Patent Publication Number: US-2023135251-A1

Title: Cell and medicament dispensing device for drug screening and method thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an automation equipment for biology and chemistry laboratories, especially to a device and a method configured to dispense minute amount of cells or minute amount of medicaments into different wells of a culture plate. 
     2. Description of the Prior Arts 
     To perform drug screening, first dispense minute amount of cells into wells of a culture plate where the cells are then cultivated for several days. When the cultivation is completed, manually prepare different kinds of medicament liquids in different containers, manually draw up and dispense precise amount of each medicament liquid into the wells with the cultivated cells one after another with a pipette. 
     However, a typical culture plate has dozens of wells, and there are several medicament liquids needed to be dispensed. As a result, simple and repetitive dispensing operation needs to be repeated for hundreds of times for each culture plate, making drug screening a long and laborious task. 
     Additionally, a disposable tip is mounted on a front end of the pipette, and the tip needs to be replaced before dispensing a different kind of cell or medicament liquid to prevent contamination. Replacement of the tip further increases the time and labor for drug screening. 
     To overcome the shortcomings, the present invention provides a cell and medicament dispensing device for drug screening and method thereof to mitigate or obviate the aforementioned problems. 
     SUMMARY OF THE INVENTION 
     The main objective of the present invention is to provide a cell and medicament dispensing device for drug screening and method thereof to automate the complex process of drug screening. 
     The cell and medicament dispensing device for drug screening is configured to inject multiple solutions into multiple solution recesses of a transfer plate. Then, liquid inside each of the solution recesses is dispensed into multiple wells of a cell culture plate with a pipette. At least one pipette-tip is detachably connected to a bottom of the pipette. The cell and medicament dispensing device comprises a base, a transfer plate serving mechanism, a transfer plate positioning mechanism, an injection mechanism, a cell culture plate positioning mechanism, and a dispensing mechanism. The base has a transfer plate entrance area, a receiving area, and a dispensing area thereon. The transfer plate serving mechanism is mounted on the base and is adjacent to the transfer plate entrance area. The transfer plate serving mechanism is configured to accommodate the transfer plate and is capable of moving the transfer plate to the transfer plate entrance area of the base. The transfer plate positioning mechanism is mounted on the base and is adjacent to the transfer plate serving mechanism. The transfer plate positioning mechanism has a positioning slider configured to connect with the transfer plate. The positioning slider is movably mounted on the base and selectively corresponds in position to the transfer plate entrance area, the receiving area, or the dispensing area. The injection mechanism is mounted on the base and is adjacent to the transfer plate positioning mechanism. The injection mechanism has multiple injection heads. Each of the injection heads is in fluid communication with a respective one of the solutions and is capable of moving to the receiving area of the base. The positioning slider is configured to align any one of the solution recesses of the transfer plate to the injection head located in the receiving area such that said injection head injects one of the solutions into the corresponding solution recess. The cell culture plate positioning mechanism is mounted on the base and configured to connect with the cell culture plate. The cell culture plate positioning mechanism has a positioning seat and a primary positioning module. The positioning seat is mounted on the base and configured to accommodate the cell culture plate. The primary positioning module is mounted on the positioning seat and configured to clamp the cell culture plate. The dispensing mechanism is mounted on the base and has a dispensing seat. The dispensing seat is configured to fix the pipette and control aspirate operation and discharge operation of the pipette. The dispensing seat is movable relative to the base and capable of moving back and forth between a position above the dispensing area of the base and a position above the cell culture plate positioning mechanism. When the dispensing seat is above the dispensing area, the dispensing seat is configured to insert the at least one pipette-tip of the pipette into any one of the solution recesses of the transfer plate and executes aspirate operation of the pipette. When the dispensing seat is above the cell culture plate positioning mechanism, the dispensing seat executes discharge operation of the pipette to release the solution aspired in the pipette into one of the wells of the cell culture plate. 
     The cell and medicament dispensing method for drug screening comprises steps as follows: 
     (a) Transfer of cells or solutions: A plate feeder of a transfer plate serving mechanism moves a transfer plate to a transfer plate entrance area on a base. The transfer plate has multiple solution recesses formed thereon. A positioning slider of a transfer plate positioning mechanism moves to the transfer plate entrance area and connects with the transfer plate located in the transfer plate entrance area. The positioning slider moves the transfer plate to a receiving area on the base. An injection mechanism injects multiple solutions into the solution recesses of the transfer plate. 
     (b) Dispensing of cells or solutions: The positioning slider moves the transfer plate to a dispensing area on the base. A cell culture plate with multiple wells is ready at a position by the cell culture plate positioning mechanism. A dispensing mechanism moves a pipette back and forth between a position above the dispensing area on the base and a position above the cell culture plate on the positioning slider to dispense liquid in each of the solution recesses into the wells of the cell culture plate. 
     The advantage of the present invention is that liquids and cells for drug screening are automatically transferred to the solution recesses of the transfer plate by coordination among the transfer plate serving mechanism, the transfer plate positioning mechanism, and the injection mechanism. Afterwards, the liquid in each of the solution recesses is automatically dispensed into the wells of the cell culture plate by coordination between the transfer plate positioning mechanism and the dispensing mechanism. As a result, the process of drug screening could be automated to reduce labor and improve quality. 
     Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a cell and medicament dispensing device for drug screening in accordance with the present invention; 
         FIG.  2    is a schematic top view of the cell and medicament dispensing device in  FIG.  1   ; 
         FIG.  3    is a partial perspective view of the cell and medicament dispensing device in  FIG.  1   ; 
         FIG.  4    is an exploded view of the cell and medicament dispensing device in  FIG.  3   ; 
         FIG.  5    is a partial perspective view of the cell and medicament dispensing device in  FIG.  1   , showing a transfer plate serving mechanism, a transfer plate retriever, and a transfer plate positioning mechanism of the dispensing device; 
         FIG.  6    is a partial perspective view of the cell and medicament dispensing device in  FIG.  1   , showing the transfer plate serving mechanism, the transfer plate retriever, and the transfer plate positioning mechanism from another angle; 
         FIG.  7    is an exploded perspective view of the transfer plate serving mechanism, the transfer plate retriever, and the transfer plate positioning mechanism of the cell and medicament dispensing device in  FIG.  6   ; 
         FIG.  8    and  FIG.  9    are operational schematic side views of the cell and medicament dispensing device in  FIG.  1   , showing operating statuses of the transfer plate serving mechanism viewed along a transverse direction; 
         FIGS.  10  to  13    are operational schematic cross sectional views of the cell and medicament dispensing device in  FIG.  1   , showing operating statuses of the transfer plate serving mechanism and the transfer plate positioning mechanism viewed along a longitudinal direction; 
         FIGS.  14  to  16    are operational schematic side views of the cell and medicament dispensing device in  FIG.  1   , showing operating statuses of the transfer plate positioning mechanism and an injection mechanism; 
         FIG.  17    is a perspective view of a cell culture plate positioning mechanism of the cell and medicament dispensing device in  FIG.  1   ; 
         FIG.  18    is an exploded perspective view of the cell culture plate positioning mechanism of the cell and medicament dispensing device in  FIG.  17   ; 
         FIGS.  19  and  20    are operational schematic side views of the cell culture plate positioning mechanism of the cell and medicament dispensing device in  FIG.  17   , showing operating statuses of the cell culture plate positioning mechanism viewed along the transverse direction; 
         FIGS.  21  and  22    are operational schematic top views of the cell culture plate positioning mechanism of the cell and medicament dispensing device in  FIG.  17   , showing operating statuses of the cell culture plate positioning mechanism; 
         FIGS.  23  and  24    are operational schematic cross sectional views of the cell culture plate positioning mechanism of the cell and medicament dispensing device in  FIG.  17   , showing operating statuses of a lid opener of the cell culture plate positioning mechanism; 
         FIG.  25    is a perspective view of a dispensing mechanism of the cell and medicament dispensing device in  FIG.  1   ; 
         FIG.  26    is an exploded perspective view of the dispensing mechanism of the cell and medicament dispensing device in  FIG.  25   ; 
         FIGS.  27  to  29    are operational schematic side views of the cell and medicament dispensing device in  FIG.  1   , showing operating statuses of the dispensing mechanism viewed along the longitudinal direction; 
         FIG.  30    is an exploded perspective view of a pipette-tip feeder of the cell and medicament dispensing device in  FIG.  1   ; 
         FIGS.  31  and  32    are operational schematic side views of the cell and medicament dispensing device in  FIG.  1   , showing operating statuses of the dispensing mechanism and the pipette-tip feeder along the transverse direction; 
         FIGS.  33  to  36    are operational schematic side views of the cell and medicament dispensing device in  FIG.  1   , showing operating statuses for replacing pipette-tips viewed along the transverse direction; 
         FIG.  37    is a schematic side view of the cell and medicament dispensing device in  FIG.  1   , showing a tip positioning module of the pipette-tip feeder being capable of moving upward and downward; and 
         FIG.  38    is a flow chart of a cell and medicament dispensing method for drug screening in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS.  2 ,  3 ,  6 ,  24 ,  25 , and  27   , a cell and medicament dispensing device for drug screening in accordance with the present invention is configured to inject multiple solutions  91  into multiple solution recesses  921  of a transfer plate  92 , and then liquid inside each of the solution recesses  921  is dispensed into multiple wells  941  (as shown in  FIG.  24   ) of a cell culture plate  94  with a pipette  93 . Each of the solutions  91  comprises one single type of medicament or one single type of cells. At least one cylindrical pipette-tip  95  (as shown in  FIG.  32   ) is detachably connected to a tip connector  931  (as shown in  FIG.  25   ) at bottom of the pipette  93 . The cell culture plate  94  preferably has an upper lid  942  detachably covering the wells  941 . 
     With reference to  FIGS.  2  to  4   , the cell and medicament dispensing device has a base  10 , a transfer plate serving mechanism  21 , a transfer plate positioning mechanism  30 , an injection mechanism  40 , a cell culture plate positioning mechanism  60 , and a dispensing mechanism  80 . In the present embodiment, the cell and medicament dispensing device further has a cell culture plate conveyer  50 , a pipette-tip feeder  70 , and a transfer plate retriever  22 . 
     The base  10  has a transfer plate entrance area  101 , a receiving area  102 , and a dispensing area  103  disposed thereon. The transfer plate entrance area  101 , the receiving area  102 , and the dispensing area  103  are disposed apart from each other along a longitudinal direction L of the base  10 . 
     With reference to  FIGS.  5  to  7   , the transfer plate serving mechanism  21  is mounted on the base  10  and is adjacent to the transfer plate entrance area  101 . A transfer plate  92  is accommodated in the transfer plate serving mechanism  21 , and the transfer plate serving mechanism  21  is capable of moving the transfer plate  92  to the transfer plate entrance area  101  of the base  10 . In the preferred embodiment, the transfer plate serving mechanism  21  has a plate stacking bracket  211 , two plate-locking clamps  212 , a plate feeder  213 , and a plate lifting actuator  214 . 
     With reference to  FIGS.  8  and  9   , the plate stacking bracket  211  forms a stacking space. The stacking space is configured to accommodate multiple spare transfer plates  96  that are stacked vertically. A plate dropping opening  2111  is formed in a bottom of the plate stacking bracket  211 . The spare transfer plates  96  in the stacking space are capable of dropping down through the plate dropping opening  2111 . 
     Each of the two plate-locking clamps  212  is mounted on a respective side of two opposite sides of the plate dropping opening  2111 . The two plate-locking clamps  212  are capable of moving toward each other to prevent the spare transfer plates  96  from passing through the plate dropping opening  2111 . 
     The plate feeder  213  is mounted under the plate dropping opening  2111  and is configured to receive the transfer plate  92  or the spare transfer plates  96  dropping down from the plate dropping opening  2111 . With reference to FIGS. and  11 , the plate feeder  213  is capable of moving to the transfer plate entrance area  101  on the base  10 . With reference to  FIGS.  8  and  9   , the plate feeder  213  has a plate lifting opening  2131  which is formed through two opposite sides of the plate feeder  213 . With reference to  FIGS.  7  and  8   , the plate lifting actuator  214  is mounted under the plate lifting opening  2131  and capable of moving upward to protrude through the plate lifting opening  2131 . 
     The transfer plate positioning mechanism  30  is mounted on the base  10  and adjacent to the transfer plate serving mechanism  21 . The transfer plate positioning mechanism  30  has a positioning slider  31 , a first plate linear module  32 , a second plate linear module  33 , a sliding plate-cover  34 , a cover driving motor  35 , and a cover gear rack  36 . 
     With reference to  FIGS.  6 ,  7 , and  14  to  16   , the positioning slider  31  is configured to connect with the transfer plate  92 . The positioning slider  31  is movably mounted on the base  10  and selectively corresponds in position to the transfer plate entrance area  101 , the receiving area  102 , or the dispensing area  103 . 
     To be specific, the first plate linear module  32  is mounted on the base  10  and extends along a transverse direction T of the base  10 . The second plate linear module  33  is mounted on the first plate linear module  32  and extends along the longitudinal direction L of the base  10 . The positioning slider  31  is mounted on the second plate linear module  33  such that the positioning slider  31  is movable in both the longitudinal direction L and transverse direction T. 
     In the preferred embodiment, the plate feeder  213  of the transfer plate serving mechanism  21  is movable to a position above the positioning slider  31 , and the positioning slider  31  is capable of moving upward and downward such that the transfer plate  92  can be transferred from the plate feeder  213  to the positioning slider  31 . Detailed operating steps of the positioning slider  31  are as described below. 
     1. With reference to  FIGS.  10  to  11   , the positioning slider  31  moves to the transfer plate entrance area  101 , and the plate feeder  213  moves to the position above the positioning slider  31 . 
     2. With reference to  FIGS.  11  and  12   , the positioning slider  31  moves upward to protrude through the plate feeder  213  via the plate lifting opening such that the transfer plate  92  rested on the plate feeder  213  is lifted by the positioning slider  31  and connected with the positioning slider  31 . 
     3. With reference to  FIGS.  12  and  13   , the plate feeder  213  moves away from the position above the positioning slider  31 , and then the positioning slider  31  moves downward to return to its original height position. 
     With reference to  FIGS.  6 ,  15 , and  16   , the cover driving motor  35  is mounted on the positioning slider  31 . The cover gear rack  36  is mounted on the positioning slider  31 , is movable along the longitudinal direction L, and is coupled to an output axis of the cover driving motor  35 . The sliding plate-cover  34  is fixed to the cover gear rack  36  such that when the cover gear rack  36  moves relative to the positioning slider  31 , the sliding plate-cover  34  is driven by the cover gear rack  36  to move relative to the positioning slider  31 . As a result, the sliding plate-cover  34  is movable to a position above the positioning slider  31  to cover the transfer plate  92  and to prevent foreign objects from falling into the solution recesses  921 . 
     The structure for moving the sliding plate-cover  34  is not limited thereby, as long as the sliding plate-cover  34  is capable of selectively covering the solution recesses  921  of the transfer plate  92 . 
     The injection mechanism  40  is mounted on the base  10  and adjacent to the transfer plate positioning mechanism  30 . The injection mechanism  40  has multiple injection heads  41 . Each of the injection heads  41  is in fluid communication with a respective one of the solutions  91 , and is movable to the receiving area  102  of the base  10 . The aforementioned positioning slider  31  is configured to align any one of the solution recesses  921  of the transfer plate  92  to the injection head  41  that is located in the receiving area  102  such that said injection head  41  injects one of the solutions  91  into the corresponding solution recess  921 . 
     In the preferred embodiment, the injection mechanism  40  has a rotary seat  42  rotatably mounted on the base  10 . The injection heads  41  are mounted on the rotary seat  42  and disposed apart from each other around a rotating axis of the rotary seat  42 . Rotation of the rotary seat  42  moves the injection heads  41  to the receiving area  102  for a given positioning, and then the injection head  41  in the receiving area  102  is aligned to the respective solution recess  921  by controlling the positioning slider  31  to the fine-tune position of the transfer plate  92  in both the longitudinal direction L and the transverse direction T. 
     With reference to  FIGS.  1  and  2   , the cell culture plate conveyer  50  is located on a side of the base  10  and configured to deliver the ready-to-process cell culture plate  94  from a cell culture device (not shown in figures) to the base  10 . Processed cell culture plate  94  is also returned to the cell culture device by the cell culture plate conveyer  50 . 
     The cell culture plate conveyer  50  has an input conveyor belt  51 , an output conveyor belt  52 , and a cell culture plate elevator  53 . The input conveyor belt  51  is configured to deliver the ready-to-process cell culture plate  94  to the cell culture plate positioning mechanism  60 . The output conveyor belt  52  is disposed under the input conveyor belt  51 . The input conveyor belt  51  and the output conveyor belt  52  operate in reverse directions. The cell culture plate elevator  53  is mounted to an end of the input conveyor belt  51 , and is capable of moving downward to an end of the output conveyor belt  52  to transfer the cell culture plate  94  from the input conveyor belt  51  to the output conveyor belt  52 . 
     With reference to  FIGS.  17  and  18   , the cell culture plate positioning mechanism  60  is mounted on the base  10  and configured to connect with the cell culture plate  94 . The cell culture plate positioning mechanism  60  has a positioning seat  61  and a primary positioning module  62 ; in the preferred embodiment, the cell culture plate positioning mechanism  60  further has a lid opener  63 , multiple suction cups  64 , a cell culture plate transfer module  65 , and a secondary positioning module  66 . 
     The positioning seat  61  is mounted on the base  10  and configured to accommodate the cell culture plate  94 . In the preferred embodiment, the cell culture plate  94  is automatically delivered to the positioning seat  61  by the cell culture plate conveyer  50 . Processed cell culture plates  94  are also returned to the cell culture device by the cell culture plate conveyer  50 . 
     With reference to  FIGS.  21  and  22   , the primary positioning module  62  is mounted on the positioning seat  61  and configured to clamp the two opposite sides of the cell culture plate  94 . To be precise, the primary positioning module  62  is a 2-Jaw parallel gripper, and can be controlled to clamp the cell culture plate  94  such that a position of the cell culture plate  94  in the transverse direction T is fixed. The primary positioning module  62  preferably clamps the two opposite sides of the cell culture plate  94  that face toward and move longitudinally away from the transverse direction T. 
     With reference to  FIGS.  23  and  24   , the lid opener  63  is mounted above the positioning seat  61 . The lid opener  63  is capable of moving upward and downward, and is capable of moving sideways. The lid opener  63  is movable to a position above the cell culture plate  94 . The suction cups  64  are mounted on a bottom surface of the lid opener  63  and are configured to adhere to the upper lid  942  of the cell culture plate  94 . In the preferred embodiment, the suction cups  64  are connected to a vacuum generator (not shown in figures) such that the suction cups  64  are adhered to the upper lid  942  by vacuum pressure. In another preferred embodiment, one suction cup  64  is sufficient for adhering to the upper lid  942 . 
     With reference to  FIGS.  18  to  20   , the cell culture plate transfer module  65  is mounted in the positioning seat  61 , and is preferably a pair of parallel conveyer belts. The cell culture plate transfer module  65  is capable of moving the cell culture plate  94  rested on the positioning seat  61  toward or away from the cell culture plate conveyer  50 . 
     The secondary positioning module  66  is mounted in the positioning seat  61 , is capable of moving upward or downward, and is configured to lift the cell culture plate  94  rested on the positioning seat  61 . When the cell culture plate  94  is lifted by the secondary positioning module  66 , two ends of the secondary positioning module  66  attach two opposite sides of the cell culture plate  94  facing toward or moving along with the longitudinal direction L to fix a position of the cell culture plate  94  in the longitudinal direction L. 
     Detailed operating steps of the cell culture plate positioning mechanism  60  are as described below. 
     1. The cell culture plate conveyer  50  delivers a ready-to-process cell culture plate  94  to the positioning seat  61 . The cell culture plate transfer module  65  roughly adjust a position of the cell culture plate  94  on the positioning seat  61 . 
     2. With reference to  FIGS.  19  and  20   , the secondary positioning module  66  moves upward to lift the cell culture plate  94  and fix the position of the cell culture plate  94  in the longitudinal direction L. 
     3. With reference to  FIGS.  21  and  22   , the primary positioning module  62  clamps the two opposite sides of the cell culture plate  94  that face toward and move longitudinally away from the transverse direction T such that a position of the cell culture plate  94  in the transverse direction T is fixed. 
     4. With reference to  FIG.  23   , the lid opener  63  moves downward to adhere to the upper lid  942  with the suction cups  64 , and then the lid opener  63  moves upwards to separate the upper lid  942  from the cell culture plate  94 . 
     5. With reference to  FIGS.  23  and  24   , the lid opener  63  moves sideways away from the position above the cell culture plate  94  to uncover partially the wells  941  of the cell culture plate  94 . 
     With reference to  FIGS.  30  to  32   , the pipette-tip feeder  70  is mounted on the base  10  and configured to deliver pipette-tips  95  packed in boxes. The pipette-tip feeder  70  has an input conveyer belt  71 , an output conveyer belt  72 , a tip positioning module  73 , a sliding tip cover  74 , and at least one UV lamp  75 . 
     The tip positioning module  73  is mounted on an end of the input conveyer belt  71 . The output conveyer belt  72  is mounted under the input conveyer belt  71 . The output conveyer belt  72  and the input conveyer belt  71  operate in opposite directions. The tip positioning module  73  is capable of moving downward to align with an end of the output conveyer belt  72 . The input conveyer belt  71  is configured to deliver unused pipette-tips  95  packed in boxes to the tip positioning module  73 , and then the tip positioning module  73  fine-tunes a position of the pipette-tip  95  for other mechanism of the present invention. 
     The sliding tip cover  74  is movably mounted on the input conveyer belt  71  and is movable to a position above the tip positioning module  73  to cover partially the pipette-tips  95  in use, thereby preventing the pipette-tips  95  unused yet from being contaminated. At least one UV lamp  75  is mounted in an inner surface of the sliding tip cover  74  to maintain the unused pipette-tips  95  in a sterilized condition with ultraviolet irradiation. 
     With reference to  FIGS.  25  to  27   , the dispensing mechanism  80  is mounted on the base  10 . The dispensing mechanism  80  has a dispensing seat  81 . In the preferred embodiment, the dispensing mechanism  80  further has a first dispensing linear module  82 , a second dispensing linear module  83 , a third dispensing linear module  84 , a tip ejector  85 , a tilt actuator  86 , and a pivot axle  87 . 
     The dispensing seat  81  is configured to fix the pipette  93  and configured to control aspirate and discharge operation of the pipette  93 . The dispensing seat  81  is movable relative to the base  10  and is movable back and forth between a position above the dispensing area  103  of the base  10  and a position above the cell culture plate positioning mechanism  60 . When the dispensing seat  81  is above the dispensing area  103 , the dispensing seat  81  is configured to insert the pipette  93  with the at least one pipette-tip  95  into any one of the solution recesses  921  of the transfer plate  92  and execute the aspirate operation of the pipette  93  to draw up liquid inside the solution recess  921 . When the dispensing seat  81  is above the cell culture plate positioning mechanism  60 , the dispensing seat  81  executes the discharge operation of the pipette  93  to release the solution  91  aspired in the at least one pipette-tip  95  into one of the wells  941  of the cell culture plate  94 . 
     In the preferred embodiment, the dispensing seat  81  moves and inserts the pipette-tip  95  into the wells  941  via the first dispensing linear module  82 , the second dispensing linear module  83 , and the third dispensing linear module  84 . To be specific, the first dispensing linear module  82  is mounted on the base and extends in the transverse direction T. The second dispensing linear module  83  is mounted on the first dispensing linear module  82  and extends in the longitudinal direction L. The third dispensing linear module  84  is mounted on the second dispensing linear module  83  and extends in vertical direction. The dispensing seat  81  is mounted on the third dispensing linear module  84 . As a result, the dispensing seat  81  has 3 degrees of freedom via the dispensing linear modules  82 ,  83 , and  84 . 
     Additionally, the dispensing seat  81  in this embodiment is movable to a position above the tip positioning module  73  of the pipette-tip feeder  70 , and then the dispensing seat  81  is movable toward the tip positioning module  73  to connect with the new pipette-tips  95 . Furthermore, the dispensing seat  81  is pivotally mounted on the base  10 . Rotation of the dispensing seat  81  relative to the base  10  is capable of aligning the tip connectors  931  of the pipette  93  with pipette-tips  95  on the tip positioning module  73  such that the centerline of the tip connectors  931  are parallel to the centerline of the pipette-tips  95 ; the rotation of the dispensing seat  81  relative to the base  10  is also capable of making the centerline of the tip connectors  931  inclined to the centerline of the pipette-tips  95 . 
     With reference to  FIGS.  25 ,  32 , and  33   , to be precise, the dispensing seat  81  is pivotally mounted on a connecting seat  841  of the third dispensing linear module  84  via the pivot axle  87 , and the pivot axle  87  is nonparallel to the tip connectors  931 . To be more precise, the pivot axle  87  substantially extends in the transverse direction T, and the pivot axle  87  is substantially perpendicular to the tip connectors  931 . As a result, the rotation of the dispensing seat  81  is capable of adjusting the centerline of the tip connectors  931  by the vertical line; it means that the rotation of the dispensing seat  81  is also capable of tilting the tip connectors  931  such that the centerline of the tip connectors  931  form an adjustable angle with the vertical line. 
     In the preferred embodiment, the tilt actuator  86  is a linear actuator mounted on the connecting seat  841 . A shaft  861  of the tilt actuator  86  is connected to the dispensing seat  81  to control a rotating angle of the dispensing seat  81  around the pivot axle  87 . 
     The tip ejector  85  is mounted on the dispensing seat  81  and configured to press against the pipette  93  to remove the pipette-tip  95  from the pipette  93 . With reference to  FIG.  26   , the tip ejector  85  has a motor  851  and a rack  852 , and the motor  851  drives the rack  852  to press against a release button (not shown in figures) on the pipette  93  to remove the pipette-tip  95  from the pipette  93 . 
     Coordination between the pipette-tip feeder  70  and the dispensing mechanism  80  makes automatic replacement of the pipette-tips  95  possible, and detailed operating steps are as described below. 
     1. The tip ejector  85  presses against the release button on the pipette  93  to remove the pipette-tips  95  from the pipette  93 . 
     2. With reference to  FIGS.  29  and  31   , the dispensing seat  81  moves to the position above the tip positioning module  73 . 
     3. With reference to  FIG.  32   , the sliding tip cover  74  moves oppositely away from the tip positioning module  73  to reveal the pipette-tips  95  on the tip positioning module  73 . 
     4. With reference to  FIG.  33   , the dispensing seat  81  is tilted by the tilt actuator  86  such that the centerline of the tip connectors  931  form an angle with the vertical line. 
     5. With reference to  FIGS.  33  and  34   , the dispensing seat  81  moves downward to partially insert a distal end  9311  (as shown in  FIG.  33   ) of each of the tip connectors  931  into a respective one of the pipette-tips  95 . 
     6. With reference to  FIGS.  35  and  36   , the tilt actuator  86  gradually straightens the dispensing seat  81  to align the centerline of the tip connectors  931  to match with the vertical line again. In the meantime, the dispensing linear modules  82 ,  83 , and  84  drive the dispensing seat  81  to gradually press the tip connectors  931  against the pipette-tips  95  such that the tip connectors  931  are eventually connected with the pipette-tips  95 , and then the dispensing seat  81  moves upward to continue dispensing operation. 
     7. With reference to  FIG.  37   , when the pipette-tips  95  delivered in a box have been depleted, the tip positioning module  73  moves downward to align with the end of the output conveyer belt  72  to send away the empty box using the output conveyer belt  72 . 
     The box retriever for the box of pipette-tips  95  is substantially similar to the transfer plate serving mechanism  21  aforementioned. The difference between the transfer plate retriever  22  and the transfer plate serving mechanism  21  is that the transfer plate retriever  22  is configured to recycle used transfer plates  92 , and therefore operating procedure of the transfer plate retriever  22  is in a reverse order compared with the transfer plate serving mechanism  21 . That is, the transfer plate retriever  22  detaches the used transfer plates  92  with the transfer plate positioning mechanism  30 , and then stacks the used transfer plates  92  in a bottom-up way. 
     With reference to  FIG.  38   , a cell and medicament dispensing method for drug screening in accordance with the present invention comprises the following steps: the first step (S 1 ) is transfer of cells or solutions; the second step (S 2 ) is dispensing of cells or solutions. The cell and medicament dispensing method is performed by the aforementioned cell and medicament dispensing device, but not limited thereto. 
     The first step (S 1 ) is transfer of cells or solutions. With reference to  FIGS.  10  to  15   , the plate feeder  213  of the transfer plate serving mechanism  21  moves the transfer plate  92  to the transfer plate entrance area  101  on the base  10 . The transfer plate  92  has multiple solution recesses  921  as aforementioned. The positioning slider  31  of the transfer plate positioning mechanism  30  moves to the transfer plate entrance area  101  and connects with the transfer plate  92 . The positioning slider  31  moves the transfer plate  92  to the receiving area  102  of the base  10 . 
     With reference to  FIGS.  3 ,  6 , and  15   , the injection mechanism  40  injects multiple solutions  91  into the solution recesses  921  of the transfer plate  92 . Each of the solution recesses  921  may be injected with one single solution  91 , or may be injected with multiple kinds of the solutions  91 . Each of the solutions  91  comprises one single type of medicament or cells. In the preferred embodiment, the sliding plate-cover  34  partially covers the openings of the solution recesses  921  to prevent foreign objects from falling into the unused part of solution recesses  921 . 
     With reference to  FIGS.  8  and  9   , multiple spare transfer plates  96  can be stacked on the transfer plate serving mechanism  21 . After the plate feeder  213  moves the transfer plate  92  to the transfer plate entrance area  101  of the base  10 , the transfer plate serving mechanism  21  moves the bottommost spare transfer plate  96  to the plate feeder  213 . By moving the bottommost spare transfer plate  96  first, risk of foreign objects falling into the spare transfer plate  96  is minimized. 
     In the preferred embodiment, the plate-locking clamps  212  first move away from each other, allowing the spare transfer plate  96  to drop down. In the meantime, the plate lifting actuator  214  moves upward and protrudes through the plate lifting opening  2131  such that only the bottommost spare transfer plate  96  is located under the plate dropping opening  2111 , keeping the other spare transfer plates  96  still above the plate dropping opening  2111 . Then, the plate-locking clamps  212  move toward each other to prevent the other spare transfer plates  96  from dropping through the plate dropping opening  2111 , and then the plate lifting actuator  214  moves downward to its original position such that the bottommost spare transfer plate  96  can stay and fix on the plate feeder  213 . 
     The second step (S 2 ) is dispensing of cells or solutions. With reference to  FIGS.  14  to  16   , the positioning slider  31  moves the transfer plate  92  to the dispensing area  103  on the base  10 . The cell culture plate  94  has multiple wells  941  as aforementioned. The dispensing mechanism  80  moves the pipette  93  back and forth between the position above the dispensing area  103  and the position above the cell culture plate  94  to dispense liquid in each of the solution recesses  921  of the transfer plate  92  into the wells  941  of the cell culture plate  94 . 
     In the preferred embodiment, the sliding plate-cover  34  moves away from the transfer plate  92  to uncover one of the openings of the solution recesses  921 . After the pipette  93  dispenses liquid in said one of the openings of the solution recesses  921 , the sliding plate-cover  34  moves back toward the transfer plate  92  to cover fully the openings of the solution recesses  921  again. 
     In summary, by coordination among the transfer plate serving mechanism  21 , the transfer plate positioning mechanism  30 , and the injection mechanism  40 , liquids and cells for drug screening are automatically transferred to the solution recesses  921  of the transfer plate  92 . Afterwards, liquid in each of the solution recesses  921  is automatically dispensed into the wells  941  of the cell culture plate  94  by coordination between the transfer plate positioning mechanism  30  and the dispensing mechanism  80 . As a result, the process of drug screening is automated to reduce labor and improve quality significantly. 
     Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure are illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.