A microfluidic chip for detecting microorganisms in the air

Abstract

The present invention discloses a microfluidic chip for detecting microorganisms in the air, comprising a chip body and a pair of polarized electrodes; the chip body is provided with a sedimentation unit, an elution unit and a mixed reaction unit, the sedimentation unit is used to precipitate microparticles in the air; the elution unit is used to elute the microparticles in the sedimentation unit; the mixed reaction unit is used to detect microorganisms attached to the microparticles; the pair of polarized electrodes is used to generate a polarized electric field perpendicular to the chip body. The microfluidic chip disclosed by the present invention integrates the functions of capturing, eluting and detecting microparticles in the air, has a simple chip structure, is easy to operate in a use method, and can efficiently and conveniently realize rapid detection of various microorganisms in gases such as air.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganism detection, and in particular to a microfluidic chip for detecting microorganisms in the air. Background Art

[0002] The amount of microorganisms in the air is one of the important indicators of indoor air quality and has a significant impact on human health and environmental safety. Microbial pollution in the air can cause many health problems, such as infectious diseases, acute toxic diseases, allergies, and other diseases, posing a threat to human health. The spread of viruses in the air, such as influenza viruses H1N1, H2N2, avian influenza viruses H5N1, H7N9, H9N2 infecting humans, etc., has posed a great threat to human health.

[0003] According to the national standard "GBT 18204.3-2013 Public Place Hygiene Inspection Method", the main method for detecting microorganisms in the air is still the culture method. The traditional culture method is the gold standard, but it is time-consuming and cannot meet the needs of rapid detection.

[0004] Therefore, it is of great significance to develop an efficient and sensitive method for detecting airborne microorganisms. Summary of the invention

[0005] The purpose of the present invention is to provide a microfluidic chip for detecting microorganisms in the air. The microfluidic chip integrates the functions of capturing, eluting and detecting microparticles in the air, and the chip has a simple structure, which can efficiently and conveniently realize the rapid detection of various microorganisms in gases such as air.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a microfluidic chip for detecting microorganisms in the air, comprising a chip body and a pair of polarized electrodes, wherein the chip body is provided with:

[0008] A sedimentation unit is used to sediment the microparticles in the air; the sedimentation unit comprises an inlet air channel, an outlet air channel and a sedimentation air channel connected between the inlet air channel and the outlet air channel, which are arranged inside the chip body; the chip body is also provided with a gas inlet and a gas outlet respectively connected to the inlet air channel and the outlet air channel, and the inlet air channel and the outlet air channel are both provided with a first isolation valve;

[0009] an elution unit, used for eluting the microparticles in the sedimentation unit; the elution unit comprises an eluent storage chamber, an inlet flow channel and an outlet flow channel; the inlet flow channel is connected between the eluent storage chamber and the inlet flow channel, and the connection is located between the first isolation valve and the sedimentation flow channel; the inlet flow channel and the outlet flow channel are both provided with a second isolation valve; and

[0010] A mixing reaction unit, used for detecting microorganisms attached to microparticles; the liquid outlet channel is connected between the liquid outlet channel and the mixing reaction unit, and the connection is located between the first isolation valve and the sedimentation channel; the mixing reaction unit includes a pneumatic mixing chamber, a working liquid storage chamber, a reaction chamber and a cleaning liquid storage chamber, the working liquid storage chamber, the reaction chamber and the pneumatic mixing chamber are respectively connected through a working liquid channel and a mixed liquid channel, and the cleaning liquid storage chamber and the reaction chamber are connected through a cleaning liquid channel; the working liquid channel, the mixed liquid channel and the cleaning liquid channel are respectively provided with a third isolation valve, a fourth isolation valve and a fifth isolation valve;

[0011] The pair of polarization electrodes are respectively arranged at the upper and lower sides of the area where the sedimentation channel is located, and are used to generate a polarization electric field perpendicular to the chip body.

[0012] Furthermore, the width of the sedimentation channel is 50 to 1000 μm, and the height is 50 to 1000 μm.

[0013] Furthermore, the sedimentation channel is a channel composed of a plurality of mutually interconnected quasi-concentric circular channels, and the distance between two adjacent quasi-concentric circular channels is 200 to 1000 μm.

[0014] Further, the gas inlet and the gas outlet are both arranged on the side of the chip body; and / or,

[0015] The gas outlet is communicated with a micro pump located outside the microfluidic chip.

[0016] Furthermore, the widths of the liquid inlet flow channel, the liquid outlet flow channel, the working liquid flow channel, the mixed liquid flow channel, and the cleaning liquid flow channel are all 10 to 500 μm, and the heights are all 10 to 500 μm.

[0017] Furthermore, a plurality of mixing chambers and a sixth isolating valve are also provided on the mixed liquid flow channel, and the plurality of mixing chambers are located between the fourth isolating valve and the sixth isolating valve.

[0018] Furthermore, the mixing chamber is a spherical, hemispherical or ellipsoidal mixing chamber.

[0019] Further, the isolation valve is arranged inside the chip body, and includes a valve cavity, a valve cover located above the valve cavity, and a first elastic membrane located between the valve cavity and the valve cover, and the valve cavity is communicated with the corresponding flow channel; the chip body is also provided with a gas interface for connecting to an external air pressure controller, and the valve cavity is communicated with the gas interface through a gas microchannel;

[0020] The air pressure controller is used to control the air pressure in the valve cavity, thereby separating or contacting the first elastic membrane with the valve cover to realize the opening or closing of the isolation valve.

[0021] Furthermore, the pneumatic mixing chamber is arranged inside the chip body, and includes an upper valve cavity, a lower valve cavity and a second elastic membrane located between the upper valve cavity and the lower valve cavity; the upper valve cavity is communicated with the corresponding flow channel; the chip body is also provided with a gas interface for connecting to an external air pressure controller, and the lower valve cavity is communicated with the gas interface through a gas microchannel;

[0022] The air pressure controller is used to control the air pressure in the lower valve cavity, thereby making the second elastic membrane contact with the lower valve cavity or the upper valve cavity to realize the opening or closing of the pneumatic mixing chamber.

[0023] Furthermore, the chip body is made of one of polystyrene, polymethyl methacrylate, polydimethylsiloxane, polycarbonate, glass, quartz, and silicon dioxide.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The microfluidic chip provided by the present invention integrates the functions of capturing, eluting and detecting microparticles in the air, and the chip structure is simple, the method is easy to operate, and can efficiently and conveniently realize the rapid detection of various microorganisms in gases such as air. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a chip body in one embodiment of the present invention;

[0027] Figure 2 A schematic diagram of the structure of a chip body in another embodiment of the present invention;

[0028] Figure 3 It is a structural schematic diagram of the isolation valve in a closed state;

[0029] Figure 4 It is a structural schematic diagram of the isolation valve in an open state;

[0030] Figure 5 It is a structural schematic diagram of a pneumatic mixing chamber in a closed state;

[0031] Figure 6 It is a structural schematic diagram of the pneumatic mixing chamber in an open state;

[0032] Wherein: 100, chip body;

[0033] 200, sedimentation unit; 210, inlet flow channel; 220, outlet flow channel; 230, sedimentation flow channel; 240, gas inlet; 250, gas outlet; 260, first isolation valve; 261, valve chamber; 262, valve cover; 263, first elastic membrane;

[0034] 300, elution unit; 310, eluent storage chamber; 320, liquid inlet channel; 330, liquid outlet channel; 340, second isolation valve;

[0035] 400, mixing reaction unit; 410, pneumatic mixing chamber; 411, lower valve cavity; 412, upper valve cavity; 413, second elastic membrane; 420, working liquid storage chamber; 421, working liquid flow channel; 422, third isolation valve; 430, reaction chamber; 431, mixed liquid flow channel; 432, fourth isolation valve; 433, sixth isolation valve; 434, mixing cavity; 440, cleaning liquid storage chamber; 441, cleaning liquid flow channel; 442, fifth isolation valve. DETAILED DESCRIPTION

[0036] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0037] In the drawings, components with the same structure are indicated by the same numerical labels, and components with similar structures or functions are indicated by similar numerical labels. Directional terms mentioned in the present invention, such as up, down, front, back, left, right, inside, outside, upper surface, lower surface, side, top surface, bottom, front end, rear end, end, etc., are only directions in the drawings and are only used to explain and illustrate the present invention, but not to limit the scope of protection of the present invention.

[0038] In the drawings, components with the same structure are indicated by the same numerical reference numerals. When some components are described as being "on" another component, the component may be directly placed on the other component; there may also be an intermediate component on which the component is placed, and the intermediate component is placed on the other component. When a component is described as being "mounted to" or "connected to" another component, the two may be understood to be directly "mounted" or "connected", or one component may be indirectly "mounted to" or "connected to" another component through an intermediate component.

[0039] As described in the background technology, the main method for detecting microorganisms in the air is still the culture method. The traditional culture method is the gold standard, but it is time-consuming, cannot meet the needs of rapid detection, and is not conducive to real-time online monitoring.

[0040] At present, other methods have also appeared in the prior art to detect microorganisms in the air, but there are still some shortcomings. For example, a Chinese patent with publication number CN114045217A (publication date is February 15, 2022) discloses an integrated device for sampling and detecting air microorganisms, including an air microorganism sampling device, a nucleic acid detection device and a nucleic acid extraction device, wherein the air microorganism sampling device includes a sampling tube and a filter membrane, a filter membrane is provided in the sampling tube, one end of the sampling tube is provided with an exhaust device for extracting the gas inside the sampling tube, and the other end is used for air intake, and the filter membrane is used to intercept the microorganisms in the air flowing through the filter membrane on the filter membrane, and then the nucleic acid extraction device extracts nucleic acid from the collected microbial sample, and the nucleic acid detection device performs nucleic acid detection on the extracted nucleic acid. Although the device can realize the sampling and detection of microorganisms in the air, its structure is complicated, and the filter membrane has a poor interception effect on particulate matter, and the filter membrane is prone to clogging during sampling.

[0041] For another example, a Chinese patent with publication number CN101760428A (published on June 30, 2010) discloses a microfluidic chip for enriching microorganisms in the air and a preparation method thereof, wherein the chip contains a sample enrichment channel and a gas channel, wherein the sample enrichment channel is composed of arrow-shaped grooves with a width of 1 to 100 μm and a length of 1 to 4 mm arranged in parallel, and each arrow-shaped groove forms a microchamber for collecting microorganisms; the sample enrichment channel can realize the collection of biological particles such as bacteria, fungi, and viruses in air samples, and can combine the enriched samples with PCR microfluidic chips and immune microfluidic chips for gene analysis or immune analysis, so as to achieve rapid detection of the content and types of microorganisms in the air. However, the sample enrichment channel in the chip has a complex structure, is difficult to process, and has high cost, and because there are a large number of dead corners in the microchamber, it is difficult to smoothly elute the enriched microorganisms.

[0042] In view of the above problems existing in the prior art, the present invention provides a novel microfluidic chip for detecting microorganisms in the air. The microfluidic chip not only integrates the functions of capturing, eluting and detecting microparticles in the air, but also has a simple chip structure and is easy to process. It can efficiently and conveniently realize the rapid detection of various microorganisms in air and other gases.

[0043] See also Figure 1The present invention provides a microfluidic chip, including a chip body 100 and a pair of polarized electrodes 500. The shape of the chip body 100 is not limited, and can be various shapes such as square, round, diamond, trapezoid, etc.; the chip body 100 in this embodiment is square. The chip body 100 is provided with a sedimentation unit 200, an elution unit 300 and a mixing reaction unit 400. The structures of these three units are described in detail below.

[0044] The sedimentation unit 200 is used to sediment fine particles in the air. Figure 1 The sedimentation unit 200 includes an inlet channel 210, an outlet channel 220, and a sedimentation channel 230 connected between the inlet channel 210 and the outlet channel 220. The chip body 100 is also provided with a gas inlet 240 and a gas outlet 250 respectively connected to the inlet channel 210 and the outlet channel 220. The air to be tested enters the sedimentation unit 200 through the gas inlet 240, and the microparticles contained therein are precipitated in the process of flowing through the sedimentation channel 230; then the air to be tested is discharged from the chip body 100 through the gas outlet 250.

[0045] In the present invention, the gas inlet and the gas outlet 250 are preferably both disposed on the side of the chip body 100. In some embodiments, the gas outlet 250 may be connected to a micro pump located outside the microfluidic chip, so that the air to be tested is driven to flow in the settling channel 230 under the suction action of the micro pump.

[0046] In the present invention, the sedimentation channel 230 is preferably a curved channel, which can increase the flow distance of the air to be tested in the microfluidic chip, thereby facilitating the full sedimentation of microparticles in the air. The present invention is not limited to the shape of the sedimentation channel 230, and various curved shapes are possible. Figure 1 In the illustrated embodiment, the sedimentation channel 230 is a channel composed of a plurality of interconnected concentric circular channels, and two adjacent concentric circular channels are smoothly connected, and the spacing is preferably 200 to 1000 μm, for example, it can be 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0047] In the present invention, in order to meet the requirements of air flow, the width of the sedimentation channel 230 is preferably set to 50-1000 μm, for example, it can be 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc., but it is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable. The height of the sedimentation channel 230 is preferably set to 50-1000 μm, for example, it can be 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc., but it is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0048] In the present invention, a first isolation valve 260 is provided on both the inlet flow channel 210 and the outlet flow channel 220. The function of the first isolation valve 260 is to open or close the inlet flow channel 210 and the outlet flow channel 220, that is, when the microparticle sedimentation operation is performed, the first isolation valve 260 is opened to allow the air to be tested to be introduced for sedimentation; and when the sedimentation is completed, the first isolation valve 260 is closed to perform the subsequent microparticle elution operation. The first isolation valve 260 is preferably controlled by pneumatics.

[0049] like Figure 3-4 As shown, in a preferred embodiment of the present invention, the first isolation valve 260 includes a valve cavity 261, a valve cover 262 located above the valve cavity 261, and a first elastic membrane 263 located between the valve cavity 261 and the valve cover 262, wherein the valve cavity 261 is connected to the inlet flow channel 210 / the outlet flow channel 220. The valve cavity 261 is recessed on the bottom wall of the inlet flow channel 210 / the outlet flow channel 220, and the valve cover 262 is convexly disposed on the top wall of the inlet flow channel 210 / the outlet flow channel 220. A plurality of gas interfaces are provided on the chip body 100, and the gas interfaces are connected to the above-mentioned valve cavity 261 through microchannels, and the gas interfaces are connected to an external air pressure controller. Therefore, the air pressure in the valve cavity 261 can be controlled by the air pressure controller. When the air pressure controller is not started, the first isolation valve 260 is in a closed state, and the first elastic membrane 263 is tightly attached to the valve cover 262, thereby closing the inlet flow channel 210 / outlet flow channel 220; when the air pressure controller controls the valve chamber 261 to be negatively pressurized, the first isolation valve 260 is in an open state, and the first elastic membrane 263 is deformed under the pressure difference on both sides, protruding into the valve chamber 261, thereby separating from the valve cover 262, thereby achieving the conduction of the inlet flow channel 210 / outlet flow channel 220. In the present invention, the two first isolation valves 260 are opened and closed synchronously, so their opening and closing can be controlled by a single gas interface.

[0050] There are a large number of tiny suspended particles in the air, and various microorganisms are generally attached to the surface of these suspended particles. By intercepting the suspended particles in the air in various ways, making them settle, and then using the collected suspended particles as samples for testing, the detection of microorganisms in the air can be achieved. At present, the methods of intercepting suspended particles by setting obstacles, filter membranes, etc. have many disadvantages.

[0051] Since the Zeta potential of suspended particles in the air is generally not zero, that is, the surface will carry an electric charge. Therefore, the principle of electrostatic dust removal can be used to collect these suspended particles. In some embodiments, the air to be tested can be ionized in advance to make the air ions charged, so that the microparticles in the air carry the same electrical charge in the collision with the air ions. Specifically, the microfluidic chip in the present invention also includes a pair of polarized electrodes 500, which are respectively arranged on the upper and lower sides of the chip body 100, and more specifically, are arranged on the upper and lower sides of the sedimentation channel 230. The polarized electrode 500 can generate a vertical electric field, and when the dielectric is placed in the electric field, under the action of the electric field, the dielectric generates an induced dipole moment along the direction of the electric field, so that polarized charges appear on the surface of the dielectric. Therefore, polarization occurs in the sedimentation channel 230 area, which will cause polarized charges to be generated on the surface of the sedimentation channel 230, and the microparticles carried in the air to be tested can be sedimented through the electrostatic attraction between the positive and negative charges.

[0052] Compared with the existing interception methods, the present invention settles the microparticles in the air based on the principles of polarization and electrostatic dust removal. It does not require processing of complex interception structures on the chip, and also avoids the problems of poor interception effect and easy clogging when using filter membranes.

[0053] In the present invention, the chip body 100 needs to be made of dielectric material (i.e., dielectric material), and such dielectric material includes but is not limited to polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polystyrene (PS), polycarbonate (PC), glass, silicon dioxide, quartz, etc.

[0054] In the present invention, the polarization electrode 500 may be a planar electrode. When a voltage is applied to a pair of planar electrodes, an electric field perpendicular to the chip surface can be generated.

[0055] In the present invention, the intensity of the polarization electric field is based on the ability to polarize the medium in the electric field more quickly. In some embodiments of the present invention, the intensity of the polarization electric field can be set to 50 to 500 V / cm, for example, 50 V / cm, 100 V / cm, 150 V / cm, 200 V / cm, 250 V / cm, 300 V / cm, 350 V / cm, 400 V / cm, 450 V / cm, 500 V / cm, etc. Preferably, after applying the voltage, it is first maintained for 30 to 60 seconds to rearrange the internal charge of the medium in the corresponding area and form polarized charges on the surface, and then the air to be tested is introduced.

[0056] The elution unit 300 is used to elute the microparticles in the sedimentation unit 200. Figure 1 The elution unit 300 includes an eluent storage chamber 310, an inlet flow channel 320, and an outlet flow channel 330. The inlet flow channel 320 is connected between the eluent storage chamber 310 and the inlet flow channel 210, and the connection is located between the first isolation valve 260 and the sedimentation flow channel 230; the outlet flow channel 330 is connected between the outlet flow channel 220 and the mixing reaction unit 400, and the connection is located between the first isolation valve 260 and the sedimentation flow channel 230.

[0057] In the present invention, the eluent storage chamber 310 is used to store the eluent. Under the action of the driving force, the eluent in the eluent storage chamber 310 can sequentially pass through the inlet flow channel 320 and the inlet flow channel 210 to enter the sedimentation flow channel 230; during the flow process, the settled microparticles are eluted and carried into the outlet flow channel 330, and finally enter the mixed reaction unit 400 for detection.

[0058] In the present invention, a second isolation valve 340 is further provided on the liquid inlet flow channel 320 and the liquid outlet flow channel 330. When the microparticles are settling, the second isolation valve 340 is closed to prevent the airflow from entering the eluent storage chamber 310 or the mixed reaction unit 400. The structure of the second isolation valve 340 is the same as that of the first isolation valve 260, and will not be repeated here.

[0059] In the present invention, the size of the inlet flow channel 320 and the outlet flow channel 330 is preferably smaller than the size of the sedimentation flow channel 230, and a smaller flow channel size is conducive to driving the eluent to flow through capillary phenomena. The width of the inlet flow channel 320 and the outlet flow channel 330 is preferably 10 to 500 μm, for example, it can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc., but is not limited to the listed values, and other values ​​or ranges not listed in the numerical range are also applicable. The height of the liquid inlet channel 320 and the liquid outlet channel 330 is preferably 10 to 500 μm, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable.

[0060] In some embodiments of the present invention, when the chip body 100 is made of a hydrophobic material, the aqueous eluent has poor wettability on the surface of the sedimentation channel 230, which leads to poor elution of particles. In this case, the surface of the sedimentation channel 230 can be hydrophilically modified, such as by modifying the surface with a hydrophilic coating, to improve the hydrophilicity of the surface of the sedimentation channel 230. In this way, during the elution process, the eluent has better wettability on the surface of the sedimentation channel 230, which is conducive to improving the elution effect.

[0061] In order to meet the requirements of air flow, the width of the sedimentation channel 230 is preferably set to 50 to 1000 μm, for example, it can be 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within this numerical range are also applicable.

[0062] The mixed reaction unit 400 is used to detect microorganisms attached to microparticles. Figure 1 The mixing reaction unit 400 includes a pneumatic mixing chamber 410, a working liquid storage chamber 420, a reaction chamber 430, a cleaning liquid storage chamber 440, a working liquid flow channel 421, a mixed liquid flow channel 431 and a cleaning liquid flow channel 441, wherein the outlet flow channel 330 in the elution unit 300 is connected between the outlet flow channel 220 and the pneumatic mixing chamber 410, the working liquid flow channel 421 is connected between the pneumatic mixing chamber 410 and the working liquid storage chamber 420, the mixed liquid flow channel 431 is connected between the pneumatic mixing chamber 410 and the reaction chamber 430, and the cleaning liquid flow channel 441 is connected between the cleaning liquid storage chamber 440 and the reaction chamber 430.

[0063] In the present invention, the working fluid flow channel 421, the mixed fluid flow channel 431, and the cleaning fluid flow channel 441 are respectively provided with a third isolation valve 422, a fourth isolation valve 432, and a fifth isolation valve 442, which are respectively used to control the opening and closing of the working fluid flow channel 421, the mixed fluid flow channel 431, and the cleaning fluid flow channel 441. The structures of the third isolation valve 422, the fourth isolation valve 432, and the fifth isolation valve 442 are the same as those of the first isolation valve 260, and are not described in detail here.

[0064] In the present invention, the structure of the pneumatic mixing chamber 410 is as follows: Figure 5-6 As shown, it includes an upper valve chamber 412, a lower valve chamber 411 and a second elastic membrane 413 located between the upper valve chamber 412 and the lower valve chamber 411. The present invention is not limited to the shape of the upper valve chamber 412 and the lower valve chamber 411, and is preferably a semicircular valve chamber. The upper valve chamber 412 is connected to the corresponding flow channel (the liquid outlet flow channel 330, the working liquid flow channel 421 and the mixed liquid flow channel 431), and the lower valve chamber 411 is separated from the upper valve chamber 412 and the corresponding flow channel by the second elastic membrane 413. A gas interface for connecting an external air pressure controller is provided on the chip body 100, and the lower valve chamber 411 is connected to the gas interface through a gas microchannel, so that the air pressure in the lower valve chamber 411 can be controlled by the air pressure controller. The pneumatic mixing chamber 410 can not only temporarily store liquid, but also play a role in sucking and discharging liquid.

[0065] Specifically, when the third isolation valve 422 and the fourth isolation valve 432 are in a closed state and the second isolation valve 340 is in an open state, the air pressure controller controls the lower valve chamber 411 to be under negative pressure. At this time, the second elastic membrane 413 is deformed under the action of the pressure difference on both sides and protrudes into the lower valve chamber 411; the deformation of the second elastic membrane 413 will generate a suction force on the flow channel of the elution unit 300, so that the eluent flows out from the eluent storage chamber 310, enters the sedimentation flow channel 230, elutes the microparticles, and then enters the pneumatic mixing chamber 410 through the liquid outlet flow channel 330.

[0066] When the second isolation valve 340 and the third isolation valve 422 are in a closed state, and the fourth isolation valve 432 is in an open state, the air pressure controller controls the lower valve chamber 411 to be under positive pressure. At this time, the second elastic membrane 413 is deformed under the action of the pressure difference on both sides and protrudes upward into the valve chamber 412; the deformation of the second elastic membrane 413 will have an extruding effect on the mixed liquid in the pneumatic mixing chamber 410, causing the mixed liquid to flow out of the pneumatic mixing chamber 410 and enter the reaction chamber 430 through the mixed liquid flow channel 431.

[0067] Therefore, by providing the pneumatic mixing chamber 410, directional delivery of the eluent and the mixed liquid is achieved.

[0068] In the present invention, the width of the working liquid flow channel 421, the mixed liquid flow channel 431 and the cleaning liquid flow channel 441 is preferably 10 to 500 μm, for example, it can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within the numerical range are also applicable. The height of the working liquid flow channel 421, the mixed liquid flow channel 431 and the cleaning liquid flow channel 441 is preferably 10 to 500 μm, for example, it can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, etc., but is not limited to the listed values, and other unlisted values ​​or ranges within this numerical range are also applicable.

[0069] In the present invention, the working liquid storage chamber 420 is used to store the working liquid required for detection, which can enter the pneumatic mixing chamber 410 through the working liquid flow channel 421 and mix with the eluent transported from the outlet flow channel 330. Different working liquids can be selected according to different detection methods. For example, the working liquid can be a fluorescent reagent, a lysate, an immunomagnetic bead, etc. In some embodiments of the present invention, when there are multiple working liquids and they cannot be mixed and stored, multiple working liquid storage chambers 420 can be set on the chip body 100, and each working liquid storage chamber 420 is connected to the pneumatic mixing chamber 410 through an independent working liquid flow channel 421.

[0070] See also Figure 2 In some embodiments of the present invention, a plurality of mixing chambers 434 and a sixth isolation valve 433 are further provided on the mixed liquid flow channel 431, and the plurality of mixing chambers 434 are located between the fourth isolation valve 432 and the sixth isolation valve 433. The mixing chamber 434 is relatively "coarse" relative to the mixed liquid flow channel 431, and the plurality of mixing chambers 434 are provided on the mixed liquid flow channel 431 in a bead-like manner and are connected to the mixed liquid flow channel 431. The shape of the mixing chamber 434 is not limited, and may be, for example, spherical, hemispherical, or ellipsoidal.

[0071] The function of the mixing chamber 434 is to fully mix the eluent and the working fluid to improve the mixing effect. During use, close the sixth isolating valve 433, open the fourth isolating valve 432, and then frequently open and close the pneumatic reaction chamber 430, so that the mixed liquid reciprocates back and forth in the mixing chamber 434, thereby achieving full mixing of the eluent and the working fluid. The principle is: when the mixed liquid enters the mixing chamber 434 from the mixed liquid flow channel 431, the flow velocity changes due to the increase in the flow cross-sectional area, resulting in irregular flow and a turbulent effect. The formation of turbulence can make the eluent and the working fluid fully contact and mix, so that the eluent and the working fluid are fully contacted to form a complex.

[0072] In the present invention, after being fully mixed and treated, the mixed solution in the pneumatic mixing chamber 410 enters the reaction chamber 430 through the mixed solution flow channel 431 for incubation. The reaction chamber 430 can be loaded with a capture medium to fix the complex. Such capture media may include antigens, antibodies, nucleic acid adsorption media, magnetic adsorption media, etc. After the incubation is completed, the waste liquid in the reaction chamber 430 is pumped to the working liquid storage chamber 420 through the pneumatic mixing chamber 410.

[0073] In the present invention, the cleaning liquid storage chamber 440 is used to store the cleaning liquid, which can flow into the reaction chamber 430 through the cleaning liquid flow channel 441, so as to clean the reaction chamber 430 and remove the unbound working liquid substances. The waste liquid after cleaning can be pumped to the working liquid storage chamber 420 through the pneumatic mixing chamber 410. In some preferred embodiments of the present invention, by controlling the pneumatic mixing chamber 410 to continuously switch between the open state and the closed state, the cleaning liquid flows back and forth between the reaction chamber 430 and the mixing chamber 434, so that the reaction chamber 430 can be rinsed multiple times, thereby achieving a better cleaning effect.

[0074] In the present invention, after the reaction chamber 430 is cleaned, the next step of microbial detection is performed. There is no limitation on the specific detection method. For example, in some embodiments, the fixed complex in the reaction chamber 430 may be fluorescently excited, and the fluorescent information may be collected and analyzed to obtain the microbial detection result; in other embodiments, the extracted nucleic acid may also be detected to obtain the microbial detection result.

[0075] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A microfluidic chip for detecting microorganisms in the air, characterized in that: It includes a chip body and a pair of polarized electrodes; the chip body is provided with: A sedimentation unit is used to sediment the microparticles in the air; the sedimentation unit comprises an inlet air channel, an outlet air channel and a sedimentation air channel connected between the inlet air channel and the outlet air channel, which are arranged inside the chip body; the chip body is also provided with a gas inlet and a gas outlet respectively connected to the inlet air channel and the outlet air channel, and the inlet air channel and the outlet air channel are both provided with a first isolation valve; an elution unit, used for eluting the microparticles in the sedimentation unit; the elution unit comprises an eluent storage chamber, an inlet flow channel and an outlet flow channel; the inlet flow channel is connected between the eluent storage chamber and the inlet flow channel, and the connection is located between the first isolation valve and the sedimentation flow channel; the inlet flow channel and the outlet flow channel are both provided with a second isolation valve; and A mixing reaction unit, used for detecting microorganisms attached to microparticles; the liquid outlet channel is connected between the liquid outlet channel and the mixing reaction unit, and the connection is located between the first isolation valve and the sedimentation channel; the mixing reaction unit includes a pneumatic mixing chamber, a working liquid storage chamber, a reaction chamber and a cleaning liquid storage chamber, the working liquid storage chamber, the reaction chamber and the pneumatic mixing chamber are respectively connected through a working liquid channel and a mixed liquid channel, and the cleaning liquid storage chamber and the reaction chamber are connected through a cleaning liquid channel; the working liquid channel, the mixed liquid channel and the cleaning liquid channel are respectively provided with a third isolation valve, a fourth isolation valve and a fifth isolation valve; The pair of polarization electrodes are respectively arranged at the upper and lower sides of the area where the sedimentation channel is located, and are used to generate a polarization electric field perpendicular to the chip body.

2. A microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The width of the sedimentation channel is 50 to 1000 μm, and the height is 50 to 1000 μm.

3. A microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The sedimentation flow channel is a flow channel composed of a plurality of mutually connected quasi-concentric circular channels, and the distance between two adjacent quasi-concentric circular channels is 200-1000 μm.

4. A microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The gas inlet and the gas outlet are both arranged on the side of the chip body; and / or, The gas outlet is communicated with a micro pump located outside the microfluidic chip.

5. A microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The widths of the liquid inlet flow channel, the liquid outlet flow channel, the working liquid flow channel, the mixed liquid flow channel and the cleaning liquid flow channel are all 10 to 500 μm, and the heights are all 10 to 500 μm.

6. A microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The mixed liquid flow channel is further provided with a plurality of mixing chambers and a sixth isolating valve, and the plurality of mixing chambers are located between the fourth isolating valve and the sixth isolating valve.

7. A microfluidic chip for detecting microorganisms in the air according to claim 6, characterized in that: The mixing chamber is a spherical, hemispherical or ellipsoidal mixing chamber.

8. The microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The isolating valve is arranged inside the chip body, and includes a valve cavity, a valve cover located above the valve cavity, and a first elastic membrane located between the valve cavity and the valve cover, and the valve cavity is communicated with the corresponding flow channel; the chip body is also provided with a gas interface for connecting to an external air pressure controller, and the valve cavity is communicated with the gas interface through a gas microchannel; The air pressure controller is used to control the air pressure in the valve cavity, thereby making the first elastic membrane separate from or contact the valve cover to realize the opening or closing of the isolation valve.

9. A microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The pneumatic mixing chamber is arranged inside the chip body, and includes an upper valve cavity, a lower valve cavity and a second elastic membrane located between the upper valve cavity and the lower valve cavity; the upper valve cavity is communicated with the corresponding flow channel; the chip body is also provided with a gas interface for connecting to an external air pressure controller, and the lower valve cavity is communicated with the gas interface through a gas microchannel; The air pressure controller is used to control the air pressure in the lower valve cavity, thereby making the second elastic membrane contact with the lower valve cavity or the upper valve cavity to realize the opening or closing of the pneumatic mixing chamber.

10. The microfluidic chip for detecting microorganisms in the air according to claim 1, characterized in that: The chip body is made of one of polystyrene, polymethyl methacrylate, polydimethylsiloxane, polycarbonate, glass, quartz and silicon dioxide.

Images