Abstract:
A dissection device for organisms includes a table bearing an organism and at least one blade lifted or lowered to approach the table. The blade includes a connecting portion, a cutting portion having a curved edge, and a neck portion connecting the connecting portion and the cutting portion. When the blade is lowered to contact the table, the cutting portion is rotated with respect to the neck portion to have rolling contact with the table from a first point to a second point of the edge.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a device and a method of dissecting cells and tissues of an organism, and more particularly relates to a device and a method for dissecting cells and tissues by rolling contact. 
         [0003]    2. Description of the Related Art 
         [0004]    Operations on organisms, such as dissection and aspiration are frequently carried out in the field of biotechnology. Laser dissection techniques, such as laser capture micro-dissection (LCM), laser micro-dissection (LMD) and laser pressure catapulting (LPC) have become the main micro-dissection techniques for organisms. The three described laser dissection techniques can be conveniently applied to tiny spots but may have generate radioactive contaminants, have high-cost and are not applicable to humid environments. 
         [0005]    U.S. Pat. No. 6,673,086 discloses a dissection device employing a needle continuously penetrating organisms for dissection. The dissecting speed of such a device is, however, low. 
       BRIEF SUMMARY OF INVENTION 
       [0006]    An embodiment of a dissection device for organisms of the invention comprises a table bearing an organism and at least one blade lifted or lowered to approach or depart from the table. The blade comprises a connecting portion, a cutting portion having a curved edge and a neck portion connecting the connecting portion and the cutting portion. When the blade is lowered to contact the table for cutting the organism, the cutting portion is rotated with respect to the neck portion to make rolling contact with the table from a first point to a second point of the edge. 
         [0007]    Lines formed by connecting every point on the edge between the first point and the second point to the neck portion are not parallel to a moving direction of the lowered blade. 
         [0008]    The invention further comprises a base lifted or lowered to approach the table. The connecting portion further comprises a through hole with which the base is engaged, thus, the base is connected to the connecting portion. 
         [0009]    When the blade is lowered to contact the table, the table moves in a first direction, substantially parallel to the line formed by the first and second points to maintain rolling contact between the blade and the table. 
         [0010]    When the blade is lowered to contact the table, the table moves in a first direction, substantially parallel to the line formed by the first and second points to maintain rolling contact between the blade and the table. 
         [0011]    The cutting portion has a first side on which the curved edge is formed and a second side on which the neck portion is formed. The first side is opposite to the second side or adjacent to the second side. 
         [0012]    The connecting portion, the neck portion and the cutting portion are integrally formed. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0013]    The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a schematic view of a dissecting device of the invention; 
           [0015]      FIG. 2   a  is a schematic view of an embodiment of a blade of the invention; 
           [0016]      FIG. 2   b  is a free body diagram of a cutting portion of the blade of  FIG. 2   a;    
           [0017]      FIG. 3  is a schematic view of another embodiment of a blade of the invention; 
           [0018]      FIG. 4  is a schematic view of another embodiment of a blade of the invention; 
           [0019]      FIG. 5  is a schematic view of another embodiment of a blade of the invention; and 
           [0020]      FIG. 6  depicts the relationship between the displacement of the blade and the contact points. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0021]    The invention discloses a dissecting device with a curved blade having an elastic structure. When the blade cuts an organism on a table, the elastic structure bends to rotate the blade. The curved blade has rolling contact with the table due to the rotation of the blade and the horizontal movement of the table. As rolling contact only occurs between the curved blade and the table, the blade cuts, rather than tears the organisms into cell pieces which have a complete shape. The structure of the dissecting device is described as follows. 
         [0022]    Referring to  FIG. 1 , the dissecting device  1000  comprises a base  100 , a plurality of blades  200  and a table  300 . The blades  200  are installed on the base  100 . An organism to be dissected is placed on the table  300 . The base  100  and the blades  200  are disposed above the table  300  and able to lower and raise to respectively approach or depart from the horizontally movable table  300 . 
         [0023]    Referring to  FIG. 2   a , the blade  200  comprises a connecting portion  210 , a neck portion  220  and a cutting portion  230 . The neck portion  220  connects the connecting portion  210  and the cutting portion  230 . The connecting portion  210  has a through hole  212  with which the base  100  is engaged. The cutting portion  230  has a curved edge  232 . Because the size of the neck portion  220  is much smaller than the connecting portion  210  and the cutting portion  230 , a gap  224  is formed between the connecting portion  210  and the cutting portion  230 . When the blade  200  descends with the base  100  to contact the table  300 , the cutting portion  230  is pushed by the normal force of the table  300  to rotate with respect to the neck portion  220 . The curved edge  232  contacts the table  300  at a first point  2321 . The blade  200  continuously descends until the cutting portion  230  completely cuts off the organism. At this time, the edge  232  contacts the table  300  at a second point  2322 . The directions of the normal force on every point between the first point  2321  and the second point  2322  do not pass through the neck portion  220 . In other words, lines formed by every point between the first point  2321  and the second point  2322  to the neck portion  220  are not parallel to the descending direction of the blade  200 . A clockwise torque is exerted on the cutting portion  230 , which rotates the cutting portion  230  to cut off the organism on the table  300 . When the organism is cut off, the curved edge  232  contacts the table  300 . At the first points  2321 , the table  300  exerts a horizontal force Fx and a normal force Fy on the edge  232 . The horizontal force Fx moves the edge  232  in x direction to slide on the table  300 . The table  300  must therefore move in the x direction to compensate for the sliding of the edge  232 , which enables the edge  232  to maintain rolling contact with the table  300  without tearing the organism. The table  300  moves at a speed proportional to the descending speed of the blade  200 . 
         [0024]      FIG. 2   b  is a free body diagram of the edge  232 . A force exerted by the base  100  to the connecting portion  210  is transferred to the cutting portion  230  via the neck portion  220 . The force −Fy exerted by the base  100  has the same magnitude but the opposite direction of the force Fy exerted by the table  300  and does not align with the force Fy, thus, a moment M is generated by the forces Fy and −Fy to rotate the cutting portion  230  with respect to the neck portion  220 . Only when the lines formed by the contact points of the edge  232  and the table  300  to the neck portion  220  are not parallel to the descending direction of the cutting portion  230 , the forces Fy and −Fy have the same magnitude and the opposite directions without alignment, whereby a moment is generated to rotate the cutting portion  230 . 
         [0025]      FIG. 3  depicts another embodiment of the blade. The blade  200 ′ comprises a connecting portion  210 , a neck portion  220 ′ and a cutting portion  230 . The blade  200 ′ has two gaps  224  and  225  on both sides of the neck portion  220 ′. Other elements of the embodiment of  FIG. 3  are the same as the embodiment of  FIG. 2   a , thus, further description thereof is omitted for brevity. In  FIG. 3 , the neck portion  220 ′ is less rigid than the neck portion  220  in  FIG. 2   a , thus, less force is required to rotate the cutting portion  230 . 
         [0026]      FIG. 4  depicts another embodiment of the blade of the invention. A blade  200 ′″ comprises a connecting portion  210 , a neck portion  220 ′″ and a cutting portion  230 . The neck portion  220 ′″ is formed by wire cutting. The neck portion  220 ′″ can be formed when a through hole  212  is formed. The neck portion  220 ′″ is hollow. Two grooves  226  and  227  are formed on both sides of the gaps  224  and  225 . The grooves  226  and  227  are connected to the neck portion  220 ′″. The described structure may increase elasticity of the neck portion  220 ′″. 
         [0027]      FIG. 5  depicts another embodiment of the blade of the invention. A blade  220 ′″ comprises a connecting portion  210 , a neck portion  220  and a cutting portion  230  having a curved edge  232 ′. Compared with the embodiment of  FIG. 2   a , the neck portion  220  is connected to one side of the cutting portion  230 , and the curved edge  232  is formed on opposite side of the cutting portion  230 . In this embodiment, the side of curved edge  232 ′ is adjacent to the side connected to the neck portion  220 . 
         [0028]    In general, the blade has a thickness of 0.05˜1 mm. In the described embodiments, the blade has a thickness of 0.4 mm. 
         [0029]    The described elastic structure allows the blade to bend and rotate, when descended for cutting an organism. When the blade descends and the table is fixed, the blade slides on the table, as shown in  FIG. 6 , wherein the X-axis represents the descended distance, and the Y-axis represents the point of the blade contacting the table. To maintain the rolling contact between the blade and the table, the table must be moved relative to the descended distance of the blade. 
         [0030]    The blade cuts the organism by rolling over the organism without sliding, thus, the blade does not tear the organism. Cells or tissues cut from the organism can retain their shape without affecting biological conditions. 
         [0031]    While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.