Abstract:
An automated metered fluid dispensing and aspirating apparatus comprising a combination delivery/removal fluid head with upper shuttle and lower reservoir assemblies is disclosed. A covered, variably positionable well table allows for mounting sample wells and automatically presenting at least one array of sample or reaction wells to the delivery/removal fluid head at a time. A fluid handling system of inter-connected tubing, pumps and valves interfaces with the delivery/removal fluid head. The fluid handling system provides reagents to and removes waste from the delivery/removal fluid head and sample wells. A control assembly, including a central processing unit and hardware, software and gas pressure sources, provides for time responsive operation and control of the delivery/removal fluid head, drive mechanisms for the table and fluid head, fluid handling system and well table. The entire apparatus is mounted on its own platform and includes separate housings for control and sample handling sections.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention is in the field of chemistry, biochemistry and microbiology. More specifically, the present invention relates to an automated apparatus having means to lyse or rupture cells on a slide for microscopic examination by addition of a material. Further, the apparatus comprises time responsive means to control the positioning of movable components, including a covered (environmentally sealed), multiple well tray and a liquid material (fluids) dispensing and handling means. In particular, the present application relates to the fluid dispensing component of the apparatus.  
       SUMMARY OF THE INVENTION  
       [0002]     The present invention is an apparatus useful in the fields of tissue culture and cytogenetics for the automated delivery and removal of fluids from a plurality of sample wells. More specifically, the present invention is an automated metered fluid dispensing and fluid aspirating apparatus. The present invention comprises a combination delivery/removal fluid head separable into an upper shuttle assembly and a lower reservoir assembly, with the shuttle assembly being variably positionable relative to the reservoir assembly by a drive mechanism. A covered, variably positionable well table provides a mechanism for mounting the sample wells and for automatically presenting at least one array of sample or reaction wells to the combination delivery/removal fluid head at a time. The well table cover closely covers each sample well and substantially reduces any evaporation of liquids from the sample wells during operation of the apparatus. Additionally, a fluid handling system of inter-connected tubing, pumps and valves in flow communication with reagent sources and waste reservoirs interfaces with the combination delivery/removal fluid head. The fluid handling system provides reagents to and removes waste from the combination delivery/removal fluid head and the sample wells. A control assembly, including a central processing unit and appropriate hardware, software and gas pressure sources, provides for the time responsive operation and control of the combination delivery/removal fluid head, the drive mechanisms for the table and the fluid head, the fluid handling system and the well table. The entire apparatus is mounted on its own platform and includes separate housings for control and sample handling sections.  
         [0003]     In particular, the present invention relates to the delivery/removal fluid head of the present invention. The delivery/removal fluid head is a combination of an upper shuffle assembly and a lower reservoir assembly. The shuttle assembly is variably positionable relative to the reservoir assembly by a separate fluid head drive mechanism. The delivery/removal fluid head assembly includes an array of decanting ports each in fluid/gas communication with a metered fluid reservoir. A fluid charging manifold, in fluid/gas communication with each metered reservoir, moves fluids materials (including reagent solutions) and gases into and out of the fluid head to charge the fluid reservoirs. The opening and closing of the decanter ports at the bottom of each fluid reservoir is accomplished by the seating and unseating of a shuttle peg against the decanter port at the bottom of the reservoir. The shuttle pegs are fixed to the shuttle assembly of the fluid head and are seated against decanter ports or removed from the fluid reservoirs by operation of the head drive mechanism positioning the shuttle assembly relative to the reservoir assembly.  
         [0004]     The shuttle pegs are hollow tubes. An aspirator nozzle is inserted into and freely passes through the hollow of each shuttle peg. When a shuttle peg is seated against its corresponding decanter port, the lower end of the peg&#39;s aspirator nozzle extends through the shuttle peg and into a sample well positioned below the decanter port of the fluid head. The upper end of the aspirator nozzle is in controlled communication with a low vacuum pressure source. With the shuttle assembly in this position (shuttle pegs seated in the decanter ports), fluids in the sample well may be aspirated from the sample well or dish. Additionally, with the shuttle assembly in this position, the fluid reservoirs of the reservoir assembly may be filled. In fact, the fluid reservoirs may be charging with a liquid reagent while the sample wells are being aspirated. The reagent solution is delivered from the fluid reservoirs into the wells below the fluid head by moving the shuttle assembly away from the reservoir assembly, which unseats the shuttle pegs from the decanter ports and withdraws them from the fluid reservoirs.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]      FIG. 1  is a schematic block diagram of the present metered fluid dispensing and aspirating apparatus of the present invention.  
         [0006]      FIG. 2A  is a partial cross-sectional view of a front elevation of the fluid delivery and removal head (“fluid head”) shown in an “open” configuration, and illustrating the close positioning of a sample well to the bottom or decant surface of the fluid head.  
         [0007]      FIG. 2B  is similar to  FIG. 2A , but showing the fluid delivery and removal head (“fluid head”) in an “closed” configuration, where the shuttle assembly has been driven downward to seat its shuffle pegs in the decanter ports.  
         [0008]      FIG. 2C  illustrates aspirator tubes biased in proper relationship to the shuttle pegs by gravity.  
         [0009]      FIGS. 3A and 3B  illustrate an alternative configuration of the fluid delivery and removal head shown in  FIGS. 2A and 2B , respectively.  
         [0010]      FIG. 4  is a perspective view a fluid head of the present invention showing the relationship of the shuttle assembly to the reservoir assembly.  
         [0011]      FIG. 5A  is a bottom plan view of the sealing surface of the manifold cover of a reservoir assembly of the present invention.  
         [0012]      FIG. 5B  is a top plan view of the manifold block of a reservoir assembly of the present invention.  
         [0013]      FIG. 6A  is an exploded view of a cross-section through the front plan of a fluid delivery/removal head of the present invention.  
         [0014]      FIG. 6B  is a cross-sectional view through the front plan of the assembled fluid delivery/removal head of  FIG. 6A .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Referring now to the drawings, the details of preferred embodiments of the present invention are graphically and schematically illustrated. Like elements in the drawings are represented by like numbers, and any similar elements are represented by like numbers with a different lower case letter suffix.  
         [0016]     As illustrated in  FIG. 1 , the present invention is a metered fluid dispenser and aspirating apparatus comprising a variably positionable well table  60 , a fluid delivery/removal head  20 , a fluid handling system  40  in flow communication with the fluid head  20  and with source and waste reservoirs (see  FIG. 1 ), and a controller assembly  80  providing for the timed responsive operation and control of the delivery/removal fluid head  20 , the fluid handling system  40  and the well table  60 .  
         [0017]     The sample well table  60  is variably positionable relative to the apparatus platform  90  of the present invention by means of a table drive mechanism  62 . The sample table  60  preferably has a plurality of sample well holders  66  arrayed on its surface  64 . Each holder  66  provides for mounting one of more sample wells (or dishes)  68 . The fluid delivery/removal head  20  is fixed relative to the platform  90 . As shown in  FIGS. 2A and 2B , the fluid head  20  is disposed closely above the well table  60  such that a sample well or dish  68  disposed on the well table surface  64  contacts the bottom reservoir surface  36  of the fluid head  20  when the sample well  68  is positioned below the fluid head  20 . The fluid head  20  provides for the controlled decanting of a metered volume of a liquid material into the sample wells  68  below it, and for removing waste fluids from the sample wells  68 . The fluid handling system  40  is in flow communication with the fluid head  20  and with the source (liquid reagent material solutions) reservoirs and with waste reservoirs. The fluid handling system  40  provides for delivering liquid materials to and removing waste from the fluid head  20  under control of the controller assembly  80 . The controller assembly  80  includes a central processing unit and appropriate hardware and software (not shown), and is in electrical communication with the well table  60 , the fluid head  20  and the fluid handling system  40 . The controller assembly  80  provides for the time responsive operation and control of the delivery/removal fluid head  20 , the fluid handling system  40  and the well table  60 .  
         [0018]     The fluid delivery/removal head  20  of the present invention is comprised of two major components: a shuttle assembly  24  and a reservoir assembly  26 . See  FIG. 2A  and  FIG. 3 . The shuttle assembly  24  is variably positionable relative to the reservoir assembly  26 . The reservoir assembly  26  is substantially fixed relative to the platform  90  of the apparatus. The positioning of the shuttle assembly  24  relative to the reservoir assembly  26  is accomplished by means of a head drive mechanism  22  under the control of the controller assembly  80 .  
         [0019]     The shuttle assembly  24  includes a shuttle bar  102 . Preferably, the shuffle  102  bar is a block or a plate made of a material and has dimensions to render it substantially rigid as it is moved or positioned relative to the reservoir assembly  26  by the head drive mechanism  22 . In one preferred embodiment, the shuttle bar  102  was made from a plate of an aluminum alloy. However, other materials are selectable by one of ordinary skill in the art for practice as a shuttle bar  102 , such as a plastic material, a composite (e.g., carbon-fiber material), and a laminate.  
         [0020]     The shuttle bar  102  has an upper bar surface  104  and a lower bar surface  106 . A plurality of vertical aspirator ports  110  extending through the shuttle bar  102  between the upper and lower bar surfaces  104  &amp;  106 . The aspirator ports  110  are arranged in a dispenser pattern. The dispenser pattern corresponds to the layout of an array of sample well holders  66  on the well table surface  64 . At the lower bar surface  106 , a shuttle peg  114  extends in a downward direction from each aspirator port  110 . In the preferred embodiments of the figures, the shuttle pegs  114  were hollow cylinders with two open peg ends connected via the interior lumen  116  of the shuttle peg  114 . In this embodiment the upper open peg end of the shuttle peg  114  defined the aspirator port  110  at the upper bar surface because the shuttle peg  114  passed completely through the shuttle bar  102 , and the lumen  116  of the shuttle peg was continuous with the aspirator port  110 .  
         [0021]      FIGS. 3A and 3B  illustrate an alternative configuration of the fluid delivery and removal head  20  as practiced in the present apparatus. In this preferred embodiment, the shuttle assembly  24  utilized gravity to bias the aspirator tubes  120  in a downward direction, and did not include the aspirator bias assembly  132  of the embodiment illustrated in  FIGS. 2A and 2B . Additionally,  FIGS. 3A and 3B  illustrate an alternative fluid reservoir  158   a . The alternative fluid reservoir  158   a  had substantially straight cylindrical dimensions, and included a volume insert  136  installed in the bottom of the fluid reservoir  158   a . The volume insert  136  was removable and replaceable. This allowed a metered volume of liquid dispensed by the reservoir to be adjustable by selecting the size of the volume insert  136  to reduce the metered volume of the fluid reservoir  158   a.    
         [0022]     As illustrated in  FIG. 4 , the continuous passage defined by the lumen  116  of the shuttle pegs  114  and the aspirator ports  110  each has an aspirator tube  120  loosely received in the continuous passage. The aspirator tube  120  itself is hollow and has a substantially straight portion which inserts into and is slidable within the lumen of the shuttle peg  114 . The straight portion of the aspirator tube  120  extends beyond the lower open peg ends of the shuttle peg  114  and above the upper bar surface  104  of the shuttle bar  102 . The aspirator tubes have an upper tube end  122  adapted to be connected to a vacuum source and a lower tube end  124  adapted to aspirate a liquid. In the preferred embodiment of the figures, the aspirator tubes  120  were made of stainless steel tubing, and were held in proper relationship in the shuttle pegs  114  by either an aspirator bias assembly  132  (including spring and stops, see  FIGS. 2A and 2B ) or by gravity (see  FIG. 2C ).  
         [0023]     Preferably, the shuttle pegs  114  are of made a chemically inert material, relative to the liquids with which it comes into contact. In the preferred embodiments shown, the shuttle pegs  114  were screwed into the shuttle bar  102 . However, the pegs  114  could have been press-fitted, adhered or fixed to the shuttle bar  102  by any means known to the ordinary skilled artisan. Additionally, it is preferred that the shuttle pegs  114  have a low friction exterior surface. In preferred embodiments of the present apparatus, the shuttle pegs  114  were accomplished in two manners: using polytetrafluoroethylene (TEFLON®) compositions and using molybdenum compositions. However, in view of the teaching herein, other shuttle peg compositions are know to and practicable in the present invention by one of ordinary skill in the art, including other plastic or elastomeric compositions.  
         [0024]     In the preferred embodiments shown in the figures, the shuttle bar  102  had at least at least two vertical guide sleeve bores  130  extending through it, between the upper and lower bar surfaces  104  &amp;  106 . Drive screw post (not shown) slideably passed through these guide sleeve bores  130 , with their lower ends mounted on the reservoir assembly  26 . A stepping-drive motor (not shown) was fixed to the shuttle bar  102  and rode up and down the drive screw posts under control of the controller assembly  80 . In this manner, the shuttle assembly  24  was positionable relative to the reservoir assembly  26 , by the action of the two stepping motors of the fluid head drive mechanism  22 . However, other means are known to one of ordinary skill in the art to accomplish the fluid head drive mechanism  22  of the present invention.  
         [0025]     As also shown in  FIGS. 2A and 2B  and others, the reservoir assembly  26  of the fluid delivery/removal head  20  includes a manifold block  150 . The manifold block  150  has a substantially flat upper manifold surface  152  and lower manifold surface  154 . A plurality of fluid reservoirs  158  extend vertically through the upper and lower manifold surfaces  152  &amp;  154  of the manifold block  150 . The fluid reservoirs  158  are disposed in the dispenser pattern. The upper manifold block surface  152  is covered with a manifold cover  160 , which is adapted to form a liquid seal against the upper manifold surface  152 . The manifold cover  160  has a plurality of peg guide through apertures  164  disposed in the dispenser pattern corresponding to the fluid reservoirs  158 . The peg guide apertures  164  each slideably receives and closely-seals against an associated shuttle peg  114  that is inserted through the peg guide apertures  164  and into the corresponding fluid reservoir  158 . In the preferred embodiment illustrated in  FIGS. 6A and 6B , a manifold gasket head  142  was used to provide a fluid seal for the fluid channel  168 .  
         [0026]     A fluid channel  168  (see  FIG. 5B ) disposed between the upper manifold surface  152  and the sealing surface  162  (see  FIG. 5A ) of the manifold cover  160 . The fluid channel  168  communicating with each of the fluid reservoirs  158  and with fluid inlet and outlet ports  170  &amp;  172  in the manifold cover  160 . The fluid inlet and outlet ports  170  &amp;  172  are in flow communication with the fluid handling system  40 . The manifold cover  160  can be fixedly sealed against the manifold block  150 . However, in the embodiment of the figures, the manifold cover  160  was removably sealed against the manifold block  150  using removable fastener  140 , e.g., through bolts and nuts or embedded fasteners.  
         [0027]     Also, in the embodiment of the figures, the fluid channel  168  was inset into the upper block surface  152  of the manifold block  150 , as shown in  FIG. 5B . Alternatively, the fluid channel could be inset into the sealing surface  162  of the manifold cover  160 . As a further alternative, the fluid channel could be inset into a manifold gasket head  142  (see  FIGS. 6A and 6B ) disposed between the manifold cover  160  and the manifold block  150 . A benefit of the latter is that this feature could be utilized to provide a means of adjusting the volume of the fluid reservoirs  158  or the reach or the shuttle pegs  114  into the fluid reservoirs  158 .  
         [0028]     The fluid reservoirs  158  of the manifold block  150  have a metered fluid volume defined by the volumetric space of the fluid reservoir  158  minus the volume displacement of the shuttle peg  114 , when the shuttle peg  114  is seated in the fluid reservoir  158 . In this configuration, the shuttle peg  114  is seated against a peg seat  30  disposed at the bottom of the fluid reservoir  158 . The peg seat  30  engages the lower end  118  the associated shuttle peg  114  and seals off the decant passage  32  of the fluid reservoir  158 . The open center of the peg seat  30  defines the decant passage  32  of the fluid reservoir  158  at the lower manifold block surface  154 . In this manner, the fluid reservoirs  158  of the manifold block  150  have a metered volume for dispensing defined by the volume of the reservoir  158  minus the displacement volume of the shuttle peg  114  when the shuttle peg  114  is seated in the fluid reservoir  158 .  
         [0029]     In a preferred embodiment practiced in the present invention, the manifold block lower surface  154  was a lower surface laminate  154   a . The lower surface laminate  154   a  included a bottom gasket  144  adjacent the manifold block lower surface  154 , followed by a manifold bottom cover  146  to seal the bottom gasket  144  in place, and a low friction interface  148  (e.g., a polyethylene sheet) below that. The bottom gasket  144  and bottom cover  146  are particularly useful for use with the reservoir block  150   a  of  FIGS. 6A and 6B , having fluid reservoirs  158  with volume inserts  136  (see also  FIGS. 3A and 3B ). The low friction interface  148  allows the sample wells or sample dishes  68  closely engage the bottom surface of the fluid delivery/removal head  20  and freely slide underneath it.  
         [0030]      FIG. 6A  is an exploded view of a cross-section through the front plan of a preferred fluid delivery/removal head  20  practiced in the present metered fluid dispenser and aspirating apparatus. The figure shows the combination fluid delivery/removal head  20  comprised a shuttle assembly  24  which was variably positionable relative to the reservoir assembly  26  by a head drive mechanism (not shown).  FIG. 6B  is a view through the front plan of the fluid delivery/removal head of  FIG. 6A  in an assembled configuration.  
         [0031]     While the above description contains many specifics, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of one or another preferred embodiment thereof. Many other variations are possible, which would be obvious to one skilled in the art. Accordingly, the scope of the invention should be determined by the scope of the appended claims and their equivalents, and not just by the embodiments.