, e.g., a multi-well plate or other vessel, such that the detector is in sensory communication with the multi-well plate or other vessel (i.e., the detector is capable of detecting the property of the plate or vessel or portion thereof, the contents of a portion of the plate or vessel, or the like, for which that detector is intended). In certain embodiments, detectors are configured to detect electromagnetic radiation originating in the wells of a multi-well container.
The detector optionally includes or is operably linked to a computer, e.g., which has system software for converting detector signal information into assay result information or the like. For example, detectors optionally exist as separate units, or are integrated with controllers into a single instrument. Integration of these functions into a single unit facilitates connection of these instruments with the computer, by permitting the use of a few or even a single communication port for transmitting information between system components. Detection components that are optionally included in the systems of the invention are described further in, e.g., Skoog et al., Principles of Instrumental Analysis, 5th Ed., Harcourt Brace College Publishers (1998) and Currell, Analytical Instrumentation: Performance Characteristics and Quality, John Wiley & Sons, Inc. (2000), which are both incorporated by reference.
The systems of the invention optionally also include at least one robotic translocation or gripping component that is structured to grip and translocate material sites, such as multi-well plates between components of the automated systems and/or between the systems and other locations (e.g., other work stations, etc.). In certain embodiments, for example, systems further include gripping components that move multi-well plates between positioning components, incubation or storage components, etc. A variety of available robotic elements (robotic arms, movable platforms, etc.) can be used or modified for use with these systems, which robotic elements are typically operably connected to controllers that control their movement and other functions. Exemplary robotic gripping devices that are optionally adapted for use in the systems of the invention are described further in, e.g., U.S. Pat. No. 6,592,324, entitled “GRIPPER MECHANISM,” issued Jul. 15, 2003 to Downs et al., and International Publication No. WO 02/068157, entitled “GRIPPING MECHANISMS, APPARATUS, AND METHODS,” filed Feb. 26, 2002 by Downs et al., which are both incorporated by reference.
X. System Component Fabrication
System components (e.g., positioning components, cleaning components, etc.) are optionally formed by various fabrication techniques or combinations of such techniques including, e.g., machining, stamping, engraving, injection molding, cast molding, embossing, extrusion, etching (e.g., electrochemical etching, etc.), or other techniques. These and other suitable fabrication techniques are generally known in the art and described in, e.g., Altintas, Manufacturing Automation: Metal Cutting Mechanics, Machine Tool Vibrations, and CNC Design, Cambridge University Press (2000), Molinari et al. (Eds.), Metal Cutting and High Speed Machining, Kluwer Academic Publishers (2002), Stephenson et al., Metal Cutting Theory and Practice, Marcel Dekker (1997), Rosato, Injection Molding Handbook, 3rd Ed., Kluwer Academic Publishers (2000), Fundamentals of Injection Molding, W. J. T. Associates (2000), Whelan, Injection Molding of Thermoplastics Materials, Vol. 2, Chapman & Hall (1991), Fisher, Extrusion of Plastics, Halsted Press (1976), and Chung, Extrusion of Polymers: Theory and Practice, Hanser-Gardner Publications (2000), which are each incorporated by reference. In certain embodiments, following fabrication, system components are optionally further processed, e.g., by coating surfaces with a hydrophilic coating, a hydrophobic coating (e.g., a Xylan 1010DF/870 Black coating available from Whitford Corporation (West Chester, Pa.), etc.), or the like, e.g., to prevent interactions between component surfaces and reagents, samples, or the like.
XI. Material Conveying Methods
In addition to the systems and computer program products described herein, the invention also relates to methods of conveying material. For example, one method includes conveying material (e.g., a cell suspension, a reagent, a buffer, a solid support suspension, etc.) through one or more material conduits of a system described herein in which the controller effects rotation of the roller support in at least one rotational increment that substantially corresponds to an integral multiple of an angular distance disposed between adjacent rollers supported by the roller support such that quantities of material conveyed to or from a material site correspond to the rotational increment. Essentially any rotational increment can be selected including, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, or more times an angular distance disposed between adjacent rollers of a given roller support. As described herein, the controller typically effects rotation of the roller support such that shearing effects on the conveyed material (e.g., cells or the like) are minimized. The controller generally effects substantially identical roller disengagements from material conduits for each conveyed quantity of material, e.g., to minimize periodic variation among the conveyed quantities of material. Further, identical rotational increments generally convey substantially uniform material volumes to or from material sites. Moreover, the rotational increments utilized as described herein are typically uncompensated for flow rate characteristics of the particular system. This simplifies the implementation of the systems and methods of the invention relative to many pre-existing approaches.
In some embodiments, material is conveyed to material sites without material conduits contacting the material site (i.e., non-contact material dispensing). For example, these methods optionally include effecting negative pressure pulses proximal to termini of material conduits with the controller after effecting rotation of the roller support in the selected rotational increment, e.g., to prevent quantities of material from adhering to external portions of material conduits. Optionally, the methods include moving material conduits with sufficient velocity to eject adherent material that adheres to external portions of the material conduits, e.g., to convey the material to a material site or to clean the external portions of the material conduits. In some embodiments, the methods include contacting adherent material that adheres to external portions of material conduits with another object (e.g., the edge of a well of a multi-well container, etc.) to remove the adherent material from the external portions of the material conduits.
As described herein, material sites optionally comprise multi-well containers (e.g., microtiter plates, etc.). In these embodiments, methods of conveying material optionally include conveying a first quantity of material into a first well of a multi-well container, moving a material conduit and/or the multi-well container relative to one another, e.g., with the positioning component such that the multi-well container is in communication with a second well of the multi-well container, conveying a second quantity of material into the second well of the multi-well container, and so forth. The moving and conveying steps are typically substantially simultaneous with one another, e.g., to effect “on-the-fly” material dispensing.
Other methods of the invention include conveying material through a material conduit such that a quantity of the material adheres to a terminal portion of the material conduit to form an adherent quantity of material. Thereafter, these methods also generally include accelerating at least the terminal portion of the material conduit towards the material site, and decelerating the terminal portion of the material conduit such that the adherent quantity of material is conveyed (e.g., ejected) from the terminal portion of the material conduit to the material site.
Essentially any biochemical or cellular assay, or synthesis reaction, can be adapted for performance in the systems and according to the methods of the invention. To illustrate, common types of assays performed in, e.g., multi-well plates include those relating to signal transduction, cell adhesion, apoptosis, cell migration, GPCR, cell permeability, receptor/ligand binding, intracellular calcium flux, membrane potential, nucleic acid hybridization, cell growth/proliferation, among many others that are known in the art. Additional details relating to certain of these and other assays involving multi-well plates are described in, e.g., Parker et al. (2000) “Development of high throughput screening assays using fluorescence polarization: nuclear receptor-ligand binding and kinase/phosphatase assays,” J. Biomolecular Screening 5(2): 77-88, Asa (2001) “Automating cell permeability assays,” Screening 1: 36-37, Norrington (1999) “Automation of the drug discovery process,” Innovations in Pharmaceutical Technology 1(2): 34-39, Fukushima et al. (2001) “Induction of reduced endothelial permeability to horseradish peroxidase by factor(s) of human astrocytes and bladder carcinoma cells: detection in multi-well plate culture,” Methods Cell Sci. 23(4): 211-9, Neumayer (1998) “Fluorescence ELISA, a comparison between two fluorogenic and one chromogenic enzyme substrate,” BPI 10(Nr. 5), Graeff et al. (2002) “A novel cycling assay for nicotinic acid-adenine dinucleotide phosphate with nanomolar sensitivity,” Biochem J. 367(Pt 1): 163-8, Rogers et al. (2002) “Fluorescence detection of plant extracts that affect neuronal voltage-gated Ca2+ channels,” Eur. J. Pharm. Sci. 15(4): 321-30, and Rappaport et al. (2002) “New perfluorocarbon system for multilayer growth of anchorage-dependent mammalian cells,” Biotechniques 32(1): 142-51, which are each incorporated by reference. Additional details relating to various methods that are optionally performed using the systems of the present invention are also described in, e.g., U.S. Patent Application No. 60/492,629, entitled “NON-PRESSURE BASED FLUID TRANSFER IN ASSAY DETECTION SYSTEMS AND RELATED METHODS,” filed Aug. 4, 2003 by Evans et al., which is incorporated by reference.
It is understood that the example and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.
This example illustrates various dispenses using an 8 tip system in which the peristaltic pump had a roller support that supported 12 rollers in which the angular distance disposed between each pair of adjacent rollers was 30°.
While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be clear to one skilled in the art from a reading of this disclosure that various changes in form and detail can be made without departing from the true scope of the invention. For example, all the techniques and apparatus described above can be used in various combinations. All publications, patents, patent applications, and/or other documents cited in this application are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication, patent, patent application, and/or other document were individually indicated to be incorporated by reference for all purposes.
This application claims the benefit of U.S. Provisional Application No. 60/527,125, filed Dec. 4, 2003, the disclosure of which is incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 60527125 | Dec 2003 | US |
