Microfluidic device for collecting and detecting aerosols, and method for collecting and detecting aerosols

Abstract

To accelerate collecting and detecting operations of aerosols, and to simplify a detection method while ensuring the freedom of the detection method.SOLUTION: A microfluidic device for collecting and detecting aerosols includes: an aerosol flow section, which is a micro flow channel having a shape in which an aerosol flowing in from the outside flows and aerosol particles in the aerosol collide with a wall surface of the flow channel due to at least one of inertial force, vortex flow, and turbulence generated by the flow of the aerosol; and one or more microwells installed continuously on the wall surface on which the aerosol particles collide in the aerosol flow section and holding a detection liquid for detecting the aerosol particles inside.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a microfluidic device for collecting and detecting aerosols and a method for collecting and detecting aerosols. [Background technology]

[0002] Pathogens such as viruses that cause infectious diseases, as well as fine particles of various pollutants, can exist in the air in the form of aerosols. Therefore, by collecting and detecting airborne aerosols, it is possible to predict and prevent infection if the aerosol particles are pathogens, or to understand the state of air pollution if the aerosol particles are pollutants. Various methods for collecting and detecting aerosols have been proposed. For example, Patent Document 1 discloses a method in which a threat substance, such as an aerosol substance, is attached to a substrate, illuminated with multiple photons, and the generated elastically scattered photons and Raman scattered photons are analyzed to analyze and identify the sample simultaneously with the attachment of the threat substance to the substrate. Furthermore, Non-Patent Document 1 discloses a technology for distinguishing between non-biological particles and aerosolized biological particles in real time by using an inertial impaction system to collide airborne pathogenic microorganisms with an impact plate and obtaining fluorescence microscopic images.

[0003] Patent Document 2 discloses a method for collecting and measuring particles in exhaled breath, in which aerosols are collected on a solid surface (the surface of a collection plate of an impactor), and then the collection plate is recovered and used to measure the collected particles. Patent Documents 3 and 4 describe biological substance detection systems, and Patent Documents 3 and 4, as well as Non-Patent Document 2, disclose a method for transferring collected aerosols into a liquid using a collection device and recovering them. Non-Patent Documents 3 and 4 also disclose a liquid-based collection method for detecting aerosols, in which a two-phase fluid consisting of an aerosol and a collection liquid is passed through a flow path to transfer particles from the gas phase to the liquid phase. [Prior art documents] [Patent documents]

[0004]

Patent Document 1

Patent document 2

Patent document 3

Patent document 4

Non-licensed literature

[0005] [Non-licensed document 1] Joon Sang Kang et al., Real-time detection of an airborne microorganism using inertial impaction and mini-fluorescent microscopy, Lab Chip 14, 244-251(2014) [Non-licensed document 2] Jing W. et al., Microfluidic Device for Efficient Airborne Bacteria Capture and Enrichment, Amal. Chem. 85, 5255-5262(2013) [Non-licensed document 3] Choi J. et al., Highly Enriched, Controllable, Continuous Aerosol Sampling Using Inertial Microfluidics and Its Application to Real-Time Detection of Airborne Bacteria, ACS Sensors 2, 513-521(2017)

Non-licensed Document 4

[0006] However, Patent Document 1 employs a method that combines elastic scattering and Raman scattering when identifying threat substances attached to a substrate, which limits the flexibility of the detection method. Furthermore, Non-Patent Document 1 uses fluorescence microscope images to distinguish between non-biological and biological particles. Therefore, with this method of collecting aerosols on a solid surface and detecting them in real time, it is difficult to identify specific aerosol particles in a mixed sample.

[0007] Furthermore, in the methods described in Patent Documents 2 to 4 and Non-Patent Document 2, in which aerosols are collected using a collection device and then subjected to detection, there is a problem of a lag time occurring between collection and detection. Furthermore, when a two-phase fluid of aerosols and a collection liquid is flowed through a flow path to collect aerosols, as in Non-Patent Document 3 and Non-Patent Document 4, there is a problem of the need to continuously supply the liquid for collection, which complicates the device configuration related to the liquid supply and requires a large amount of liquid for collection. Therefore, there has been a demand for a technology that provides a high degree of freedom in the detection method while minimizing the complexity of the device configuration and the operations related to detection and the lag time between aerosol collection and detection. [Means for solving the problem]

[0008] The present disclosure can be realized in the following forms. (1) According to one aspect of the present disclosure, there is provided a microchannel device for collecting and detecting aerosols, comprising: an aerosol flow section, which is a microchannel through which an aerosol flowing in from the outside flows and has a shape such that aerosol particles in the aerosol collide with a channel wall surface due to at least one of inertial force, vortex flow, and turbulence generated by the aerosol flow; and one or more microwells, which are provided contiguous with the wall surface of the aerosol flow section against which the aerosol particles collide, for holding a detection liquid for detecting the aerosol particles. According to this type of microchannel device, aerosol collection and detection can be performed in the microwells containing the detection liquid, eliminating the need for operations such as subjecting the collected aerosol to detection, thereby enabling faster operations from collection to detection. Furthermore, in the microchannel device, the detection liquid only needs to be placed in the microwells prior to the aerosol collection operation, eliminating the need to supply the detection liquid after the collection operation begins. This simplifies the configuration for supplying the detection liquid and reduces the amount of detection liquid required. Furthermore, because the microwells, together with the aerosol flow section, are formed as microchannels, the amount of detection liquid used for detection can be reduced, thereby reducing the cost required for aerosol detection. Furthermore, because aerosol detection is performed using the detection liquid placed in the microwells, various liquid-based detection methods can be employed, increasing the flexibility of the detection method and allowing the device to be used to detect various aerosols. (2) In the microfluidic device for collecting and detecting aerosols of the above configuration, the aerosol flow section may include a curved portion in the flow channel shape as the portion having the shape where aerosol particles in the aerosol collide with the flow channel wall surface. With this configuration, the aerosol flow section is simply configured to have a curved portion, and the aerosol can collide with the flow channel wall surface due to inertial force or vortex flow, thereby efficiently collecting the aerosol in the microwell. (3) In the microfluidic device for collecting and detecting aerosols according to the above embodiment, the aerosol flow section may include the curved portion having a spiral shape. With this configuration, the curved portions, which are shaped so that aerosol particles collide with the wall surface of the flow channel, are arranged at a high density, thereby improving the efficiency of collecting aerosols. (4) The microfluidic device for collecting and detecting aerosols of the above configuration may further include a humidifying section for humidifying the aerosol flow section. This configuration can prevent the detection solution in the microwells from evaporating and decreasing during aerosol detection. This allows for longer and more stable detection operations. (5) In the microfluidic device for aerosol collection and detection of the above-described embodiment, the humidifying section may be a water reservoir section that is provided in communication with the aerosol flow section and that holds water. With this configuration, water can be stored in the humidifying section in advance prior to the aerosol collection and detection operations, thereby simplifying the humidifying operation. (6) The microchannel device for collecting and detecting aerosols of the above configuration may further include an aerosol inlet section through which the aerosol flows from the outside into the microchannel device, and a communication channel that connects the aerosol inlet section to the aerosol circulation section, and the water reservoir may be provided in communication with the communication channel. With this configuration, by providing a humidifier in communication with the communication channel upstream of the aerosol circulation section, evaporation of the detection liquid can be suppressed in all microwells provided continuously on the wall surface of the aerosol circulation section. (7) The microfluidic device for collecting and detecting aerosols according to the above embodiment may further include a connecting flow path connecting the communicating flow path and the water storage portion, the connecting flow path being formed to have a larger cross-sectional area than the connecting flow path. With this configuration, when water is introduced into the combined space of the communicating flow path and the water storage portion and then removed from the communicating flow path to retain water in the water storage portion, the operation of removing water from the communicating flow path while leaving water in the water storage portion becomes easy. (8) According to another aspect of the present disclosure, there is provided a method for collecting and detecting an aerosol, which uses the microfluidic device for collecting and detecting an aerosol according to any one of (1) to (7), fills the microwells with the detection liquid, generates a pressure difference between the upstream end and downstream end of the aerosol flow section in the aerosol flow direction, causes the aerosol to flow in the aerosol flow section, collects aerosol particles in the aerosol flowing through the aerosol flow section in the detection liquid in the microwells, and detects the aerosol particles in the microwells. According to this aerosol collection and detection method, aerosol collection and detection can be performed in a microwell containing a detection liquid, eliminating the need for operations such as subjecting the collected aerosol to detection, thereby enabling faster operations from collection to detection. Furthermore, because the detection liquid is placed in the microwell prior to the aerosol collection operation, there is no need to supply the detection liquid after the collection operation begins, simplifying the configuration for supplying the detection liquid and reducing the amount of detection liquid required. Furthermore, because a microchannel device is used in which the microwell and the aerosol flow section are formed as microchannels, the amount of detection liquid used for detection can be reduced, thereby reducing the cost required for aerosol detection. Furthermore, because aerosols are detected using the detection liquid placed in the microwell, various liquid-based detection methods can be adopted, increasing the flexibility of detection methods and allowing the device to be used to detect various aerosols. The present disclosure can be realized in various forms other than those described above, for example, a method of using a microchannel device for capturing and detecting aerosols, or an aerosol detection apparatus equipped with a microchannel device for capturing and detecting aerosols. [Brief explanation of the drawings]

[0009] [Figure 1A] FIG. 1 is a plan view showing a schematic configuration of a microchannel device according to a first embodiment. [Figure 1B] FIG. 1 is a cross-sectional view illustrating a schematic configuration of a microchannel device according to a first embodiment. [Figure 2] FIG. 1 is an explanatory diagram showing an example of an aerosol collection and detection device. [Figure 3] FIG. 1 is an explanatory diagram showing an example of aerosol detection using a microfluidic device. [Figure 4] FIG. 1 is an explanatory diagram showing an example of aerosol detection using a microfluidic device. [Figure 5] FIG. 10 is a plan view showing a schematic configuration of a microchannel device according to a second embodiment. [Figure 6] FIG. 10 is a plan view showing a schematic configuration of a microchannel device according to a third embodiment. [Figure 7A] FIG. 10 is an explanatory diagram showing the microchannel device when the entire device is filled with liquid. [Figure 7B] FIG. 10 is an explanatory diagram showing the microwells and humidifying section filled with liquid. [Figure 8] FIG. 10 is an explanatory diagram showing the state in which a microwell is filled with a liquid. [Figure 9] FIG. 10 is an explanatory diagram showing the results of investigating the effect of humidifying the aerosol by the humidifying unit. [Figure 10A] Brightfield image of a site containing microwells. [Figure 10B] Fluorescence image of the same field as in Figure 10A. [Figure 11A] Brightfield image of a site containing microwells. [Figure 11B] Fluorescence image of the same field as in Figure 11A. [Figure 12] FIG. 10 is an explanatory diagram showing the results of measuring the luminance after 20 minutes. [Figure 13] FIG. 10 is an explanatory diagram showing the fluorescence brightness observed after 20 minutes. DETAILED DESCRIPTION OF THE INVENTION

[0010] A. First embodiment: 1A and 1B are explanatory diagrams showing a schematic configuration of a microchannel device 10 according to a first embodiment of the present disclosure. Fig. 1A is a plan view, and Fig. 1B is a cross-sectional view showing the state of cross section BB in Fig. 1A. Note that Figs. 1A and 1B do not accurately represent the dimensional ratios of the various parts.

[0011] The microchannel device 10 of this embodiment is a plate-like member having a microchannel formed therein, and is a device for collecting and detecting aerosols introduced into the microchannel from the outside. The microchannel device 10 includes an aerosol flow section 12, a microwell 14, an aerosol inlet section 20, a communicating channel 16, and an aerosol outlet section 22.

[0012] The aerosol flow section 12 is a microchannel through which the aerosol flowing in from the outside flows. The aerosol flow section 12 has a shape that causes aerosol particles in the aerosol to collide with the wall surface of the flow channel due to at least one of inertial force, vortex flow, and turbulence generated by the flow of the aerosol. The aerosol flow section 12 of this embodiment has a curved portion where the flow channel is curved, and the aerosol flowing through the aerosol flow section 12 collides with the wall surface of the flow channel at the curved portion due to inertial force and vortex flow. More specifically, the aerosol flow section 12 has a curved portion where the flow channel is spiral-shaped.

[0013] The microwells 14 are provided contiguously with the wall surface of the aerosol flow section 12 on which aerosol particles collide, and are structures for retaining detection liquid for detecting aerosol particles therein. That is, the wall surface of the aerosol flow section 12 on which the aerosol collides and the wall surface of the microwells 14 are continuous, and the flow path constituting the aerosol flow section 12 communicates with the space within the microwells 14. In this embodiment, multiple microwells 14 are provided along the outer peripheral wall surface of the spiral-shaped aerosol flow section 12, protruding so as to extend further outward from the outer peripheral wall surface. FIG. 1A shows the overall configuration of the microchannel device 10, as well as an enlarged view of a portion of the aerosol flow section 12 in which the microwells 14 are provided. Also, in FIG. 1A, the hatched microwells 14 indicate the state in which detection liquid is retained in the microwells 14. As shown enlarged in FIG. 1A, the aerosol flowing through the aerosol flow section 12 generates inertial forces and vortices due to the vortex shape of the aerosol flow section 12, causing aerosol particles Asp in the aerosol to collide with the wall surface of the flow channel. At this time, where microwells 14 are provided continuously with the wall surface of the flow channel, the aerosol particles Asp enter the microwells 14 and are collected in the detection liquid held in the microwells 14. The detection liquid then reacts with the aerosol particles Asp, and the aerosol is detected by detecting the state resulting from this reaction. Aerosol detection will be described in detail later.

[0014] The aerosol inlet section 20 is a structure for introducing an aerosol from the outside into the microchannel device 10, and is an opening that opens on the surface of the microchannel device 10. The communicating channel 16 is a microchannel that connects the aerosol inlet section 20 and the aerosol distribution section 12. In this embodiment, the communicating channel 16 is formed as a straight channel so as to connect the outer end of the spirally shaped aerosol distribution section 12 to the aerosol inlet section 20, but the communicating channel 16 may have a shape other than straight. Furthermore, the aerosol inlet section 20 may be provided at the end of the spirally shaped aerosol distribution section 12 without providing the communicating channel 16.

[0015] The aerosol outlet section 22 is a structure for discharging the aerosol that has passed through the microchannel device 10 to the outside of the microchannel device 10, and is an opening that communicates with the inner end of the spirally formed aerosol circulation section 12 and opens on the surface of the microchannel device 10. When the microchannel device 10 is in use, a pressure difference is generated between the upstream end and downstream end of the aerosol circulation section 12 in the aerosol flow direction, i.e., between the aerosol inlet section 20 and the aerosol outlet section 22. This allows the aerosol to circulate within the aerosol circulation section 12 from the aerosol inlet section 20 side toward the aerosol outlet section 22 side.

[0016] The method for generating a pressure difference between the aerosol inlet portion 20 and the aerosol outlet portion 22 is not particularly limited, and various methods can be employed. For example, a method in which a pump is connected to the aerosol outlet portion 22 to generate a suction force on the aerosol outlet portion 22 side can be mentioned. In this case, for example, by opening the aerosol inlet portion 20 to the atmosphere and driving the pump, aerosol in the atmosphere can be introduced into the aerosol flow portion 12. Alternatively, a syringe containing the aerosol to be detected may be connected to the aerosol inlet portion 20 side, and the aerosol may be introduced into the aerosol flow portion 12 by pushing the aerosol with the syringe. Alternatively, when detecting aerosol in exhaled breath, exhaled breath may be blown into a tube connected to the aerosol inlet portion 20.

[0017] The microchannels, such as the aerosol flow section 12, the microwells 14, and the communicating channels 16, may be formed so that the channel height and width, which are the dimensions of the channel, or the channel diameter, which is the diameter of a circle having an area equivalent to the cross-sectional area of the channel, are 1 μm or more and 1 mm or less. From the viewpoint of optimizing the channel resistance when the aerosol flows, the channel diameter of the aerosol flow section 12 is preferably 100 μm or more. In the microwells 14, the channel diameter of a plane perpendicular to the direction in which the aerosol flow section 12 protrudes outward from the outer wall surface of the aerosol flow section 12 is preferably equal to or smaller than the channel diameter of the aerosol flow section 12. This is because, when the detection liquid is introduced to fill the aerosol flow section 12 and the microwells 14 with the detection liquid and then removed from the aerosol flow section 12 to retain the detection liquid in the microwells 14, the operation of removing the detection liquid from the aerosol flow section 12 while leaving the detection liquid in the microwells 14 becomes easier.

[0018] The constituent material of the microchannel device 10 only needs to be processable to form a microchannel. Furthermore, when an optical method, for example, is employed as a detection method using the microchannel device 10, the constituent material of the microchannel device 10 only needs to be transparent or translucent so that aerosols can be detected in a state where they are trapped in the detection liquid in the microwells 14. However, because various methods, such as electrochemical methods, can be employed as detection methods using the microchannel device 10, transparency or translucency of the constituent material of the microchannel device 10 is not essential. Examples of constituent materials of the microchannel device 10 include silicone resins such as polydimethylsiloxane (PDMS), cycloolefin resins, acrylic resins, and glass.

[0019] FIG. 1B shows an example of the configuration of microchannel device 10, which has a three-layer structure in which plate-like members made of the materials described above are stacked. Here, microchannel device 10 is constructed by stacking plate-like members 10a to 10c in this order. Plate-like member 10b has through-holes formed therein that have the shapes shown in FIG. 1A as aerosol flow section 12, microwells 14, and communicating flow channels 16. Plate-like member 10a has through-holes that become aerosol inlet section 20 and aerosol outlet section 22 (however, FIG. 1B shows only aerosol inlet section 20). Plate-like member 10c does not have through-holes. Microchannel device 10 can be fabricated by stacking and bonding such plate-like members 10a to 10c. Alternatively, microchannel device 10 may be formed by stacking two plate-like members. In this case, for example, recesses that will become aerosol flow section 12, microwells 14, and communicating channels 16 may be formed on the surface of one of the plate-like members, and through-holes that will become aerosol inlet section 20 and aerosol outlet section 22 may be formed in one of the plate-like members. Then, the surface of such a plate-like member on which the recesses are formed may be joined to the other plate-like member. Alternatively, recesses that will become aerosol flow section 12, microwells 14, and communicating channels 16 may be formed on each of the opposing surfaces of two plate-like members, and the two may then be joined together.

[0020] The aerosols to be detected using the microchannel device 10 can be, for example, bioaerosols containing bacteria, fungi, pollen, viruses, cells, DNA, RNA, etc. with aerosol particles having a diameter of 100 μm or less, metal aerosols, and exhaust gas aerosols.

[0021] The type of detection liquid may be selected according to the type of aerosol to be detected, and the combination of the selected detection liquid and aerosol may cause a specific reaction between the detection liquid and aerosol particles that enables aerosol detection. In the microfluidic device 10 of this embodiment, it is not intended to add or replace detection liquid to the microwells 14 during the aerosol detection operation. Therefore, the detection liquid used may be a detection liquid that, when placed in the microwells 14 in advance, enables the reaction for detecting the aerosol collected in the microwells 14 (all reactions if multiple reactions occur before detection) to proceed.

[0022] The reaction that occurs between the detection solution and the aerosol to detect the aerosol can be a variety of reactions, such as a reaction that produces chemiluminescence or bioluminescence, a reaction that becomes detectable by fluorescence, or a reaction that involves a color reaction. A detection method can be appropriately selected depending on the reaction that occurs between the aerosol and the detection solution, so that the extent of the reaction can be detected. When detecting a luminescence or color reaction, for example, detection can be performed visually or using equipment such as a camera, photodiode, or photomultiplier tube. For such detection, a light source for detection can be appropriately selected from natural light, ambient light, LED light, laser, incandescent lamp, mercury lamp, xenon lamp, etc., as needed. Furthermore, the reaction that occurs between the detection solution and the aerosol can include, in addition to a reaction that produces luminescence or color, an electrical reaction that involves, for example, a change in current value.

[0023] A specific example of the reaction that occurs between the aerosol and the detection solution is described below. When the aerosol particles to be detected are bacteria, fungi, cells, etc. (hereinafter also referred to as bacteria, etc.), for example, an ATP assay (ATP method) using bioluminescence can be applied. It is known that there is a correlation between the amount of ATP derived from cells and the number of cells, and ATP is produced by reacting with magnesium ions (Mg 2+In the presence of ATP, the ATP reacts with a firefly luciferin-luciferase reagent to produce light. The ATP method is a well-known method that utilizes the above principle. Therefore, by measuring the amount of ATP using an ATP detection reagent containing luciferin and luciferase as a detection solution, bacteria and other aerosol particles can be detected. The above light emission can be detected, for example, using a camera.

[0024] Furthermore, when the aerosol particles to be detected are bacteria or the like, the BactoLumix method may be applied. The BactoLumix method is a method in which active oxygen generated in the oxidation-reduction reaction between NAD(P)H (quinone oxidoreductase), an enzyme found in bacteria, and menadione is detected by adding a luminescent substrate, and is a well-known method that makes it possible to measure the amount of luminescence proportional to the number of viable bacteria. Therefore, by measuring NAD(P)H using a reagent containing menadione and the luminescent substrate for the BactoLumix method as a detection solution, bacteria or the like as aerosol particles can be detected. The luminescence can be detected, for example, using a camera.

[0025] Furthermore, when the aerosol particles to be detected are cells, various fluorescent esterase substrates, including calcein-AM and fluorescein diacetate derivatives, can be used. Upon entering the cells, the fluorescent esterase substrates are hydrolyzed by intracellular esterases to generate a fluorescent signal. Therefore, cells as aerosol particles can be detected by measuring fluorescence using a detection solution containing the fluorescent esterase substrate. The fluorescence can be detected, for example, using a fluorescence microscope.

[0026] Furthermore, electrochemical measurement can also be used when the aerosol particles to be detected are bacteria, fungi, pollen, viruses, cells, etc., and antibodies have been obtained for them. If the antibody to be detected is immobilized on an electrode incorporated in the microwell 14, when the aerosol particles to be detected are captured in the detection solution in the microwell 14 and bind to the antibody, the exchange of charges between the electrode and the electrolyte changes, resulting in changes in resistance and current value. By detecting such changes, the desired target can be detected.

[0027] Furthermore, when the aerosol particles to be detected are nucleic acids such as DNA or RNA, or when the aerosol particles to be detected are viruses or bacteria, etc., and the aerosol particles are detected by detecting the nucleic acids contained in the viruses or bacteria, etc., a detection solution containing a nucleic acid staining reagent may be used. Examples of the nucleic acid staining reagent that can be used include SYBR Green I and ethidium bromide. The staining results may be detected using, for example, a camera.

[0028] When the aerosol particles to be detected are nucleic acids such as DNA or RNA, or when the aerosol particles to be detected are viruses, bacteria, or the like and the aerosol particles are detected by detecting the nucleic acids contained in the viruses, bacteria, or the like, it is desirable to amplify the nucleic acids in the detection solution in the microwells 14. Examples of methods for amplifying nucleic acids in the detection solution include the LAMP (Loop-Mediated Isothermal Amplification) method, the PCR (Polymerase Chain Reaction) method, and the RPA (Recombinase Polymerase Amplification) method. Of these, the LAMP and RPA methods are desirable because they allow the amplification reaction to proceed at a constant temperature. The LAMP method is also desirable because it is relatively easy to detect the progress of the amplification reaction.

[0029] When nucleic acid amplification is performed in a detection solution using a LAMP reagent containing primers designed according to the nucleic acid to be detected, magnesium pyrophosphate is generated in the detection solution, causing the detection solution to become cloudy. Aerosol particles can be detected by optically measuring the turbidity or visually confirming the cloudy appearance. Furthermore, when the LAMP method is used for nucleic acid amplification, nucleic acid amplification can be detected as a color change (color reaction) by adding an indicator such as calcein or hydroxynaphthol blue to the detection solution. The color reaction can be detected, for example, using a camera or visually. Furthermore, when the RPA method is used for nucleic acid amplification, a fluorescent probe can be used to detect fluorescence, for example, using a camera or visually.

[0030] When the aerosol to be detected is a metal aerosol, a detection solution containing a metal indicator, which is a colorimetric reagent that reacts with specific metal ions to produce a color, can be used to detect the ionized metal in the detection solution. For example, when a detection solution containing the colorimetric reagent 5-Br-PAPS is used, it is possible to detect not only zinc ions but also cadmium ions, iron ions, nickel ions, cobalt ions, etc. The color reaction can be detected visually or using a camera, for example.

[0031] When the aerosol to be detected is an exhaust gas aerosol, an appropriate detection liquid can be selected depending on the particles or components to be detected in the aerosol. For example, when sulfur oxides, which generate sulfate ions in the liquid, are to be detected, sulfur oxides in the exhaust gas can be detected by a method (barium sulfate turbidimetry) in which a barium-containing reagent is used as the detection liquid to precipitate barium sulfate and measure turbidity. In this case, the barium-containing reagent may further contain polyethylene glycol (PEG) or glycerin as a stabilizer. Turbidity can be confirmed, for example, by laser intensity.

[0032] FIG. 2 is an explanatory diagram showing a schematic configuration of an apparatus 30 as an example of an aerosol detection apparatus including a microchannel device 10. The apparatus 30 houses the microchannel device 10 in a housing 32, which further includes a light source 34 that illuminates the surface of the microchannel device 10, a camera 36 that captures images of the microwells 14 of the microchannel device 10 from above for aerosol detection, a pump 38, and a heater 40. One end of a tube 42, the other end of which is open to the atmosphere outside the housing 32, is connected to the aerosol inlet 20 of the microchannel device 10. The other end of a tube 44, the other end of which is connected to the pump 38, is connected to the aerosol outlet 22 of the microchannel device 10. Therefore, by driving the pump 38, outside air containing aerosols is drawn into the aerosol flow section 12 via the aerosol inlet 20, where the aerosols are collected in the detection solution in the microwells 14, allowing a reaction for detection to proceed, and the aerosols can be detected using the camera 36.

[0033] As shown in FIG. 2, when a heater 40 for heating the microchannel device 10 is provided, the detection reaction can be carried out at a desired temperature higher than room temperature. For example, when nucleic acids are the detection target and nucleic acid amplification is performed by the LAMP method or the RPA method, heating can be performed using the heater 40 to a temperature suitable for amplification. When nucleic acids are amplified by the PCR method, a cooling device can be provided in addition to the heater 40 and controlled so that the temperature increases and decreases according to a predetermined pattern. When viruses are the detection target and nucleic acids are extracted from viruses captured in a detection solution, the microchannel device 10 can be heated using the heater 40 to a temperature suitable for nucleic acid extraction in the nucleic acid extraction step.

[0034] In an example using the device 30 of FIG. 2, aerosols in the environment are sucked in and collected by a pump 38, a color reaction caused by heating to detect the aerosols is initiated, and the results are confirmed using a camera 36. Specifically, for example, when airborne viruses in a hospital are to be detected, the aerosols in the air are sucked in by the pump 38 and collected in the microwells 14, and RNA is extracted from the viruses by heating using a heater 40. At this time, if the microwells 14 are previously filled with a solution containing an RT-LAMP reagent and a naphthol blue reagent, the reaction temperature can be changed by the heater 40 to amplify the DNA to be detected, causing the naphthol blue reagent to react, and the color reaction can be detected by the camera 36.

[0035] FIG. 3 is an explanatory diagram showing another example of aerosol detection using the microfluidic device 10. In FIG. 3, components and the like common to those in FIG. 2 are assigned the same reference numerals. Here, as in FIG. 2, aerosols in the environment are sucked and collected by a pump 38, a color reaction for detecting the aerosols is allowed to proceed, and the results are visually confirmed. Specifically, for example, when detecting suspended particles of zinc or cadmium contained in the air of a zinc refining plant, the aerosols in the air are sucked by the pump 38 and collected in the microwells 14, and a colorimetric reaction of the 5-Br-PAPS reagent filled in the microwells 14 is allowed to proceed. Observer A visually confirms the results of the colorimetric reaction using ambient light, thereby detecting zinc or cadmium.

[0036] FIG. 4 is an explanatory diagram showing yet another example of aerosol detection using the microfluidic device 10. In FIG. 4, components and the like common to those in FIG. 2 are assigned the same reference numerals. In the apparatus 130 shown in FIG. 4, a light source 34 that illuminates the surface of the microfluidic device 10 is attached to the side wall of the housing 32, and a color filter 46 is attached to cover the top surface of the housing 32. Here, subject B breathes into the microfluidic device 10 through a tube 42, and aerosol particles to be detected (e.g., varicella-zoster virus DNA) in the breath are collected. At this time, the microwells 14 are filled with an RPA reagent and heated using a heater 40, amplifying the varicella-zoster virus DNA and causing it to react with the fluorescent probe. A diagnosis can be made by an observer C visually observing only the fluorescence through the color filter 46.

[0037] According to the microchannel device 10 of this embodiment configured as described above, aerosols are collected and detected in the microwells 14 holding the detection liquid, eliminating the need to subject the collected aerosols to detection. By performing collection and detection simultaneously, the process from collection to detection can be expedited.

[0038] Furthermore, in the microchannel device 10, it is sufficient to place the detection liquid in the microwells 14 prior to the aerosol collection operation, and there is no need to supply the detection liquid after the collection operation has begun. This simplifies the configuration for supplying the detection liquid, and reduces the amount of detection liquid required. Furthermore, in the microchannel device 10, the aerosol flow section 12 and the microwells 14 are formed as microchannels, so the amount of detection liquid used for detection can be reduced. By reducing the amount of detection liquid in this way, the cost required for aerosol detection can be reduced.

[0039] Furthermore, the microfluidic device 10 of this embodiment detects aerosols using a detection liquid placed in the microwells 14, and therefore, as described above, various liquid-based detection methods can be employed. This high degree of freedom in detection methods allows the device to be used to detect various aerosols.

[0040] Furthermore, in the microchannel device 10 of this embodiment, the entire aerosol flow section 12 has a spiral shape with curved sections, and microwells 14 are provided along the channel walls throughout the aerosol flow section 12. That is, curved sections shaped to cause aerosol particles to collide with the channel wall surfaces and microwells 14 that actually capture the aerosol are provided at a high density. Therefore, the entire aerosol flow section 12 can efficiently generate inertial force and vortex flow, and can also capture the aerosol.

[0041] The shape of the aerosol flow section 12 may be a shape other than a spiral shape. For example, a curved portion, which is a portion having a shape where aerosol particles in the aerosol collide with a flow path wall surface and changes the flow direction of the aerosol, may be formed only in a portion of the aerosol flow section 12. Specifically, for example, the shape may be an arc shape having a single curved portion or a wave shape having curved portions and straight portions alternately repeated. Furthermore, the flow path shape of the flow direction change section of the aerosol flow section 12, which changes the flow direction of the aerosol to generate inertial force, vortex flow, or turbulence, may be a curved portion or a bent portion in which the flow path bends at a specific angle, such as a right angle. In such a flow direction change section, by providing microwells 14 on the flow path wall surface where the aerosol particles collide, the aerosol can be efficiently collected.

[0042] B. Second embodiment: FIG. 5 is a plan view showing a schematic configuration of a microchannel device 110 of the second embodiment. In the microchannel device 110 of the second embodiment, components common to those of the microchannel device 10 of the first embodiment are designated by the same reference numerals. In addition to the same structure as the microchannel device 10, the microchannel device 110 further includes a humidifier 26 for humidifying the aerosol flow section 12. The humidifier 26 of the second embodiment is a space formed within the microchannel device 110 and is configured as a water reservoir for holding water. The humidifier 26 and the communicating flow section 16 are connected by a connecting flow section 28. The number of connecting flow sections 28 can be set arbitrarily, but in the second embodiment, a plurality of connecting flow sections 28 are provided along the direction in which the communicating flow section 16 extends. By storing water in the humidifier 26 prior to the aerosol detection operation of causing the aerosol to flow into the aerosol flow section 12, the aerosol passing through the aerosol flow section 12 can be humidified by the water in the humidifier 26. As shown in FIG. 2, a heater 40 may be attached to the microchannel device 110 and the humidifying section 26 may be heated by the heater 40, thereby promoting humidification of the aerosol passing through the communicating channel 16.

[0043] 5, microchannel device 110 has a structure that allows fluid to be supplied to or discharged from a microchannel inside microchannel device 110, and includes a humidification opening 24 as openings that open on the surface of microchannel device 110, in addition to aerosol inlet section 20 and aerosol outlet section 22. Humidification opening 24 is provided at a position that overlaps with humidification section 26.

[0044] When introducing a detection liquid into the microwells 14 prior to detecting aerosols using the microchannel device 110, the air inside the microchannel device 110 is degassed in a vacuum desiccator, and then the detection liquid is supplied from the aerosol outlet 22 to the aerosol flow section 12, filling the microwells 14 with the detection liquid up to just before the communicating flow channel 16 (near the boundary between the aerosol flow section 12 and the communicating flow channel 16). In this way, when the detection liquid is supplied to the aerosol flow section 12 after degassing the flow channel including the microwells 14, the supplied detection liquid is introduced into each microwell 14. Thereafter, the detection liquid is aspirated from the aerosol outlet 22 and removed from the aerosol flow section 12, thereby allowing the detection liquid to be retained in the microwells 14.

[0045] When introducing water into the humidifying unit 26 prior to aerosol detection using the microchannel device 110, water is supplied to the humidifying unit 26 through the humidifying opening 24 to fill the humidifying unit 26 with water. If the water overflows into the communicating flow path 16 at this time, the water can be removed from the communicating flow path 16 by sucking it through the aerosol inlet 20. In this way, the humidifying unit 26 can be filled with water. The humidifying opening 24 is closed during aerosol detection.

[0046] It should be noted that the humidifying section 26 has a relatively large cross-sectional area of the flow path because it forms a space for storing water. Therefore, when water overflows from the humidifying section 26 into the communicating flow path 16 and it becomes necessary to remove the water from the communicating flow path 16 while leaving the water in the humidifying section 26, it is desirable to form the communicating flow path 16 with a larger cross-sectional area (the area of the cross section perpendicular to the direction of fluid flow in the flow path) than the connecting flow path 28, in order to perform the water removal operation well, thereby increasing the relative flow path resistance of the connecting flow path 28. In this case, the communicating flow path 16 may be a flow path with a flow path diameter of more than 1 mm, rather than a microflow path.

[0047] With this configuration, when aerosol detection is performed, it is possible to prevent the detection liquid in the microwells 14 from evaporating into the aerosol-containing gas flowing through the aerosol flow section 12. The degree of evaporation of the detection liquid in the microwells 14 can vary depending on, for example, the temperature of the microchannel device 110 when aerosol detection is performed, the flow channel diameter of the flow channel in the microchannel device 110 through which the aerosol flows, the flow rate of the gas flowing through the microchannel device 110, etc. The microchannel device 110 can prevent evaporation of the detection liquid, so that the detection operation can be performed for a longer period of time and stably, even when aerosol detection is performed under conditions that make the detection liquid likely to evaporate, such as when aerosol detection is performed at a relatively high temperature.

[0048] Furthermore, in the microchannel device 110, the humidifying unit 26 is connected to the communicating channel 16 via the connecting channel 28 to humidify the aerosol before introducing it into the aerosol flow section 12, thereby achieving the effect of suppressing evaporation of the detection liquid in all of the microwells 14 provided along the aerosol flow section 12. However, the connection point of the humidifying unit 26 may be a different point other than the communicating channel 16, and for example, it may be connected to the middle of the aerosol flow section 12.

[0049] In the second embodiment, the humidifier 26 has a rectangular outer periphery in top view and a grid-like channel shape formed by the regular vertical and horizontal arrangement of pillars 27, but may have a different shape. For example, if the material constituting the microchannel device 110 is strong enough, the pillars 27 may not be provided.

[0050] Furthermore, in the second embodiment, water can be stored in the humidifying unit 26 in advance of the aerosol collection and detection operations, eliminating the need to supply water for humidification during the collection and detection operations, thereby simplifying the humidification operation. Instead of providing the humidifying unit 26 within the microchannel device 110 to humidify the aerosol flowing through the microchannel device, a humidifier provided outside the microchannel device may be connected to the flow path within the microchannel device. However, providing a humidifying unit within the microchannel device simplifies the overall configuration of the aerosol detection apparatus including the microchannel device, and eliminates the need for special control for humidification.

[0051] C. Third embodiment: FIG. 6 is an explanatory diagram showing a schematic configuration of a microchannel device 210 of a third embodiment, similar to FIG. 1A. In the microchannel device 210 of the third embodiment, parts common to the microchannel device 10 of the first embodiment are denoted by the same reference numerals. The aerosol flow section 212 formed in the microchannel device 210 does not have a curved section like the aerosol flow section 12 of the first embodiment, and extends linearly from the aerosol inlet section 20 to the aerosol outlet section 22. Hereinafter, for convenience, the direction from the aerosol inlet section 20 to the aerosol outlet section 22 will be referred to as the "aerosol flow direction." In the aerosol flow section 212, as shown in FIG. 6, large-diameter sections 212a having a relatively large flow path cross-sectional area and small-diameter sections 212b having a relatively small flow path cross-sectional area are alternately provided along the aerosol flow direction, and the flow path cross-sectional area abruptly increases or decreases at the boundary between the large-diameter sections 212a and the small-diameter sections 212b. When the aerosol flows through the aerosol flow section 212, turbulence occurs mainly in the area where the cross-sectional area of the flow path changes, causing the aerosol to collide with the flow path wall of the aerosol flow section 212. Therefore, in the third embodiment, the area including the location where the cross-sectional area of the flow path suddenly increases or decreases is the area having a shape where aerosol particles in the aerosol collide with the flow path wall surface. In the third embodiment, microwells 14 for holding detection liquid are provided at opposing positions on the flow path walls of the large diameter section 212a and the small diameter section 212b of the aerosol flow section 212.

[0052] Even with this configuration, the same effects as in Example 1 can be obtained: the operations from collection to detection of aerosols can be expedited, the configuration for supplying the detection liquid can be simplified to reduce the amount of detection liquid required, and flexibility in selecting the aerosol detection method and the type of aerosol to be detected can be ensured.

[0053] D. Other Embodiments: In the above-described embodiments, the aerosol inlet portion 20 is provided at one end of the aerosol flow portion where the microwell 14 is formed, and the aerosol outlet portion 22 is provided at the other end, but different configurations may be used. For example, aerosol inlet portions may be provided at both ends of the aerosol flow portion, and the aerosol outlet portion 22 may be provided in the middle of the aerosol flow portion. With such a configuration, for example, two types of aerosol collection and detection operations can be performed simultaneously by supplying aerosol samples from different locations to each aerosol inlet portion.

[0054] Furthermore, in each of the above-described embodiments, the multiple microwells 14 are arranged in a regular pattern along the aerosol flow direction in the aerosol flow section 12 or the aerosol flow section 212, but a different configuration may also be used. For example, the multiple microwells 14 may be arranged randomly. Furthermore, the number of microwells 14 may be one, or any number greater than one may be set. If microwells 14 are provided continuously on the wall surface of the aerosol flow section on which the aerosol particles collide, the same effects as those of the above-described embodiments can be obtained. [Example]

[0055] <Filling liquid into microwells> Microchannel devices having configurations similar to the microchannel device 110 of the second embodiment shown in FIG. 5 and the microchannel device 210 of the third embodiment shown in FIG. 6 were fabricated, and liquids were filled into the microwells 14 and humidifier 26. Each microchannel device was fabricated using polydimethylsiloxane (PDMS). In the microchannel device 110, the height of each channel was 500 μm, the aerosol flow section 12 had a channel width of 500 μm, the microwells 14 had an opening width of 500 μm, the microwells 14 had a depth of 750 μm, the communicating channel 16 had a channel width of 1.5 mm, the connecting channel 28 had a channel width of 500 μm, and the connecting channel 28 had a channel length of 750 μm. The humidifier 26 had an outer periphery of 10 mm square, and the pillars 27 had an outer periphery of 600 μm square. In addition, in the microchannel device 210, the height of each channel was 500 μm, the channel width of the large diameter section 212a was 1 mm, the channel length of the large diameter section 212a was 1 mm, the channel width of the small diameter section 212b was 500 μm, the channel length of the small diameter section 212b was 1 mm, the opening width of the microwell 14 was 500 μm, and the depth of the microwell 14 was 500 μm.

[0056] 7A and 7B are explanatory diagrams showing the state in which the microchannel device 110 of the second embodiment shown in FIG. 5 has been fabricated and filled with liquid. FIG. 7A shows the state in which the entire microchannel in the microchannel device has been filled with ink liquid. FIG. 7B shows the state in which the ink liquid has been sucked and removed using a pipette from the aerosol flow section 12 and the communicating flow section 16 in the state shown in FIG. 7A via the aerosol outlet section 22 and the aerosol inlet section 20. It was confirmed that by filling and removing the liquid as described above, it is possible to fill only the microwells 14 and the humidifier section 26 with the desired liquid and enable gas to flow through the communicating flow section 16 and the aerosol flow section 12.

[0057] 8 is an explanatory diagram showing the state in which the microchannel device 210 of the third embodiment shown in FIG. 6 has been fabricated and filled with liquid. In FIG. 8, ink liquid is supplied from the aerosol inlet portion 20 while the ink liquid that has flowed through the aerosol flow portion 212 is discharged from the aerosol outlet portion 22, thereby filling the entire flow channel in the microchannel device 210 with ink liquid, and then the ink liquid is removed by sucking it out of the aerosol flow portion 212 using a pipette via the aerosol outlet portion 22. It was confirmed that by filling and removing the liquid as described above, it is possible to fill only the microwells 14 with the desired liquid and allow gas to flow through the aerosol flow portion 212.

[0058] <Confirming the effectiveness of the humidifier> 9 is an explanatory diagram showing the results of an investigation into the effect of humidifying the aerosol flowing through the aerosol flow section 12 using the humidifier 26, using the microchannel device 110 shown in FIGS. 7A and 7B. Here, the state in which the humidifier 26 was filled with water (ultrapure water) was defined as "humidification," and the state in which the humidifier 26 was empty was defined as "non-humidification." Air was circulated from the aerosol inlet 20 to the aerosol outlet 22 with the microwells 14 filled with solution, and the evaporation of the solution in the microwells 14 was observed. Air was circulated by connecting a pump (MP-60, AS ONE Corporation) to the aerosol outlet 22 side via a mass flow controller (1SLM, FCON Corporation) and drawing air at a flow rate of 50 mL / min.

[0059] The change in the liquid volume in the microwell 14 was measured using image analysis software ImageJ. Specifically, the distance from the bottom of the rectangular microwell 14 (the surface of the microwell 14 farthest from the interface with the aerosol outlet 22) to the gas-liquid interface in the microwell 14 (hereinafter also referred to as the "liquid level") was measured every minute. In Figure 9, the horizontal axis represents the elapsed time from the start of the air flow. The vertical axis represents the relative liquid level, where the liquid level at the start of the air flow is set to 1. As shown in Figure 9, with "no humidification," the solution in the microwell 14 evaporated within 5 minutes of the start of the measurement, whereas with "humidification," the solution was retained in the microwell 14 for more than 20 minutes after the start of the measurement. This is thought to be because evaporation of the water in humidifier 26 humidifies the inhaled air, increasing the humidity of the air flowing through aerosol flow section 12 and suppressing evaporation of the solution filled in microwells 14. As described above, it was confirmed that providing humidifier 26 to humidify the gas flowing through aerosol flow section 12 suppresses evaporation of the detection liquid in microwells 14 and enables a longer period of time for aerosol collection and detection.

[0060] <Confirmation of aerosol particle capture using fluorescent beads> It was confirmed that aerosol particles can be collected in the microwells 14 using the microfluidic device 110 shown in Figures 7A and 7B and the microfluidic device 210 shown in Figure 8. Here, fluorescent beads (Fluoresbrite YG, Polyscience) with a particle size of 1 µm were used as a model of aerosol particles.

[0061] The fluorescent bead collection operation using the microchannel device 110 was performed as follows. Specifically, the solution containing the fluorescent beads was sprayed at a flow rate of 0.2 mL / min for 1 minute using a nebulizer (NE-C803, Omron Healthcare Co., Ltd.) in a sealed desiccator (LH, AS ONE Corporation). Simultaneously, a pump (MP-60, AS ONE Corporation) was connected to the aerosol outlet 22 of the microchannel device 110 in the desiccator, and air was suctioned at a pressure of -0.75 MPa for 5 minutes to aspirate the sprayed fluorescent bead-containing solution from the aerosol inlet 20. At this time, the microwells 14 were filled with a 1.5% aqueous solution of sodium alginate (80-120, Fujifilm Wako Pure Chemical Industries, Ltd.) gelled with a 150 mM solution of calcium chloride (special grade, Fujifilm Wako Pure Chemical Industries, Ltd.). After the above-mentioned 5-minute intake, the microfluidic device 110 was taken out of the desiccator and observed using a fluorescence microscope (BIOREVO, Keyence Corporation).

[0062] FIG. 10A is a bright-field image of a region of the microfluidic device 110 containing a microwell 14, and FIG. 10B is a fluorescent image of the same field of view as FIG. 10A. In FIG. 10B, the open arrow indicates fluorescent beads trapped at the gas-liquid interface between the aerosol flow section 12 and the microwell 14. As shown in FIGS. 10A and 10B, fluorescent beads were observed adhering to the gas-liquid interface of the microwell 14. This is thought to be due to the inertial force of the fluorescent beads as they flow through the spiral-shaped aerosol flow section 12 and secondary flows of the vortex flowing toward the outer wall of the flow channel, which transported the fluorescent beads to the microwell 14. As described above, it was demonstrated that even aerosol particles with a diameter of approximately 1 μm can be collected in the microwell 14 using the microfluidic device 110.

[0063] The fluorescent bead collection operation using the microchannel device 210 was performed as follows. Specifically, the solution containing the fluorescent beads was sprayed for 1 minute at a flow rate of 0.2 mL / min using a nebulizer (NE-C803, Omron Healthcare Co., Ltd.) in a sealed desiccator (VL, AS ONE Corporation). Simultaneously, a pump (MP-60, AS ONE Corporation) was connected to the aerosol outlet 22 of the microchannel device 210 in the desiccator via a mass flow controller (1SLM, FCON Corporation). Air was suctioned at a flow rate of 50 mL / min for 5 minutes, and the sprayed fluorescent bead-containing solution was drawn through the aerosol inlet 20. At this time, the microwells 14 were filled with a 1.5% aqueous solution of sodium alginate (80-120, Fujifilm Wako Pure Chemical Industries, Ltd.) gelled with a 150 mM solution of calcium chloride (special grade, Fujifilm Wako Pure Chemical Industries, Ltd.). After the above-mentioned 5-minute intake, the microfluidic device 210 was taken out of the desiccator and observed using a fluorescence microscope (BIOREVO, Keyence Corporation).

[0064] FIG. 11A is a bright-field image of a region of the microfluidic device 210 that includes a microwell 14, and FIG. 11B is a fluorescent image of the same field of view as FIG. 11A. In FIG. 11B, the open arrow indicates fluorescent beads trapped at the gas-liquid interface between the aerosol flow section 12 and the microwell 14. As shown in FIGS. 11A and 11B, fluorescent beads were observed adhering to the gas-liquid interface of the microwell 14. This is thought to be because the fluorescent beads were transported to the microwell 14 by turbulence caused by a sudden change in the channel width (channel cross-sectional area). As described above, it was demonstrated that even aerosol particles with a diameter of approximately 1 μm can be collected in the microwell 14 using the microfluidic device 210.

[0065] <Example of detection of plasmid DNA> 7A and 7B, it was confirmed that plasmid DNA, as an example of aerosol, can be collected and detected. Here, a plasmid containing the EGFP gene, a green fluorescent protein gene, was used as the plasmid DNA, and DNA amplification was performed in the microwells 14 by the RPA method.

[0066] The collection and detection of plasmid DNA using the microfluidic device 110 was performed as follows. A solution of a plasmid containing an EGFP sequence (concentration: 50 pg / mL) was sprayed for 5 minutes at a flow rate of 0.2 mL / min using a nebulizer (NE-C803, Omron Healthcare Co., Ltd.) in a sealed desiccator (VL, AS ONE Corporation). Simultaneously, a pump (MP-60, AS ONE Corporation) was connected to the aerosol outlet 22 of the microfluidic device 110 in the desiccator via a mass flow controller (1SLM, FCON Corporation) and suctioned at a flow rate of 50 mL / min for 5 minutes, thereby drawing the sprayed plasmid solution from the aerosol inlet 20. At this time, the microwells 14 were previously filled with an RPA solution (TwistAmp exo, TwistDx) containing a primer specifically detecting EGFP, an enzyme for polymerase reaction, and a fluorescent probe that specifically binds to the amplification site. In addition to the above-described operation of collecting the plasmid, a similar microfluidic device 110 was used as a control, and a liquid not containing the plasmid was sprayed into the desiccator in the same manner and sucked into the microfluidic device 110. After the above-described 5-minute suction, the microfluidic device 110 was removed from the desiccator and incubated at 40°C to carry out a DNA amplification reaction. Then, 20 minutes after the start of the amplification reaction, observation was carried out using a fluorescence microscope (BIOREVO, Keyence Corporation).

[0067] Figure 12 is an explanatory diagram showing the results of measuring brightness using a fluorescence microscope after 20 minutes of DNA amplification. Figure 12 shows the results for n≧4 (n is the number of microwells 14 measured), and the error bars represent the standard deviation. Figure 13 shows images of the fluorescence brightness visually observed after 20 minutes of DNA amplification. As shown in Figures 12 and 13, a significant difference was observed between the control and the sample after 20 minutes. This is thought to be due to the detection solution emitting fluorescence because the plasmid collected as aerosol was amplified by the RPA method in the microwells 14. This confirmed that selective detection of bioaerosols is possible using a microfluidic device equipped with microwells 14 that share a collection and detection unit.

[0068] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0069] The present disclosure can also be realized in the following forms. [Application example 1] A microfluidic device for collecting and detecting aerosols, comprising: an aerosol flow section which is a micro flow channel having a shape in which an aerosol flowing in from the outside flows and aerosol particles in the aerosol collide with a wall surface of the flow channel due to at least one of inertial force, vortex flow, and turbulence generated by the flow of the aerosol; one or more microwells provided continuously on a wall surface of the aerosol flow section on which the aerosol particles collide, the microwells holding a detection liquid for detecting the aerosol particles; A microfluidic device for aerosol collection and detection. [Application example 2] The microfluidic device for collecting and detecting aerosols according to Application Example 1, The aerosol flow section includes a curved portion having a curved flow path shape as a portion having a shape at which aerosol particles in the aerosol collide with a flow path wall surface. A microfluidic device for aerosol collection and detection. [Application example 3] The microfluidic device for collecting and detecting aerosols according to Application Example 1 or 2, The aerosol flow section has the curved section in which the flow path shape is a spiral shape. A microfluidic device for aerosol collection and detection. [Application example 4] The microchannel device for collecting and detecting aerosols according to any one of Application Examples 1 to 3, The aerosol flow section may further include a humidifying section. A microfluidic device for aerosol collection and detection. [Application example 5] The microfluidic device for collecting and detecting aerosols according to Application Example 4, The humidifying section is a water storage section that is provided in communication with the aerosol flow section and that stores water. A microfluidic device for aerosol collection and detection. [Application Example 6] The microchannel device for collecting and detecting aerosols according to Application Example 5 further comprises: an aerosol inlet portion through which an aerosol flows from the outside into the microchannel device; a communication flow path that communicates the aerosol inlet portion with the aerosol circulation portion; Equipped with The water storage section is provided in communication with the communication flow path. A microfluidic device for aerosol collection and detection. [Application Example 7] The microchannel device for collecting and detecting aerosols according to Application Example 6 further comprises: a connecting flow path that connects the communication flow path and the water storage section; The communication flow path is formed to have a larger flow path cross-sectional area than the connection flow path. A microfluidic device for aerosol collection and detection. [Application Example 8] A method for collecting and detecting aerosols, comprising: Using the microfluidic device for collecting and detecting aerosols according to any one of Application Examples 1 to 7, Filling the microwells with the detection solution; a pressure difference is generated between an upstream end and a downstream end in the aerosol flow direction in the aerosol flow section, causing the aerosol to flow in the aerosol flow section, and aerosol particles in the aerosol flowing through the aerosol flow section are collected in the detection liquid in the microwells; Detecting the aerosol particles in the microwells Aerosol collection and detection methods. [Explanation of symbols]

[0070] 10,110,210...Microfluidic Devices 10a to 10c... Plate-shaped members 12,212...Aerosol Distribution Department 14...Microwell 16...Communicating flow path 20...Aerosol inlet 22...Aerosol outflow section 24...Humidification opening 26...Humidification unit 27...Column part 28...Connecting channel 30,130…equipment 32…Case 34…Light source 36...Camera 38...Pump 40...Heater 42, 44...Tube 46...Color filter 212b…Small diameter part 212a...Large diameter section

Claims

1. A microfluidic device for collecting and detecting aerosols, comprising: an aerosol flow section which is a micro flow channel having a shape in which an aerosol flowing in from the outside flows and aerosol particles in the aerosol collide with a wall surface of the flow channel due to at least one of inertial force, vortex flow, and turbulence generated by the flow of the aerosol; one or more microwells provided continuously on a wall surface of the aerosol flow section on which the aerosol particles collide, the microwells holding a detection liquid for detecting the aerosol particles; A microfluidic device for collecting and detecting aerosols, comprising:

2. The microchannel device for collecting and detecting aerosols according to claim 1, The aerosol flow section includes a curved portion having a curved flow path shape as a portion having a shape at which aerosol particles in the aerosol collide with a flow path wall surface. A microfluidic device for aerosol collection and detection.

3. 3. The microchannel device for collecting and detecting aerosols according to claim 2, The aerosol flow section has the curved section in which the flow path shape is a spiral shape. A microfluidic device for aerosol collection and detection.

4. The microchannel device for collecting and detecting aerosols according to claim 1, The aerosol flow section may further include a humidifying section. A microfluidic device for aerosol collection and detection.

5. The microfluidic device for collecting and detecting aerosols according to claim 4, The humidifying section is a water storage section that is provided in communication with the aerosol flow section and that stores water. A microfluidic device for aerosol collection and detection.

6. The microchannel device for collecting and detecting aerosols according to claim 5, further comprising: an aerosol inlet portion through which an aerosol flows from the outside into the microchannel device; a communication flow path that communicates the aerosol inlet portion with the aerosol circulation portion; Equipped with The water storage section is provided in communication with the communication flow path. A microfluidic device for aerosol collection and detection.

7. The microchannel device for collecting and detecting aerosols according to claim 6, further comprising: a connecting flow path that connects the communication flow path and the water storage section; The communication flow path is formed to have a larger flow path cross-sectional area than the connection flow path. A microfluidic device for aerosol collection and detection.

8. A method for collecting and detecting aerosols, comprising: Using the microchannel device for collecting and detecting aerosols according to any one of claims 1 to 7, Filling the microwells with the detection solution; a pressure difference is generated between an upstream end and a downstream end in the aerosol flow direction in the aerosol flow section, causing the aerosol to flow in the aerosol flow section, and aerosol particles in the aerosol flowing through the aerosol flow section are collected in the detection liquid in the microwells; Detecting the aerosol particles in the microwells Aerosol collection and detection methods.

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