Patent Publication Number: US-2010107781-A1

Title: Measurement apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a measurement apparatus, and particularly relates to a measurement apparatus that is provided with a measurement chip in which a channel through which a liquid can flow is formed and in which a testing substance to be measured is adhered to a side wall in the channel. 
     BACKGROUND ART 
     Heretofore, a measurement apparatus has been known that, with a measurement chip in which a channel through which a liquid can flow is formed and in which a testing substance to be measured is adhered to a side wall in the channel, measures characteristics of the testing substance by respectively separately supplying various solutions to the channel of the measurement chip and detecting reaction states of the testing substance. 
     For example, in Patent Document 1: Japanese Patent Application Laid-Open No. 2006-98369, a measurement apparatus is disclosed that measures characteristics of a testing substance by: respectively separately supplying various solutions to channels; causing light beams to be incident at various angles with respect to surfaces of adherence portions at which the testing substance is adhered, and detecting light intensity distributions for respective reflection angles of totally reflected light beams; and detecting, from the detected light intensity distributions, reflection angles at which dark lines occur due to occurrences of attenuated total reflection, which are caused by surface plasmon resonance (Surface Plasmon Resonance: SPR). 
     DISCLOSURE OF INVENTION 
     Problem to be Solved by the Invention 
     Now, as illustrated in  FIG. 16 , when a solution flows in a channel of a measurement chip, flow of the solution within the channel is in a layered flow state. Consequently, the closer to the wall face in the channel, the slower the speed of the liquid. 
     Therefore, in a measurement apparatus of this type, at a time of replacing a solution in the channel, as illustrated in  FIG. 17 , replacement of the solution in the channel is implemented by flowing a solution for a prescribed time (for example, five seconds) at a certain speed, but a liquid quantity of the solution that is required for replacing the solution in the channel is large, which has been a problem. 
     In light of the above, the present invention will provide a measurement apparatus capable of replacing a solution in a channel with a small liquid quantity. 
     Means for Solving the Problem 
     A first aspect of the present invention provides a measurement apparatus that is provided with: a channel member in which a channel through which liquid can flow is formed and in which a testing substance to be measured is adhered on a wall surface in the channel; a supply unit that supplies to the channel a solution to be used in testing of a characteristic of the testing substance; and a control section that, at a time of replacing the solution in the channel, controls the supply unit so as to supply the solution to the channel in a prescribed quantity at a first speed, thereafter supply the solution for a prescribed time at a second speed which is slower than the first speed, and thereafter supply the solution at a third speed which is faster than the second speed. 
     According to the constitution described above, the channel through which liquid can flow is formed in the channel member, the testing substance that is a measurement subject is adhered at the side wall in the channel, and solutions to be used in measurement of characteristics of the testing substance are supplied to the channel by the supply unit. 
     At the time of replacing a solution in the channel, the supply unit is controlled by the control section so as to supply a solution to the channel in the prescribed quantity at the first speed, then supply it for the prescribed time at the second speed, which is slower than the first speed, and thereafter supply it at the third speed, which is faster than the second speed. 
     Thus, at the time of replacing a solution in the channel of the channel member, in which the channel through which liquid can flow is formed and in which the testing substance to be measured is adhered on the side wall in the channel, the solution is supplied to the channel in the prescribed quantity at the first speed, then supplied for the prescribed time at the second speed, which is slower than the first speed, and thereafter supplied at the third speed, which is faster than the second speed. Thus, the solution in the channel may be replaced with a small liquid quantity. 
     Herein, at the time of replacing a solution in the channel, the control section may control the supply unit so as to supply the solution to the channel in the prescribed quantity at the first speed, then stop the supply for the prescribed time, and thereafter supply it at the third speed. 
     It is preferable if the prescribed time is a time corresponding to diffusion of solution in a vicinity of the wall surface in the channel to the center part of a cross-section of the channel. 
     Further, it is preferable if the prescribed quantity is a quantity that replaces solution at least from a supply aperture of the channel at which the solution is supplied to an adherence portion at which the testing substance is adhered. 
     Further yet, the supply unit may be configured to respectively separately supply to the channel plural kinds of solution to be used in measurements of characteristics of the testing substance, and the control section configured to perform the control at a time of replacing a solution in the channel with a solution of a different kind. 
     Furthermore, according to a second aspect of the present invention, a measurement apparatus is provided that is provided with: a channel member in which a channel through which liquid can flow is formed and in which a testing substance to be measured is adhered on a wall surface in the channel; a supply unit that supplies to the channel a solution to be used in testing of a characteristic of the testing substance; and a control section that, at a time of supplying the solution from the supply unit and replacing the solution in the channel, controls the supply unit so as to, partway through supplying the solution, stop the supply of the solution for a prescribed time. 
     According to the constitution described above, the channel through which liquid can flow is formed in the channel member, the testing substance that is a measurement subject is adhered at the side wall in the channel, and solutions to be used in measurement of characteristics of the testing substance are supplied to the channel by the supply unit. 
     At the time of supplying a solution from the supply unit and replacing a solution in the channel, the supply unit is controlled by the control section so as to, partway through supplying the solution, stop the supply of the solution for the prescribed time. 
     Thus, at the time of replacing the solution in the channel of the channel member, in which the channel through which liquid can flow is formed and in which a testing substance to be measured is adhered on the side wall in the channel, the supply of solution is stopped for the prescribed time partway through supplying the solution. Therefore, the solution in the channel may be replaced with a small liquid quantity. 
     EFFECT OF THE INVENTION 
     Thus, according to the aspects of the present invention, a solution in a channel may be replaced in a small liquid quantity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the whole of a biosensor relating to an exemplary embodiment. 
         FIG. 2  is a perspective view of the interior of the biosensor relating to the exemplary embodiment. 
         FIG. 3  is a plan view of the interior of the biosensor relating to the exemplary embodiment. 
         FIG. 4  is a side view of the interior of the biosensor relating to the exemplary embodiment. 
         FIG. 5  is a perspective view of a measurement chip relating to the exemplary embodiment. 
         FIG. 6  is an exploded perspective view of the measurement chip relating to the exemplary embodiment. 
         FIG. 7  is a view illustrating a state in which a light beam is incident on a measurement region and a reference region of the measurement chip relating to the exemplary embodiment. 
         FIG. 8  is a view in which a channel member of the measurement chip relating to the exemplary embodiment is seen from a lower side. 
         FIG. 9  is a perspective view illustrating a vertical driving mechanism of an infusion head of the biosensor relating to the exemplary embodiment. 
         FIG. 10  is a schematic structural diagram of a liquid pumping section of the biosensor relating to the exemplary embodiment. 
         FIG. 11  is a a schematic diagram of a vicinity of an optical measurement section of the biosensor relating to the exemplary embodiment. 
         FIG. 12  is a schematic block diagram of a control section of the biosensor relating to the exemplary embodiment and peripherals thereof. 
         FIG. 13  is a graph showing speeds of a solution that is supplied to a liquid channel relating to the exemplary embodiment. 
         FIG. 14A  is a (first) schematic view illustrating a state in replacement of a solution in the liquid channel relating to the exemplary embodiment. 
         FIG. 14B  is a (second) schematic view illustrating a state in replacement of the solution in the liquid channel relating to the exemplary embodiment. 
         FIG. 14C  is a (third) schematic view illustrating a state in replacement of the solution in the liquid channel relating to the exemplary embodiment. 
         FIG. 14D  is a (fourth) schematic view illustrating a state in replacement of the solution in the liquid channel relating to the exemplary embodiment. 
         FIG. 15  is a graph illustrating a different example of speeds of the solution that is supplied to the liquid channel. 
         FIG. 16  is a diagram illustrating an example of a measurement chip in which a channel is formed. 
         FIG. 17  is a graph illustrating speed of a solution that is supplied to a conventional liquid channel. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Herebelow, an exemplary embodiment of the present invention will be described while referring to the drawings. 
     A biosensor  10 , which serves as a measurement apparatus relating to the present exemplary embodiment, is a surface plasmon sensor that measures interaction of a protein Ta with a sample A, using surface plasmon resonance that occurs at a surface of a metallic film. 
     As shown in  FIG. 1  to  FIG. 4 , the biosensor  10  is provided with a lower case  11  and an upper case  12 . The upper case  12  is structured with thermal insulating members and covers the whole of an upper half of the biosensor  10 . The interior of the upper case  12  is thermally insulated from the exterior and from the interior of the lower case  11 . Handles  13 , which are configured to enable upward opening, are attached to a front side of the upper case  12 . A display  14  and an input section  16  are disposed at the outside of the upper case  12 . 
       FIG. 2  is a view illustrating the interior of the biosensor  10  seen from the rear side of  FIG. 1  with the upper case  12  removed.  FIG. 3  is a view in which the interior of the casing is seen from above, and  FIG. 4  is a side view of the interior seen from the front side of  FIG. 2 . 
     Inside the upper case  12 , an infusion head  20 , a measurement section  30 , a sample stock section  40 , a pipette tip stock section  42 , a buffer stock section  44 , a cooling section  46 , a measurement chip stock section  48 , a radiator  60 , a radiator air-blowing fan  62 , and a horizontal-direction air-blowing fan  64  are provided. 
     The sample stock section  40  is constituted with a sample stacking section  40 A and a sample setting section  40 B. In the sample stacking section  40 A, sample plates  40 P are stacked in a Z direction (a vertical direction) and accommodated. The sample plates  40 P stock respectively different analyte solutions as samples to be used in measurements of characteristics of testing substances in individual cells. One of the sample plates  40 P is conveyed from the sample stacking section  40 A to the sample setting section  40 B by an unillustrated conveyance mechanism and is set in place therein. 
     The pipette tip stock section  42  is constituted with a pipette tip stacking section  42 A and a pipette tip setting section  42 B. In the pipette tip stacking section  42 A, pipette tip stockers  42 R which retain plural pipette tips, are stacked in the Z direction and accommodated. One of the pipette tip stockers  42 P is conveyed from the pipette tip stacking section  42 A to the pipette tip setting section  42 B by an unillustrated conveyance mechanism and is set in place therein. 
     The buffer stock section  44  is constituted with a bottle accommodation section  44 A and a buffer supply section  44 B. In the bottle accommodation section  44 A, a plural number of bottles  44 C are accommodated. The bottles  44 C retain buffer fluids which serve as reference samples that are references for measurement. A buffer plate  44 P is set in place in the buffer supply section  44 B. The buffer plate  44 P is divided into plural strips, and buffer fluids with different concentrations are retained in the respective divisions. Holes H are structured in an upper portion of the buffer plate  44 P. Pipette tips CP are inserted into the holes H at a time of access by the infusion head  20 . Buffer fluid is supplied to the buffer plate  44 P from the bottles  44 C by hoses  44 H. 
     A correction plate  45  is disposed adjacent to the buffer supply section  44 B, and the cooling section  46  is disposed adjacent thereto. The correction plate  45  is a plate for implementing adjustments of concentrations of buffer fluids, and is structured with plural cells in the form of a matrix. Samples requiring cooling are disposed in the cooling section  46 . The cooling section is set to a low temperature, and the samples thereon are maintained in a low temperature state. 
     A measurement chip accommodation plate  48 P is set in place at the measurement chip stock section  48 . A plural number of measurement chips  50  are stored in the measurement chip accommodation plate  48 P. 
     A measurement chip conveyance mechanism  49  is provided between the measurement chip stock section  48  and the measurement section  30 . The measurement chip conveyance mechanism  49  is structured to include a retention arm  49 A, which nips and retains a measurement chip  50  from two sides, a ball-screw  49 B which, by turning, moves the retention arm  49 A in a Y direction, and a conveyance rail  49 C, which is arranged in the Y direction and on which the measurement chip  50  is placed. At a time of measurement, a single measurement chip  50  is placed on the conveyance rail  49 C from the measurement chip accommodation plate  48 P by the measurement chip conveyance mechanism  49 , is moved toward the measurement section  30  while being nipped by the retention arm  49 A, and is set in place. 
     As shown in  FIG. 5  and  FIG. 6 , the measurement chip  50  is structured with a dielectric block  52 , a channel member  54  and a retention member  56 . 
     The dielectric block  52  is constituted with a transparent resin or the like that is transparent to light beams, and is provided with a prism portion  52 A, which is a bar shape of which cross sectional profile is trapezoid, and retained portions  52 B, which are formed integrally with the prism portion  52 A at two end portions of the prism portion  52 A. A metallic thin film  57  is formed on an upper face that is the wider of two faces of the prism portion  52 A that are parallel to one another. The dielectric block  52  functions as what is known as a prism. At a time of measurement in the biosensor  10 , light beams are incident from one of the two side faces of the prism portion  52 A that are not parallel to one another, and light beams that are totally reflected at a boundary face of the thin film  57  are emitted from the other of the two side faces. 
     For adhering a protein Ta, which is a testing substance to be measured, onto the thin film  57 , a linker layer  57 A is formed at the surface of the thin film  57 . The protein Ta is adhered onto this linker layer  57 A. 
     Engaging protrusions  52 C, which engage with the retention member  56 , are formed along upper side edges at the two side faces of the prism portion  52 A. Flange portions  52 D, which engage with the conveyance rail  49 C, are formed along side edges at the lower side of the prism portion  52 A. 
     As illustrated in  FIG. 6 , the channel member  54  is provided with six base portions  54 A, and four cylindrical members  54 B stand erect from each of the base portions  54 A. At each set of three base portions  54 A, upper portions of ones of the cylindrical members  54 B standing erect from each of the base portions  54 A are joined by a joining member  54 D. The channel member  54  is constituted with a material that is soft and capable of resilient deformation, for example, a noncrystalline polyethylene elastomer. Thus, because the channel member  54  is constituted with a material capable of resilient deformation, closeness of contact thereof with the dielectric block  52  is high, and sealing of liquid channels  55  that are structured between the channel member  54  and the dielectric block  52  is assured. 
     The retention member  56  is formed as a long strip, and is formed in a shape in which an upper face member  56 A and two side face members  56 B are structured in a cap shape. In the side face members  56 B, engaging holes  56 C are formed, which engage with the engaging protrusions  52 C of the dielectric block  52 , and windows  56 D are formed, which partially correspond with light paths of the light beams. The retention member  56  is attached to the dielectric block  52  by the engaging holes  56 C and the engaging protrusions  52 C engaging. The channel member  54  is formed integrally with the retention member  56 , and is disposed between the retention member  56  and the dielectric block  52 . Receiving portions  59  are formed at the upper face member  56 A at positions corresponding with the cylindrical members  54 B of the channel member  54 . The receiving portions  59  are formed in substantially cylindrical shapes. 
     As shown in  FIG. 7 , two channel grooves  54 C, in substantial letter-S shapes in a bottom face view, are formed in the base portion  54 A. Each of end portions of the channel grooves  54 C is communicated with a central cavity portion of one of the cylindrical members  54 B. The bottom face of the base portion  54 A is in close contact with the upper face of the dielectric block  52 , and the liquid channels  55  are constituted by gaps that are structured between the channel grooves  54 C and the upper face of the dielectric block  52  and by the central cavity portions. Herein, the volumes of the liquid channels  55  relating to the present exemplary embodiment are set at 7 μl. 
     Two of the liquid channels  55  are structured at an individual base portion  54 A. At each of the liquid channels  55 , entry and exit apertures  53  of the liquid channel  55  are structured at upper end faces of the cylindrical members  54 B. 
     Here, of the two liquid channels  55 , one is used as a measurement channel  55 A and the other one is used as a reference channel  55 R. Measurements are performed in a state in which the protein Ta is adhered on the thin film  57  at the measurement channel  55 A (on the linker layer  57 A) and the protein Ta is not adhered on the thin film  57  at the reference channel  55 R (on the linker layer  57 A). 
     As illustrated in  FIG. 7 , respective light beams L  1  and L 2  are incident on the measurement channel  55 A and the reference channel  55 R. As illustrated in  FIG. 8 , the light beams L 1  and L 2  are irradiated at inflection portions of the S shapes that are disposed on a center line M of the base portion  54 A. Hereinafter, a region of illumination of the light beam L 1  at the measurement channel  55 A is referred to as a measurement region E 1 , and a region of illumination of the light beam L 2  at the reference channel  55 R is referred to as a reference region E 2 . The reference region E 2  is a region at which measurement is performed for correcting data obtained from the measurement region E 1  at which the protein Ta is adhered. 
       FIG. 9  illustrates detailed structure of the infusion head  20 . 
     The infusion head  20  is provided with twelve infusion tubes  20 A. The infusion tubes  20 A are retained by a retention member  20 B so as to be arranged in a single row along the direction of arrow Y, which is orthogonal to the X direction. The infusion tubes  20 A are configured as pairs of two adjacent tubes, one being for liquid supply and the other for liquid discharge. Pipette tips CP are attached to distal end portions of the infusion tubes  20 A. The pipette tips CP are stocked in the pipette tip stockers  42 P, and may be replaced as necessary. 
     As shown in  FIG. 2 , the infusion head  20  is provided at an upper portion of the interior of the upper case  12 , and is movable in the direction of arrow X by a horizontal driving mechanism  22 . The horizontal driving mechanism  22  is structured by a ball-screw  22 A, a motor  22 B and guide rails  22 C. The ball-screw  22 A and guide rails  22 C are disposed along the X direction. Two of the guide rails  22 C are provided in parallel, one of which is disposed to be separated by a prescribed spacing to the lower side of the ball-screw  22 A. 
     The infusion head  20  is moved in the X direction along the guide rails  22 C by the ball-screw  22 A turning in accordance with rotary driving of the motor  22 B. By this X direction movement, the infusion head  20  is movable to, respectively, positions opposing the cooling section  46 , the correction plate  45 , the buffer supply section  44 B (the buffer plate  44 P), the measurement section  30  (the measurement chip  50 ), the sample setting section  40 B (the sample plates  40 P) and the pipette tip setting section  42 B (the pipette tip stockers  42 P). 
     As shown in  FIG. 9 , a vertical driving mechanism  24 , which moves the infusion head  20  in the direction of arrow Z, is provided at the infusion head  20 . The vertical driving mechanism  24  is structured to include a motor  24 A and a driving shaft  24 B disposed in the Z direction. The vertical driving mechanism  24  moves the infusion head  20  in the Z direction by the driving shaft  24 B turning in accordance with rotary driving of the motor  24 A. By this Z direction movement, the infusion head  20  is made capable of access to the pipette tip stocker  42 P set in place at the pipette tip setting section  42 B, the sample plate  40 P set in place at the sample setting section  40 B, the buffer plate  44 P set in place at the buffer supply section  44 B, the correction plate  45 , a plate set in place at the cooling section  46 , the measurement chip  50  set in place at the measurement section  30  and so forth. 
     As shown in  FIG. 10 , a pump driving section  26  is connected to the infusion head  20 . The pump driving section  26  is provided with a first pump  27  and a second pump  28 . The first pump  27  and the second pump  28  are provided in respective correspondence with the aforementioned pairs of infusion tubes  20 A. The first pump  27  is structured by a syringe pump, and is provided with a first cylinder  27 A, a first piston  27 B, and a first motor  27 C that drives the first piston  27 B. The first cylinder  27 A is connected with the infusion head  20  via piping  27 H. The second pump  28  is also structured by a syringe pump, and is provided with a second cylinder  28 A, a second piston  28 B, and a second motor  28 C that drives the second piston  28 B. The second cylinder  28 A is connected with the infusion head  20  via piping  28 H. 
     Rotary driving of each of the first motor  27 C and the second motor  28 C is controlled and driving of the first piston  27 B and the second piston  28 B is controlled. Thus, the infusion head  20  is capable of adjusting liquid quantities of solutions that are aspirated and discharged, and speeds of the solutions during aspiration and discharge. 
     Meanwhile, as shown in  FIG. 4 , the measurement section  30  is structured to include an optics table  32 , a light emission section  34  and a light reception section  36 . At the optics table  32  are formed, as seen from a side direction: an upper pedestal  32 A with a horizontal flat face at the middle of an upper portion, an emission inclined portion  32 B that descends in a direction away from the upper pedestal  32 A, and a light reception inclined portion  32 C that is disposed to sandwich the upper pedestal  32 A at the opposite side thereof from the emission inclined portion  32 B. The measurement chip  50  is set in place on the upper pedestal  32 A, along the Y direction. The light emission section  34 , which emits the light beams L 1  and L 2  towards the measurement chip  50 , is disposed at the emission inclined portion  32 B of the optics table  32 . The light reception section  36  is disposed at the light reception inclined portion  32 C. A water-cooling jacket  32 J, which cools the optics table  32 , is provided adjacent to the optics table  32 . 
     As shown in  FIG. 11 , a light source  34 A and a lens unit  34 B are provided at the light emission section  34 . At the light reception section  36 , a lens unit  36 A and a CCD  36 B are provided. The CCD  36 B is connected with an image processing section  38 , to which a control section  70  that administers overall control of the biosensor  10  is connected. 
     A light beam L in a diverging state is emitted from the light source  34 A. The lens unit  34 B incorporates a polarizing beam splitter, separates the light beam L that is incident from the light source  34 A into a P polarization component and an S polarization component, and divides the P polarization component of the light beam L into two relatively thick parallel light beams L 1  and L 2  with a certain width with respect to the Z direction. Then the lens unit  34 B causes the two parallel light beams L 1  and L 2  to be incident on the measurement region E 1  and the reference region E 2  at the boundary face between the thin film  57  and the dielectric block  52 , such that the light beams L 1  and L 2  are in convergent light states at the measurement region E 1  and the reference region E 2  with various incidence angles that are equal to or more than a total reflection angle. Hence, the light beams L 1  and L 2  that are incident at the measurement region E 1  and the reference region E 2  are totally reflected at various reflection angles from the boundary face between the dielectric block  52  and the thin film  57 . The totally reflected light beams L 1  and L 2  are focused through the lens unit  36 A at the CCD  36 B. The CCD  36 B is configured as an area sensor with a light-receiving surface with an area capable of receiving light of both the two totally reflected light beams L 1  and L 2 . The CCD  36 B generates and outputs image information representing the images focused at the light-receiving surface. The outputted image information is inputted to the image processing section  38 . In the image processing section  38 , prescribed processing is carried out on the basis of the inputted image information, and refractive index variation data is calculated for the measurement region E 1  and the reference region E 2 . The calculated refractive index variation data is outputted to the control section  70 . 
     Here, the sample and the buffer liquid are respectively separately provided at the measurement chip  50  and, respectively, the light beam L is emitted from the light emission section  34  and the light beams L 1  and L 2  are irradiated at the measurement region E 1  and the reference region E 2 . When reflection angles that produce dark lines are respectively found in the light beams L 1  and L 2  that are totally reflected at the measurement region E 1  and the reference region E 2 , the refractive index variation data is found on the basis of a difference between an angular difference between reflection angles that produce dark lines at the sample and buffer liquid in the measurement region E 1  and an angular difference between reflection angles that produce dark lines at the sample and buffer liquid in the reference region E 2 . The light beams L 1  and L 2  that are incident at particular incidence angles on the boundary face between the thin film  57  and the dielectric block  52  excite surface plasmons at the boundary face. Accordingly, reflected light intensities of the light beams L 1  and L 2  that are incident at the particular incidence angles fall sharply and are observed as dark lines. The incidence angles of the light beams L 1  and L 2  that are dark lines are total reflection attenuation angles θ SP , and the differences in variations (angular differences) between the total reflection attenuation angles θ SP  at the measurement region E 1  and the reference region E 2  serve as the refractive index variation data. 
       FIG. 12  shows a block diagram illustrating functional structure of a control system that controls operations of the biosensor  10 . 
     As shown in this drawing, the display  14  and the input section  16  are connected to the control section  70 . 
     The aforementioned motor  22 B, motor  24 A, first motor  27 C and second motor  28 C are also connected to the control section  70 . 
     The control section  70  controls movement of the infusion head  20  in the X direction and the Z direction by controlling rotary driving of the motor  22 B and the motor  24 A. The control section  70  also controls aspiration and discharge of the sample and the buffer liquid in the pipette tips CP that are attached to the infusion tubes  20 A of the infusion head  20 , by controlling rotary driving of the first motor  27 C and the second motor  28 C. 
     At the control section  70 , in accordance with operation instructions to the biosensor  10  that are inputted by an operator through the input section  16 , measurement processing is executed, including infusion of solutions of samples, buffer liquid and the like into the liquid channels  55  of the measurement chip  50 , acquisition of refractive index data, and analysis and the like. Further, the control section  70  measures reaction states between the protein Ta and the sample A on the basis of the refractive index variation data inputted by the image processing section  38 , and displays measurement results at the display  14 . 
     Next, operation of the biosensor  10  relating to the present exemplary embodiment when measuring characteristics of a protein Ta will be described. 
     When solutions of samples and buffer liquid or the like are to be supplied to the liquid channels  55  of the measurement chip  50 , the biosensor  10  causes the infusion head  20  to move to over the cooling section  46 , sample setting section  40 B, buffer supply section  44 B or the like in which solutions to be measured are stored, and aspirates the solutions with the pipette tips CP attached to ones of the pairs of infusion tubes  20 A (a total of six). Aspiration quantities at this time are quantities corresponding to two channels, for supply to the pairs of liquid channels  55 A and  55 R. Then, the pipette tips CP at the six infusion tubes  20 A that have aspirated the solutions are inserted into ones (hereinafter referred to as supply apertures  53 A) of the entry and exit apertures  53  at the measurement channel  55 A side of the measurement chip  50 , and the pipette tips CP attached to the six infusion tubes  20 A of the row for discharge are inserted into the others (hereinafter referred to as discharge apertures  53 B) of the entry and exit apertures  53 . Then, half-quantities of the solutions are supplied from the infusion tubes  20 A at the supply apertures  53 A, and this is implemented by intaking the liquid with the infusion tubes  20 A at the discharge apertures  53 B. Next, the remaining half-quantities of the solutions in the pipette tips CP are similarly supplied to the reference channel  55 R side. 
     During this supply of the solution to the measurement channels  55 A and reference channels  55 R of the measurement chip  50 , by controlling rotary driving of the first motor  27 C and the second motor  28 C, as illustrated in  FIG. 13 , the control section  70  supplies a prescribed quantity of a solution that corresponds with a volume of the liquid channel  55  (for example, 7 μl) at a first speed (for example, 10 μl/s). Thereafter, the supply is stopped for a prescribed time corresponding to diffusion of solution in the vicinity of a wall surface in the liquid channel  55  to the center part of a cross-section of the liquid channel  55  (for example, 5 seconds). Thereafter, control is performed so as to supply a pre-specified quantity of equal to or more than the volume of the liquid channel  55  (for example, 18 μl) at a third speed (for example, 5 μl/s). 
     Thus, for example, as shown in  FIG. 14A  to  FIG. 14D , in a case in which the interior of the liquid channel  55  was filled with a solution A (see  FIG. 14A ), when the above-mentioned prescribed quantity of a solution B is supplied at the above-mentioned first speed, flow of the solution in the liquid channel  55  is in a layered flow state. Therefore, the solution A is replaced with the solution B at the center part of the cross-section of the liquid channel  55  (see  FIG. 14B ). Then, when the supply of the solution B is stopped for the above-mentioned prescribed time, the solution A in the vicinity of the wall surface in the liquid channel  55  diffuses to the center part of the cross-section of the liquid channel  55  (see  FIG. 14C ). Thereafter, by the supply of the solution B being supplied, the solution A in the liquid channel  55  is replaced with the solution B (See  FIG. 14D ). 
     According to the present exemplary embodiment as described above, after the above-mentioned prescribed quantity of the solution B is supplied, supply of the solution B is stopped for the above-mentioned prescribed time. Consequently, the solution in the liquid channel  55  may be replaced with a small liquid quantity. 
     Herein, in the present exemplary embodiment a case of the supply of the solution B being temporarily stopped from supplying for the aforementioned prescribed time has been described, but the present invention is not to be limited by this. For example, the solution B may be supplied to the aforementioned prescribed quantity at the aforementioned first speed, and then supplied for the aforementioned prescribed time at a second speed which is slower than the aforementioned first speed (for example, 2 μl/s). 
     Further, in the present exemplary embodiment a case has been described in which the first speed and the third speed are different, but the present invention is not to be limited by this. For example, as illustrated in  FIG. 15 , the first speed and the third speed may be the same speed. Moreover, the third speed may be faster than the first speed. 
     Further again, in the present exemplary embodiment a case has been described in which a quantity corresponding to the volume of the liquid channel  55  serves as the aforementioned prescribed quantity, but the present invention is not to be limited by this. For example, it is sufficient if the prescribed quantity is a quantity that replaces the solution at least in the channel from the supply aperture  53 A at which the solution is supplied to the adherence portion at which the testing substance is adhered, and moreover is preferably kept to not more than the volume of the liquid channel  55 . 
     Further yet, in the present exemplary embodiment a case has been described in which the supply of solution to the liquid channel  55  is temporarily stopped from supplying for the aforementioned prescribed time regardless of the presence or absence of a solution in the liquid channel  55 , but the present invention is not to be limited by this. For example, whether or not a solution has been supplied to each liquid channel  55  of each measurement chip  50  may be memorized at the control section  70 , and the supply of a solution may be stopped from supplying for the aforementioned prescribed time if the solution is being supplied to a liquid channel  55  to which a solution has already been supplied. 
     Moreover, a kind of solution that has been supplied to each liquid channel  55  in each measurement chip  50  may be memorized in the control section  70 , and the supply of a solution may be stopped from supplying for the aforementioned prescribed time if a solution in a liquid channel  55  is being replaced with a solution of a different kind. 
     Otherwise, as the measurement apparatus in the present exemplary embodiment, a surface plasmon sensor has been described as an example. However, a measurement apparatus is not limited to being a surface plasmon sensor. 
     The disclosures of Japanese Patent Application No. 2007-071024 are incorporated into the present specification by reference in their entirety.