A system and method for detecting microorganisms in water.

Abstract

This invention discloses an aquatic microbial detection system and method. The aquatic microbial detection system includes a water pretreatment unit, a microfluidic chip, a waste liquid collection unit, an optical detection unit, and a control unit. This invention utilizes a microfluidic chip for aquatic microbial detection. The use of a first six-way valve and a second six-way valve saves space required for piping. Through the rational design of each unit, the aquatic microbial detection system achieves miniaturization. Furthermore, each capture microwell of the microfluidic chip contains only one target microorganism. The optical detection system excites the captured target microorganisms with fluorescence, obtaining a fluorescence image showing the fluorescence emitted by each target microorganism. Therefore, this system can accurately detect the number of target microorganisms to the single digit.

Description

Technical Field

[0001] This invention belongs to the field of water sample pollutant monitoring technology, specifically relating to a water body microbial detection system and detection method. Background Technology

[0002] Various water bodies, especially polluted ones, contain abundant organic matter, providing ideal conditions for the growth of various microorganisms. Therefore, different water bodies harbor different organisms. The microorganisms in these water bodies mainly include algae, bacteria, and fungi. Ocean shipping is the most important mode of international logistics. Due to navigational safety and cargo transshipment needs, ocean-going vessels inevitably inject or discharge ballast water into or out of near-shore waters. Ballast water contains marine microorganisms, including planktonic plants and animals, bacteria, and viruses. The International Maritime Organization (IMO) estimates that more than 3,000 aquatic species are transported worldwide daily via ballast water. Over the past 20-30 years, the rate of non-native species introduced into the marine environment via ballast water is estimated at 30%, causing serious invasive species problems and being one of the main causes of global marine biodiversity loss. Invasive species, lacking natural predators in their new environments, will proliferate rapidly, threatening local aquatic biodiversity, disrupting the ecological balance between species in native waters, and causing significant environmental impacts. Therefore, it is crucial to reduce the risk of invasive non-native marine species and strengthen the protection of the marine environment and biodiversity. Therefore, conducting microbial testing in water bodies is expected to add new biological data to marine safety research, especially providing technical means for maritime supervision of ballast water discharge, and also providing scientific basis for marine environmental protection and the development and utilization of biological resources.

[0003] Existing microbial detection systems, such as CN104593475B, can count microbial colonies or detect microbial content at the order-of-magnitude level, but cannot achieve high-precision detection of small numbers of microorganisms. Summary of the Invention

[0004] The primary objective of this invention is to overcome the deficiencies of the prior art and provide a water microbial detection system.

[0005] Another object of the present invention is to provide a method for detecting microorganisms in water using the above-described water microbial detection system.

[0006] The technical solution of the present invention is as follows:

[0007] A water microbial detection system includes a water pretreatment unit, a microfluidic chip, a waste liquid collection unit, an optical detection unit, and a control unit;

[0008] The water pretreatment unit includes a water sample storage tank, a buffer solution storage tank, a first filter, and a second filter, wherein the pore size of the first filter is larger than that of the second filter.

[0009] The microfluidic chip has a capture channel with a start end and an end end at the two ends. The sidewall of the capture channel has several capture microwells, each of which can capture one microorganism to be tested.

[0010] The waste liquid collection unit includes a first waste liquid tank and a second waste liquid tank;

[0011] An optical detection unit includes a laser emitter and a fluorescence signal detector arranged opposite to each other;

[0012] The first six-way valve has a first to a sixth end arranged in a counterclockwise circumferential direction and a seventh end located in the middle. The first six-way valve has a first state and a second state: in the first state, the first end, the seventh end and the fifth end are connected in sequence; in the second state, the third end, the seventh end and the fifth end are connected in sequence.

[0013] The second six-way valve has a first to a sixth port arranged in a counterclockwise circumferential direction and a seventh port located in the middle. The second six-way valve has a first filtration state, a second filtration state, a first waste discharge state, and a second waste discharge state. In the first filtration state, the first port, the seventh port, and the second port are connected in sequence. In the second filtration state, the third port, the seventh port, and the fourth port are connected in sequence. In the first waste discharge state, the first port, the seventh port, and the fifth port are connected in sequence. In the second waste discharge state, the third port, the seventh port, and the fifth port are connected in sequence.

[0014] The water sample storage tank is connected to the first end via a first peristaltic pump. The buffer solution storage tank is connected to the third end via a second peristaltic pump. The fifth end is connected to the inlet of the first filter. The outlet of the first filter is connected to the first port. The inlet and outlet of the second filter are connected to the second and third ports of the second six-way valve, respectively. The fourth port is connected to the starting end via a third peristaltic pump. The fifth port is connected to the second waste liquid tank. The ending end is connected to the first waste liquid tank. The laser emitter and the fluorescence detector are respectively located on both sides of the microfluidic chip. The control unit is connected to the first filter, the second filter, the microfluidic chip, the laser emitter, and the fluorescence signal detector.

[0015] In a preferred embodiment of the present invention, the fluorescence detector receives fluorescence image data formed by the microfluidic chip and transmits it to the control unit. The fluorescence image data includes the wavelength, intensity, and number of fluorescence dots.

[0016] In a preferred embodiment of the present invention, the capture channels are in the form of several connected U-shapes, trapezoids, or broken lines.

[0017] In a preferred embodiment of the present invention, the microfluidic chip includes a microelectrode layer, and a capture channel is formed on the microelectrode layer.

[0018] In a preferred embodiment of the present invention, the pore size of the first filter is greater than or equal to the maximum particle size of the microorganism to be tested, and the pore size of the second filter is less than or equal to the minimum particle size of the microorganism to be tested.

[0019] In a preferred embodiment of the present invention, the first end and the seventh end or the seventh end and the fifth end are connected by a metering tube.

[0020] In a preferred embodiment of the present invention, the water microbial detection system further includes a cleaning solution storage tank, with the starting end branching to form a sample inlet channel and a cleaning channel. The sample inlet channel is connected to a second six-way valve via a third peristaltic pump, and the cleaning channel is connected to the cleaning solution storage tank via a fourth flow pump.

[0021] In a preferred embodiment of the present invention, the microfluidic chip has an injection port through which fluorescent reagent enters the capture channel.

[0022] In a preferred embodiment of the present invention, the control unit includes a controller and a host computer, the host computer being connected to the controller, and the controller being connected to the first filter, the second filter, the microfluidic chip, the laser emitter, and the fluorescence signal detector.

[0023] In a preferred embodiment of the present invention, the control unit includes a controller and a host computer, the host computer being connected to the controller, and the controller being connected to the first filter, the second filter, the microfluidic chip, the laser emitter, and the fluorescence signal detector.

[0024] A method for detecting microorganisms in water bodies, using the aforementioned water body microorganism detection system.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention utilizes microfluidic chips for aquatic microbial detection. The use of a first six-way valve and a second six-way valve saves space required for piping. Through the coordinated and rational design of each unit, the aquatic microbial detection system is miniaturized. Furthermore, each capture microwell of the microfluidic chip captures only one microorganism to be tested. The optical detection system excites the captured microorganisms with fluorescence, obtaining a fluorescence image showing the fluorescence emitted by each microorganism. Therefore, this system can accurately detect the number of microorganisms to be tested down to the single digit.

[0027] 2. In some preferred embodiments, a fluorescence signal detector detects the intensity and wavelength of the fluorescence to obtain information on the activity and species of the microorganism to be tested.

[0028] 3. In some preferred embodiments, the microfluidic chip combines hydrodynamic capture technology and dielectrophoretic capture technology, which has good separation and capture performance for individual microorganisms, thereby improving the accuracy of the water microbial detection system.

[0029] 4. This invention eliminates the need for PCR testing on the captured microorganisms, allowing direct detection of fluorescence emitted by a single microorganism, and thus requires less detection time. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the various units and their connections in the aquatic microbial detection system according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of the components and their control connection relationship with the control unit in the water microbial detection system of this invention.

[0032] Figure 3 This is a schematic diagram of the connection of the first six-way valve in the first state according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the connection of the first six-way valve in the second state according to an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the connection of the second six-way valve in the first filtration state according to an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the connection of the second six-way valve in the second filtration state according to an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the connection of the second six-way valve in the first waste discharge state according to an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the connection of the second six-way valve in the second waste discharge state according to an embodiment of the present invention;

[0038] Figure 9 This is a top view of the microfluidic chip in the water microbial detection system of this invention.

[0039] Figure reference numerals: 1-Water pretreatment unit, 11-Water sample storage tank, 12-Buffer solution storage tank, 13-First filter, 14-Second filter, 2-Microfluidic chip, 21-Capture channel, 211-Starting end, 2111-Sample inlet channel, 2112-Cleaning channel, 212-Termination end, 213-Capture microwell, 3-Optical detection unit, 31-Laser emitter, 32-Fluorescence signal detector, 41-First six-way valve, 411-First end, 412-Second end, 413-Third end, 414-Fourth end 415-Fifth end, 416-Sixth end, 417-Seventh end, 42-Second six-way valve, 421-First port, 422-Second port, 423-Third port, 424-Fourth port, 425-Fifth port, 426-Sixth port, 427-Seventh port, 43-First peristaltic pump, 44-Second peristaltic pump, 45-Third peristaltic pump, 46-Fourth peristaltic pump, 5-Waste liquid collection unit, 51-First waste liquid tank, 52-Second waste liquid tank, 6-Cleaning fluid storage tank, 7-Control unit, 71-Controller, 72-Host computer. Detailed Implementation

[0040] The technical solution of the present invention will be further explained and described below through specific embodiments. In this embodiment, "connection" is achieved through pipeline connection, and "control connection" includes wired control connection and wireless control connection.

[0041] Please see Figure 1 The water microbial detection system includes a water pretreatment unit 1, a microfluidic chip 2, an optical detection unit 3, a first six-way valve 41, a second six-way valve 42, a first peristaltic pump 43, a second peristaltic pump 44, a third peristaltic pump 45, a fourth peristaltic pump 46, a waste liquid collection unit 5, a cleaning liquid storage tank 6, and a control unit 7.

[0042] Among them, such as Figure 2 As shown, the water pretreatment unit 1 includes a water sample storage tank 11, a buffer solution storage tank 12, a first filter 13, and a second filter 14. The pore size of the first filter 13 is larger than that of the second filter 14. The inlet of the first filter 13 is connected to the water sample storage tank 11 and the buffer solution storage tank 12 respectively, and the outlet of the first filter 13 is connected to the second filter 14.

[0043] The microfluidic chip 2 has a capture channel 21, with a start end 211 and a stop end 212 at its two ends. The sidewall of the capture channel 21 has a number of capture microwells 213, each of which can capture one microorganism to be tested.

[0044] The optical detection unit 3 includes a laser emitter 31 and a fluorescence signal detector 32 arranged opposite to each other;

[0045] The first six-way valve 41 has a first to a sixth end (411-416) arranged sequentially in a counterclockwise circumferential direction and a seventh end 417 located in the middle. The first six-way valve 41 has a first state and a second state. In the first state, as... Figure 3 As shown, the first terminal 411, the seventh terminal 417, and the fifth terminal 415 are connected sequentially. In the second state, as... Figure 4 As shown, the third end 413, the seventh end 417, and the fifth end 415 are connected in sequence.

[0046] The second six-way valve 42 has a first to a sixth port (421-426) arranged in a counterclockwise circumferential direction and a seventh port 427 located in the middle. The second six-way valve 42 has a first filtration state, a second filtration state, a first waste discharge state, and a second waste discharge state. Figure 5 As shown, in the first filtering state, the first port 421, the seventh port 427, and the second port 422 are connected sequentially. Figure 6 As shown, in the second filtering state, the third port 423, the seventh port 427, and the fourth port 424 are connected sequentially. Figure 7 As shown, in the first waste state, the first port 421, the seventh port 427, and the fifth port 425 are connected sequentially. Figure 8 As shown, in the second waste state, the third port 423, the seventh port 427 and the fifth port 425 are connected in sequence.

[0047] Waste liquid collection unit 5 includes a first waste liquid tank 51 and a second waste liquid tank 52.

[0048] The water sample storage tank 11 is connected to the first end 411 via the first peristaltic pump 43. The buffer solution storage tank 12 is connected to the third end 413 via the second peristaltic pump 44. The fifth end 415 is connected to the inlet of the first filter 13. The outlet of the first filter 13 is connected to the first port 421. The inlet and outlet of the second filter 14 are connected to the second port 422 and the third port 423 of the second six-way valve 42, respectively. The fourth port 424 is connected to the starting end 211 via the third peristaltic pump 45. The fifth port 425 is connected to the second waste liquid tank 52. The ending end 212 is connected to the first waste liquid tank 51. The laser emitter 31 and the fluorescence detector 32 are respectively disposed on both sides of the microfluidic chip 2. The control unit 7 is connected to the first filter 13, the second filter 14, the microfluidic chip 2, the laser emitter 31, and the fluorescence signal detector 32.

[0049] The water pretreatment unit 1 includes a water sample storage tank 11, a buffer solution storage tank 12, a first filter 13, and a second filter 14. In this assembly, the water sample storage tank 11 contains the water sample to be tested, and the buffer solution storage tank 12 contains a buffer solution. The water sample and the buffer solution can enter the first filter 13 through a first six-way valve 41, driven by a first peristaltic pump 43 and a second peristaltic pump 44, respectively. The pore size of the first filter 13 is larger than that of the second filter 14. The first filter 13 and the second filter 14 constitute a sieving device to screen out microorganisms with particle sizes between the pore sizes of the first filter 13 and the second filter 14 from the water sample to be tested. In this embodiment, the pore size of the first filter 13 is 50 μm and the pore size of the second filter 14 is 10 μm. The water sample to be tested and the buffer solution are filtered by the first filter 13 and the second filter 14 to remove impurities with a particle size greater than 50 μm and impurities with a particle size less than 10 μm to obtain a test solution containing the microorganisms to be tested. After that, the test solution leaves the water pretreatment unit 1 through the second filter 14 and enters the microfluidic chip 2.

[0050] The microfluidic chip 2 has a microelectrode layer (not shown in the figure), and the microelectrode layer has trapping channels 21 formed thereon. For example... Figure 9 As shown, the capture channel 21 is roughly shaped as a series of interconnected U-shapes. The sidewall of the capture channel 21 has several capture microwells 213. The capture channel 21 has a starting end 211 and a ending end 212. The starting end 211 branches to form a sample inlet channel 2111 and a cleaning channel 2112. The sample inlet channel 2111 is connected to the second filter 14 through a third peristaltic pump 45. The cleaning channel 2112 is connected to the cleaning solution storage tank 6 through a liquid inlet channel.

[0051] Since the capture channels 21 are formed on the microelectrode layer and are multiple interconnected U-shaped structures, after an electric field is applied to the microfluidic chip 2, the microorganisms to be tested entering the microfluidic chip 2 are separated and captured by the capture microwells 213 under the combined action of dielectrophoresis and viscosity. Specifically, in this embodiment, since each capture microwell 213 can only accommodate one microorganism to be tested, when the test liquid flows in the capture channel 21, once the capture microwell 213 captures the microorganism to be tested, the microorganism to be tested occupies that capture microwell 213, and other microorganisms to be tested can only flow backward into the next capture microwell 213, and excess test liquid is discharged from the termination end 212.

[0052] In this embodiment, the microfluidic chip 2 captures the target microorganism through the combined effects of dielectrophoresis and viscosity. Therefore, the control unit 7 is connected to the microfluidic chip 2 to control the application of an electric field to the capture channel 21 by the microfluidic chip 2. In other possible implementations, the microfluidic chip 2 may not have a microelectrode layer; it only needs to form the capture channel 21. The microfluidic chip 2 may also capture the target microorganism through at least one of dielectrophoretic capture, magnetic capture, acoustic capture, viscous capture, and droplet capture.

[0053] The number of capture microwells 213 can be set according to the detection requirements. In this embodiment, the microfluidic chip 2 has 5000 capture microwells 213. Since the number of capture microwells 213 is limited, if the number of microorganisms to be tested in the test solution is greater than the number of capture microwells 213, the excess microorganisms to be tested will be discharged from the termination end 212 along with the test solution. If all the microorganisms to be tested are captured by the capture microwells 213, the water microbial detection system can count the microorganisms to be tested. If the number of microorganisms to be tested is greater than the number of capture microwells 213, it indicates that the number (density) of microorganisms to be tested in the water body exceeds the standard.

[0054] In addition, the microfluidic chip 2 also has an injection port (not shown in the figure), which is connected to the capture channel 21. The fluorescent reagent enters the capture channel 21 through the injection port and binds to the specific microorganisms to be tested in the capture channel 21.

[0055] Continue to refer to Figure 2 The optical detection unit 3 includes a laser emitter 31 and a fluorescence signal detector 32, which are respectively disposed on both sides of the microfluidic chip 2. The laser emitter 31 emits a laser beam into the microfluidic chip 2, exciting the test microorganisms bound to the fluorescent reagent to emit fluorescence. The fluorescence signal detector 32 detects the fluorescence and forms a fluorescence image, which records whether each capture microwell 213 in the microfluidic chip 2 emits light, as well as the intensity and wavelength of the fluorescence. The data collected by the fluorescence signal detector 32 is then transmitted to the control unit 7. By counting the luminescent capture microwells 213, the number of test microorganisms in the test solution can be obtained. The fluorescence intensity characterizes the activity of the test microorganisms in that capture microwell 213, and the wavelength characterizes the species of the test microorganisms.

[0056] The first end 411 of the first six-way valve 41 is connected to the water sample storage tank 11, the third end 413 is connected to the buffer solution storage tank 12, the fifth end 415 is connected to the first filter 13, and the sixth end 416 and the second end 412 are connected through the metering tube 417 (or metering ring).

[0057] When the first six-way valve 41 is in the first state, the water sample to be tested enters the first six-way valve 41 from the first end 411 under the drive of the first peristaltic pump 43, and flows sequentially through the seventh end 417 and the fifth end 415 into the first filter 13. When the first six-way valve 41 is in the second state, the buffer solution can enter the first six-way valve 41 from the third end 413 under the drive of the second peristaltic pump 44, and flow sequentially through the seventh end 417 and the fifth end 415 into the first filter 13.

[0058] The first port 421 of the second six-way valve 42 is connected to the sample outlet of the first filter 13, the second port 422 is connected to the sample inlet of the second filter 14, the third port 423 is connected to the sample outlet of the second filter 14, the fourth port 424 is connected to the sample inlet channel 2111 of the starting end 211, and the fifth port 425 is connected to the second waste liquid pool 52.

[0059] When the second six-way valve 42 is in the first filtration state, the mixed solution of the water sample to be tested and the buffer solution obtained after the large-particle impurities are removed by the first filter 13 flows sequentially through the first port 421, the seventh port 427 and the second port 422 into the second filter 14.

[0060] When the second six-way valve 42 is in the second filtration state, it is further filtered by the second filter 14 to remove impurities and microorganisms with excessively small particle size. Then it flows through the third port 423, the seventh port 427 and the fourth port 424 in sequence, and enters the capture channel 21 from the sample inlet channel 2111.

[0061] When the second six-way valve 42 is in the first waste discharge state, the first port 421, the seventh port 427 and the fifth port 425 are connected in sequence to discharge the waste in the first filter 13 to the second waste liquid pool 52.

[0062] When the second six-way valve 42 is in the second waste discharge state, the third port 423, the seventh port 427 and the fifth port 425 are connected, and the waste in the second filter 14 is discharged to the second waste liquid pool 52.

[0063] The cleaning fluid reservoir 6 is used to store the cleaning fluid. The cleaning fluid reservoir 6 is connected to the cleaning channel 2112 of the microfluidic chip 2. The cleaning fluid enters the capture channel 21 through the cleaning channel 2112 to clean the microfluidic chip 2.

[0064] The waste liquid collection unit 5 includes a first waste liquid tank 51 and a second waste liquid tank 52. The first waste liquid tank 51 is connected to the terminal end 212 of the capture channel 21 and is used to collect the test liquid, buffer solution, and cleaning liquid discharged from the capture channel 21. The second waste liquid tank 52 is connected to the first filter 13 and the second filter 14 respectively via a second six-way valve 42, and is used to collect the waste liquid or filter residue from the first filter 13 and the second filter 14.

[0065] The control unit 7 includes a controller 71 and a host computer 72. The host computer 72 is connected to the controller 71, and the controller 71 is connected to the microfluidic chip 2, the fluorescence signal detector 32, the first filter 13, the second filter 14, the first peristaltic pump 43, the second peristaltic pump 44, the third peristaltic pump 45, and the fourth peristaltic pump 46. The host computer 72 is used to issue control commands to the controller 71 and receive data transmitted by the controller 71. The controller 71 is used to control the microfluidic chip 2, the fluorescence signal detector 32, the first filter 13, the second filter 14, the first peristaltic pump 43, the second peristaltic pump 44, the third peristaltic pump 45, and the fourth peristaltic pump 46.

[0066] In addition, the aquatic microbial detection system also includes a power supply (not shown in the figure) to power the aforementioned components.

[0067] The following describes the specific operation of the water microbial detection method using the above-mentioned water microbial detection system (the operation of each component is controlled by the host computer 72 through the controller 71, and will not be described in detail below):

[0068] Set the first six-way valve 41 to the first state, turn on the first peristaltic pump 43, and drive the water sample to be tested through the first six-way valve 41 into the first filter. Turn off the first peristaltic pump 43, switch the first six-way valve 41 to the second state, set the second six-way valve 42 to the first filtration state, turn on the second peristaltic pump 44 and the first filter 13, and the buffer solution enters the first filter 13 and mixes with the water sample to be tested to form a mixed solution. The first filter 13 removes impurities with larger particle sizes (in this embodiment, larger particle size refers to a particle size greater than 50 μm of the pore size of the first filter 13). Switch the second six-way valve 42 to the second filtration state, turn on the second filter 14, and the mixed solution flows sequentially through the first filter 13, the second six-way valve 42 and the second filter 14. After filtration by the second filter 14, a test solution containing microorganisms of a specific particle size (in this embodiment, the specific particle size is 10 μm-50 μm) is obtained.

[0069] The second peristaltic pump 44 is turned off, and the third peristaltic pump 45 is turned on, driving the test solution from the injection channel 2111 into the capture channel 21 and flowing towards the termination end 212. During the flow, the solution is captured by the capture microwells 213 located on the side wall of the capture channel 21. Each capture microwell 213 captures only one analyte microorganism, and the remaining analyte microorganisms continue to flow towards the termination end 212 and are then captured or discharged with the test solution to the first waste liquid pool 51. After the injection is completed, the third peristaltic pump 45 is turned off, and the fourth peristaltic pump 46 is turned on, driving the cleaning solution from the cleaning channel 2112 into the capture channel 21 to flush the remaining analyte microorganisms in the main channel of the capture channel 21 to the first waste liquid pool 51, so that the microfluidic chip 2 only contains analyte microorganisms in the capture microwells 213.

[0070] Turn off the fourth peristaltic pump 46, add fluorescent reagent into the capture channel 21 through the injection port so that the fluorescent reagent binds to the microorganism to be tested and forms a fluorescent label on or inside the microorganism. Then turn on the fourth peristaltic pump 46 to flush out excess fluorescent reagent.

[0071] The fourth peristaltic pump 46 is turned off, and the optical detection unit 3 is turned on, causing the laser emitter 31 to emit a laser towards the microfluidic chip 2. The microorganisms to be tested are excited to fluoresce. The fluorescence signal detector 32 receives and processes the fluorescence signal to obtain a fluorescence image of the microfluidic chip 2. Then, the fluorescence signal detector 32 transmits the fluorescence image to the host computer 72 through the controller 71. The host computer 72 analyzes the number of fluorescent spots, the intensity of the fluorescence, and the wavelength in the fluorescence image to determine the number, activity, and type of the microorganisms to be tested in the test solution.

[0072] In addition, when a large amount of waste accumulates in the first filter 13 or the second filter 14 and needs to be discharged, simply switch the second six-way valve 42 to the first waste discharge state or the second waste discharge state.

[0073] The above method can achieve automated detection of microorganisms in water by setting relevant programs in the host computer, or users can issue instructions for each operation separately in the host computer.

[0074] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A system for detecting microorganisms in water, characterized in that, It includes a water pretreatment unit, a microfluidic chip, a waste liquid collection unit, an optical detection unit, and a control unit; The water pretreatment unit includes a water sample storage tank, a buffer solution storage tank, a first filter, and a second filter. The pore size of the first filter is larger than that of the second filter. The first filter and the second filter screen out microorganisms of the test size from the water sample and introduce them into the microfluidic chip. The microfluidic chip is equipped with a capture channel, which is in the form of several connected U-shaped, trapezoidal or zigzag-shaped channels. The two ends of the capture channel are the start end and the end end, respectively. The sidewall of the capture channel has several capture microwells, and each capture microwell can capture one microorganism to be tested. The waste liquid collection unit includes a first waste liquid tank and a second waste liquid tank; The optical detection unit includes a laser emitter and a fluorescence signal detector arranged opposite each other; The first six-way valve has a first to a sixth end arranged in a counterclockwise circumferential direction and a seventh end located in the middle. The first six-way valve has a first state and a second state: in the first state, the first end, the seventh end and the fifth end are connected in sequence; in the second state, the third end, the seventh end and the fifth end are connected in sequence. The second six-way valve has a first to a sixth port arranged in a counterclockwise circumferential direction and a seventh port located in the middle. The second six-way valve has a first filtration state, a second filtration state, a first waste discharge state, and a second waste discharge state. In the first filtration state, the first port, the seventh port, and the second port are connected in sequence. In the second filtration state, the third port, the seventh port, and the fourth port are connected in sequence. In the first waste discharge state, the first port, the seventh port, and the fifth port are connected in sequence. In the second waste discharge state, the third port, the seventh port, and the fifth port are connected in sequence. The water sample storage tank is connected to the first end via a first peristaltic pump. The buffer solution storage tank is connected to the third end via a second peristaltic pump. The fifth end is connected to the inlet of the first filter. The outlet of the first filter is connected to the first port. The inlet and outlet of the second filter are connected to the second and third ports of the second six-way valve, respectively. The fourth port is connected to the starting end via a third peristaltic pump. The fifth port is connected to the second waste liquid tank. The ending end is connected to the first waste liquid tank. The laser emitter and the fluorescence detector are respectively located on both sides of the microfluidic chip. The control unit is connected to the first filter, the second filter, the microfluidic chip, the laser emitter, and the fluorescence signal detector.

2. The aquatic microbial detection system as described in claim 1, characterized in that, The fluorescence detector receives fluorescence image data generated by the microfluidic chip and transmits it to the control unit. The fluorescence image data includes the wavelength, intensity, and number of fluorescence dots.

3. The aquatic microbial detection system as described in claim 1, characterized in that, The microfluidic chip includes a microelectrode layer, and the capture channel is formed on the microelectrode layer.

4. The aquatic microbial detection system as described in claim 1, characterized in that, The pore size of the first filter is greater than or equal to the maximum particle size of the microorganism to be tested, and the pore size of the second filter is less than or equal to the minimum particle size of the microorganism to be tested.

5. The aquatic microbial detection system as described in claim 1, characterized in that, The first end and the seventh end, or the seventh end and the fifth end, are connected by a metering tube.

6. The aquatic microbial detection system as described in claim 1, characterized in that, The water microbial detection system also includes a cleaning solution storage tank. The starting end branches to form a sample inlet channel and a cleaning channel. The sample inlet channel is connected to a second six-way valve through a third peristaltic pump, and the cleaning channel is connected to the cleaning solution storage tank through a fourth flow pump.

7. The aquatic microbial detection system as described in claim 1, characterized in that, The microfluidic chip has an injection port through which fluorescent reagent enters the capture channel.

8. The aquatic microbial detection system as described in claim 1, characterized in that, The control unit includes a controller and a host computer. The host computer is connected to the controller, and the controller is connected to the first filter, the second filter, the microfluidic chip, the laser emitter, and the fluorescence signal detector.

9. A method for detecting microorganisms in water, characterized in that, The detection is performed using the water microbial detection system according to any one of claims 1-8.

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