Chemistry: analytical and immunological testing – Automated chemical analysis – Utilizing a moving indicator strip or tape
Reexamination Certificate
2001-04-30
2002-03-12
Warden, Jill (Department: 1743)
Chemistry: analytical and immunological testing
Automated chemical analysis
Utilizing a moving indicator strip or tape
C436S043000, C436S046000, C436S049000, C436S174000, C436S179000, C436S180000, C422S063000, C422S066000, C422S067000, C422S091000, C422S105000
Reexamination Certificate
active
06355487
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the dispensing of substances, such as biological reagents and samples. More particularly, the invention provides an apparatus and method for transferring small volumes of substances onto one or more substrates.
BACKGROUND OF THE INVENTION
As the sensitivity of analytical techniques continues to improve, it is increasingly desirable to carry out chemical and biochemical assays using very small volumes of samples/reagents. This is especially true in situations involving expensive substances. Accordingly, it is now popular to utilize very small volumes of such substances laid down as “spots” on the surface of a substrate, such as a slide, micro-card, chip or membrane.
Not only is it often desirable to provide ultra-small volumes of individual samples and/or reagents in the form of spots, it is becoming increasingly popular to arrange numerous such spots in close proximity to one another in the form of an array on a substrate. For example, a lab technician might need to evaluate a specimen for the presence of a wide assortment of target biological and/or chemical compounds, or to determine the reaction of many different specimens against one or more reagents, such as labeled probes. High-density array formats, or “microarrays,” permit many reactions to be carried out in a highly parallel fashion, saving space, time and money.
A variety of methods are currently available for making microarrays. Microarrays can be made, for example, by a robotic arm device having a spotting tip that moves successively between a sample-pickup well in a sample array, e.g., a microtitre plate, and a selected array position. Although high-density arrays of selected substances can be constructed by this approach, the production time and efficiency is limited by the fact that the regions of the microarray (or microarrays, if several are being constructed at once) are deposited one-by-one in a serial fashion. Additional time and effort is required where a plurality of different substances are laid down in the array, as the spotting tip must be cleaned and dried prior to being used with each new substance.
Multi-channel micropipette devices are available for laying down several reagent spots at once. Devices of this type typically have 8 or 12 micropipettes, fixed side-by-side in a linear array. Generally, these devices are unsuitable for quickly producing very dense arrays, as the size of each micropipette and any associated service connections (e.g., supply tubing, electrical connections, etc.) limits the minimal center-to-center spacing (pitch) that can be achieved for adjacent spots. Also, since only a few spots (usually 8 or 12) can be laid down at a time with such devices, the production of very dense arrays, e.g., having hundreds or thousands of spots with a submillimeter pitch, tends to be a very tedious and time-consuming process.
Another technique employs an array of pins arranged to simultaneously dip into an array of reservoirs, e.g., the 96 wells of a microtitre plate, to pick up one or more selected substances for transfer to a substrate, such as a membrane. Similar to the multi-channel pipette devices, the pitch spacing is limited by the size of each pin. Also, the pins of such arrays are typically arranged to match the pitch of a conventional supply-well array, typically 2¼, 4½, or 9 mm center-to-center. Thus, similar to the multi-channel pipetters, the production of very dense arrays can only be accomplished by sequentially laying down a number of sub-arrays, e.g., in a staggered or interleaved fashion—a very cumbersome and inefficient endeavor.
As an additional disadvantage, most of the known spotting techniques require the handling or transfer of substances between multiple receptacles (e.g., pipettes, flasks, vials, etc.) and/or flow lines (e.g., channels, hoses, tubing). Such transfers frequently result in a loss or contamination of the substance, thereby reducing the overall efficiency and sensitivity of the assay. Particularly with regard to expensive substances, it is generally desirable to keep such losses to a minimum.
In view of the above, the need is apparent for a device and method useful for delivering a micro-volume of a substance onto a substrate in a quick and efficient manner. Preferably, the device should be relatively easy to use, cost effective and readily adaptable for the production of micro-arrays having a great number of individual spots.
SUMMARY OF THE INVENTION
In one of its aspects, the present invention provides an apparatus for spotting a selected substance (e.g., a liquid sample or reagent, or micro-particles such as beads) onto one or more substrates.
In one general embodiment, the apparatus of the invention includes a base, adapted to hold one or more reagents, and a conveyor. The conveyor includes a movable surface defining (i) a plurality of spaced, tandemly-arranged substrate-support regions, each of which is adapted to support a substrate, and (ii) an opening between each adjacent pair of substrate-support regions. The conveyor is operable to advance the substrate-support regions along a transport pathway extending over the base. Further included is a transfer instrument or head having a spotting tip mounted for movement along an axis, toward and away from a raised position at which the tip is disposed above the conveyor surface. Shifting means, e.g., an actuator (such as a solenoid, or the like), are operatively connected to the tip for moving the same along its axis. A control unit is operatively connected to the conveyor and the actuator. At the direction of the control unit, a selected opening of the conveyor surface can be advanced to a position generally aligned with the axis of the transfer tip, at which point the control unit can signal the shifting means to shift the tip away from its raised position through such opening to contact reagent in the base. The shifting means can then withdraw the tip from the reagent and through the opening by shifting the tip toward its raised position. A selected site of a substrate-support region upstream of the selected opening can then be advanced to a position generally aligned with the axis of the transfer tip, at which point the control unit can signal the shifting means to shift the tip away from its raised position toward such site to transfer a selected amount of reagent from the tip to a selected region of a substrate at the substrate-support region.
According to one embodiment, one or more additional transfer heads and associated shifting means are disposed at spaced positions along the transport pathway, and structure is provided in the base for holding one or more reagents at each of the spaced positions. Such structure can include, for example, one or more tube holders (e.g., apertures or bores formed along a top surface of the base). The various transfer heads can be positioned along a line running parallel with the transport pathway, or one or more of the transfer heads can be laterally offset from the other transfer heads.
In one embodiment, a plurality of transfer heads are disposed in a row extending laterally or obliquely across the conveyor surface at one or more of the spaced positions along the transport pathway.
One embodiment contemplates a channel or cavity extending through at least a portion of the base. For example, an elongate channel can extend longitudinally through a central region the base. Optionally, a flow line can communicate a remote fluid source with the channel. In one such arrangement, a fluid flow line is connected to a fitting at one end of the channel. An outlet of the flow line is arranged so as to direct a selected fluid, passed through the line, into and along the channel. The channel can further include an egression port, e.g., at a distal end, through which any fluid(s) directed into the channel can exit.
In one embodiment, the base of the apparatus is adapted to hold one or more reagent reservoirs (e.g., tubes, vials, or the like) such that a lower region of each reservoir extends at least parti
Frazier Jeffrey D.
Handy Dwayne K
PE Corporation (NY)
Warden Jill
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