JP4546889B2 - Chip with weighing unit - Google Patents

Description

  The present invention relates to a chip having a measuring unit for measuring a sample.

Biochemistry that measures the concentration of enzymes and their products that are active in the liver, kidneys, pancreas, etc., in order to diagnose liver and biliary tract diseases and alcoholic liver disorders and observe the treatment Inspection is widely conducted. As a chip for performing such a biochemical test, Patent Document 1 discloses a blood analysis chip that centrifuges plasma using centrifugal force. FIG. 11 is a plan view of a blood analysis chip disclosed in Patent Document 1. FIG. A blood sample is introduced through opening 28 and held in blood holding chamber 36. Here, in the blood analysis chip, a predetermined amount of the target component in the blood is accurately measured and mixed with the reagent or reacted. Therefore, the blood sample in the blood analysis chip is introduced into the blood separation chamber from the blood holding chamber 36 by centrifugal force, and the target sample is centrifuged. The separated sample is weighed by the sample measuring means 63. By using the sample weighed in this way, accurate analysis or the like can be performed.
U.S. Pat. No. 4,883,763

  However, the measurement by the sample measuring means 63 cannot be performed accurately depending on the properties of the target sample. For example, in the case of a solution with low wettability of the sample, as shown in FIG. 12A, the liquid level at the sample measuring means 63 rises due to the surface tension. On the other hand, in the case of a sample having high wettability, the liquid level is recessed as shown in FIG. In this way, the liquid level rises and falls depending on the properties of the sample, and the amount to be measured differs from the amount to be weighed by the amount of the sample raised and recessed. Therefore, the sample cannot be accurately measured.

  Therefore, an object of the present invention is to provide a chip capable of accurately measuring a sample.

  In order to solve the above-described problems, the first invention of the present application provides a chip having a measuring unit for measuring a sample by rotation around a rotation axis. Here, the weighing unit includes a weighing unit main body that is filled with the sample at the time of weighing, a first end that is connected to one end of the weighing unit main body and is an inlet for the sample, and the other end of the weighing unit main body. And a second end connected to the. Further, when the sample is measured by rotating the tip about the rotation axis, the sample liquid level at the first end and the sample liquid level at the second end are centered on the rotation axis. The distance between the sample liquid surface at the first and second end portions and the rotation shaft is concentric with respect to the rotation, and is closer to or the same as the distance between the measuring unit main body and the rotation shaft.

  When the sample is weighed, the sample is sequentially introduced from the first end portion to the measuring portion main body and the second end portion, and the chip is rotated around the rotation axis. Then, the sample fills the measuring unit main body and has a liquid level at the first end and the second end. This is because the distance between the sample liquid surface and the rotating shaft at the first and second end portions is closer to or the same as the distance between the measuring unit main body and the rotating shaft. Thus, since the sample has a liquid level only at the first end and the second end, the area of the liquid level is small. Generally, when the wettability of a sample is low, the liquid level rises due to surface tension, and when the wettability is high, the liquid level is dented. As described above, since the area of the sample liquid surface is small with respect to the volume of the measuring unit main body, measurement errors due to surface tension can be minimized. In addition, since the influence of wettability is small, it is not necessary to perform, for example, an inner wall treatment for improving the wettability of the sample on the measuring unit main body, the first end, and the second end through which the sample passes. Therefore, the manufacturing cost of the chip can be reduced. Moreover, the said chip | tip can be used without considering surface tension also about the sample which has different surface tension.

A second invention of the present application provides the chip according to the first invention, wherein the measuring unit further includes a take-out tube that branches off from the second end and causes the sample overflowing from the second end to flow out.
For example, a sample that satisfies the weighing unit main body, the first end, and the second end is introduced into the chip, and the chip is rotated about the rotation axis. Due to the centrifugal force caused by this rotation, the liquid level in the second end and the liquid level in the first end are positioned concentrically. At this time, the sample overflowing from the second end flows out through the take-out pipe branched from the second end. Therefore, the weighing unit including the first end, the weighing unit main body, and the second end is filled with a predetermined amount of sample. Therefore, even when an excessive sample is introduced into the chip, a desired amount of sample can be accurately weighed by the weighing unit.

A third invention of the present application provides the chip according to the first invention, wherein the measuring unit is further connected to the second end, and further includes an air hole for applying atmospheric pressure to the sample liquid surface of the second end. To do.
The sample tends to flow out from the branching point of the second end portion along the wall surface of the extraction tube due to the surface tension. By taking in air from the air holes, it is possible to cut off the sample that tends to flow excessively from the second end portion along the wall surface of the take-out pipe at the branch point. Therefore, the sample can be accurately measured in the measuring unit.

According to a fourth invention of the present application, in the first invention, the measuring portion main body, the first end portion, and the second end portion are formed in a U-shaped tube or a V-shaped tube having an opening with respect to the rotation shaft. Provide a chip.
By forming the measuring portion main body, the first end portion, and the second end portion in a U-shaped tube or a V-shaped tube, it is possible to prevent air bubbles in the flow channel or the sample from adhering to the flow channel wall. . Therefore, the sample can be accurately measured without being affected by bubbles. For example, the sample is sequentially introduced into the first end portion, the measuring portion main body, and the second end portion by rotating the tip about the rotation axis. At this time, since the U-shaped tube or the V-shaped tube is formed to have an opening with respect to the rotation axis, the generated bubbles cannot receive the centrifugal force and adhere to the flow channel wall. And is discharged from the measuring section.

  According to the present invention, since the area of the sample liquid surface is small with respect to the volume of the measuring unit main body, measurement errors due to surface tension can be minimized.

(Summary of Invention)
The chip has a measuring unit for measuring a sample. In addition, the measurement of the sample in the measurement unit is performed by rotating the chip around the rotation axis. The measuring unit has a first end for introducing the sample into the measuring unit main body and a second end for extracting the sample from the measuring unit main body. Further, the cross-sectional areas of the first end and the second end are formed so as to be smaller than the measuring unit main body. When measuring by rotating the tip, the sample has a liquid surface at the first end and the second end while filling the main body of the measuring unit. Since the first end portion and the second end portion have a smaller cross-sectional area than the measuring portion main body, the area of the sample liquid surface at the first end portion and the second end portion is compared with the case where the measuring portion main body has the sample liquid surface. And get smaller. Therefore, the measurement error due to the surface tension of the sample can be minimized.

<Example Embodiment>
(Constitution)
FIG. 1 is an exploded plan view of a chip according to the present invention, and FIG. 2 is an explanatory view showing a relationship between a rotating shaft and each part of the chip. The chip 1 is formed by bonding a first substrate 3 and a second substrate 5 which are plate-like substrates. The first substrate 3 is formed with an inlet 7a through which a sample is introduced, an air hole 9a that is an air inlet, and an outlet 11a for taking out the sample. Further, the second substrate 5 is formed with intake ports 7b, air holes 9b, and intake ports 11b corresponding to the intake port 7a, the air holes 9a, and the outlet port 11a, respectively. Furthermore, the second substrate 5 has a weighing unit body 13a, a first end 13b that connects the weighing unit body 13a and the intake port 7a, and a second end 13c that connects the weighing unit body 13a and the air hole 9a. And a take-out tube 19 are provided. The take-out pipe 19 branches off from the middle of the first end 13b, and connects the first end 13b and the outlet 11b. Here, the weighing unit 13 for weighing the sample includes a weighing unit main body 13a, a first end 13b connected to one end of the weighing unit main body 13a, and a second end 13c connected to the other end of the weighing unit main body 13a. Composed. Moreover, the cross-sectional area of the 1st end part 13b or the 2nd end part 13c is smaller than the cross-sectional area of the measurement part main body 13a. Furthermore, the area of the liquid surface per volume of the sample measured by the measuring unit 13 is preferably 0.01 to 1 mm 2 / μl, more preferably 0.1 to 1 mm 2 / μl. Moreover, since the cross-sectional shape of the 1st end part 13b or the 2nd end part 13c has a smaller cross-sectional area, the circular shape is more preferable than the rectangular shape.

  In this inspection chip 1, the sample is weighed by rotation around the rotation shaft 21 as shown in FIG. 2. Therefore, at least a part of the first end portion 13b and the second end portion 13c is located closer to the rotating shaft 21 than the measuring portion main body 13a. Here, the wall surface closest to the rotation shaft 21 among the wall surfaces constituting the measuring unit main body 13a is defined as a wall surface A, and the position where the take-out pipe 19 branches from the first end portion 13b is defined as a branch point B. The distance between the branch point B and the rotating shaft 21 is designed to be closer than the distance between the wall surface A of the measuring unit body 13 a and the rotating shaft 21. That is, the measuring unit main body 13a is designed to be farther from the rotating shaft 21 than the branch point B.

(Relationship between sample liquid level and rotating shaft during measurement)
FIG. 3 is an explanatory diagram for explaining the state of the sample during measurement. As shown by the hatched portion in FIG. 3, the sample fills the weighing unit main body 13 a and has a liquid surface at the first end portion 13 b and the second end portion 13 c in the rotation at the time of weighing around the rotation shaft 21. Specifically, the relationship between the sample liquid level during measurement and the rotating shaft 21 will be described next.

  Samples to be weighed are taken from the intakes 7a and 7b. The chip 1 is rotated around the rotation shaft 21, and the sample is introduced from the intake port 7 b to the first end 13 b and is introduced into the measuring unit main body 13 a. Here, as described above, the branch point B is located closer to the rotating shaft 21 than the wall surface A of the measuring unit main body 13a. Therefore, the sample is introduced into the second end portion 13c while filling the measuring portion main body 13a. Furthermore, since the take-out pipe 19 is branched from the middle of the second end 13c, the sample in the second end 13c is introduced into the take-out port 11b through the take-out pipe 19. That is, the sample overflowing from the branch point B with the take-out pipe 19 in the second end portion 13c is introduced into the take-out port 11b. Therefore, the liquid level Y of the sample in the second end portion 13c is located at the branch point B in the second end portion 13c. Furthermore, the sample also has a liquid level X at the first end 13b. Here, the distance between the rotating shaft 21 and the liquid level X in the first end portion 13b is substantially the same as the distance between the rotating shaft 21 and the liquid level Y in the second end portion 13c. That is, the liquid level X and the liquid level Y are located on a concentric circle 21 a centering on the rotation shaft 21.

In addition, in FIG. 3, the distance of the liquid level X and the liquid level Y from the bottom part C of the measurement part main body 13a is comparable. However, the distances from the rotary shaft 21 to the liquid level X and the liquid level Y may be substantially the same, and as shown in FIG. 4, the distances from the bottom C of the measuring unit body 13a to the liquid level X and the liquid level Y are different. May be.
(Air hole)
The sample tends to flow out from the branch point B of the second end portion 13c along the wall surface of the take-out pipe 19 due to the surface tension. And the liquid level Y of the sample in the 2nd end part 13c may be located in the direction away from the rotating shaft 21 rather than the branch point B. Therefore, the amount measured by the measuring unit 13 may be smaller than the amount to be originally measured. Therefore, by taking in air from the air holes 9b, the sample that tends to flow excessively from the second end portion 13c along the wall surface of the take-out pipe 19 at the branch point B is cut off. Thereby, the sample can be accurately weighed in the weighing unit 13.

  Further, as shown in FIG. 1, air is also taken into the first end portion 13b via the outlets 7a and 7b. Here, the positions of the liquid levels of the first end portion 13b and the second end portion 13c are determined by the branch point B between the second end portion 13c and the take-out pipe 19, but there is a possibility that other influences may also be affected. . For example, the amount of the sample introduced into the measuring unit main body 13a, the first end 13b and the second end 13c, the pressure applied to the liquid surface of the first end 13b or the second end 13c, the rotational torque, etc. Affected by. For example, when the pressure in the second end 13c is larger than the pressure in the first end 13b, the liquid level of the second end 13c is further away from the rotary shaft 21 than the liquid level of the first end 13b. Will be located. On the other hand, when the pressure in the second end 13c is smaller than the pressure in the first end 13b, the liquid level of the second end 13c is closer to the rotation shaft 21 than the liquid level of the first end 13b. Will come to be located. As described above, atmospheric pressure is applied to the liquid level of the first end portion 13b via the outlet 7b, and atmospheric pressure is applied to the liquid level of the second end portion 13c via the air hole 9b. As described above, the air hole 9 through which air can be introduced is provided to make the pressure applied to the liquid level constant, thereby eliminating the fluctuation in the position of the liquid level due to the pressure fluctuation as described above and performing accurate measurement. be able to. Further, by reducing the parameters that change the position of the liquid level, it is possible to easily adjust the amount of the sample to be introduced, adjust the rotational torque, or design the measuring unit.

(Modification 1)
FIG. 5 is a plan view showing Modification 1 of the measuring unit 13. In the above, air holes 9a and 9b connected to the second end portion 13c are provided. The sample may flow out from the second end portion 13c along the wall surface to the take-out pipe 19 due to the surface tension. However, if the amount of the sample that fluctuates due to the flow is within an error range, the air holes 9a and 9b are not provided. May be. Therefore, as shown in FIG. 5, you may provide the taking-out pipe | tube 19 so that it may continue from the 2nd end part 13c.

(Modification 2)
FIG. 6 is a plan view showing a second modification of the measuring unit 13. In FIG. 1 described above, the distance between the branch point B and the rotating shaft 21 is designed to be closer than the distance between the wall surface A of the measuring unit main body 13a and the rotating shaft 21. However, when the sample is weighed, it may be designed so that the liquid level is located only at the first end 13b and the second end 13c, for example, as shown in FIG. In FIG. 6, the distance between the wall surface A closest to the rotating shaft 21 and the rotating shaft 21 in the measuring unit main body 13 a is about the same as the distance between the liquid surface X and the liquid surface Y and the rotating shaft 21. In this case, the sample has a liquid surface at the first end portion 13b and the second end portion 13c while filling the inside of the measuring portion main body 13a.

(Modification 3)
FIG. 7 is a plan view showing a third modification of the measuring unit 13. The measuring portion main body 13a, the first end portion 13b, and the second end portion 13c may be formed in a U-shaped tube or a V-shaped tube shape having an opening with respect to the rotating shaft 21. Even when the measuring portion is formed in the shape as shown in FIG. 7, the liquid level is located at the first end portion 13b and the second end portion 13c. Accurate weighing is possible.

  Further, as shown in FIG. 7, by forming the measuring unit 13 in a U-shaped tube or a V-shaped tube, it is possible to prevent air bubbles in the flow channel and the sample from adhering to the flow channel wall of the measuring unit 13. it can. Therefore, the sample can be accurately measured without being affected by bubbles. For example, the sample is sequentially introduced into the first end portion 13b, the weighing unit main body 13a, and the second end portion 13c by rotating the chip around the rotation shaft 21. At this time, since the U-shaped tube or the V-shaped tube is formed so as to have an opening with respect to the rotation shaft 21, the generated bubbles cannot receive the centrifugal force and adhere to the flow channel wall. It moves along the wall and is emitted from the metering unit 13.

(Function and effect)
As described above, since the sample has a liquid level only at the first end 13b and the second end 13c, the area of the liquid level is small. Generally, when the wettability of a sample is low, the liquid level rises due to surface tension, and when the wettability is high, the liquid level is dented. In the present invention, since the area of the sample liquid surface is small with respect to the volume of the measuring unit main body 13a, measurement errors due to surface tension can be minimized. Further, since the influence of wettability is small, it is not necessary to perform, for example, an inner wall treatment for improving the wettability of the sample on the measuring unit main body 13a, the first end 13b, and the second end 13c through which the sample passes. Therefore, the manufacturing cost of the chip can be reduced. In addition, the tip can be used for samples having different surface tensions without considering the surface tension of each sample.

<Example>
(Constitution)
FIG. 8 is a plan view of a chip according to an embodiment of the present invention. The chip 100 includes a blood introduction unit 107, a centrifuge unit 122, a blood cell separation unit 124, an air hole 109, a measuring unit 113, a take-out pipe 119, a waste liquid reservoir 111, a reagent reservoir 125, a mixing unit 127, and a detection path 129.

Whole blood collected from a human body or the like is introduced into the blood introduction unit 107. The centrifugal separator 122 centrifuges plasma from whole blood by the rotation of the chip 100 around the rotation shaft 121. The blood cell separation unit 124 holds the centrifuged blood cells.
The weighing unit 113 is the weighing unit 13 having the same configuration as that of FIG. 7 described above, and is formed in a V shape having an opening with respect to the rotating shaft 123. Here, the measurement part 113 has a thin tubular shape, and the surface area of the solution located inside becomes small.

  The air holes 109 and the take-out pipe 119 have the same configuration as the air holes 9 and the take-out pipe 19 shown in FIG. Both the extraction tube 119 and the air hole 109 are connected to the end of the V-shaped measuring unit 113. The take-out tube 119 is formed so as to be bent from the end of the measuring unit 113, and a predetermined amount of plasma can be measured by the measuring unit 113 due to the bent shape. That is, when the measuring unit 113 is filled with a predetermined amount, the plasma overflowing from the measuring unit 113 flows out from the take-out tube 119. The air hole 109 takes in air in order to prevent the plasma from flowing out excessively from the measuring unit 113 to the take-out tube 119. The waste liquid reservoir 111 holds the plasma extracted from the extraction tube 119.

The reagent reservoir 125 holds a reagent mixed with plasma in the mixing unit 127. The reagent in the reagent reservoir 125 is introduced from the reagent reservoir 125 into the mixing unit 127 by rotation about the rotation shaft 121. Further, the plasma in the measuring unit 113 is further introduced into the mixing unit 127 by rotation about the rotation shaft 121. In the mixing unit 127, the plasma and the reagent are mixed.
Plasma and reagents mixed by the mixing unit 127 are introduced into the detection unit 129. Then, for example, the target component in the plasma is detected by irradiating the detection unit 129 with light and detecting the wavelength of the emitted light.

(processing)
A sample processing method in the chip 100 will be described. FIG. 9 is a schematic diagram showing the processing flow of the sample in the chip.
Step S1: For example, whole blood collected from a human body or the like is introduced into the blood introduction unit 107. In addition, a reagent for reacting with the target component is introduced into the reagent reservoir 125.

Step S2: Whole blood taken into the blood introduction unit 107 is introduced into the centrifuge unit 122 by the rotation of the chip 100 around the rotation shaft 121. Then, blood cells in the blood are introduced into the blood cell separator 124, and plasma is separated into the centrifugal separator 122. Further, the reagent in the reagent reservoir 125 is introduced into the mixing unit 127 by the rotation about the rotation shaft 121.
Step S3: Next, plasma is introduced into the measuring unit 113 by the rotation of the chip 100 around the rotation shaft 123. The plasma overflowing from the measuring unit 113 is introduced into the waste liquid reservoir 111 through the extraction pipe 119 under the influence of the atmospheric pressure from the air hole 109 and the centrifugal force. At this time, the blood level of the plasma measured by the measuring unit 113 is located in the tube of the measuring unit 113. Therefore, since the area of the liquid surface is small, accurate measurement is performed while minimizing measurement errors due to surface tension.

Step S4: The rotation is switched around the rotation axis 121, and the plasma measured by the measuring unit 113 is introduced into the mixing unit 127 and mixed with the reagent.
Step S5: The mixed plasma and reagent are introduced into the detection unit 129, and the target component is detected by light irradiation.
<Comparative example>
(Constitution)
FIG. 10 is a plan view of a chip according to a comparative example of the present invention. The chip 200 includes a blood introduction unit 203, a centrifuge unit 201, a measuring unit 205, reagent reservoirs 219a and 219b, and a mixing unit 217. Here, the measuring unit 205 has a shape different from that of the present invention. That is, as shown in Patent Document 1, the shape of the sample liquid surface in the measuring unit 205 is larger than that of the present invention. In FIG. 10, the whole blood introduced into the blood introduction unit 203 is separated by the centrifuge unit 201 by the rotation about the rotation shaft 310. Then, plasma is introduced into the measuring unit 205 and measured by rotation about the rotation shaft 311. In FIG. 10, the plasma introduced into the measuring unit 205 is indicated by oblique lines. Thus, the sample liquid level in the measuring unit 205 is large. The plasma measured by the measuring unit 205 is introduced into the mixing unit 217 and mixed with the reagent by rotation around the rotation shaft 310.

(Measurement result in the weighing unit)
Table 1 shows the measurement variation of various samples in the measurement unit 113 shown in FIG. 8 of the experimental example and the measurement unit 205 shown in FIG. 10 of the comparative example. Here, samples 1 to 3 are used, and a light weight variation CV (coefficient of variation) value is calculated when the inner wall processing is not performed on the measuring unit (no inner wall processing) and when the inner wall processing is performed (with inner wall processing). did.

検体１〜３：それぞれ異なるヒト全血から血球分離して得られた血漿１〜３。
検体４：Ｌタイプワコー酵素キャリブレータ（和光純薬製）：人工血清を精製した試薬であり、含有成分をある一定の濃度になるように調整した試薬。
内壁処理：テフロン（登録商標）、フッ素系コーティング剤で流路内壁をコーティング。撥水性を向上させることで血漿の濡れ性を低める。

Samples 1-3: Plasmas 1-3 obtained by separating blood cells from different human whole blood.
Specimen 4: L-type Wako Enzyme Calibrator (manufactured by Wako Pure Chemical Industries): A reagent obtained by purifying artificial serum and containing components adjusted to a certain concentration.
Inner wall treatment: Teflon (registered trademark), coating the inner wall of the channel with a fluorine coating. Reduce wettability of plasma by improving water repellency.

  As shown in Table 1 above, it can be seen that when there is no inner wall treatment in the experimental example and no inner wall treatment in the comparative example, there is less measurement variation in the experimental example. Further, comparing the presence of the inner wall processing in the experimental example with the inner wall processing in the comparative example shows that the measurement variation in the experimental example is similarly smaller. From the above, it can be seen that the sample can be accurately weighed by the weighing unit configured as in the present invention.

  Since the solution can be accurately measured by the measuring unit of the present invention, the present invention can be applied to various fluid chips that require accurate analysis and the like.

The exploded plan view of the chip concerning the present invention. Explanatory drawing which shows the relationship between a rotating shaft and each part of a chip | tip. Explanatory drawing for demonstrating the state of the sample at the time of measurement. Explanatory drawing for demonstrating the position of a liquid level. The top view which shows the modification 1 of a measurement part. The top view which shows the modification 2 of a measurement part. The top view which shows the modification 3 of a measurement part. The top view of the chip | tip which concerns on the Example of this invention. The schematic diagram which shows the process flow of the sample in a chip | tip. The top view of the chip | tip which concerns on the comparative example of this invention. The top view of the blood analysis chip currently disclosed by patent document 1. FIG. Explanatory drawing which shows the mode of the liquid level in the sample measurement means of patent document 1. FIG.

Explanation of symbols

9: air hole 11: outlet 13: metering unit 13a: metering unit body 13b: first end 13c: second end 19: take-out pipe 21: rotating shaft

Claims (3)

A chip having a measuring unit for measuring a sample by rotation about a rotation axis,
The weighing unit is
A weighing unit body that is filled with the sample during weighing;
A first end connected to one end of the weighing unit body and serving as an inlet for the sample;
A second end connected to the other end of the weighing unit body;
A take-off tube that branches off from the second end and causes the sample overflowing from the second end to flow out;
Have
The branch point from the second end of the take-out pipe is located on the rotary shaft side of the wall surface that constitutes the measuring unit main body, the wall surface closest to the rotary shaft,
When the sample is measured by rotating the tip about the rotation axis, the sample liquid level at the first end and the sample liquid level at the second end are rotated about the rotation axis. A chip that is concentric and has a distance between the sample liquid surface and the rotating shaft at the first and second end portions that is closer to or the same as the distance between the measuring unit body and the rotating shaft.   2. The chip according to claim 1, wherein the measuring unit is further connected to the second end and further has an air hole for applying atmospheric pressure to the sample liquid surface of the second end.   2. The chip according to claim 1, wherein the measuring unit main body, the first end, and the second end are formed in a U-shaped tube or a V-shaped tube having an opening with respect to the rotation shaft.

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