Patent Publication Number: US-7713487-B1

Title: Pipette guide and method

Description:
FIELD OF THE INVENTION 
     The invention herein pertains to laboratory procedures, particularly procedures involving the transfer of chemical reagents using a single or multichannel manual or electronic pipette. 
     DESCRIPTION OF THE PRIOR ART AND OBJECTIVES OF THE INVENTION 
     In recent years costs for laboratory testing and analysis has dramatically risen due in part to the increased salaries of qualified laboratory employees and technicians. In addition, the cost of materials used has also risen including the cost for supplies, such as well plates, chemical reagents and other resources. Manual loading by pipettes of chemical reagents into well plates having either 96 or 384 reservoirs is commonplace. Well plates exhibiting more numerous reservoirs are usually robotically loaded. With few exceptions laboratories commonly utilize manual pipette loading of well plates having 384 or fewer reservoirs. Such well plate loading is often routine and monotonous causing laboratory technicians carrying out such testing and analysis to become inattentive, easily distracted or confused as to the particular reservoir to be loaded next. Sometimes duplication and omissions occur. At other times cross contamination occurs from one reservoir to another due to improper techniques employed in pipette loading. 
     Once it has been determined that a single reservoir has been improperly loaded or overloaded in a well plate, the error may require the technician to discard the current well plate and start anew. Such errors can be expensive, time consuming and libelous, depending on the particulars of the test or analysis conducted. 
     Thus with the problems and disadvantages of current well plate loading techniques using manual pipettes, methods and equipment the present invention was conceived and one of its objectives is to ensure faster, more accurate reservoir loading by pipette using manual procedures. 
     It is another objective of the present invention to provide a pipette guide and method which limits the number of well plate reservoirs exposed at any particular time and helps prevent cross contamination. 
     It is yet another objective of the present invention to provide a pipette guide which can be locked onto a standard skirted or non-skirted well plate during loading. 
     It is still another objective of the present invention to provide a pipette guide which includes a movable slotted slide for outlining a single row of reservoirs for pipette loading. 
     It is yet another objective of the present invention to provide a reservoir isolator which will allow only one specific reservoir in a row to be loaded while shielding immediately adjacent reservoirs from contamination. 
     It is a further objective of the present invention to provide a method of well plate loading using a manual pipette which will allow greater accuracy and eliminate errors, retesting and analysis. 
     It is also an objective of the present invention to provide a pipette guide which can be easily locked onto a well plate for loading and readily removed for placement on another well plate as needed. 
     Various other objectives and advantages of the present invention will become apparent to those skilled in the art as a more detailed description is set forth below. 
     SUMMARY OF THE INVENTION 
     The aforesaid and other objectives are realized by providing a pipette guide and method, of use which ensure more accurate and efficient reagent delivery to selected well plate reservoirs. The pipette guide includes a cover having a movable slide mounted thereon. The slide is slotted to outline a single row of reservoirs when used with a conventional well plate. A window formed in the cover allows the slide to span the window, outlining selected rows of reservoirs as desired. A slide rod is affixed to the slide from which a single reservoir isolator is suspended. The reservoir isolator is coincidentally aligned with the slide slot whereby a specific reservoir in the row outlined is available for reagent delivery from the pipette. 
     In use, the pipette guide is secured to the well plate by a manual lock beneath the cover. The lock frictionally engages the side of the well plate to hold it in place during use. Once the well plate has been fully loaded, the lock can be released and the pipette guide placed on another well plate for subsequent loading. 
     A side rod affixed along one edge of the pipette guide cover includes notches for engagement by a resilient clip. As the slide is movably joined to the side rod, the clip will provide slide indexing along the cover as each successive notch is engaged. If the wrong series of notches is selected for a particular well plate the incorrect movement of the slide will be readily apparent to the user. The rod can be loosened and rotated to reveal a second series of notches. Each set of notches on the side rod corresponds to the number of reservoir rows of the well plate. In addition, a slide rod likewise includes two (2) sets of notches which correspond to the number of reservoirs in a particular row as outlined by the slide slot. 
     Thus, by using the pipette guide in the reservoir loading process less likelihood of an error exists due to the outlining and isolation of particular selected reservoirs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of the invention as positioned on a fragmented laboratory counter; 
         FIG. 2  illustrates an end view of the pipette guide with the slide raised approximately 30° from the cover; 
         FIG. 3  depicts a top view of the pipette guide with the side rod and slide rod somewhat withdrawn; 
         FIG. 4  demonstrates a bottom view of the pipette guide as seen in  FIG. 3 ; 
         FIG. 5  features a side view along lines  5 - 5  of  FIG. 3  with the reservoir isolator clip exploded therefrom; 
         FIG. 6  shows the slide removed from the cover and the reservoir isolator rotated about 100° to expose the reservoirs below; and 
         FIG. 7  illustrates the c-shaped clip as removed from the slide. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT AND OPERATION OF THE INVENTION 
     For a better understanding of the invention and its operation, turning now to the drawings,  FIG. 1  shows preferred pipette guide  10  attached to conventional well plate  20  (seen also in  FIG. 2 ) which comprises ninety-six (96) reservoirs  21  shown therein. Pipette guide  10  can also be affixed to other conventional well plates having for example, 384 reservoirs (not shown) as desired. 
     In use well plate  20  is placed on conventional non-slip rubber or polymeric mat  25  supported on a table or laboratory counter  28 . While mat  25  is not absolutely necessary, it prevents well plate  20  from any advertent movement as reagent  22  is manually loaded into reservoirs  21  of well plate  20  through standard pipette  24 . Reagent  22  can be any number of conventional laboratory chemicals, solutions, solvents and the like as are commonly employed during laboratory testing and analysis. 
     When loading well plate  20  as in various laboratory procedures, user  12  (as illustrated in fragmented fashion in  FIG. 1 ) may become tired, distracted or interrupted during this tedious process. When fatigue occurs, a particular reservoir  21  may be inadvertently omitted or duplicate loading may occur. When using a well plate having a high density of reservoirs, problems significantly increase if the well openings are small and more difficult to see. Pipette guide  10  thereby greatly facilitates the accurate loading of reservoirs  21  and increases the efficiency and accuracy of user  12 . 
     In  FIG. 2 , pipette guide  10  is shown with cover  11  atop well plate  20 . Cover  11  surrounds the top and edges of well plate  20  and is locked thereon for convenience purposes. Pipette guide  10  is formed from a conventional plastic, preferably polycarbonate although other standard materials may be used. Cover  11  defines large central window  13  which exposes all reservoirs  21  within well plate  20 . 
     Pipette guide  10  is releasably attached to well plate  20  as shown in  FIG. 4  by lock  14  which is slidable on rail  15  and is mounted at an approximate 7½ degree angle to the longitudinal axis (not shown) of cover  11 . Thus, as lock  14  is maneuvered on rail  15 , it will frictionally engage well plate  20  thus securing pipette guide  10  to well plate  20  as needed. To remove pipette guide  10  from well plate  20 , lock  14  is simply slid along rail  15  from well plate  20  as shown by arrow  16  in  FIG. 4 . 
     As earlier explained, pipette guide  10  is employed for more efficient and accurate pipette loading by user  12 . As shown in  FIGS. 1 and 3 , once pipette guide  10  is locked to well plate  20  and placed on mat  25 , slide  17  is then manipulated whereby slot  18  will expose a selected reservoir row (one row of the twelve rows of a typical ninety-six (96) reservoir well plate). Slot  18  extends laterally and exposes all eight (8) reservoirs  21  of a particular row of well plate  20 . Slide  17  is configured to expose only one row of reservoirs  21  while shielding and concealing adjacent rows along each side of the selected exposed row to prevent cross-contamination. As seen in  FIG. 1  reagent can therefore be placed only within the exposed row of reservoirs  21  without moving slide  17 . Slide  17  is pivotally attached to cover  11  along the side thereof as shown in  FIG. 2 . Slide  17  includes dependent flange  19  shown in  FIGS. 4 and 5  and includes channel  23  for receiving side rod  27 . Thus, slide  17  moves along side rod  27  of cover  11  and exposes (through slot  18 ) only one row of reservoirs  21  at a time in well plate  20 . Side rod  27  is preferably formed of stainless steel and includes a series of opposing notches  29 ,  30  therealong, as seen in  FIG. 3 . Twelve (12) notches  29  correspond with the twelve (12) rows of reservoirs in well plate  20 . Thirty-six (36) notches  30  in the other side of side rod  27  correspond with the 36 rows of reservoirs in a standard 384 reservoir well plate (not seen). Thus, in using pipette guide  10 , user  12  will first select the particular well plate desired, whether the 96 or 384 reservoir type, and will then position side rod  27  for a 96 reservoir well plate or will rotate side rod  27 , 180° for a 384 reservoir well plate to allow notches  30  to be in an active position. The notches selected in side rod  27  are chosen by releasing lock nut  31  from threads  32  ( FIG. 4 ) by turning lock nut  31  and when sufficiently loosened, square shoulders  33  proximate head  34  are withdrawn from cover rod lug  35  seen in  FIG. 3 . Next, side rod  27  is manually rotated 180°. Lock nut  31  is then rotated in the opposite direction to drive or tighten threads  32  therein, causing shoulders  33  to once again enter cover rod lug  35 , having a square cross-sectional channel  37 , thereby preventing rotation of side rod  27 . As would be understood, additional rotation of lock nut  31  tightens side rod  27  as threads  32  move through cover rod lugs  36  ( FIG. 3 ) which sandwich lock nut  31  therebetween. Cover rod lugs  36  include openings  38  ( FIG. 5 ) to allow side rod  27  to pass therethrough as lock nut  31  is rotated. 
     Well plates are manufactured with consistent center-to-center dimensions but variations in the outer well plate dimensions are usual. Thus, lock nut  31  can be manually rotated for a fine adjustment to exactly center index slide  17  on the initial row of reservoirs. 
     To precisely index slide  17  as it moves from row to row of reservoirs  21  along well plate  20 , flange  19  includes c-shaped metal clip  39  as shown in  FIG. 5 . C-shaped clip  39  seen enlarged in  FIG. 7  has a flattened upper portion  40  for engagement with notches  29  or  30  in side rod  27  and a lower rounded portion  40 ′ which surrounds or engages side rod  27  to maintain clip  39  thereon. When a row of reservoirs  21  have been loaded by pipette  24  as shown in  FIG. 1 , c-shaped clip  39  allows slide  17  to be manually moved to the next reservoir row desired and in conjunction with notches  29  allows slide  17  to thereby index the correct distance for alignment of slot  18  with the next row of reservoirs  21 . Thus, clip  39  assists user  12  in fast, accurate access to a desired reservoir row in well plate  20 . 
     When only one specific reservoir  21  is to be loaded by pipette, reservoir isolator  44  as shown in  FIGS. 1 and 6  is used. Isolator  44  is slidably mounted on lateral slide rod  45  as seen in  FIG. 6  through channel  57 . Lateral slide rod  45  is similar to side rod  27  and is mounted on slide  17  using slide lugs  47  and  48  ( FIG. 6 ). Rectangular channel  49  of slide lug  47  prevents rod  45  from inadvertent turning and allows alignment for employing either notches  50  or  51  seen in  FIG. 3  as desired as earlier explained. Slide lugs  48  likewise receive slide rod  45  and lock nut  52  is used to tighten threaded lateral slide rod  45  therein in a selected position. C-shaped clip  41  as shown in  FIG. 5  is inserted into isolator slot  55  as seen in  FIG. 3  for selected engagement with notches  50  or  51  to allow reservoir isolator  44  to precisely move or index from one reservoir to another in an accurate, precise manner. 
     As further seen in  FIGS. 1 and 6  reservoir isolator  44  includes port  58 , ridge  59  and lower end  60  of ridge  59 . Lock nut  52  can be manually rotated to precisely center port  58  over the initial reservoir  21  to insure accurate, subsequent movement of reservoir isolator  44 . Ridge  59  surrounds the bottom of port  58  to thus decrease the distance from reservoir isolator  44  to a particular reservoir  21  as lower end  60  of ridge  59  is substantially flush with the bottom of slide  17  while in coincidental alignment therewith. By decreasing this distance, greater accuracy in pipetting is obtained and the chances of cross contamination with adjacent reservoirs  21  are diminished. 
     In the preferred method of use of pipette guide  10 , a desired well plate  20  having either 96 or 384 reservoirs  21  is selected. Pipette guide  10  is then placed atop the well plate such as well plate  20  shown in  FIG. 1  and lock  14  is then urged along rail  15  into engagement with well plate  20  ( FIG. 4 ). Next, well plate  20  with pipette guide  10  is placed on a suitable friction producing surface such as rubber mat  25  atop a laboratory counter  28  or the like ( FIG. 1 ). Slide  17  is manually moved and positioned whereby slot  18  exposes a selected row of reservoirs  21  and by using conventional pipette  24 , or a multi-channel pipette (not seen), reservoirs  21  can then be filled. If all reservoirs  21  in the row are to be filled, pipette  24  is used to load all reservoirs  21 . However, if only one or a few selected reservoirs are to be loaded than reservoir isolator  44  is manually indexed along lateral slide rod  45  to a selected reservoir  21 . After loading, reservoir isolator  44  can be moved to another reservoir  21  in the same row as desired or can be pivoted on slide rod  45  to an upward or dormant position as shown in  FIG. 6 . Slide  17  is then indexed along side rod  27  to the next desired row of reservoirs  21  and the loading process repeated as needed. 
     Once the desired number of selected reservoirs and rows are so loaded, lock  14  is then loosened and pipette guide  10  removed from well plate  20  for further processing of the reservoir contents. Pipette guide  10  can then be placed on another well plate  20  and the process repeated as needed. 
     The illustrations and examples provided herein are for explanatory purposes and are not intended to limit the scope of the appended claims.