JP6195211B2 - Microfluidic device - Google Patents

Description

  The present invention relates to a microfluidic device.

  A microfluidic device is a device capable of reacting a reaction solution containing a very small amount of sample or reagent, and includes a microreaction device (microreactor), an integrated DNA device, a microelectrophoresis device, and the like.

  The microfluidic device is used in a reaction device that gives a desired temperature change to a reaction solution. By using the microfluidic device, the temperature change applied to the reaction solution can be accelerated.

  Conventionally, there is a nucleic acid amplification device that amplifies a target nucleic acid by repeatedly applying a temperature change, but the target nucleic acid can be amplified at high speed by using a microfluidic device as the nucleic acid amplification device.

  For example, Patent Document 1 and Non-Patent Document 1 disclose a configuration in which a device is divided into a plurality of different temperature regions, and a meandering channel that is meandered so that the reaction solution repeatedly passes through each temperature region is disclosed. Has been.

  With this configuration, it is possible to apply a desired temperature change to the reaction solution at high speed only by causing the reaction solution to advance into the meandering flow path. Thereby, nucleic acid amplification can be performed at high speed when a solution containing nucleic acid is used as the reaction solution.

JP 2002-18271 A

Science, vol. 282, pp. 484 (1998)

  However, in the conventional microfluidic device described above, each region of the plurality of temperature regions exists separately, so that there is an intermediate region that does not contribute to the reaction of the reaction solution between one temperature region and the other temperature region. Exists. If the intermediate region is present, the reaction solution may induce a nonspecific reaction, which may reduce the reaction efficiency of the reaction solution.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a microfluidic device that can suppress a decrease in reaction efficiency of a reaction solution.

  In order to achieve the above object, one aspect of the microfluidic device according to the present invention is a microfluidic device including a flow path through which a reaction solution flows, wherein the flow path is set to a first different temperature. It is configured to pass through a temperature region and a second temperature region, and a cross-sectional area of the flow path in an intermediate region between the first temperature region and the second temperature region is the first temperature region and the second temperature region. It is smaller than the cross-sectional area of the flow path in the second temperature region.

  In one aspect of the microfluidic device according to the present invention, the flow path may be a meandering flow path configured to alternately and repeatedly pass through the first temperature region and the second temperature region. Good.

  Further, in one aspect of the microfluidic device according to the present invention, the reaction solution contains a target nucleic acid, and the target nucleic acid is subjected to a polymerase chain reaction by passing through the meandering channel. Nucleic acid amplification may be performed.

  Further, in one aspect of the microfluidic device according to the present invention, the reaction solution contains bacteria or viruses as the substance to be measured, and the microfluidic device contains the substance to be measured contained in the reaction solution. It may be detected.

  In one aspect of the microfluidic device according to the present invention, the width of the flow path in the intermediate region may be smaller than the width of the flow path in the first temperature region and the second temperature region.

  In one aspect of the microfluidic device according to the present invention, the cross-sectional area of the flow path may be adjusted by a pillar provided in the flow path.

  Moreover, in one aspect of the microfluidic device according to the present invention, the flow path is configured to pass through a reaction part in which the first temperature region and the second temperature region exist, and the flow path is The cross-sectional area of the reaction part as a whole may decrease monotonously or may decrease stepwise.

  According to the present invention, a decrease in reaction efficiency of a reaction solution can be suppressed.

FIG. 1 is a perspective view showing a schematic configuration of a microfluidic device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the microfluidic device according to the embodiment of the present invention. FIG. 3 is a plan view of the microfluidic device according to the embodiment of the present invention. FIG. 4 is a cross-sectional view of the microfluidic device according to the embodiment of the present invention. FIG. 5 is a diagram for explaining a temperature cycle in the microfluidic device according to the embodiment of the present invention. FIG. 6A is an enlarged plan view of a main part of a flow path in the microfluidic device according to the embodiment of the present invention. FIG. 6B is a cross-sectional view of the flow path in the microfluidic device according to the embodiment of the present invention taken along line X-X ′ in FIG. 6A. FIG. 7 is a diagram showing the characteristics of the flow path in the microfluidic device according to the embodiment of the present invention. FIG. 8A is an enlarged plan view of a main part of a flow path in the microfluidic device according to the first modification of the present invention. FIG. 8B is a cross-sectional view of the flow path in the microfluidic device according to Modification 1 of the present invention taken along line X-X ′ of FIG. 8A. FIG. 9A is an enlarged plan view of a main part of a flow path in a microfluidic device according to Modification 2 of the present invention. FIG. 9B is a cross-sectional view of the flow path in the microfluidic device according to Modification 2 of the present invention taken along line X-X ′ in FIG. 9A. FIG. 10 is an enlarged plan view showing the flow path of the microfluidic device according to the third modification of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangement positions and connection forms of components, and steps and order of steps shown in the following embodiments are merely examples, and are not intended to limit the present invention. Absent. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a schematic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected to the substantially same structure, The overlapping description is abbreviate | omitted or simplified.

(Embodiment)
The configuration of the microfluidic device 1 according to the embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view showing a schematic configuration of a microfluidic device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the microfluidic device, and FIG. 3 is a plan view of the microfluidic device. FIG. 4 is a cross-sectional view of the microfluidic device.

  As shown in FIGS. 1 to 4, the microfluidic device 1 according to the present embodiment is a device (microchip) including a flow channel 100 through which a reaction solution flows, and the flow channel 100 is at a predetermined different temperature. It passes through the set first temperature range and second temperature range. And although mentioned later for details, the cross-sectional area of the flow path 100 in the intermediate | middle area | region between a 1st temperature range and a 2nd temperature range is larger than the cross-sectional area of the flow path 100 in a 1st temperature range and a 2nd temperature range. It is getting smaller.

  The flow channel 100 is a reaction flow channel through which the reaction solution flows one-way, and is provided to pass through at least the reaction unit 110. The reaction part 110 is an area for reacting the reaction solution. In the present embodiment, the reaction solution is a solution containing a target nucleic acid as a sample, and specifically, an aqueous solution containing a target nucleic acid and a reaction reagent for amplifying the target nucleic acid. Therefore, the reaction unit 110 in the present embodiment is a nucleic acid amplification reaction unit, and the reaction unit 110 amplifies the target nucleic acid contained in the reaction solution. Note that the reaction solution may contain certain alcohols, surfactants, and the like.

  As described above, the microfluidic device 1 in the present embodiment is used as a nucleic acid amplification device for amplifying a target nucleic acid as a sample. Hereinafter, a case where a PCR (Polymerase Chain Reaction) method is performed using the microfluidic device 1 will be described. The PCR method is a technique for amplifying target DNA by a temperature cycle. In addition to the target DNA, the reaction solution (reaction fluid) contains a PCR primer, a polymerase enzyme, a buffer, and the like. By giving a temperature cycle to such a reaction solution, the target DNA can be amplified. The amplification amount of the amplified DNA can be detected by a reaction detection mechanism.

  The microfluidic device 1 as a nucleic acid amplification device includes an introduction part (inlet) 120 into which a reaction solution containing a target nucleic acid is introduced, and a reaction part for amplifying a target nucleic acid contained in the reaction solution introduced into the introduction part 120 110, a discharge unit (drain) 130 for discharging the reaction solution containing the target nucleic acid amplified by the reaction unit 110, and a heater unit 140 for heating the reaction solution containing the target nucleic acid.

  Specifically, the microfluidic device 1 includes a first substrate 10, a second substrate 20, and a heater unit 140. The heater unit 140 includes a first heater block 141 and a second heater block 142 having different set temperatures. Note that the outer shape of the microfluidic device 1 in the present embodiment is, for example, a substantially rectangular shape having a vertical length of 40 mm and a horizontal length of 20 mm.

  Hereinafter, the detailed configuration of each component of the microfluidic device 1 will be described in detail with reference to FIGS.

[First substrate]
As shown in FIG. 2, the first substrate 10 includes a first recess 11 constituting a part of the introduction part 120, a second recess 12 constituting a part of the discharge part 130, and a groove part constituting the flow path 100. 13. As the first substrate 10, for example, a silicon substrate can be used.

  The groove 13 (flow channel 100) is formed so as to connect the first recess 11 and the second recess 12. The reaction solution flows through the groove 13 (channel 100). Specifically, when the reaction solution is introduced into the first recess 11 (introduction portion 120), the reaction solution proceeds in the groove 13 (channel 100) toward the second recess 12 (discharge portion 130). To do.

  As shown in FIG. 3, the flow path 100 is a meandering flow path formed to meander, and includes a first heater block 141 (first temperature region) and a second heater block 142 (second temperature region). It is configured to pass alternately and repeatedly.

  Specifically, the flow path 100 in the reaction unit 110 is formed so as to be continuously folded (reciprocated) while bending the linear flow path at predetermined intervals. The number of turns of the flow path 100 in the reaction unit 110 is, for example, about 20 to 70 cycles. As an example, the length of the flow channel 100 (main flow channel 100a) per cycle can be 32 mm.

  The flow channel 100 in the present embodiment includes a plurality of linear main flow channels 100a having a predetermined length, and a sub flow channel 100b that connects ends of the main flow channels 100a in each row facing each other. The main channel 100a and the sub channel 100b are provided in the reaction unit 110.

  The main flow path 100 a is provided so as to be substantially orthogonal to the longitudinal direction of the first heater block 141 and the second heater block 142 so as to straddle the first heater block 141 and the second heater block 142. The sub flow channel 100 b is provided so as to be substantially parallel to the longitudinal direction of the first heater block 141 and the second heater block 142.

  The flow path 100 further includes an introduction flow path 100c that is a flow path for guiding the reaction solution from the introduction section 120 to the reaction section 110, and a discharge flow for guiding the reaction solution from the reaction section 110 to the discharge section 130. 100d.

  The starting end of the introduction channel 100c is an inlet of the entire channel 100, and the end of the introduction channel 100c is the inlet of the channel 100 in the reaction section. Further, the start end of the discharge channel 100d is an outlet of the channel 100 in the reaction section, and the end of the discharge channel 100d is an outlet of the entire channel 100.

  In the present embodiment, a silicon oxide film is formed on the inner surface of the groove 13 constituting the channel 100. By forming the silicon oxide film, the wall surface of the channel 100 (groove portion 13) can be hydrophilized. In the present embodiment, a silicon oxide film is formed on all of the main flow channel 100a, the sub flow channel 100b, the introduction flow channel 100c, and the discharge flow channel 100d.

  The channel 100 configured in this way is a micro channel, and for example, the cross-sectional shape is rectangular. In this case, the channel width (groove width) of the groove 13 constituting the channel 100 is, for example, 50 μm, and the depth of the groove 13 is 50 μm.

  In addition, the cross-sectional shape of the groove part 13 is not restricted to a rectangle, It can be made into a semicircle or an inverted triangle. Moreover, the 1st recessed part 11 and the 2nd recessed part 12 can be made into the recessed part of circular opening, for example. Further, the material of the first substrate 10 is not limited to silicon, and may be resin or glass.

[Second board]
As shown in FIG. 1, the second substrate 20 is a lid that covers the first substrate 10 and is disposed on the first substrate 10. As the second substrate 20, for example, a glass substrate can be used.

  As shown in FIG. 2, the second substrate 20 is provided with a first through hole 21 that penetrates the second substrate 20 as a part of the introduction part 120. The second substrate 20 is provided with a second through hole 22 that penetrates the second substrate 20 as a part of the discharge unit 130. The first through hole 21 and the second through hole 22 are, for example, through holes having a circular opening.

  By placing the second substrate 20 on the first substrate 10, the flow path 100 in which the opening of the groove 13 is closed and all directions are sealed is configured. Thereby, the flow path 100 has a configuration in which the entire circumference of the wall surface in a cross section perpendicular to the liquid solution feeding direction (traveling direction) is closed, and is connected to the external space only at the introduction part 120 and the discharge part 130. Become. Thus, by closing all the directions of the flow path 100, it can suppress that a reaction solution volatilizes during liquid feeding.

  The material of the second substrate 20 is not limited to glass but may be resin or silicon.

[Heater part]
As shown in FIGS. 1 to 3, the heater unit 140 is disposed at least in the reaction unit 110, and the reaction solution fed to the flow path 100 of the reaction unit 110 is given a predetermined temperature by the heater unit 140. The

  In the present embodiment, the reaction unit 110 includes a first heater block 141 and a second heater block 142 that are set to predetermined different temperatures as the heater unit 140. That is, the reaction unit 110 has two temperature regions that are set to predetermined different temperatures by the two heater blocks, the first heater block 141 and the second heater block 142.

  The first heater block 141 and the second heater block 142 are heaters using metal blocks made of a metal such as a rectangular parallelepiped aluminum or stainless steel, for example. As the heater unit 140, a metal thin film heater or the like in which a metal thin film is formed on a glass substrate by printing or the like can be used in addition to the heater block.

  The region where the first heater block 141 set to the first temperature is disposed is the first temperature region. The region where the second heater block 142 set to the second temperature is disposed is a second temperature region which is a temperature region different from the first temperature region.

  In the present embodiment, the temperature of the first heater block 141 is set to be higher than the temperature of the second heater block 142. That is, the region where the first heater block 141 is disposed is a high temperature region, and the region where the second heater block 142 is disposed is a low temperature region.

  The temperature of the first heater block 141 which is a high temperature region is 90 ° C. to 98 ° C. which is a temperature at which the reaction solution does not evaporate. In this embodiment, the temperature is about 95 ° C. which is the denaturation reaction temperature of the nucleic acid amplification reaction. On the other hand, the temperature of the second heater block 142 which is a low temperature region is, for example, 50 ° C. to 75 ° C., and in this embodiment, the temperature is about 60 ° C. which is the annealing / elongation reaction temperature.

  As shown in FIG. 3, the heater unit 140 is connected to the temperature control unit 210. Thereby, each temperature of the first heater block 141 and the second heater block 142 can be controlled by the temperature control unit 210.

  The first heater block 141 and the second heater block 142 are arranged with a predetermined gap. The first substrate 10 is disposed on the first heater block 141 and the second heater block 142. Specifically, the first substrate 10 is placed on the heater unit 140 such that the main channel 100 a in the channel 100 straddles the first heater block 141 and the second heater block 142. Thereby, the flow path 100 is comprised so that two temperature areas may reciprocate in multiple cycles.

  With this configuration, as shown in FIG. 5, when the reaction solution 300 is introduced from the introduction unit 120, the reaction solution 300 is divided into two temperature regions in the reaction unit 110 (the first heater block 141 and the second heater block 142). The liquid is sent to the discharge unit 130 so as to pass alternately. That is, a heat cycle can be applied to the reaction solution 300 flowing through the flow path 100.

  Here, a nucleic acid amplification method using the microfluidic device 1 according to the embodiment of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 4, the reaction solution 300 is injected into the introduction part 120 using a pipette. In the present embodiment, a solution in which a reaction solution containing a target nucleic acid and a reaction reagent are mixed in advance is introduced into the introduction unit 120 of the microfluidic device 1 as a reaction solution.

  The reaction solution 300 introduced into the introduction unit 120 is sent from the introduction unit 120 to the reaction unit 110 through the channel 100 (introduction channel 100c).

  The reaction solution that has reached the reaction unit 110 passes through the main flow path 100a and the sub flow path 100b so as to reciprocate between the first heater block 141 and the second heater block 142 repeatedly. That is, since the reaction solution is fed while reciprocating between the high temperature region (first heater block 141) and the low temperature region (second heater block 142) of the heater unit 140, heating and cooling are alternately repeated. become. Thereby, the target nucleic acid contained in the reaction solution is amplified by repeating the denaturation reaction in the high temperature region and the annealing / extension reaction in the low temperature region. As described above, since the reaction solution can be raised and lowered while the solution is fed, a very high-speed flow PCR can be realized. Therefore, the target nucleic acid contained in the reaction solution can be amplified at high speed.

  Thereafter, the reaction solution is sent from the reaction unit 110 to the discharge unit 130 through the discharge channel 100d. In the present embodiment, when the tip of the reaction solution introduced into the introduction unit 120 reaches the discharge unit 130, the introduction of the solution containing the target nucleic acid (the reaction solution in this embodiment) into the introduction unit 120 is stopped. At this time, the reaction solution is filled in the flow path 100. The reaction solution that has reached the discharge unit 130 is discharged from the discharge unit 130 as needed.

  In this way, the reaction solution proceeds in the channel 100. In the present embodiment, the channel 100 has a hydrophilic wall surface having a sharp contact angle θ as a capillary force carrying mechanism for feeding the reaction solution by capillary force (capillary force). Specifically, silicon oxide films are formed on three wall surfaces on the bottom and both sides of the groove 13 in a cross section perpendicular to the liquid feeding direction of the reaction solution 300. By forming the silicon oxide film, the surface of the groove 13 can be hydrophilized, and the inner wall surface of the channel 100 can be made hydrophilic.

  As a result, the reaction solution is self-propelled (Self-propelled flow) in the flow path 100 due to the capillary force generated at the gas-liquid interface, and thus automatically proceeds in the flow path 100. That is, the reaction solution is periodically changed in temperature in the reaction unit 110 while being fed into the flow path 100 by automatic conveyance.

  Note that a part of the wall surface of the channel 100 may be a hydrophilic surface, but it is preferable that the entire circumference of the wall surface of the channel 100 in a cross section perpendicular to the liquid feeding direction is a hydrophilic surface. In this case, not only the surface of the groove 13 of the first substrate 10 but also the surface (inner surface) of the second substrate 20 may be a hydrophilic surface. As the ratio of the hydrophilic surface of the wall surface in the cross section of the channel 100 is larger, the capillary force with respect to the reaction solution can be increased.

[Characteristic configuration and effects]
Next, the characteristic configuration and operational effects of the microfluidic device 1 according to the embodiment of the present invention will be described with reference to FIGS. 6A, 6B, and 7. FIG. 6A is an enlarged plan view of a main part of a flow path in the microfluidic device according to the embodiment of the present invention, and is an enlarged view of a portion P surrounded by a solid line in FIG. 6B is a cross-sectional view of the flow path in the microfluidic device according to the embodiment of the present invention, taken along the line XX ′ in FIG. 6A. FIG. 7 is a diagram showing the characteristics of the flow path in the microfluidic device according to the embodiment of the present invention.

  As shown in FIGS. 6A and 6B, in the microfluidic device 1 in the present embodiment, the flow path 100 (main flow path 100a) in the intermediate area A3 between the first temperature area A1 and the second temperature area A2 is disconnected. The area is smaller than the cross-sectional area of the flow channel 100 (main flow channel 100a) in the first temperature region A1 and the second temperature region A2.

Specifically, the width _{W 3} of the channel 100 in the intermediate area A3 is smaller than the width _{W 2} of the channel 100 in the width _{W 1} and the second temperature region A2 of the channel 100 in the first temperature region A1 (W ₃ <W ₁ , W ₂ ). That is, the flow path 100 (main flow path 100a) is constricted in the intermediate region A3.

In the present embodiment, the width W ₁ of the flow path in the first temperature region A 1 is the same as the width W ₂ of the flow path 100 in the second temperature region A 2 (W ₁ = W ₂ ).

Further, the depth _{D 1} of the flow channel 100 in the first temperature region A1, the depth _{D 2} of the channel 100 in the second temperature region A2, the depth _{D 3} of the channel 100 in the intermediate region A3 are both Is the same (D ₁ = D ₂ = D ₃ ). That is, in the first temperature region A1, the second temperature region A2, and the intermediate region A3, the depth of the flow path 100 is constant along the liquid feeding direction.

  The first temperature region A1 is a region where the first heater block 141 is disposed. Therefore, the temperature of the first temperature region A1 is the temperature set by the first heater block 141.

  The second temperature region A2 is a region where the second heater block 142 is disposed. Therefore, the temperature of the second temperature region A2 is the temperature set by the second heater block 142.

  The intermediate area A3 is an area between the first heater block 141 and the second heater block 142. That is, the intermediate area A3 is an area where neither the first heater block 141 nor the second heater block 142 exists. The temperature of the intermediate region A3 is an intermediate temperature between the temperature set by the first heater block 141 and the temperature set by the second heater block 142. That is, the intermediate region A3 is an intermediate temperature region.

  The first temperature region A1 and the second temperature region A2 are regions that contribute to the reaction of the reaction solution introduced into the microfluidic device 1. For example, when flow PCR is realized by the microfluidic device 1, a temperature cycle is applied to the nucleic acid by the first temperature region A1 and the second temperature region A2. On the other hand, the intermediate region A3 is a region that does not contribute to the reaction of the reaction solution.

The flow path 100 configured in this way has characteristics as shown in FIG. In FIG. 7, the flow rates of the reaction solution 300 in the first temperature region A1, the second temperature region A2, and the intermediate region A3 are respectively v ₁ , v _2, and v _3, and the first temperature region A1 and the second temperature region each cross-sectional area of the flow path 100 in the A2 and the intermediate region _A3, and the S 1, _{S 2} and _{S 3.}

As shown in FIG. 7, S ₁ / S ₃ (S ₂ / S ₃ ) and v ₃ / v ₁ (v ₃ / v ₂ ) have a positive correlation that is directly proportional. In the present embodiment, S ₁ / S ₃ (S ₂ / S ₃ ) = v ₃ / v ₁ (v ₃ / v ₂ ).

Thus, for example, the cross-sectional area _{S 1} of the flow path 100 in the first temperature region A1 is twice the cross-sectional area _{S 3} of the channel 100 in the intermediate region A3, the speed _{v 1} of the reaction solution 300 in the first temperature region A1 Is ½ times the velocity v ₃ of the reaction solution 300 in the intermediate region A3.

  As described above, according to the microfluidic device 1 in the present embodiment, the cross-sectional area of the flow channel 100 in the intermediate region A3 is smaller than the cross-sectional area of the flow channel 100 in the first temperature region A1 and the second temperature region A2. .

  Thereby, when the reaction solution 300 flows through the flow path 100 (main flow path 100a) from upstream to downstream, the time during which the reaction solution 300 exists in the intermediate region A3 can be shortened. As a result, even if the unnecessary intermediate region A3 exists, the possibility that the reaction solution 300 induces a nonspecific reaction in the intermediate region A3 can be suppressed. Therefore, it is possible to suppress a decrease in reaction efficiency due to a non-specific reaction.

  In the present embodiment, a solution containing the target nucleic acid is used as the reaction solution, and the flow path 100 is configured to pass through the first temperature region A1 and the second temperature region A2 alternately and repeatedly. . Accordingly, a decrease in the amplification efficiency of nucleic acid amplification due to a non-specific reaction can be suppressed, and a highly efficient flow PCR can be realized. That is, highly efficient nucleic acid amplification can be realized.

  In the present embodiment, the depth of the channel 100 in the first temperature region A1, the second temperature region A2, and the intermediate region A3 is made constant along the liquid feeding direction, and the width of the channel 100 is adjusted. The cross-sectional area of the flow path 100 in the intermediate region A3 is made smaller than that of other portions. Thereby, the flow path 100 can be easily produced by etching or the like.

  Furthermore, by making the depth of the flow path 100 constant, the optical path length of the measurement light can be kept constant when performing optical measurement by scanning laser light from above the flow path 100. Thereby, measurement accuracy can be improved. For example, the amount of nucleic acid amplification can be calculated with high accuracy.

(Modification)
Hereinafter, modifications of the microfluidic device in the above embodiment will be described.

(Modification 1)
8A is an enlarged plan view of the main part of the flow path in the microfluidic device according to the first modification of the present invention, and FIG. 8B is a microfluidic according to the first modification of the present invention along the line XX ′ in FIG. 8A. It is sectional drawing of the flow path in a device.

  In the microfluidic device in the present modification, as in the microfluidic device 1 in the above embodiment, the cross-sectional areas of the flow channel 100 (main flow channel 100a) in the intermediate region A3 are the first temperature region A1 and the second temperature region A2. Is smaller than the cross-sectional area of the flow channel 100 (main flow channel 100a).

  The microfluidic device in this modification differs from the microfluidic device 1 in the above embodiment in that the cross-sectional area of the channel 100 is adjusted by the width of the channel 100 in the above embodiment, In this modification, the cross-sectional area of the flow channel 100 is adjusted by the depth of the flow channel 100.

Specifically, as shown in FIG. 8B, the depth _{D 3} of the channel 100 in the intermediate area A3 is a flow path 100 at the depth _{D 1} and the second temperature region A2 of the channel 100 in the first temperature region A1 It is shallower than the depth D ₂ (D ₃ <D ₁ , D ₂ ). In the present embodiment, the depth D of the channel in the first temperature region A1 and the depth _{D 2} of the channel 100 in the second temperature region A2 are the same _(D 1 _{= D} 2).

Further, as shown in FIG. 8A, the width of the flow channel 100 is constant in the first temperature region A1, the second temperature region A2, and the intermediate region A3, and the width W ₁ of the flow channel 100 in the first temperature region A1; and the width _{W 2} of the channel 100 in the second temperature region A2, are both the same and the width _{W 3} of the channel 100 in the intermediate region _{A3 (W 1 = W 2 =} W 3).

  As described above, according to the microfluidic device in the present modification, the cross-sectional area of the flow path 100 in the intermediate region A3 is the flow in the first temperature region A1 and the second temperature region A2 as in the microfluidic device 1 in the above embodiment. The cross-sectional area of the path 100 is smaller.

  Thereby, since the time for which the reaction solution 300 exists in the intermediate | middle area | region A3 can be reduced similarly to the said embodiment, the fall of the reaction efficiency by the nonspecific reaction of the reaction solution 300 can be suppressed.

(Modification 2)
9A is an enlarged plan view of the main part of the flow path in the microfluidic device according to the second modification of the present invention, and FIG. 9B is a microfluidic according to the second modification of the present invention along the line XX ′ in FIG. 9A. It is sectional drawing of the flow path in a device.

  In the microfluidic device in the present modification, as in the microfluidic device 1 in the above embodiment, the cross-sectional areas of the flow channel 100 (main flow channel 100a) in the intermediate region A3 are the first temperature region A1 and the second temperature region A2. Is smaller than the cross-sectional area of the flow channel 100 (main flow channel 100a).

  The microfluidic device in this modification differs from the microfluidic device 1 in the above embodiment in that the cross-sectional area of the channel 100 is adjusted by the width of the channel 100 in the above embodiment, In this modification, the cross-sectional area of the flow channel 100 is adjusted by the pillar 160.

  Specifically, as shown in FIGS. 9A and 9B, a plurality of columnar pillars 160 are erected in the flow path 100 of the intermediate region A3. Accordingly, the cross-sectional area of the flow path 100 in the intermediate region A3 can be made smaller than the first temperature region A1 and the second temperature region A2 by the amount of the pillar 160.

  In addition, the depth of the flow path 100 in 1st temperature area | region A1, 2nd temperature area | region A2, and intermediate | middle area | region A3 is constant along a liquid feeding direction.

  As described above, according to the microfluidic device in the present modification, the cross-sectional area of the flow path 100 in the intermediate region A3 is the flow in the first temperature region A1 and the second temperature region A2 as in the microfluidic device 1 in the above embodiment. The cross-sectional area of the path 100 is smaller.

  Thereby, since the time for which the reaction solution 300 exists in the intermediate | middle area | region A3 can be reduced similarly to the said embodiment, the fall of the reaction efficiency by the nonspecific reaction of the reaction solution 300 can be suppressed.

  Further, by providing the pillar 160 as in this modification, the diffusibility of the sample and the reagent in the reaction solution 300 can be improved.

(Modification 3)
FIG. 10 is an enlarged plan view showing the flow path of the microfluidic device according to the third modification of the present invention.

  In the microfluidic device in this modification, the flow path 100 in the reaction unit 110 includes a region where the cross-sectional area decreases along the liquid feeding direction. Specifically, as shown in FIG. 10, the cross-sectional area of the flow path 100 in the reaction unit 110 is decreased stepwise. In FIG. 10, the widths of the plurality of line-shaped main flow paths 100 a in the flow path 100 are narrowed for each line along the liquid feeding direction of the reaction solution 300. Note that the width and depth of the main channel 100a in each line are constant.

  With this configuration, the liquid feeding speed of the reaction solution 300 flowing in the flow channel 100 can be kept constant. Therefore, the reaction solution existence time in each temperature region of the first temperature region and the second temperature region can be kept constant, so that the reaction efficiency of the reaction solution can be further improved. Moreover, since the flow path 100 is linear, the design and production of the flow path 100 are easy.

  Furthermore, by making the depth of the flow channel 100 constant, the flow channel 100 can be easily manufactured collectively by etching or the like, and optical measurement is performed by scanning laser light from above the flow channel 100. At this time, since the optical path length of the measurement light can be kept constant, the measurement accuracy can be improved.

  Although not shown, the cross-sectional area of the flow channel 100 in the reaction unit 110 may be monotonously decreased. In this case, it is conceivable that the flow path 100 has a tapered structure in which the depth is constant along the liquid feeding direction and the width gradually decreases.

  With this configuration, the pressure loss and the capillary force can be continuously changed, so that the liquid feeding speed of the reaction solution can be kept more constant. Therefore, the reaction efficiency of the reaction solution can be further improved.

(Other)
As described above, the microfluidic device according to the present invention has been described based on the embodiment and the modification. However, the present invention is not limited to the embodiment and the modification.

  For example, in the above-described embodiment and modification, the flow PCR in the reaction unit 110 is the meandering flow channel, and the flow PCR is repeatedly applied to the reaction solution containing the target nucleic acid, but the target nucleic acid is included instead of the flow PCR. It is good also as PCR which gives a temperature change to a reaction solution repeatedly. However, PCR can be carried out more efficiently by using the flow as in the above embodiment.

  Moreover, in the said embodiment and modification, although the flow path 100 was a meandering flow path, it is not restricted to this. For example, a plurality of high-temperature regions (95 ° C.) and a plurality of low-temperature regions (60 ° C.) are alternately arranged in a line, and a substrate on which a linear flow path is formed is arranged on the substrate, thereby allowing flow. You may comprise so that a path may pass through a high temperature field and a low temperature field by turns.

  Moreover, in the said embodiment and modification, although the heater part 140 was set as two temperature ranges, it is good also as three or more temperature ranges from which a temperature range differs mutually. In this case, the flow path should just be comprised so that the reaction solution may periodically pass through the several temperature area | region from which a reaction solution differs.

  Moreover, in the said embodiment and modification, although the setting of each temperature of a several temperature area was performed with the heater block, you may set temperature using other temperature control members, such as a Peltier device.

  Moreover, in the said embodiment and modification, although the reaction solution sent the flow path 100 by capillary force, it is not restricted to this. For example, the reaction solution may be sent by connecting a syringe pump to the channel 100. However, it is possible to send the reaction solution at low cost and simply by feeding the reaction solution by capillary force.

  Further, in the above embodiment and the modification, the example in which the microfluidic device is applied to the nucleic acid amplification device for performing the PCR method has been described, but the microfluidic device in the above embodiment and the modification is measured. You may apply to the sensor device for detecting a substance. For example, the microfluidic device can be applied to a sensor device for performing an immunochromatography method.

  In this case, the reaction solution introduced into the microfluidic device contains bacteria or viruses as the substance to be measured, and the microfluidic device detects the substance to be measured contained in the reaction solution. Bacteria and viruses each have characteristic DNA. Therefore, by designing a primer targeting the characteristic DNA, the microfluidic device can be used as a sensor for detecting the type and amount of bacteria and viruses. For example, the antigen in the introduced reaction solution moves through the channel 100 while forming an immune complex with the antibody, and the immune complex is trapped on the capture antibody prepared in advance in the channel 100. Thereby, the antigen in the reaction solution can be detected.

  In addition, a form obtained by making various modifications conceived by those skilled in the art with respect to each embodiment and modification, and any combination of components and functions in the embodiment without departing from the spirit of the present invention Forms to be made are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Microfluidic device 10 1st board | substrate 11 1st recessed part 12 2nd recessed part 13 Groove part 20 2nd board | substrate 21 1st through-hole 22 2nd through-hole 100 channel 100a main channel 100b subchannel 100c introduction channel 100d discharge channel DESCRIPTION OF SYMBOLS 110 Reaction part 120 Introduction part 130 Discharge part 140 Heater part 141 1st heater block 142 2nd heater block 160 Pillar 210 Temperature control part 300 Reaction solution

Claims (6)

A microfluidic device comprising a flow path through which a reaction solution flows,
The flow path is a meandering flow path configured to alternately and repeatedly pass through the first temperature region, the intermediate region, and the second temperature region,
The first temperature region and the second temperature region are regions set to predetermined different temperatures by a temperature control member,
Region located between the first temperature region and the second temperature region is the middle region,
The intermediate region is a region where the temperature is not set by the temperature control member,
The microfluidic device, wherein a cross-sectional area of the channel in the intermediate region is smaller than a cross-sectional area of the channel in the first temperature region and the second temperature region. The reaction solution contains a target nucleic acid,
The microfluidic device according to claim 1, wherein the target nucleic acid is amplified by a polymerase chain reaction when the reaction solution passes through the meandering flow path. The reaction solution contains bacteria or viruses as substances to be measured,
The microfluidic device according to claim 1, wherein the microfluidic device detects the substance to be measured contained in the reaction solution. The microfluidic device according to any one of claims 1 to 3 , wherein a width of the channel in the intermediate region is smaller than a width of the channel in the first temperature region and the second temperature region. The microfluidic device according to any one of claims 1 to 3 , wherein a cross-sectional area of the flow path is adjusted by a pillar provided in the flow path. The flow path is constituted by a plurality of line-shaped main flow paths formed so as to be continuously folded,
Wherein in the said flow path in each of the first temperature region and second temperature region, the line-shaped claim sectional area for each main channel are decreased and or stepwise decreased monotonically 1-5 The microfluidic device according to any one of the above.

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