JP5062399B2 - Microchannels and microreactors - Google Patents

Description

  The present invention relates to a microchannel and a microreactor.

In recent years, the analysis of the human genome (human gene information) has been completed, and the relationship between abnormal proteins that produce abnormal gene structures and diseases is being elucidated. By elucidating this relationship, the development method of new drugs has changed from existing methods that rely on developers' experiences and intuition to drugs and compounds to search for compounds that act directly on abnormal proteins and make them new drugs. Yes. By adopting this method, it is expected that the period of new drug development required for nearly 20 years will be shortened to about 5 years in the future.
In the search for a new drug candidate compound, the physical binding amount between the abnormal protein and the new drug candidate compound is generally used as an index. As a method for measuring the amount of binding, a compound that has previously been bound with a labeling substance such as an enzyme, a luminescent substance, or a radioisotope is used. However, at present, a method of performing measurement without using a labeling substance is attracting attention.
As one of the methods, a measurement method using a reactor is shown. A reactor is a device in which an introduction path and a waste liquid path are formed in a chip made of semiconductor, glass, resin, etc., and a reaction tank is provided between them. In the reaction tank, a sensor having an abnormal protein fixed in advance is installed. In the reactor configured as described above, when the sample liquid to be measured containing the compound is poured from the introduction path using a pump, the compound in the sample liquid to be measured reacts with the abnormal protein previously set in the reaction tank, and reacts. The later waste liquid is discharged from the waste liquid path. A substance fixed in advance in the reaction vessel is called a ligand, and a substance supplied as a solution is called an analyte.

In the reaction vessel, some of the analytes in the sample liquid to be measured are bound to the ligand and fixed to the sensor. When the analyte-ligand reaction reaches equilibrium (ie, the amount of analyte immobilized on the sensor is equal to the amount of analyte leaving the sensor), the amount of analyte immobilized on the ligand is constant. Amount. This amount is necessary data for new drug development.
Examples of the technology relating to such a reactor include the following. That is, this is a technique that uses the vibration of a piezoelectric vibrator (particularly a quartz crystal vibrator) as a sensor to measure the viscosity of a sample in contact with the surface of the piezoelectric vibrator and the minute mass attached to the vibrator. More specifically, when an AC voltage is applied to the electrodes formed on both sides of the piezoelectric vibrator, resonance occurs at a specific frequency determined from the material characteristics and shape of the piezoelectric vibrator. Therefore, when a substance adheres to the electrode of the piezoelectric vibrator, the resonance frequency of the whole vibrator changes according to the attached mass. By detecting this change, the technique is to measure the mass of the substance attached to the electrode.
However, such mass measurement means cannot detect a specific substance. For this reason, there is a need for a technique capable of fixing the means for adsorbing or capturing only a specific substance at a predetermined position and measuring the mass of only the specific substance. As a technique that meets such a requirement, a technique that utilizes an antigen-antibody reaction for protein detection is known (see, for example, Patent Document 1). When such a configuration is used for a sensor, a minute mass of a specific measurement target substance can be measured. In addition to the reactor described above, a device in which a valve, a liquid flow path, a liquid inlet and a liquid outlet are formed in one chip substrate is called a microreactor.
JP 2000-338022 A

When the measurement described in Patent Document 1 is performed, the liquid feed pump must always feed liquid uniformly. This is because the reaction amount between the ligand and the analyte is affected by the flow rate of the liquid, and the oscillation frequency of the piezoelectric vibrator drifts due to a change in the internal pressure of the flow path due to a change in the flow rate.
However, as for the conventional liquid feeding pump used in this type of measurement, a diaphragm type or a roller type is the mainstream, and anyway, pulsation occurs during liquid feeding. As described above, this pulsation becomes measurement noise and prevents precise measurement.

Therefore, as a liquid feeding method without pulsation, a method of flowing the solution into the microreactor using gravity can be considered. Because this method does not use a pump, pulsation does not occur.
In order to realize this method, it is preferable to configure the microchannel using a hydrophobic material, for example, plastic. This is because if the material is hydrophobic, the liquid can be repelled, so that the liquid can flow uniformly without staying inside the microchannel.
However, plastics have the disadvantage that proteins tend to adsorb nonspecifically. On the other hand, glass is a material that hardly causes nonspecific adsorption of proteins. However, since glass is hydrophilic, when a microchannel is manufactured using glass, a force that keeps the solution inside the microchannel acts and liquid feeding using gravity cannot be performed.

  The present invention has been made in view of such circumstances, and by suppressing the occurrence of pulsation, the accuracy of mass measurement of a specific substance can be improved, and nonspecific adsorption can be suppressed. Another object of the present invention is to provide a microchannel and a microreactor including the microchannel.

In order to solve the above problem, in the micro flow channel according to claim 1, a micro flow channel for supplying liquid to the sensor or discharging the liquid supplied to the sensor, the flow channel body used in an upright state Has a first wall surface portion that exhibits hydrophobicity and a second wall surface portion that exhibits hydrophilicity, which are divided by a dividing surface parallel to the flow path center line, and the flow path of the first wall surface portion. A circumferential length along a plane perpendicular to the center line is La, a contact angle between the first wall surface portion and the liquid is θa, and a circumference along a surface perpendicular to the flow path center line of the second wall surface portion. When the length is Lb and the contact angle between the second wall surface portion and the liquid is θb, the flow path body satisfies the condition represented by the following expression (1).
La · cos θa + Lb · cos θb <0 (1)

Here, when liquid is present in the standing channel body, when the contact angle between the wall surface of the channel body and the liquid is θ, the force of T · cos θ per unit length is exerted on the liquid due to surface tension. Work vertically upward (T is surface tension).
Therefore, in the case of the microchannel according to claim 1, the vertically upward force received by the surface tension between the liquid existing in the channel main body and the first wall surface portion is La,
T · La · cos θa.
Similarly, the vertically upward force that the liquid existing in the flow path body receives from the second wall surface due to the surface tension is T · Lb · cos θb because the circumference is Lb.

As a result, the vertically upward force that the liquid existing in the flow path body receives from the surrounding wall surface portion due to the surface tension is a value obtained by adding the force received from the first wall surface portion and the force received from the second wall surface portion. Yes, it is expressed by the following equation (4).
T · La · cos θa + T · Lb · cos θb (2)
When the equation (2) is modified, the following equation (3) is obtained.
T (La · cos θa + Lb · cos θb) (3)

  Here, in the invention according to claim 1, as shown in the equation (1), the condition is that La · cos θa + Lb · cos θb is negative. T is a surface tension and is a positive constant. Therefore, the vertically upward force that the liquid existing in the flow path body receives by the surface tension from the surrounding wall surface, which is expressed by the expression (3), becomes negative. For this reason, the liquid which exists in a flow-path main body will flow below by the force of only surface surface force. In addition, since the flow channel body is used in an upright state, gravity is further applied to the liquid existing in the flow channel body. As a result, the liquid existing in the flow channel body surely flows downward.

  In addition, the flow channel body has a first wall surface portion that exhibits hydrophobicity and a second wall surface portion that exhibits hydrophilicity, which are divided by a dividing surface parallel to the flow channel center line. Compared to the case where the flow path body is constituted only by the wall surface portion having hydrophobicity, the nonspecific adsorption can be suppressed by the amount of the wall surface portion having hydrophilicity.

In the microchannel according to the present invention, it is preferable that the contact angles θa and θb satisfy the conditions of the following expressions (6) to (8).
θa> θb (4)
θa> 90deg (5)
θb <90 deg (6)
It may be difficult to determine whether a substance belongs to hydrophilicity or hydrophobicity. Here, without discussing whether it is hydrophilic or hydrophobic, whether the contact angle between the liquid and the wall surface portion exceeds 90 degrees or less can be determined instead of hydrophilic or hydrophobic. Therefore, when selecting the material of the first wall surface portion or the second wall surface portion, it is sufficient to examine only the contact angle with the liquid, so that the selection becomes easy.

In the microchannel according to the present invention, it is preferable that the channel body has a polygonal cross-sectional shape orthogonal to the channel centerline.
In the case where the flow path body is formed on the mating surface of the two members, there is a method in which a groove is formed in advance on at least one of the mating surfaces of both members, and the two members are joined. In this case, the grooves formed on the mating surfaces of the members are more accurate and easier to process if they have a polygonal cross section (for example, a square shape) than a circular arc. For this reason, in the case where a flow path body having a polygonal cross section is formed on the mating surface of the two members, it is easier to obtain accuracy and processing than forming a flow path body having another cross sectional shape.

In the microchannel according to the present invention, it is preferable that the channel body has a circular cross section perpendicular to the channel centerline.
When flowing a liquid, if there is a corner, stagnation occurs, making it difficult to flow uniformly. Here, since the cross-sectional shape of the flow path body is circular, the liquid in the flow path body can flow uniformly without causing stagnation.

In the microchannel according to the present invention, it is preferable that the first wall surface portion is made of plastic and the second wall surface portion is made of glass.
Here, since the flow path main body is made of commonly used materials such as plastic and glass, it can be easily manufactured and the cost can be reduced.

In the microchannel according to the present invention, the first wall surface portion is formed by a groove surface in which a part of the surface of the plastic plate is cut into a U shape, and the second wall surface portion is formed by the surface of the glass plate. Preferably it is formed.
The microreactor according to the present invention uses the microchannel according to any one of claims 1 to 6 as an introduction path and a waste liquid path, and is included in the liquid between the introduction path and the waste liquid path. It is characterized in that a reaction tank having a sensor that reacts with a substance to be mixed is interposed.
In this case, the microreactor has the advantages of the microchannel described above.

  According to the present invention, by suppressing the occurrence of pulsation, the accuracy of mass measurement of a specific substance can be improved, and nonspecific adsorption can also be suppressed.

Hereinafter, each embodiment of the present invention will be described.
<First Embodiment>
Hereinafter, a microreactor including a microchannel in the first embodiment of the present invention will be described with reference to the drawings.
1 is a cross-sectional view of the microreactor, FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1, and FIG. 3 is a front view of a plastic plate.

As shown in FIG. 1, a microreactor 1 includes a glass plate 2, a plastic plate 3 that is appropriately joined to one surface of the glass plate 2 by a joining means (for example, an adhesive), and the plastic plate 3 of the glass plate 2. And a piezoelectric vibrator sensor (for example, a quartz vibrator sensor) 4 attached at a substantially central position in the height direction of the surface opposite to the joint surface.
An introduction path 5 for introducing a liquid to the piezoelectric vibrator sensor 4 is formed from the upper end portion to the center portion at the mating portion of the glass plate 2 and the plastic plate 3, and the piezoelectric vibrator sensor 4 is disposed at the mating portion. A waste liquid path 6 for discharging the liquid fed to the outside is formed so as to reach the lower end from the center. The upper end of the introduction path 5 is a liquid introduction port 5a, and the lower end of the waste liquid path 6 is a liquid discharge port 6a.

A reaction tank 8 is formed between the glass plate 2 and the piezoelectric vibrator sensor 4 via an annular partition wall 7. The reaction portion 4a of the piezoelectric vibrator sensor 4 is exposed in the reaction tank 8. When a specific substance is contained in the sample liquid to be measured, the reaction unit 4a uses an antigen-antibody reaction when detecting a specific protein, for example, a means for adsorbing or capturing only the specific substance. Adsorption or capture means are provided. In addition, the introduction path 5 and the waste liquid path 6 communicate with the reaction tank 8 through communication paths 9 and 9 formed integrally with the glass plate 2, respectively.
Further, a valve (not shown) is interposed in the introduction path 5 or the communication path 9 so that liquid feeding / stopping of the liquid flowing through the introduction path 5 can be controlled.

The introduction path 5 will be described. Since the waste liquid path 6 has substantially the same configuration as the introduction path 5, the description thereof is omitted here.
The introduction path 5 constitutes a micro flow path for feeding a small amount of liquid to the piezoelectric vibrator sensor 4. As shown in FIG. 4, the introduction path 5 includes a flow path body 10 that is used in a standing state. The channel body 10 has a quadrangular cross-sectional shape perpendicular to the channel center line J. In addition, the flow channel body 10 includes a first wall surface portion 11 and a second wall surface portion 12 that are divided by a dividing surface S parallel to the flow channel center line J.
The first wall surface portion 11 is formed by the surface of a groove in which a part of the surface of the plastic plate 3 is cut into a U shape, and has hydrophobicity. The second wall surface portion 12 is formed by the surface of the glass plate 2 and has hydrophilicity.

The circumferential length along the surface perpendicular to the flow path center line of the first wall surface portion 11 is La, the contact angle between the first wall surface portion 11 and the liquid (for example, water) is θa, and the flow path of the second wall surface portion. When the circumferential length along the plane orthogonal to the center line is Lb, and the contact angle between the second wall surface portion 12 and the liquid is θb (see FIG. 5), the flow path body 10 is expressed by the above-described equation (1). It shall satisfy the conditions expressed.
Furthermore, both the contact angles θa and θb satisfy the conditions represented by the above-described equations (4) to (6).

Next, the operation of the microreactor will be described.
First, for example, water (fresh water) is supplied from the liquid introduction port 5 a to fill the introduction path 5, the reaction tank 8, and the waste liquid path 6. In this case, as will be described later, the water may be filled by using gravity or surface tension, but the present invention is not limited to this, and the pump may be used to fill the water. This is because at this time, measurement by the piezoelectric vibrator sensor 4 is not performed, and the flow path of the microreactor is simply filled with water.

Next, after supplying a predetermined amount of the sample liquid to be measured from the liquid inlet 5a, subsequently, buffer water is supplied from the liquid inlet 5a.
Here, a case where water is supplied into the introduction path 5 will be considered.
The introduction path 5 has a rectangular parallelepiped shape with a depth t, a width w, and a height h as shown in FIG. Therefore, when water is filled in the introduction path 5 and the specific gravity is ρ, gravity W applied to the water filled in the introduction path 5 is expressed by the following equation (7) (g is Gravity acceleration).
ρ · g · t · w · h (7)
On the other hand, the vertically upward force due to the surface tension T between the water in the introduction path 5 and the wall surface is expressed by the following equation (8).
T · w · cos θa + T · 2t · cos θa + T · w · cos θb (8)

Here, assuming that the gravity applied to the water in the introduction path 5 is balanced with the force vertically above due to the surface tension applied to the water, the following equation (9) is established.
ρ · g · t · w · h = T · w · cos θa + T · 2t · cos θa + T · w · cos θb (9)

When the above equation (9) is transformed,
h = (T / (ρ · g)) ((cos θa) / t + 2 (cos θa) / w + (cos θb) / t) (10)
It becomes.

Here, a specific numerical value is substituted into the above equation (10).
For example, contact angle θa = 112 (deg), contact angle θb = 30 (deg),
ρ = 998.2 (kg / m ² ), g = 9.8 (m / s ² ),
T = 0.00728 (N / m), w = 0.5 (mm), and t = 0.08 (mm) are substituted.
Then
h = 0.03456 (m)
Is obtained.

That is, assuming that the contact angles θa and θb are the above values and the depth t and the width w of the introduction path 5 are the above values, the height h of the introduction path 5 is 0.03456 (m). If there is, the gravity applied to the water in the introduction path 5 and the force vertically above due to the surface tension applied to the water will balance, and the water in the introduction path 5 will not rise or fall on the spot. Stop.
On the other hand, when the height h of the introduction path 5 exceeds 0.03456 (m), the water in the introduction path 5 is more affected by gravity than the surface tension and descends. On the other hand, if the height h of the introduction path 5 is less than 0.03456 (m), the water in the introduction path 5 rises due to a stronger surface tension. Can not flow.

On the other hand, without considering the influence of gravity, let us consider a condition for flowing the water existing in the introduction path 5 downward only by the surface tension acting on the water existing in the introduction path 5. In order to satisfy this condition, it is only necessary that the upward force due to the surface tension T between the water in the introduction path 5 and the wall surface expressed by the above equation (8) is negative.
The above equation (8) can be transformed into the following equation (11).
T ((w + 2t) · cos θa + w · cos θb) (11)
Here, as shown in FIG. 4, w + 2t is nothing but the circumferential length La along the liquid surface of the first wall surface portion 11, and w is the circumference along the liquid surface of the second wall surface portion 12. It is none other than the length Lb. Therefore, the equation (11) can be transformed into the following equation (12).
T (La · cos θa + Lb · cos θb) (12)

  In the equation (12), it is obvious that La · cos θa + Lb · cos θb is negative from the condition of the equation (1) as described above. T is a surface tension and is a positive constant. Therefore, the vertically upward force that the liquid existing in the flow channel body receives by the surface tension from the surrounding wall surface, which is expressed by the equation (12), is always negative. As a result, in the microchannel according to the first embodiment, since the condition of the expression (1) is satisfied as described above, the liquid existing in the channel body flows downward by the force of only the surface surface force. Become. In addition, since the flow path body is used in an upright state, gravity is further applied to the liquid existing in the flow path body, and the liquid existing in the flow path body surely flows downward.

Here, when La and Lb in the above equation (1) are respectively replaced with the depth t and the width w of the introduction path 5 of this embodiment, the following equation (13) is obtained.
(W + 2t) · cos θa + w · cos θb <0 (13)
If a specific contact angle θa = 112 (deg) and a contact angle θb = 30 (deg) are respectively substituted into the equation (13),
w <1.5246t
Is obtained.
That is, on the condition that the contact angles θa and θb are the above values, if the depth t and the width w of the introduction path 5 satisfy the relationship of w <1.5246t, the liquid existing in the flow path body 10 is Without being affected by gravity, it flows downward by the surface force alone.

By the way, as described above, the liquid in the introduction path 5 always flows into the reaction tank 8 through the communication path 9 at a uniform speed without generating pulsation. When the liquid is water, no change occurs in the reaction part 4a of the piezoelectric vibrator sensor 4 even if it passes through the reaction tank 8. However, when the sample liquid to be measured interposed between water reaches the reaction tank 8, the specific substance contained in the sample liquid to be measured comes into contact with the reaction part 4a and is adsorbed or captured by the reaction part 4a. Is done. At this time, the resonance frequency of the piezoelectric vibrator of the piezoelectric vibrator sensor 4 changes according to the mass of the specific substance adsorbed on the reaction part 4a. By detecting this change, the mass of the specific substance adsorbed by the reaction unit 4a can be measured with high accuracy.
That is, by suppressing the occurrence of pulsation, the accuracy of mass measurement of a specific substance can be improved. Moreover, since the flow path body 10 includes the first wall surface portion 11 exhibiting hydrophobicity and the second wall surface portion 12 exhibiting hydrophilicity, only the wall surface portion exhibiting hydrophobicity, such as plastic, is used. Compared with the case where the flow path main body is configured, nonspecific adsorption can be suppressed by the amount of the wall surface portion showing hydrophilicity.
The waste liquid after reaction in the reaction tank 8 is discharged to the outside through the communication path 9 and the waste liquid path 6.

<Second Embodiment>
FIG. 6 shows a second embodiment of the present invention. In the second embodiment, the overall configuration of the microreactor is omitted because it is substantially the same as that of the first embodiment, and only the microchannel is shown here.
The microchannel shown here is different from that of the first embodiment in that the cross-sectional shape of the channel body of the microchannel is different.
That is, in the first embodiment, the cross-sectional shape orthogonal to the flow path center line J of the flow path body is formed in a quadrangular shape, but in this second embodiment, the flow path center line of the flow path body 21 A cross-sectional shape orthogonal to J is formed in a circular shape.

In the second embodiment as well, the flow path main body 21 constituting the micro flow path used in an upright state is provided at the joining portion of the glass plate 2 and the plastic plate 3. The flow path body 21 is formed by cutting into an arc shape so that the opposing portions of the glass plate 2 and the plastic plate 3 have a radius of curvature r and a predetermined opening angle, respectively. That is, also in the second embodiment, the flow channel main body 21 is divided by the division surface S parallel to the flow channel center line J, and the first wall surface portion 22 that exhibits hydrophobicity and the second wall surface that exhibits hydrophilicity. It will have the wall part 23.
Also in this embodiment, the circumferential length along the surface orthogonal to the flow path center line of the first wall surface portion 22 is La, the contact angle between the first wall surface portion 22 and the liquid is θa, and the second wall surface When the circumferential length along the surface orthogonal to the flow path center line of the portion 23 is Lb and the contact angle between the second wall surface portion and the liquid 23 is θb, the condition shown in the above equation (1) is satisfied.

  Also in this embodiment, the same effect as in the first embodiment, that is, by suppressing the occurrence of pulsation, the accuracy can be improved when measuring the mass of a specific substance, and nonspecific adsorption can be performed. The effect which can be suppressed is acquired. In this embodiment, since the cross-sectional shape orthogonal to the flow path center line J of the flow path body 21 is formed in a circular shape, there is an effect that a uniform flow without stagnation can be obtained.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first embodiment, the cross-sectional shape orthogonal to the flow path center line of the flow path main body is formed in a quadrangular shape, but is not limited thereto, and may be a triangular shape or a polygonal shape of 5 or more. . In the first embodiment, when the flow path body is formed, the U-shaped groove is formed only on the mating surface of the plastic plate 3 among the mating surfaces of the plastic plate 3 and the glass plate 2. However, the present invention is not limited to this, and a U-shaped groove may be formed on the opposing surfaces of both plates 2 and 3.

In the first and second embodiments, in forming the flow path body having the first wall surface portion exhibiting hydrophobicity and the second wall surface portion exhibiting hydrophilicity, the hydrophobicity, which is a different material, is used. Although it forms in the joint part of the plastic plate 3 to show, and the glass plate 2 to show hydrophilicity, it is not restricted to this, Both board | plate materials are comprised with a common material, for example, a glass plate or a plastic plate, and these A flow path body having a first wall surface portion that exhibits hydrophobicity and a second wall surface portion that exhibits hydrophilicity may be formed by performing surface processing only on a necessary portion of the opposing surfaces of the plate material. .
Moreover, in the said embodiment, when forming the 1st wall surface part which shows hydrophobicity in the flow path main body, and the 2nd wall surface part which shows hydrophilic property, the surrounding wall of a flow path main body is divided into 2 to the circumferential direction. However, the present invention is not limited thereto, and the peripheral wall of the flow channel body is divided into a plurality of four or more in the circumferential direction, and the first wall surface portion showing hydrophobicity and the second wall surface showing hydrophilicity The parts may be arranged alternately.

It is sectional drawing which shows the microreactor of 1st Embodiment of this invention. It is sectional drawing which follows the II-II line of FIG. It is a front view of the plastic plate which comprises the said micro reactor. It is a perspective view which shows the micro flow path of a micro reactor. (A), (b) is sectional drawing which shows a contact angle, respectively. It is a perspective view which shows the micro flow path of the micro reactor which shows 2nd Embodiment of this invention.

Explanation of symbols

1 microreactor
2 glass plates
3 plastic plates
4 Piezoelectric vibrator sensor 5 introduction path (micro flow path)
6 Waste liquid path (micro flow path)
8 reaction tank 9 communication path 10, 21 flow path body 11, 22 first wall surface portion 12, 23 second wall surface portion

Claims (7)

A microchannel for supplying liquid to the sensor or discharging the liquid supplied to the sensor,
A flow path body used in an upright state has a first wall surface portion showing hydrophobicity and a second wall surface portion showing hydrophilicity, which are divided by a dividing surface parallel to the flow path center line,
The circumferential length of the first wall surface portion along a plane orthogonal to the flow path center line is La, the contact angle between the first wall surface portion and the liquid is θa, and the flow path of the second wall surface portion. When the circumferential length along the surface orthogonal to the center line is Lb, and the contact angle between the second wall surface portion and the liquid is θb,
The microchannel characterized in that the channel body satisfies a condition represented by the following formula.
La · cos θa + Lb · cos θb <0 2. The microchannel according to claim 1, wherein the contact angles θa and θb satisfy a condition represented by the following expression.
θa> θb
θa> 90deg
θb <90deg   The microchannel according to claim 1 or 2, wherein the channel body has a polygonal cross-sectional shape perpendicular to the channel centerline.   The microchannel according to claim 1 or 2, wherein the channel body has a circular cross-sectional shape perpendicular to the channel centerline. It said first wall portion is constituted by plastic, microchannel according to any one of claims 1 to 4, wherein the second wall portion is characterized by being composed of glass. The first wall surface portion is formed by a groove surface in which a part of the surface of a plastic plate is cut into a U-shape, and the second wall surface portion is formed by a surface of a glass plate. The microchannel according to any one of claims 1 to 5. A sensor that reacts with a substance contained in the liquid between the introduction path and the waste liquid path, wherein the micro flow path according to any one of claims 1 to 6 is used as the introduction path and the waste liquid path. A microreactor characterized in that a reaction tank having a medium is interposed.

Images