JP4811267B2 - Microchip and analytical device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microchip which prevents air bubbles from mixing in a sample liquid, does not have measurement errors caused by deficiency in the collection of sample liquids, and enhances the distribution accuracy of the sample liquid. <P>SOLUTION: The microchip for sampling liquid droplets by capillary action is equipped with an injection port 1, having an injection width larger than the liquid droplets and having a recessed part in the projection part, projected from the body part on which the microchip is mounted and the capillary cavity 3 connected to a holding chamber 4 for holding the liquid sampled through the injection port 1, and the capillary cavity 3 that communicates with the injection port 1 is constituted so that the side part of the projection part is opened so as to come into contact with the open air. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a microchip for electrochemically or optically analyzing a biological fluid and an analysis device using the microchip.

  Conventionally, there is a method of electrochemically or optically analyzing a biological fluid using a microchip in which a microchannel is formed. As a method for electrochemical analysis, as a biosensor for analyzing a specific component in a sample solution, for example, a current value obtained by a reaction between glucose in blood and a reagent such as glucose oxidase supported in the sensor is obtained. Some measure blood glucose levels by measuring them.

  In the analysis method using a microchip, the fluid can be controlled using a rotating device having a horizontal axis, and the sample liquid is measured, the cytoplasmic material is separated and separated using a centrifugal force. Therefore, various biochemical analyzes can be performed.

  As a conventional sample liquid collecting method for introducing a sample into a microchip, there is an electrochemical biosensor shown in FIG. 8, and the sample liquid is introduced into the cavity 212 by capillary action from the suction port 208, and the working electrode 201, It is guided to a position where the counter electrode 202 and the reagent layer 210 are located. At this time, the sample is quantitatively collected with the volume of the cavity 212. The current value generated by the reaction between the sample solution and the reagent at the working electrode 201 and the counter electrode 202 is read by connecting to an external measuring device (not shown) through leads 203 and 204 (Patent Document 1).

  Further, in the centrifugal transfer biosensor shown in FIG. 9, the sample liquid is quantitatively collected from the inlet 313 into the first capillary cavity 312 by capillary action, and then the centrifugal force is applied to the sample liquid in the capillary cavity 312. The liquid is transferred to the receiving cavity 317 via the first flow path 314, and the reagent that has reacted with the reagent in the receiving cavity 317 is centrifuged, and only the solution component is collected in the second cavity 316 by capillary force, and optically collected. Can read the reaction state (Patent Document 2).

Further, in the centrifugal transfer biosensor shown in FIG. 10, the sample is transferred from the inlet port 409 to the outlet port 410 by capillary force, and each capillary cavity 404a-f is filled with the sample solution, and then generated by rotation of the biosensor. The sample liquid in each capillary cavity is distributed at the position of each vent hole 406a-g by centrifugal force and transferred to the next processing chamber (not shown) through each connected microconduit 407a-f (patented) Reference 3).
JP 2001-159618 A Japanese National Publication No. 4-504758 JP-T-2004-529333

  However, in the conventional configuration, when the sample liquid disappears before filling the capillary cavity, or when the sample liquid is separated from the inlet during sampling, bubbles due to the influence of the surface tension near the inlet are mixed, If the orientation of the device is changed during handling, the sample in the capillary cavity may move and bubbles may be mixed in. If bubbles are mixed in, the missing sample solution will be added later and aspirated. Even if it tries to make it, since the bubble in a capillary cavity cannot escape outside, it had the subject that a bubble part could not be filled and a fixed amount of sample liquid could not be extract | collected.

  The present invention solves the conventional problem by making the center of the injection port of the microchip concave so that the sample liquid flows from the end of the flow channel when spotted, and into the capillary cavity. It is an object of the present invention to provide a microchip that can prevent air bubbles from being mixed and can collect a sample solution any number of times until the capillary cavity is filled.

In order to solve the above conventional problems, the analysis device of the present invention is the microchip which droplets of fluid collected by capillary action, wherein the microchip is mounted has a droplet size larger injection width of said fluid that includes an inlet having a concave protrusion which protrudes from the main body portion, and a capillary cavity which is connected to the holding chamber over holding a fluid taken through said inlet capillary cavity communicating with said inlet Is an analytical device comprising a microchip, wherein the side of the protrusion is also opened to contact the outside air, and the fluid injected into the injection port of the microchip is used as the capillary of the microchip. Air bubbles are transferred to the holding chamber that temporarily holds a predetermined amount through the cavity and the holding chamber reaches the required amount of fluid. Accumulate in the holding chamber by enabling multiple spotting without occurrence, and transfer the fluid accumulated from the holding chamber to a measuring chamber for optically measuring the fluid through a capillary channel. The fluid is measured and analyzed .

    The present invention solves the conventional problem by configuring the shape of the inlet of the microchip to be concave with respect to the direction in which the sample solution enters, and can prevent air bubbles from being mixed into the capillary cavity. An object of the present invention is to provide a microchip capable of collecting a sample solution any number of times until it fills the capillary cavity and reliably collecting a predetermined amount of sample solution.

Hereinafter, embodiments of the microchip of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 shows a perspective view of the inlet shape in the first embodiment of the present invention. (A) shows the shape of the injection port in which the bubble countermeasure of this embodiment is taken, and (b) shows the case where the mixing of the bubble cannot be sufficiently prevented with a shape in which the injection port is simply projected. FIG. 2 shows the inlet and the shape of the inlet in the microchip 200 according to the first embodiment of the present invention. In the first embodiment, the case where the cross-sectional shape is rectangular is shown as an example. FIG. 2A shows a top view and a front view of the microchip 200 in order from the top, and FIG. FIG. 2C shows a lower substrate of the analysis device 100 including the microchip 200. FIG.

  Although the structure of the analysis device 100 will be described with reference to FIG. 5, the microchip 200 is formed integrally with the lower substrate of the analysis device 100. Here, FIGS. 2A and 2B schematically show the capillary cavity 3 including the inlet 1 that forms part of the flow path shown in the analysis device 100. The microchip 200 is integrally formed when the flow path of the analysis device 100 is formed, and the flow paths are connected and formed. The microchip 200 shown in the first embodiment includes a capillary cavity 3, an inlet 1, and an outlet 2. In this example, the cross-sectional shape of the capillary cavity 3 of the microchip 200 is rectangular, and the shape of the injection port 1 is V-shaped when viewed from above, as shown in FIG. It is rectangular when viewed from the side to be spotted, that is, from the front. Further, the width L of the injection port 1 is set to be larger than the droplet diameter of the sample liquid so that when the sample liquid is spotted, it flows from the left and right ends of the injection port 1 or from one side. By setting in this way, even when the microchip 200 is directed in the direction of gravity, there is a structure in which bubbles are not generated in the capillary cavity 3.

  As an example, in the present invention, the width L of the injection port 1 is 4 mm, and the portion h protruding from the analysis device 100 is h = 1.8 mm. The thickness t of the injection port 1 is set to t = 0.02 mm like the capillary cavity 3. The central part of the injection port 1 has a concave shape, and the side part of the projection part is also open and in contact with the outside air, so that it can be spotted from anywhere. The size of the microchip 200 can be changed as appropriate in order to obtain an appropriate size for the sample liquid collecting portion of the analysis device 100. The thickness w of the lower substrate 10 in which the microchip 200 is integrated is 3 mm, the thickness of the upper substrate 9 is 5 mm, and is approximately 65 mm square. The thickness of the capillary cavity 3 forming the flow path of the sample solution, that is, the depth of the flow path is 0.02 mm.

On the other hand, the depth of the holding chamber 4 connected to the capillary cavities 3 and formed on the lower substrate of the analysis device 100 is 0.3 mm to 0.5 mm and the thickness of the capillary cavities 3 (that is, the depth of the flow path). ) Form deeper. By setting in this way, the sample liquid injected into the capillary cavity 3 does not proceed to the holding chamber 4 only by the capillary force, and utilizes the centrifugal force obtained by rotating the analysis device 100, thereby using the sample liquid. It is for transporting.
Of course, the same effect can be obtained with any shape such as a circle or an ellipse as long as the capillary cavity 3 has a cross-sectional shape other than a rectangular shape as long as the capillary force acts.

  Further, the wall surface constituting the injection port 1 is formed of a hydrophilic material as shown in FIG. 3 so that the contact angle is less than a predetermined angle. Specifically, the contact angle with the wall surface of the inlet 1 is provided to be less than 90 degrees, which is generally said to be hydrophilic. Naturally, the smaller the contact angle, the easier it is for the sample liquid to travel in the flow path, which means that the capillary force works strongly.

FIG. 4 shows the difference in flow pattern due to the difference in inlet shape.
FIG. 4 (a) shows a case where the central portion of the injection port 1 protruding from the analysis device 100 is concave and V-shaped, with a width L = 4 mm and a protruding height h = 1.8 mm. ) Having a width L = 2 mm and a protruding height h = 0.8 mm, (c) is a case where the injection port 1 protruding from the analysis device 100 protrudes in an arc shape with a radius R = 2 mm, (d) Is the same shape as (c) and projects in a circular arc shape with a radius R = 1 mm. In addition, the figure shows the movement when the second and third times are applied.

  As for FIG. 4C, when the sample liquid that first flows in through the inlet 1 flows into the capillary cavity 3 and the interface between the sample liquid near the inlet 1 and the inlet 1 are separated, If it is applied twice, it will flow into the capillary cavity 3 with air bubbles contained between the liquids. This also applies to the case where such a protruding shape is not provided in the injection port 1. When the liquid once spotted is spotted again from the center of the inlet 1, it has occurred in the spotted portion of the inlet 1. This is because the escape route of bubbles disappears.

  That is, when the application is performed twice, the sample liquid flows in through the air layer at the time of the second application, but when the injection port 1 is formed to be convex, This is because all the generated air does not go out of the cavity and remains in the sample liquid as bubbles near the inlet 1. Therefore, in order not to leave bubbles, it is necessary to form an air escape path when the inlet 1 is spotted for the second time.

  In the case shown in FIG. 4A, it is possible to flow into the capillary cavity 3 without including bubbles. This is because the spotted droplets flow from the left and right V-shaped injection ends at the same time or from one side of the V-shaped injection end before spotting the center of the injection port 1 larger than the droplets, Since air can be released from the V-shaped valley in the central portion of the injection port 1 or the other one side wall surface portion that is not spotted, it can be spotted without containing bubbles.

  That is, at the time of the second spotting, as shown in FIGS. 4A and 4A, the sample liquid is spotted with air sandwiched in the inlet 1 but is formed in a concave shape. This is because an inclined cavity is connected to the inlet 1 from the top to the bottom of the side wall portion of the inlet 1, and the cavity from the top to the bottom of the side wall portion of the inlet 1 becomes an air escape path.

  Here, in FIG. 4B, the shape is the same as that in FIG. 4A, but the width L of the injection port 1 is 2 mm, which is smaller than the diameter of the liquid drop, and the protrusion height h is also low, 0.8 mm. In this case, as shown in FIGS. 4 (b) and (1), when the liquid droplets are spotted twice so as to cover the entire injection port 1, there is no escape route for the generated bubbles, and bubbles are generated and the sample liquid is generated. May remain inside. The same applies to FIG. 4D. That is, the shape of the inlet is the same as that in FIG. 4C, and when the arc-shaped radius of the inlet is set to be narrow as R = 1, there is no escape route for the generated bubbles when spotted twice. It may remain in the sample solution.

  FIG. 5 shows whether the dimensions can be changed. In FIGS. 1A and 1B, the case where the inlet width 1 is changed to 2 to 4 mm and the protruding height is changed to 0.8 to 1.8 mm is shown. Even in the shape of the present embodiment as shown in FIG. 1 (a), if the width of the inlet 1 is narrow with respect to the amount of liquid to be spotted, the inlet 1 will flow in a state containing bubbles, so the width of the inlet 1 is larger than 2 mm. It is desirable to set. However, it is desirable in terms of the occupied area when designing the analysis device 100 that the width and protrusion height are designed to be 10 mm or less from the size of the droplets to be spotted at one time. Of course, other values can be taken depending on the size of the analysis device 100. In the present embodiment, it is appropriate that the size of the analysis device 100 is 65 mm × 54 mm × 10 mm, the width of the injection port is 4 mm, and the protrusion height is about 2 mm or less. Moreover, if it is a concave shape from which such an effect is acquired, it will not be limited to this.

FIG. 6 shows the shape of the top view of the microchip for another example of the inlet shape in the first embodiment of the present invention. In the present embodiment, the droplets deposited at the two protruding inlets 1 are first introduced into either one, or even if introduced from the center, the structure allows the air to escape from the left and right ends. good. Therefore, with the structure shown in (a) to (e), by setting the width of the injection port 1 to 3 mm or more and the projection height to 1.2 mm or more, it can be attached twice without causing bubbles. . 6A shows a case where the top surface shape of the injection port 1 is concave, FIG. 6B shows a case where it is U-shaped, FIG. 6C shows a case where it protrudes in a triangular shape on one side, and FIG. (E) shows the case where it protrudes in a both-sides triangle shape. In any case, the shape of the injection port 1 takes into account the escape route of the generated bubbles.
(Embodiment 2)
FIG. 7 shows the analysis device 100 to which the microchip 200 is attached.

  FIG. 7A shows the upper substrate 9 of the analysis device 100, and FIG. 7B shows the lower substrate 10 of the analysis device 100.

  In FIG. 7B, the analysis device 100 temporarily puts a sample solution such as blood injected into the injection port 1 of the microchip 200 shown in Embodiment 1 into the holding chamber 4 by a predetermined amount via the capillary cavity 3. Hold on. The holding chamber 4 carries an analysis reagent (not shown). Then, the sample solution and the analysis reagent are mixed, and the mixed solution is transferred to the measurement chamber 5 via the capillary channel 6. The measurement chamber 5 communicates with a capillary channel 7 having an air opening hole 8. The mixture of the sample liquid and the analysis reagent transferred to the measurement chamber 5 is analyzed by measuring predetermined items by an optical method.

  In the measurement of the sample liquid, the measurement chamber 5 is irradiated with light, and the reaction state between the liquid sample to be examined and the analysis reagent is optically analyzed. Since the absorbance changes depending on the rate of reaction between the sample solution and the analysis reagent, predetermined items are measured by measuring the absorbance of the irradiated light, and the reaction state can be analyzed.

  Here, in the present invention, the capillary cavity 3, the flow path 6, and the flow path 7 are formed with a depth of 0.02 mm to less than 0.3 mm. However, if the sample liquid flows by capillary force, this dimension is used. It is not limited to. In general, since liquid such as blood is measured and analyzed, 0.02 mm to less than 0.3 mm is desirable.

  The holding chamber 4 and the measurement chamber 5 are formed with a depth of 0.3 mm to 0.5 mm, which is the amount of sample solution and the conditions for measuring the absorbance (optical path length, measurement wavelength). The reaction concentration of the sample solution, the type of reagent, etc.). Then, the sample liquid transferred to the measurement chamber 5 is optically measured.

  In the present embodiment, the sample solution is held in the holding chamber 4 via the capillary cavity 3 that communicates with the inlet 1 of the microchip 200 using the capillary force. The wall surface of the flow path 6 is subjected to a hydrophilic treatment. Examples of the hydrophilic treatment method include a surface treatment method using an active gas such as plasma, corona, ozone, and fluorine, and a surface treatment using a surfactant or a hydrophilic polymer. It is done. Here, hydrophilicity means that the contact angle with water is less than 90 degrees.

  Further, as shown in FIG. 7, the analysis device 100 is configured by bonding an upper substrate 9 and a lower substrate 10, and a fine uneven shape is formed on the surface of the lower substrate 10 facing the upper substrate 9. A microchannel structure is formed, and each function works such as transfer of a sample solution and holding a predetermined amount of solution. The injection port 1 has a shape protruding from one side of the main body of the analysis device 100, so that it can be easily spotted with a fingertip or the like. It has the effect of preventing it. When the mixing of the reagent and the sample liquid reaches a predetermined level, the sample liquid in the holding chamber 4 is carried by the capillary force through the flow path 6 to the inlet of the measurement chamber 5, and the analysis device is moved at a predetermined number of rotations. The centrifugal force generated by rotation is transferred to the measurement chamber 5. The transferred sample liquid is optically measured for predetermined items in the measurement chamber 5.

  The microchip 200 according to the present invention prevents the bubbles from being mixed into the capillary cavity 3 for collecting the sample liquid, and can collect the sample liquid any number of times until the capillary cavity 3 is filled. It has the effect of improving the liquid distribution accuracy, and is useful as a sample liquid collection method, a distribution transfer method, etc. in the analytical device 100 used for measuring the components of biological fluids with an electrochemical sensor or an optical sensor. It is.

1 is a perspective view of an injection port shape of a microchip according to Embodiment 1 of the present invention. (A) Top view and front view of microchip in Embodiment 1 of the present invention (b) AA cross-sectional view of the microchip in Embodiment 1 of the present invention (c) Analysis in Embodiment 1 of the present invention Perspective view of the lower substrate of the device Diagram for explaining contact angle of surface tension The figure which shows the flow pattern by the difference in the injection port shape of the microchip in Embodiment 1 of this invention The figure which shows the propriety by the dimension change of the microchip in Embodiment 1 of this invention The figure which shows the other inlet shape of the microchip in Embodiment 1 of this invention 1 is an exploded perspective view of an analysis device according to Embodiment 1 of the present invention. The figure for demonstrating the structure of the electrochemical type biosensor of a prior art example The figure for demonstrating the structure of the centrifugal transfer type biosensor of a prior art example. The figure for demonstrating the sample liquid distribution structure of the centrifugal transfer type biosensor of a prior art example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection port 2 Outlet 3 Capillary cavity 4 Holding chamber 5 Measurement chamber 6, 7 Flow path 8 Atmospheric release hole 9 Upper substrate 10 Lower substrate 100 Analytical device 200 Microchip 201 Working electrode 202 Counter electrode 203, 204 Lead 205 Insulating substrate 206 Cover 207 Spacer 208 Suction port 209 Air escape hole 210 Reagent layer 212 Cavity 310 Wall 312 First cavity 313 Inlet 314 Flow path 315 Filter material 316 Upper compartment 317 Low compartment 318 Core 401 Continuous microconduit 402, 403 Upper part 404a-f Capillary cavity 405a-e Conduit portion 406a-g Top vent 407a-f Connected microconduit 408a-f Valve function 409 Inlet port 410 Outlet port

Claims (3)

The droplets of the fluid in the micro chip be collected by capillary action, an inlet having a concave protrusion the microchip has a droplet size larger injection width of the fluid protruding from the main body to be attached, the a capillary cavity which is connected to the holding chamber over for holding is through the inlet collecting fluid, comprising a capillary cavity communicating with said inlet, that in contact with the outside air to the side even opening of the protrusion An analysis device comprising a microchip characterized in that the fluid injected into the injection port of the microchip is transferred to the holding chamber that temporarily holds a predetermined amount via the capillary cavity of the microchip. The holding chamber can be spotted multiple times without generating bubbles until the required amount of fluid is in the holding chamber. And the fluid accumulated in the holding chamber is transferred to a measurement chamber for optically measuring the fluid through a capillary channel, and the fluid is measured and analyzed. . The centrifugal force generated by rotating the analysis device, analysis device according to claim 1, characterized in that transferring the injected from the injection port of the microchip fluid to the holding chamber from the outlet of the microchip . The analysis device according to claim 1 , wherein the inlet shape is any one of a V shape, a concave shape, a U shape, and a triangular shape.

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