Abstract:
Provided are: a cell tray provided with a concave part for supporting a cell aggregate and a hole formed on the bottom of the concave part; and a device for producing a cell structure, said device being provided with the cell tray and a puncture part passing through the cell tray and the cell aggregate, characterized in that the puncture part passes through the cell aggregate supported by the concave part until the tip thereof intrudes into the hole. Also provided is a system for producing a cell structure, said system comprising: a determination part that examines the characteristics of cell aggregates; a fractionation part that classifies the cell aggregates depending on the results of the examination by the determination part; a discharge part that disposes the cell aggregates in a cell tray depending on the results of the classification by the fractionation part; a puncture part that pass through a plurality of cell aggregates disposed in the cell tray; and a holding part that aligns and holds a plurality of puncture parts passing through a plurality of cell aggregates.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a cell tray, and a device, a method and a system for producing a three-dimensional cell structure. 
       BACKGROUND ART 
       [0002]    Conventionally, a technique in which a plurality of cell aggregates are stacked to form a three-dimensional structure is known. In this technique, a plurality of cell aggregates that are arranged on a culture plate are picked up and pierced on each of needle-shaped bodies protruding from a support to contact each other. After the cell aggregates have fused with each other, the cell aggregates are pulled out from the needle-shaped body thereby obtaining a three-dimensional cell structure. Various techniques are known for picking up the cell aggregates arranged on a culture plate and pierce them on a needle-shaped body. Patent Document 1 discloses a technique in which a cell aggregate on a culture plate is sucked into a pipette and then transferred to a needle-shaped body, where pressure is applied to the cell aggregate for piercing the cell aggregate on the needle-shaped body, a technique in which a cell aggregate on a culture plate is held and transferred with a small-sized robot arm to be pierced on a needle-shaped body, and a technique in which a cell aggregate on a culture plate is held with tweezers to be pierced on a needle-shaped body. Patent Document 2 discloses a technique in which a cell aggregate on a culture plate is sucked on a tip of a suction nozzle that has a diameter smaller than the diameter of the cell aggregate, and pushed against a needle-shaped body until the needle-shaped body penetrates from the tip to inside of the suction nozzle, thereby piercing the cell aggregate on the needle-shaped body. 
       RELATED ART 
     Patent Documents 
       [0003]    [Patent Document 1] International Publication No. WO2008123614 
         [0004]    [Patent Document 2] International Publication No. WO2012176751 
       SUMMARY OF THE INVENTION 
       [0005]    According to the conventional techniques, however, the step of picking up a cell aggregate from a culture plate through the step of piercing the cell aggregate on a needle-shaped body needs to be carried out as a sequential manner, which requires time. In addition, since the position of the cell aggregate on the culture plate as well as the position of the needle-shaped body are unknown, there is a need for detecting the positions of the cell aggregate and the needle-shaped body by an image recognition technique. In this case, detection result may vary depending on the optical characteristics of the detected object and the lighting conditions, causing increase in the processing time and decrease in yield. 
         [0006]    The present invention was made in view of these problems, and has objectives of achieving a cell tray that is capable of easily piercing a plurality of cell aggregates, and a device, a method and a system for producing a cell structure. 
         [0007]    A cell tray according to the first invention of the present application is characterized by comprising a concave part configured to support a cell aggregate, and a through part provided at the bottom of the concave part, through which a needle-shaped member can pass. Preferably, the through part comprises a soft material configured to allow a needle-shaped member to pass therethrough. Alternatively, the through part may comprise a hole. The cell tray may further comprise a flat part that is provided at the bottom of the concave part and that has a planar surface substantially perpendicular to the advancing direction of the needle-shaped member. Preferably, the cell tray further comprises a marker configured to indicate the concave part. In addition, the diameter of the hole is preferably smaller than the diameter of the cell aggregate. While a cell aggregate or a mixed cluster of cells and a scaffold material such as collagen may be used, the cell aggregate is preferred. The device for producing a cell structure may further comprise a receiving member configured to hold liquid. 
         [0008]    According to the second invention of the present application, the device for producing a cell structure is characterized by comprising a cell tray including a concave part configured to support a cell aggregate and a through part provided at the bottom of the concave part, and a puncturing unit configured to pierce the cell aggregate, and the puncturing unit configured to pierce the cell aggregate supported by the concave part until the tip of the puncturing unit intrudes into the hole. 
         [0009]    Preferably, the cell tray comprises a plurality of concave parts and a plurality of through parts, and the puncturing unit that has pierced the cell aggregate is configured to further pierces a cell aggregate disposed in other concave part until the puncturing unit intrudes into the other through part. The through part is a hole which may have a bottom and acylindrical hole. Preferably, the device for producing a cell structure further comprises a receiving member that is configured to hold liquid, wherein the liquid held in the receiving member is configured to enter the concave part. Preferably, the concave part comprises a mortar shape, and the hole comprises a cylindrical shape, wherein the concave part is coaxial with the hole. Preferably, the puncturing unit comprises a plurality of needle-shaped bodies arranged in a line, and the plurality of concave parts are regularly arranged, and the distance between the centers of the adjacent concave parts is equal to the distance between the centers of the adjacent needle-shaped bodies. While a cell aggregate or a mixed cluster of cells and a scaffold material such as collagen may be used, the cell aggregate is preferred. 
         [0010]    A method according to the third invention of the present application is characterized by comprising the step of piercing the puncturing unit into a cell aggregate disposed in a concave part until the puncturing unit intrudes into the through part of the cell tray. 
         [0011]    A method for producing a cell structure according to the fourth invention of the present application is characterized by comprising the steps of: disposing a cell aggregate into a concave part of the cell tray; and piercing the puncturing unit into the cell aggregate disposed in the concave part until the puncturing unit intrudes into the through part provided at the bottom of the concave part. 
         [0012]    Preferably, the concave parts and the through parts are more than one, where the disposing step is a step of disposing a cell aggregate in each of the plurality of concave parts and the piercing step is repeated to further pierce the puncturing unit into a cell aggregate disposed in other concave part. Preferably, the method for producing a cell structure further comprises the steps of: arranging the plurality of puncturing units piercing the plurality of cell aggregates such that the cell aggregates make contact with each other; and pulling the puncturing units out from the cell aggregates after the cell aggregates have fused with each other. Preferably, the method further comprises the step of sorting the cell aggregates, wherein the disposing step is a step of disposing the cell aggregates sorted in the sorting step. 
         [0013]    A system for producing a cell structure according to the fifth invention of the present application is characterized by comprising: a determination unit configured to examine a characteristic of a cell aggregate; a sorting unit configured to sort the cell aggregate according to the examination result from the determination unit; a dispensing unit configured to dispose the cell aggregate into the cell tray according to the sorting result from the sorting unit; a puncturing unit configured to pierce the plurality of cell aggregates disposed in the cell tray; and a retaining member configured to arrange and retain the plurality of puncturing units that have pierced the plurality of cell aggregates. 
         [0014]    Preferably, the system further comprises a post-processing module comprising an assembling unit configured to house the plurality of retaining members such that the cell aggregates make contact with each other; a first circulating unit configured to circulate liquid inside the retaining member and a second circulating unit configured to circulate liquid outside the retaining member inside the assembling unit. Preferably, the cell tray comprises: a base; a concave part provided in the base and configured to support a cell aggregate; and a through part provided at the bottom of the concave part, wherein the puncturing unit configured to pierce the cell aggregate supported by the concave part until the tip of the puncturing unit intrudes into the through part. 
         [0015]    The present invention provides a cell tray that is capable of easily piercing a plurality of cell aggregates, and a device, a method and a system for producing a cell structure. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0016]      FIG. 1  A cross-sectional view schematically showing a cell tray and a table carrying cell aggregates. 
           [0017]      FIG. 2  A partial plan view schematically showing a part of the cell tray and the table. 
           [0018]      FIG. 3  A block diagram schematically showing a stacking module. 
           [0019]      FIG. 4  A view showing a step of piercing cell aggregates. 
           [0020]      FIG. 5  A view showing the step of piercing cell aggregates. 
           [0021]      FIG. 6  A view showing the step of piercing cell aggregates. 
           [0022]      FIG. 7  A block diagram schematically showing a sorter module. 
           [0023]      FIG. 8  A block diagram schematically showing a post-processing module. 
           [0024]      FIG. 9  A perspective view schematically showing a collecting unit. 
           [0025]      FIG. 10  A block diagram schematically showing a sorter. 
           [0026]      FIG. 11  A perspective view schematically showing an aligning frame. 
           [0027]      FIG. 12  A plan view showing an aligning frame placed with needles piercing cell aggregates. 
           [0028]      FIG. 13  A side view showing stacked aligning frames. 
           [0029]      FIG. 14  A perspective view of a three-dimensional cell structure. 
           [0030]      FIG. 15  An end face view schematically showing a cell tray. 
           [0031]      FIG. 16  A view showing a step of piercing cell aggregates. 
           [0032]      FIG. 17  A plan view showing an aligning frame placed with needles piercing cell aggregates. 
           [0033]      FIG. 18  A perspective view of a three-dimensional cell structure. 
           [0034]      FIG. 19  A partial cross-sectional view of the cell tray. 
           [0035]      FIG. 20  Partial cross-sectional view of the cell tray. 
           [0036]      FIG. 21  Partial cross-sectional view of the cell tray. 
       
    
    
     DESCRIPTION OF REFERENCE NUMERALS 
       [0000]    
       
           5  Plate 
           10  Sorter module 
           11  Cell aggregate feeder 
           12  Collecting unit 
           12   a  Pipetter 
           12   b  Cylindrical pipe 
           12   c  Pipe supporter 
           13  Sorter 
           13   a  Hopper section 
           13   b  Flowing section 
           13   c  Determination unit 
           13   d  Sorting unit 
           13   e  Dispensing unit 
           14  Cell tray 
           14   a  Hole 
           14   b  Concave part 
           14   c  Leg part 
           14   d  ID 
           14   e  Base 
           14   f  Surface 
           14   g  Marker 
           14   h  Opening part 
           14   i  Bottom part 
           14   j  Flat part 
           14   k  Through part 
           15  Magazine 
           16  Discarding unit 
           20  Stacking module 
           21  Needle feeder 
           21   a  Needle 
           21   b  Needle holder 
           22  Skewer 
           22   a  Chuck 
           22   b  Laser oscillator 
           22   c  Laser detecter 
           22   d  Position determination unit 
           22   e  Driver 
           24  Table 
           24   a  Ledge 
           25  Assembling unit 
           25   a  Aligning frame 
           25   b  Upper groove 
           25   c  lower groove 
           25   d  Window part 
           25   e  Upper bar 
           25   f  Lower bar 
           25   g  Side bar 
           26  Cell stacking unit 
           30  Post-processing module 
           31  Culture unit 
           32  First circulating unit 
           32   a  First pump 
           32   b  First pipe 
           33  Second circulating unit 
           33   a  Second pump/heater 
           33   b  Second pipe 
       
     
       DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0093]    First, a cell tray  14  and a table (receiving member)  24  according to one embodiment of the present invention will be described with reference to  FIGS. 1 and 2 . 
         [0094]    The cell tray  14  is mainly provided with a base  14   e , holes  14   a , concave parts  14   b  and leg parts  14   c , where the concave parts  14   b  are formed in the base  14   e , and the holes  14   a  are provided at the bottom of the concave parts  14   b . The base  14   e  is a rectangular plate, which is made of a non-cell toxic material such as stainless steel. The holes  14   a  and the concave parts  14   b  penetrate in the thickness direction of the base  14   e . The hole  14   a  and the concave part  14   b  serve as a cell support. The concave part  14   b , for example, is a mortar shape well, which has a predetermined depth in the thickness direction (for example, substantially half the thickness) of the base  14   e  from the surface thereof. At the concave part  14   b , the opening part  14   h  that opens at the surface  14   f  of the base  14   e  and the bottom part  14   i  formed inside the base  14   e  are circular, where the diameter of the opening part  14   h  is longer than the diameter of the bottom part  14   i . The cross-section across the axis of the concave part  14   b  has a truncated cone shape. The hole  14   a  has a cylindrical shape, where the diameter of the hole  14   a  equals the diameter of the bottom part  14   i . The cross-section across the axis of the hole  14   a  has a rectangular shape. The hole  14   a  and the concave part  14   b  are formed coaxially. The leg part  14   c  is formed from the same material as the base  14   e , and elongates from the end of the base  14   e  towards the thickness direction of the base  14   e . Accordingly, when the cell tray  14  is placed on the table  24 , a space is formed between the bottom surface of the table  24  and the base  14   e . Referring to  FIG. 2 , the concave parts  14   b  are regularly arranged in a matrix on the surface  14   f . In each column, the distances between the centers of the adjacent concave parts  14   b  are equal. 
         [0095]    The surface  14   f  of the base  14   e  is provided with an ID  14   d  and markers  14   g . The ID  14   d  is a code specific to the cell tray  14 , which serves as an identifier for individual cell tray  14  and is indicated on the surface  14   f . The markers  14   g  are, for example, four line segments indicated around the concave part  14   b  on the surface  14   f . Two markers  14   g  are arranged on each of the two straight lines that are orthogonal to the center axis of the concave part  14   b  and that are orthogonal to each other. As described above, the concave part  14   b  has a mortar shape while the cell aggregate is substantially spherical. Therefore, when a cell aggregate is disposed in the concave part  14   b , the cell aggregate partially fits into the hole  14   a  and thus the cell aggregate is naturally positioned at the center of the concave part  14   b . Moreover, the center of the cell aggregate is substantially at a position where the straight lines connecting the markers  14   g  meet. Here, the cell aggregate may be a cell aggregate (cell aggregate) or a mixed cluster of cells and a scaffold material such as collagen, while it is preferably a cell aggregate. 
         [0096]    The table  24  is a receiving pan with a shape and a size capable of accommodating the entire cell tray  14 . The cell tray  14  and a buffer liquid such as a phosphate buffered saline or a culture solution containing a physiologically active substance are placed inside the table  24 . The amount of the buffer liquid or the culture solution is an amount that allows the cell tray  14  to be entirely immersed in the buffer liquid or the culture solution so that the cell aggregate does not exposed to air. The table  24  is provided with a plurality of aligning ledges  24   a . The aligning ledge  24   a  has a substantially cuboid shape and protrudes inward from the inner side surface as well as the bottom surface of the table  24 . Two at each corner, i.e., a total of eight ledges  24   a , are provided. The aligning ledges  24   a  protruding from the bottom surface of the table  24  has a length such that it engages with the leg part  14   c  to immobilize the cell tray  14 . The length of the aligning ledges  24   a  protruding from the inner side surface of the table  24  is such that the cell tray  14  can be fixed at a given position inside the table  24 . the buffer liquid or the culture solution can easily pass through the hole  14   a.    
         [0097]    Next, a cell stacking unit (device for producing a cell structure)  26  according to one embodiment of the present invention will be described with reference to  FIG. 3 . 
         [0098]    The cell stacking unit  26  is mainly provided with a cell tray  14 , a skewer  22  and a table  24 . 
         [0099]    The skewer  22  is mainly provided with a chuck  22   a , a laser oscillator  22   b , a laser detecter  22   c , a position detection unit  22   d  and a driver  22   e . The chuck  22   a  picks up and retains a needle  21   a  from a needle feeder  21  described below. The needle  21   a  has a conical needle-shaped body that is made from a non-cell adhesive material such as stainless steel. The diameter of the cross-section of the needle  21   a  can be any diameter that does not disrupt the cell aggregate upon piercing the cell aggregate and that does not prevent fusion of the cell aggregates. For example, the diameter may be 50 micrometers to 300 micrometers. The term “non-cell adhesive” refers to a property that can interfere a cell from adhering via an extracellular adhesion factor. The laser oscillator  22   b  radiates a laser beam towards the cell tray  14  placed on the table  24 . The laser detecter  22   c  receives the light reflected from the cell tray  14 . The position detection unit  22   d  calculates the positional relationship between the needle  21   a  and the cell tray  14  based on the reflected light, and determines the drive amount of the needle  21   a  based on the positional relationship. The procedure for calculating the positional relationship will be described below. Based on the drive amount determined by the position detection unit  22   d , the driver  22   e  drives the chuck  22   a  to stick the needle  21   a  into the cell aggregate disposed on the cell tray  14 . Furthermore, the driver  22   e  moves the needle  21   a  piercing the cell aggregate to an assembling unit  25 . 
         [0100]    Here, the material of the needle  21   a  and the cell tray  14  is not limited to stainless steel, and may be, but not limited to, other non-cell adhesive material: specifically, a resin such as polypropylene, nylon, a material with a fluorine-coated surface, Teflon (registered trademark), poly-HEMA, an acrylic plate, a vinyl chloride plate, an ABS resin plate, a polyester resin plate or a polycarbonate plate, or an engineering plastic such as PP (polypropylene), ABS (acrylonitrile butadiene styrene), PE (polyethylene), POM (polyacetal), PC (polycarbonate), PEEK (polyether ether ketone), MCN (monomer casting nylon), 6N (6 nylon) and 66N (66 nylon). Besides these materials, a material with a lower cell adhesion property may be used. 
         [0101]    Next, with reference to  FIGS. 4 to 6 , the process for the needle  21   a  to pierce a plurality of cell aggregates will be described. In the following description, the aligning ledges  24   a  are provided between the edge of the leg part  14   c  and the bottom of the table  24 . First, the laser oscillator  22   b  irradiates a laser beam toward the cell tray  14  placed on the table  24 . Then, the laser detecter  22   c  receives the light reflected from the cell tray  14 . The position detection unit  22   d  confirms the position of the marker  14   g  based on the luminance of the reflected light, by which calculates the positional relationship between the needle  21   a  and the cell tray  14 . Then, the position detection unit  22   d  determines the drive amount of the needle  21   a  based on the calculated positional relationship. The driver  22   e  drives the chuck  22   a  based on the drive amount determined by the position detection unit  22   d  to move the needle  21   a  a immediately above the cell aggregate  101   a  disposed on the cell tray  14 . Subsequently, the driver  22   e  lowers the needle  21   a  toward the cell aggregate  101   a  to pierce the cell aggregate  101   a . As the needle  21   a  is lowered for a predetermined length, the tip of the needle  21   a  intrudes into the hole  14   a . By providing the hole  14   a , the needle  21   a  can pierce the cell aggregate  101   a  only for the predetermined length. After lowering the needle  21   a  for a predetermined length, the driver  22   e  raises the needle  21   a . At this point, the needle  21   a  is stuck in the cell aggregate. Then, the laser oscillator  22   b , the laser detecter  22   c , the position detection unit  22   d  and the driver  22   e  again conduct the same processes as described to move the needle  21   a  immediately above the next cell aggregate  101   b  to pierce the next cell aggregate  101   b  (see  FIG. 5 ). By repeating these processes for desired times, a desired number of cell aggregates can be pierced into the needle  21   a  (see  FIG. 6 ). The amount of lowering the needle  21   a  toward the cell aggregate is determined according to the size of the cell aggregates and the number of the cell aggregates to be pierced, that is, according to the position of the cell aggregates on the needle  21   a . Specifically, the lowering length is the longest when the first cell aggregate is pierced with the needle  21   a , and the lowering length becomes slightly shorter than the diameter of the next cell aggregate. By slightly shortening the lowering length, the cell aggregates contact to each other and thus can easily be fused with each other. By repeating these processes, a plurality of needles  21   a  each piercing a plurality of cell aggregates can be obtained. Here, the first cell aggregate may be pierced for a shorter lowering length, i.e., shallower, than the lowering length shown in  FIG. 4 , and the lowering length may be determined such that the first cell aggregate is further moved by the subsequently pierced second cell aggregate. After piercing the desired number of cell aggregates with the needle  21   a , the driver  22   e  moves the needle  21   a  piercing the cell aggregates to the assembling unit  25  described below. 
         [0102]    Next, a system for producing a cell structure according to one embodiment of the present invention will be described with reference to  FIGS. 7 to 14 . The system for producing a cell structure is mainly provided with a cell tray  14 , a sorter module  10  (see  FIG. 7 ), a stacking module  20  and a post-processing module  30  (see  FIG. 8 ). 
         [0103]    Referring to  FIG. 7 , the sorter module  10  will be described. The sorter module  10  is mainly provided with a cell aggregate feeder  11 , a collecting unit  12 , a sorter  13 , a cell tray  14 , a magazine  15  and a discarding unit  16 , and has a function of disposing cell aggregates into the cell tray  14 . 
         [0104]    The cell aggregate feeder  11  incorporates a plate  5  placed with cell aggregates from outside the sorter module  10 . The plate  5  will be described below. The magazine  15  houses a plurality of cell trays  14 . The cell tray  14  housed in the magazine  15  is transported with a feeder (not shown) to the sorter  13 . 
         [0105]    The collecting unit  12  will be described with reference to  FIG. 9 . The collecting unit  12  is mainly provided with a pipetter  12   a  and a plate  5 . The pipetter  12   a  is mainly provided with a plurality of cylindrical pipes  12   b  whose tip parts has a diameter larger than the diameter of the cell aggregate, and a pipe supporter  12   c  for arranging and supporting the plurality of cylindrical pipes  12   b  in a line at regular intervals. A plurality of concaves are formed at regular intervals on the plate  5 . The distance between the concaves and the distance between the cylindrical pipes  12   b  are the same. Cells disposed, on the plate  5  will aggregate with each other with time to form a cell aggregate  100 , and settle in these concaves. The end of the cylindrical pipe  12   b  opposite to the tip part is applied with a negative pressure. With the force of this negative pressure, the tip part of the cylindrical pipe  12   b  suck up the cell aggregate  100  disposed on the plate  5 . Specifically, the pipette suctions to dispose the cell aggregate  100  on the tip part. The pipetter  12   a  having the cell aggregate  100  at the tip part of the cylindrical pipe  12   b  feeds the cell aggregate  100  into the sorter  13 . 
         [0106]    The sorter  13  will be described with reference to  FIG. 10 . The sorter  13  is mainly provided with a hopper section  13   a , a flowing section  13   b , a determination unit  13   c , a sorting unit  13   d  and a plurality of dispensing units  13   e , and has a function of examining and sorting the cell aggregate  100  incorporated from the hopper section  13   a  according to the characteristic thereof. The characteristic of the cell aggregate  100  may be the size, the shape and the survival rate of the cell aggregate  100 . The hopper section  13   a  has a funnel, and incorporates and accumulates the cell aggregates  100  from the pipetter  12   a  via the port of the funnel. The flowing section  13   b  is a pipe with an inner diameter that allows the cell aggregates  100  to pass through, and connects the leg of the funnel with the determination unit  13   c , the sorting unit  13   d , the dispensing unit  13   e  and the discarding unit  16 . The determination unit  13   c  tests and determines the characteristic of the cell aggregate  100  and culture solution. The sorting unit  13   d  sends the cell aggregate  100  to the discarding unit  16  or the plurality of dispensing units  13   e  according to the determination result from the determination unit  13   c . Specifically, the cell aggregates  100  are sorted by the determination unit  13   c  and the sorting unit  13   d . The dispensing unit  13   e  disposes the cell aggregates  100  on the concave parts  14   b  of the cell tray  14 . The discarding unit  16  houses the cell aggregate  100  received from the sorting unit  13   d.    
         [0107]    The stacking module  20  will be described with reference to  FIG. 3 . The stacking module  20  is mainly provided with a needle feeder  21 , a skewer  22 , a table  24  and an assembling unit  25 . The needle feeder  21  is mainly provided with a plurality of needles  21   a  having a puncturing unit or a needle-shaped body and a needle holder  21   b . The needle holder  21   b  retains the plurality of needles  21   a . The cell tray  14  housed in the magazine  15  is placed on the table  24  with a tray feeder (not shown) and carried beneath the skewer  22 . 
         [0108]    The assembling unit  25  will be described with reference to  FIGS. 11 to 13 . The assembling unit  25  is provided with an aligning frame  25   a  that serves as a retaining member. The aligning frame  25   a  is a rectangular frame that is provided with a first bar  25   e , a second bar  25   f , two side bars  25   g , a plurality of first grooves  25   b  and a plurality of second grooves  25   c . The first bar  25   e , the second bar  25   f  and the side bar  25   g  have cuboid shapes. The lengths of the first bar  25   e  and the second bar  25   f  are the same, while the lengths of the two side bars  25   g  are the same. The first bar  25   e , the second bar  25   f  and the side bars  25   g  have an expandable mechanism that allows expansion in the longitudinal direction, for example, a telescopic mechanism. Therefore, the lengths of the first bar  25   e , the second bar  25   f  and the side bars  25   g  may appropriately be determined according to the size of the three-dimensional cell structure produced. The first grooves  25   b  are grooves with circular arc-shaped cross-sections, which are provided on one side of the first bar  25   e . The second grooves  25   c  are grooves with circular arc-shaped cross-sections, which are provided on one side of the second bar  25   f . The numbers of the first grooves  25   b  and the second grooves  25   c  are the same, while the axes of the first grooves  25   b  and the second grooves  25   c  coincide. The distance between the adjacent first grooves  25   b  is the same as or slightly shorter than the diameter of the cell aggregate. The same also applies to the second grooves  25   c . Accordingly, the cell aggregates make close contact with each other and thus can easily be fused with each other. Using an expandable mechanism similar to the one described above, the distance between the adjacent first grooves  25   b  and the second grooves  25   c  can be changed according to the diameter of the cell aggregate. The number of the first grooves  25   b  and the second grooves  25   c  may appropriately be determined according to the size of the three-dimensional cell structure produced. The first bar  25   e , the second bar  25   f  and the two side bars  25   g  form a rectangular window part  25   d  inside the aligning frame  25   a . The needle  21   a  that has pierced a plurality of cell aggregates is loosely fitted into the first groove  25   b  and the second groove  25   c .  FIG. 12  shows a state where the needles  21   a  are loosely fitted into all of the first grooves  25   b  and the second grooves  25   c . Referring to  FIG. 13 , the aligning frames  25   a  are stacked in the thickness direction within the assembling unit  25 . The number of the stacked aligning frames  25   a  may appropriately be determined according to the size of the three-dimensional cell structure produced. After stacking a desired number of aligning frames  25   a , an aligning frame  25   a  without any loosely fit needle  21   a  is stacked on so as to fix all of the needles  21   a  in the aligning frame  25   a.    
         [0109]    Next, the post-processing module  30  will be described with reference to  FIG. 8 . The post-processing module  30  is mainly provided with a culture unit  31 , a first circulating unit  32  and a second circulating unit  33 . The culture unit  31  houses the plurality of aligning frames  25   a  that have been stacked in the assembling unit  25 . The first circulating unit  32  is provided with a first pump  32   a  and a first pipe  32   b . The first pump  32   a  is connected to the inside of the aligning frame  25   a  via the first pipe  32   b  to circulate the buffer liquid or the culture solution. Since the buffer liquid or the culture solution contains nutrients, oxygen or the like, the cell aggregate positioned inside the aligning frame  25   a  can be fused without death. The second circulating unit  33  is provided with a second pump/heater  33   a  and a second pipe  33   b . The second pump/heater  33   a  is connected to the inside of the culture unit  31  outside the aligning frame  25   a  via the second pipe  33   b  to circulate a temperature-retaining liquid while maintaining the liquid to stay at a constant temperature. By circulating the temperature-retaining liquid, the cell aggregates can be maintained at a given temperature. After a predetermined period of time in this state, the cell aggregates fuse with each other. Thereafter, all of the needles  21   a  are pulled out the cell aggregates while keeping the cell aggregates housed in the aligning frame  25   a , thereby obtaining a complete three-dimensional cell structure  101  in the aligning frame  25   a  (see  FIG. 14 ). 
         [0110]    According to the invention of the present application, a large number of cell aggregates can easily and rapidly be pierced to rapidly obtain a three-dimensional cell structure with any shape. 
         [0111]    Moreover, by using the cell tray of the invention of the present application, a cell aggregate can easily be disposed at a specific position. In addition, the marker  14   g  can be used to easily specify the position of a cell aggregate, by which the cell aggregate can rapidly be pierced with a needle. 
         [0112]    In the cell tray  14 , the hole  14   a  may not run through the base  14   e  in the thickness direction thereof, and may have a bottomed cylindrical shape (see  FIG. 15 ). The depth of the hole  14   a  has a length that does not allow the tip of the needle  21   a  to touch the bottom of the hole  14   a  as the needle  21   a  is lowered for a predetermined length. By providing the hole  14   a , the needle  21   a  can be pierced into the cell aggregate  101   a  only for a predetermined length. 
         [0113]    In the cell tray  14 , a flat part  14   j  with a substantially horizontal planar surface may be provided between the hole  14   a  and the concave part  14   b  (see  FIG. 19 ). Here, substantially horizontal means a direction that is substantially perpendicular to the advancing direction of the needle. The flat part  14   j  supports the cell aggregate in the direction opposite to the advancing direction of the needle  21   a  as the needle  21   a  pierces the cell aggregate. This can decrease the possibility of the cell aggregate to be dragged by the needle  21   a  into the hole  14   a . Additionally, a through part  14   k  made from a soft material that allows the needle  21   a  to pierce therethrough can be provided at the bottom of the concave part  14   b  (see  FIG. 20 ). The soft material may, for example, be a sponge, a rubber, urethane, silicone or the like. As the needle  21   a  pierces a cell aggregate, the through part  14   k  supports the cell aggregate in the direction opposite to the advancing direction of the needle  21   a . The needle  21   a  that has pierced through the cell aggregate further pierces the through part  14   k . This can decrease the possibility of the cell aggregate to be dragged by the needle  21   a  into the cell tray  14 . Additionally the through part  14   k  can be provided with a hole  14   a  (see  FIG. 21 ). In this case, the inner diameter of the hole  14   a  may be smaller or larger than the outer diameter of the needle  21   a . When the inner diameter of the hole  14   a  is smaller than the outer diameter of the needle  21   a , the needle  21   a  that has pierced through the cell aggregate spreads out the hole  14   a  and further pierces through the through part  14   k . As the needle  21   a  pierces a cell aggregate, the through part  14   k  supports the cell aggregate in the direction opposite to the advancing direction of the needle  21   a . This can decrease the possibility of the cell aggregate to be dragged by the needle  21   a  into the cell tray  14 . 
         [0114]    According to the present invention, the position of the cell aggregate to be pierced with the needle  21   a  can be controlled to produce a cell structure with any shape. For example, with reference to  FIG. 16 , the device for producing a cell structure can also produce a three-dimensional cell structure having a hollow structure. The shape and the size of the hollow structure may arbitrary be designed. For example, a wall surface can be formed with cell aggregates with a hollow inside to produce a cylindrical (tunnel-like) three-dimensional cell structure. When a three-dimensional cell structure produced has a hollow structure, the lowering length of the needle  21   a  toward the cell aggregate is determined according to the size of the hollow structure. Specifically, the lowering length is decreased for a length corresponding to the size of the hollow structure. This allows a space to be provided for a length corresponding to the size of the hollow structure between the cell aggregate  101   a  and the cell aggregate  101   b . The resultants are arranged in the aligning frame  25   a  (see  FIG. 17 ), and cultured in the post-processing module  30  for a predetermined period of time, thereby producing a three-dimensional cell structure having a hollow structure. In a case where a three-dimensional cell structure with a hollow structure is produced, the first circulating unit  32  is capable of delivering nutrients, oxygen or the like contained in the buffer liquid or the culture solution to the cells inside the cell aggregate via the hollow structure. This allows production of a three-dimensional cell structure with a larger volume. 
         [0115]    The lengths of the concave part  14   b  and the hole  14   a  in the axial direction are not limited to the above-mentioned lengths. 
         [0116]    Furthermore, the hole  14   a  may not be produced and instead the concave part  14   b  may run through the base  14   e  in the thickness direction. In other words, the concave part  14   b  may also serve as a hole. 
         [0117]    The plurality of needles may be used simultaneously. Specifically, each of the plurality of needles can pierce the cell aggregates at the same time. This allows shortening of the time required for piercing all of the cell aggregates. In this case, the distance between the centers of the adjacent concave parts  14   b  is equal to the distance between the centers of the adjacent needle-shaped bodies. 
         [0118]    The number of the aligning ledges  24   a  is not limited to the above-mentioned number and may be any number that allows the cell tray  14  to be fixed at a given position in the table  24 . 
         [0119]    The shapes of the opening part  14   h  and the bottom part  14   i  of the concave part  14   b  are not limited to a circle, and may be rectangle, an eclipse or other shape. The diameter of the hole  14   a  and the diameter of the bottom part  14   i  may not be the same as long as the concave part  14   b  and the hole  14   a  run through. Additionally, the hole  14   a  does not have to have a cylindrical shape. 
         [0120]    The three-dimensional cell structure may consist only of the same type of cells or may contain multiple types of cells. The same type of cells refer to functionally equivalent cells that are derived from the same tissue or organ of the same species. A cell construct containing multiple types of cells can be obtained by applying cell aggregates that are formed from different types of cells (for example, cell aggregate A made from cells a and cell aggregate B made from cells b) to the invention of the present application. Here, cells a and cells b may be any cells as long as these cell aggregates can fused with each other. Cells a and cells b may be, for example, cells derived from different tissues (or organs) of the same species, cells derived from the same tissues (or organs) of different species, or cells derived from different tissues (or organs) of different species. Moreover, the number of different types of cells used is not limited to two, and three or more types of cells may be used. The cell aggregate may contain one or more types of cells. In this case, the three-dimensional cell structure may be produced by using only a cell aggregate that contains one type of cells, may be produced by using a plurality of cell aggregates that respectively consist of different types of cells, may be produced by using only a cell aggregate that contains multiple types of cells, or may be produced by using a cell aggregate that contains one type of cells and a cell aggregate that contains different types of cells. 
         [0121]    While a number of embodiments of the present invention have been described with reference to the attached drawings, it is obvious for those skilled in the art that modification can be applied to the structure and relationship of each component without departing from the scope and the spirit of the claimed invention.