Abstract:
A slide processing apparatus comprises a slide or processing station which may include a plurality of cuvettes, each cuvette configured to receive a slide. A reagent fluid supply is coupled to each cuvette to deliver and apply reagent for treatment of the slide. A slide gripper is disposed above the slide processing station and is configured to move the slide in and out of the cuvettes. A screw assembly is disposed adjacent the slide processing station, the screw assembly configured to receive a plurality of slides, wherein rotation of the screw assembly advances the plurality of slides for engagement by the slide gripper.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY CLAIMS 
     This application is a continuation of application Ser. No. 13/857,965 filed Apr. 5, 2013, now U.S. Pat. No. 9,091,621, which is incorporated herein by reference for all purposes. 
    
    
     TECHNICAL FIELD 
     The present invention relates to apparatus for staining or other processing of microscope slides. More particularly, the present invention relates to apparatus for handling and processing multiple slides at once. 
     BACKGROUND OF THE INVENTION 
     Devices are known to automate the often tedious processing of microscope slides for analysis. For example, commonly assigned U.S. Pat. Nos. 7,452,506 and 6,468,764 disclose a method and apparatus for automated Gram staining of single microscope slides. The stainer disclosed in those patents is a single-slide variety: it can treat only one slide at a time. GGB Company LLC of Wichita Falls, Tex. sells a single-slide stainer embodying this technology under the model number AGS-1000, and it has proven to be a technical and commercial success, accurately staining thousands if not millions of microscope slides. 
     Other automated staining and processing apparatuses are known, some of which can handle multiple or more than one slide at a time. These multiple staining devices variously employ carousels or robot arms to move slides from station to station for application of reagents and the like. None, however, match the Gram stain accuracy of the AGS-1000. 
     A need exists for improved slide processing apparatus capable of performing slide processing operations on multiple or more than one microscope slide. 
     SUMMARY OF THE INVENTION 
     It is a general object of the present invention to provide a microscope slide staining or processing apparatus capable of processing multiple microscope slides. This and other objects of the invention are achieved with a slide processing apparatus comprising a slide or processing station which may include a plurality of cuvettes, each cuvette configured to receive a slide. A reagent fluid supply is coupled to each cuvette to deliver and apply reagent for treatment of the slide. A slide gripper is disposed above the slide processing station and is configured to move the slide in and out of the cuvettes. A screw assembly is disposed adjacent the slide processing station, the screw assembly configured to receive a plurality of slides, wherein rotation of the screw assembly advances the plurality of slides for engagement by the slide gripper. 
     According to a preferred embodiment of the invention, the screw assembly further comprises a pair of parallel, spaced-apart screws, each of the screws having threads. A motor and controller rotate each of the screws, wherein slides are placed between the screws with their edges engaged by the threads and controlled rotation of the screws moves the slides. 
     According to a preferred embodiment of the invention, the screw assembly further comprises a first screw assembly disposed on one side of the cuvettes and a second screw assembly disposed on an opposite side of the cuvettes, the first screw assembly for advancing untreated slides, the second screw assembly for advancing treated slides. 
     According to a preferred embodiment of the invention, the cuvettes further comprise a pair of cuvettes for applying crystal violet; a pair of cuvettes for applying Gram&#39;s iodine; a single cuvette to apply acid alcohol; and a pair of cuvettes to apply safranin, wherein application of crystal violet, Gram&#39;s iodine, acid alcohol and safranin can occur simultaneously. 
     According to a preferred embodiment of the invention, the slide gripper further comprises a pair of jaws mounted on linear bearings for horizontal movement above the cuvettes and between the cuvettes and the screw assembly. 
     Other objects, features and advantages of the present invention will become apparent with reference to the figures and the detailed description, which follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the apparatus according to the present invention. 
         FIG. 2  is a front elevation view of the apparatus with the shroud or cover removed. 
         FIG. 3  is an enlarged front elevation view of a portion of  FIG. 2 . 
         FIG. 4  is an enlarged perspective view of a portion of  FIG. 2 . 
         FIG. 5  is an end, fragmentary view of a portion of  FIG. 2 . 
         FIG. 6  is a side elevation view of a portion of  FIG. 5 . 
         FIG. 7  is an enlarged view of a portion of  FIG. 2 . 
         FIG. 8  is a schematic view of a rinse water reservoir according to the present invention. 
         FIG. 9  is a schematic illustration of the pneumatic power source and reservoir according to the present invention. 
         FIG. 10  is a block diagram depicting the controller for the slide processing apparatus according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the Figures, and particularly to  FIG. 1 , a multiple-slide staining apparatus  11  according to an embodiment of the present invention is shown. The exterior of the device includes loading  13  and unloading  15  ports, through which microscope slides are loaded and unloaded, and a touch-screen monitor and input device  17  or user interface for accessing control functions of the apparatus. Various access panels may be provided. 
       FIG. 2  illustrates apparatus  11  with the shroud removed. A generally L-shaped (viewed from the end, see  FIG. 5 ) panel mounts the various components of the slide stainer according to the present invention. First and second or load and unload screw assemblies  31  and  41  are mounted on panel  21  on either side of a slide processing station  51  and are driven by geared motors  37 ,  47 . Load and unload screw assemblies  31 ,  41  hold the microscope slides and advance them toward or away from slide processing station  51 . An arm  71  and gripper  73  remove the slides from the load screw assembly  31 , place them selectively in slide processing station  51 , and move them from station  51  to unload screw assembly  41 . 
       FIG. 3  illustrates a first or load screw assembly  31 . Each of the screw assemblies  31 ,  41  is similar and comprises a pair of parallel, spaced apart lead- or conveyor screws  33 ,  35 . Microscope slides are captured or held between the threads of each pair of screws and controlled rotation by a geared motor  37  advances the slides toward slide processing station or cuvette assembly  51  (in the case of load screw assembly  31 ) and away from slide processing station  51  (in the case of unload screw assembly  41 ). 
     Each slide has a biological tissue or fluid sample or specimen applied to it. It is this specimen that is stained, processed, or treated by the apparatus according to the present invention, typically for microscopic analysis by a human technician. As shown, the plurality of microscope slides are preferably oriented “vertically,” with one shorter end up and are maintained in a parallel, spaced-apart relationship while carried by screw assemblies  31 ,  41 . 
     Although screw assemblies  31 ,  41  are illustrated as relatively permanently mounted to panel  21 , they could also be part of a removable “cassette” assembly that permits loading and unloading of the cassette away from apparatus  11 . Motors, gears, and controllers for rotating the screws in the cassette would preferably remain mounted on panel  21 . 
     An arm assembly  71  is positioned above slide processing station or cuvette assembly  51  and has a slide gripper  73  that traverses on linear bearings  75  to grip or pick up a slide from load screw assembly  31 , deposit the slide into a selected cuvette in slide processing station  51  for processing, and remove the slide from the selected cuvette and either deposit it in the next selected cuvette or into the threads of screw assembly  41  for storage of processed slides until they can be removed for analysis. Arm assembly  71  is powered by a motor  79 . 
     A manual or bypass slide tray  91  is provided between screw assembly  31  and slide processing station  51 . If the need arises to process a microscope slide that is not in the queue of load screw assembly  31 , it can be placed in manual slide tray  91 , which is provided with an optical sensor that senses the presence of a slide so that arm assembly can take the slide from tray  91  rather than load screw assembly  31 . 
     A plurality of (seven) peristaltic reagent pumps  101  are associated with each of the seven cuvettes ( FIG. 3 ). Peristaltic pumps are preferred because slide processing reagents can be corrosive and the pumps are by nature positive displacement, which permits metering of fluid quantity without use of separately controlled valves. These pumps are connected to reagent reservoirs (not shown, but preferably mounted on the reverse side of panel  21 ) and to cuvettes to supply reagent to each cuvette for slide processing. According to a preferred embodiment of the present invention, there are seven cuvettes and seven reagent pumps  101 , each reagent pump  101  supplying reagent to a single cuvette. 
     There are also a plurality of water and drain peristaltic pumps  201  mounted underneath panel  21 . Water pumps  201  are connected to a source of water and drain pumps  201  to a drain. Each of the water and drain pumps  201  (a total of 14) is connected to one of the seven cuvettes for rinsing and draining each cuvette as desired or necessary. 
     Reagent, water, and drain pumps  101 ,  201  are identical in configuration and capacity. Drain pumps  201  have their suction end in communication with the cuvette, rather than the discharge end, as in the case of reagent and water pumps. Drain pumps therefore remove fluid from the cuvettes rather than supply it, as in the case of reagent and water pumps. Preferably, drain pumps  201  are cycled forward and reverse to agitate rinse fluid in each cuvette prior to being actuated forward to drain or remove fluid from the cuvette. By using controlled positive-displacement pumps, the use of “wet” valves, and associated corrosion and reliability problems, is avoided. The only valves in the system are associated with the various pneumatically controlled elements (gripper  73  and kicker  93 ), which avoid the problems of valves exposed to liquids. 
       FIG. 4  is a perspective view of slide processing station or cuvette assembly  51 , showing the seven cuvettes used in a preferred embodiment of the present invention. In the preferred embodiment of the invention, the slide processing technique is the Gram stain, which applies crystal violet (and rinses with water), then Gram&#39;s iodine (and rinses with water), followed by decolorizing with acid alcohol (and analysis of the decolorizing fluid to detect the level of staining in the slide specimen), and finished with safranin. In this preferred and illustrative embodiment, two cuvettes  53  are provided for crystal violet, two cuvettes  55  for Gram&#39;s iodine, one cuvette  57  for the acid alcohol decolorizing step (the fastest step), and another pair of cuvettes  59  for safranin. Gram stain processing occurs as disclosed in U.S. Pat. Nos. 7,452,506 and 6,468,764, which are incorporated herein by reference, with the optoelectronic detection of decolorization level, which indicates that a slide is properly stained. An optical sensor  61  is mounted adjacent and above each cuvette to detect the presence or absence of a slide in the cuvette. Although the illustrated and preferred embodiment processes microscope slides according to the Gram stain method disclosed in the foregoing patents, it can be easily adapted to perform other slide processing techniques, by changing the supplied reagents and/or number of cuvettes. 
       FIG. 4  also shows one of the seven cuvettes  59 , which is exemplary of all of them. As can be seen, cuvette  59  is generally rectangular in configuration and has a recess or cavity opening at the upper end to receive a microscope slide. Cuvette  59  is connected by tubing  65  to one of the reagent pumps  101  for controlled delivery of a quantity of reagent (in the case of cuvette  59 , safranin) to cuvette for slide treatment. Cuvette  59  is also connected by tubing  67  to a water pump  201  and water supply and by tubing  69  to a drain pump  201  and drain for respectively rinsing and draining cuvette  59 . Optical sensors  63  are provided to detect the presence and level of reagent and rinse water in each cuvette and communicate that information to a computer controller. 
       FIG. 5  illustrates arm  71  and gripper  73 , which comprises a pair of opposing, horizontally moving jaws  77 . As shown in  FIG. 2 , arm  71  is driven by a motor  79  and traverses horizontally on linear bearings  75  above slide processing station  51  and its cuvettes  53 ,  55 ,  57 ,  59  and between load and unload screw assemblies  31 ,  41 . Jaws  77  move relative to one another to grip or engage the upper end of a microscope slide, remove it from first or load screw assembly  31 , and deposit it in a sequence of cuvettes according to the slide processing sequence or algorithm. 
     A pneumatically operated kicker  93  is positioned below the slide in the ultimate or pick-up position of load screw assembly  31  to engage the bottom end of the microscope slide to raise the upper end of the slide for gripping by jaws  77  of slide gripper (a raised slide is shown in  FIG. 2 ). When slide processing is complete, jaws  79  grip the upper end of the slide and deposit it between the threads of second or unload screw assembly  41  for storage until analysis. 
     Pumps  101 ,  201  are controlled and operated by electric stepper motors, as are load and unload screw assemblies  31 ,  41 . Gripper  73  is controlled and operated pneumatically, as is slide kicker  93 . 
       FIG. 6  illustrates the relationship between gripper  73 , a microscope slide, one of screws  33 ,  35  of screw assembly  31 , and slide kicker  93  at the point where the slide is removed from load screw assembly  31 , the ultimate or pickup position. A deflector  81  (see  FIG. 5  also) formed of relatively resilient and flexible spring steel, is positioned between jaws  77  of gripper  33  to urge and maintain the slide in a vertical position so that its upper end can be grasped by jaws  77 . Also, the upper portion of slide kicker  93  is shown in engagement with the bottom of the slide, raising it for engagement or gripping by jaws  77  of gripper  73 . 
       FIG. 7  is an enlarged view of the end of one of screws  33 ,  35  of load screw assembly  31 . Due to variation in the thickness of microscope slides, the space and angle or pitch between adjacent threads of screw  33  may permit or cause the slide to tilt forward, away from vertical. Deflector  81  described in  FIG. 6  above helps return the slide to vertical for engagement by jaws  77  of gripper  73 . A generally rectangular notch or recess  39  is provided in the leading face of the last full thread of each screw  33 ,  35  to provide “room” or clearance for the slide to be urged and maintained in the vertical position by deflector  81  without breakage. 
       FIG. 8  illustrates schematically a rinse water reservoir  103  according to the present invention. Reservoir  103  typically is a jug or other commercial container of deionized water that resides outside of the shroud or cover of apparatus  11 . It is connected by one or more tubes  105  to the rinse water pumps  101 . An air breather line  107  vents reservoir  103  to atmosphere and extends to the bottom of reservoir  103 . Line  107  also includes a pneumatic pressure sensor  109 . Sensor  109  detects pressure exerted on the air in line  107  by the hydrostatic pressure of water in reservoir  103 . Sensor  109  is calibrated when reservoir  103  is empty and full of deionized water and periodically purges line  107  to insure accuracy. The hydrostatic pressure measured by sensor  109  corresponds to the fluid level in reservoir and sensor communicates this level to the controller to insure ready supply of rinse water and indicate when the reservoir needs replacement or refilling. 
       FIG. 9  is a schematic depiction of the pneumatic power source and reservoir of the present invention that supplies pneumatic pressure or power to the various pneumatic components of slide processing apparatus  11 , including and gripper  73  and slide kicker  93 . A pump  801  pressurises a reservoir  803  to a pressure of approximately 28-30 psi. Pump assembly  801  includes an electric motor  805  connected by an eccentric to a reciprocating air pump  807  that provides pressurized air at 15-18 psi. The output of pump  801  is supplied to reservoir via a tube or conduit  809 . A one-way check valve  811  is placed in conduit  809  to retain pressurized air in reservoir  803 , while admitting further air in, permitting pressure to build in reservoir. A solenoid-operated two-position T valve  813  is placed in the conduit  809  between pump  805  and check valve  811 . T valve  813  is switchable between an open position venting conduit  809  to atmosphere to depressurize the system and a closed position (indicated by the dashed line) coupling pump  801  to reservoir  803  to pressurize the reservoir. The solenoid of T valve  813  is in the same circuit as motor  805  current supply so that when motor is running, T valve  813  is in the closed position, and when it is not running, T valve  813  is in the open position, venting to atmosphere. 
       FIG. 10  is a high-level block diagram depicting the controller for the slide processing apparatus according to the preferred embodiment of the present invention. A CPU  501 , preferably an ARM  9  microprocessor, provides central control over all functions of the apparatus according to the present invention and provides display functions to and accepts input from a user interface  503 , which preferably is a touch-screen ( 17  in  FIG. 1 ). CPU  501  is in two-way communication (RSC-232/C) with two second-level processors: a motion processor  505  and a fluid processor  507 , both of which preferably are ARM  7  microprocessors. 
     Motion processor  505  controls the motion or movement of screw assemblies ( 31 ,  41  in  FIG. 2 ) via their electric motors, as well as gripper  73 , kicker  93 , and pressure sensor  109 , each of which is pneumatically operated. It is thus responsible for controlling movement of microscope slides through the apparatus according to the present invention. Motion processor  505  receives input from optical sensors  61 , among others. 
     Fluid processor  507  is responsible for control of fluid supply (reagents, rinse water, drain functions) and the actual slide processing involving primarily the timing and quantity of fluids applied to the slide in the cuvettes, and operation of the decolorizing process. Fluid processor  507  receives input from sensors  63  and  109  and those similar sensors associated with reagent reservoirs, among others. Fluid processor  507  is in overall control of seven cuvette or pump processors  509 . 
     Preferably, for the Gram stain process described above, there are seven pump processors  509 , one for each of the seven cuvettes employed in the process. Each pump processor is preferably an 8051 Core microprocessor in bidirectional (preferably IIC) communication with a reagent pump  101  (more accurately its motor), a water or rinse pump  201 , and a drain pump  201  associated with each cuvette. Thus, pump processors  509  control the operation of pumps  101 ,  201  and thereby the delivery of reagent and water to each cuvette and the draining of such fluids from the cuvette. Pump processors  509  and their circuit boards are identical and interchangeable. 
     In operation, slides are loaded vertically in load screw assembly  31 , which then rotates to advance the slides toward processing station  51 . Arm  71  and gripper  73  then take a slide from the ultimate or pick-up position in load screw  31  and place the slide in the first cuvette  53  (for application of crystal violet and rinse in the Gram stain example). Arm  71  and gripper  73  then return to load screw assembly  31 , which has advanced another slide into the ultimate position. Arm  71  and gripper  73  then pick up that slide and move it into the second crystal violet cuvette  53 . As the application of crystal violet completes (controlled by time and/or volume of reagent), the first slide is moved to the first Gram&#39;s iodine cuvette  55  and arm  71  and gripper  73  return to load screw  31  (which again has advanced) and places the third slide in the now-vacant first crystal violet cuvette  53 . Arm  71  then moves between load screw  31  and cuvettes, moving slides from cuvette to cuvette as each process completes and filling the then-vacant cuvettes with a new slide for the next process. This operation proceeds, placing slides in alternating fashion through the crystal violet  53 , Gram&#39;s iodine  55 , and safranin cuvettes  59 . The exception is the acid alcohol or decolorizing cuvette  57 , which process occurs sufficiently quickly (roughly twice as fast as the crystal violet, Gram&#39;s iodine, and safranin processes, that is 15-30 seconds compared with 30-60 seconds) that each successive slide can be treated in one cuvette  57 . Optical sensors  61  monitor which cuvettes are occupied and which are vacant. As the application of safranin concludes, the slide is picked up by arm  71  and gripper  73  and placed into the first or unload position in the unload screw assembly  41 , which then advances to create a vacant first position for the next slide. If a single (or more) slide needs to be processed out of order, a slide can be loaded into bypass  91 , where it will be transferred into a cuvette instead of the slide in the ultimate position of load screw assembly  31 , and will be moved through the cuvettes in similar fashion. This process permits automated Gram staining at approximately one slide per minute or 60-70 per hour. As mentioned above, the apparatus according to the present invention can be adapted to other slide staining or treatment processes, achieving similar efficiency gains. 
     The invention has been described with reference to illustrative and preferred embodiments. It is thus not limited, but is susceptible to variation and modification without departure from the scope of the claims, which follow.