Portable Plankton Monitoring Device Based on Microfluidic Sampling and Multi-Perspective Imaging

Abstract

The portable plankton monitoring device based on microfluidic sampling and multi-view imaging belongs to the field of marine ecological environment monitoring technology. It includes a sealed cabin with a water inlet and a drain outlet, and the sealed cabin is equipped with a microscopic imaging device, a flip motor, a water pumping device, a water storage tank, an injection pump, a control module, a data transmission module and a transmission line; the microscopic imaging device integrates a detachable flow glass slide, a detachable biological microscope lens, a global motion camera and a light source, and the flip motor drives the microscopic imaging device to a vertical or horizontal orientation. The device adopts an integrated monitoring solution that combines "microfluidic automatic sampling-multi-view microscopic imaging" in one, solving the problems commonly found in existing plankton monitoring methods, such as reliance on manual sampling, cumbersome detection procedures, unclear flow glass slide imaging, and difficulty in capturing the multi-dimensional structural characteristics of plankton cells. It achieves a reduction in the volume of the imaging device and improves the comprehensiveness and accuracy of plankton morphological identification.

Description

Technical Field

[0001] The present invention relates to the field of in-situ real-time observation of plankton used on offshore platforms, and in particular to a portable plankton monitoring device based on microfluidic sampling and multi-view imaging, belonging to the technical field of marine ecological monitoring. Background Art

[0002] Plankton, a microscopic group of organisms that inhabit ocean waters and include plankton and zooplankton, is a vital component of primary marine production and the structural stability of marine ecosystems. Plankton fixes carbon dioxide and releases oxygen through photosynthesis, which is crucial for maintaining the ecological balance of water bodies and participating in the global carbon cycle. However, as the trend of ocean eutrophication intensifies, some plankton populations may experience explosive growth in a short period of time, triggering severe marine ecological disasters such as red tides and green tides (such as the Enteromorpha disaster), resulting in the destruction of fishery resources, deterioration of water quality, and imbalance in the ecosystem. Therefore, achieving real-time monitoring of plankton and disaster warnings has become a key technical requirement in the current field of marine ecological and environmental monitoring.

[0003] Existing technologies for detecting planktonic cells mainly include laboratory offline analysis and on-site in-situ monitoring, but both have obvious technical limitations: (1) Traditional laboratory detection methods mainly rely on manual sampling and manual analysis with optical microscopes. The operation process is cumbersome, the detection cycle is long, and there is a lack of real-time performance. In addition, due to the single-view imaging method, it is difficult to effectively obtain the three-dimensional morphological information of cells, which makes it difficult to accurately distinguish between similar species, affecting the accuracy of species classification and biomass estimation; (2) Existing in-situ automated monitoring devices such as ZL 2019106547768 use multiple cameras and circulation units to shoot cells, without considering the depth of field of the camera, resulting in low imaging clarity, the use of multiple cameras, and redundant imaging devices; its circulation unit is simply a glass container made of glass material, which is large in size and does not consider the matching problem between the circulation unit and the camera; the camera lens is far away from the glass slide, which is not conducive to imaging of tiny cells; (3) Existing systems are generally large in size, high in power consumption, and rely on external power supply and a stable environment. They are not suitable for integrated deployment on mobile platforms such as buoys and unmanned boats, and are difficult to meet the long-term online monitoring needs in marine field environments. The above technical bottlenecks restrict the monitoring efficiency and intelligence level of planktonic cells in key application scenarios such as marine disaster warning, ecological assessment, and pollution tracking. There is an urgent need for a new monitoring technology solution that integrates miniaturization, intelligence, and real-time capabilities. Summary of the Invention

[0004] To enable real-time monitoring of changes in plankton abundance and species in designated sea areas, as well as real-time early warning of marine biohazards, this invention provides a portable plankton monitoring device based on microfluidic sampling and multi-view imaging for use on marine platforms. This device overcomes the shortcomings of traditional in situ plankton observation equipment, enabling marine researchers to obtain real-time information on plankton abundance and population distribution, providing active support for the prevention and control of marine hazards such as enteromorpha and green tides.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0006] A portable plankton monitoring device based on microfluidic sampling and multi-view imaging is characterized by comprising a sealed cabin with a water inlet and a water outlet on the cabin body, wherein the sealed cabin is provided with a microscopic imaging device, a rotating motor, a water pumping device, a water storage tank, an injection pump, and a control circuit including a data transmission module;

[0007] The microscopic imaging device integrates optical illumination, autofocus, microscopy, and imaging, and includes a C-shaped frame with a global motion camera installed. A light source is installed at one end of the C-shaped frame, and a detachable flow-through glass slide and a detachable biological microscope lens are installed at the other end. The flow-through glass slide is located between the light source and the biological microscope lens and is perpendicular to the emission direction of the light source. The biological microscope lens is directly facing the emission direction of the light source. The focusing method uses an electric lifting platform to control the distance between the biological microscope lens and the flow-through glass slide. The optical path of the global motion camera is perpendicular to the optical path of the biological microscope lens, and imaging is performed in a reflective manner.

[0008] The rotating motor shaft is connected to the middle of the outer side of the C-shaped frame and drives the microscopic imaging device to make the circulating glass slide circulate in two ways: vertically and horizontally;

[0009] The pumping device pumps seawater from the water inlet to the water storage tank, and the injection pump pumps water from the water storage tank to the flow glass and then discharges it through the drain port. The injection pump and the flow glass, and the flow glass and the drain port are connected by hoses.

[0010] The control circuit uses the data transmission module to transmit the images taken by the microscopic imaging device to the host computer.

[0011] The biological microscope lenses of the microscopic imaging device are equipped with four groups of microscope lenses: 4x, 10x, 20x, and 40x.

[0012] The inner diameter width and depth of the flow glass slide are designed according to the depth of field of the global motion camera, that is, the width and depth are within the camera field of view and depth of field.

[0013] When used with a 10x lens, a cubic quartz glass tube with an inner diameter of 48*0.8*0.4mm in length, width and height is designed to capture clear multi-layered cells.

[0014] The water inlet is provided with a filter screen, and a solenoid valve is provided between the water inlet and the water pumping device.

[0015] The injection volume of the injection pump is 1.25 ml, the fixed speed of each step is 6.25 ul / min, and the speed switching of 1-300 steps can be achieved.

[0016] The injection pump rate is set to 25ul / min for the best extraction effect. One cycle takes about 30 minutes, and 36 ml of liquid can be extracted per day.

[0017] The pumping device extracts seawater to obtain the original sample liquid, which is filtered through a 200 μm filter to remove impurities and enters the water storage tank.

[0018] A high-precision syringe pump precisely controls the flow rate of the cell suspension, enabling stable and clear flow cytometric images to be obtained within the microfluidic channel. Specifically, the outlet of the reservoir is connected to the inlet of the flow slide via a flexible connecting hose, and the syringe pump is connected to the outlet of the flow slide, forming a flow channel to ensure continuous and uniform cell flow during observation. To flexibly control the flow rate of planktonic cells and ensure clear imaging of planktonic cells, a dynamic extraction method combining fast and slow pumping is employed to enable multi-angle flow cytometric observation of planktonic cells.

[0019] The described microscopic imaging device integrates optical illumination, autofocus, microscopy, and videography. It boasts a compact structure, high functional integration, and strong adaptability, enabling multi-view, high-resolution imaging of flowing cell samples. The biomicroscope lens is housed internally, with its top facing the flow chip, enabling precise focusing. It also provides an LED light source and a built-in variable aperture diaphragm to prevent image flicker. Rotating the entire imaging module enables both horizontal and vertical observation, transmitting cell images in real time and capturing the morphological characteristics of planktonic cells from multiple perspectives.

[0020] Furthermore, to facilitate regular replacement of the flow-through slide, a flexible screw is used for mounting. The camera and lens optical paths are connected by reflection, positioned at the bottom of the C-shaped frame. This reduces the distance between the camera and the object while maintaining the same optical path, thus reducing the size of the imaging device and achieving a compact design.

[0021] The control circuit can use conventional components and transmit the collected data to the host computer through an integrated data transmission module. After the host computer transmits the image acquired by the camera to the intelligent model via the data transmission line, it detects and tracks in real time, and outputs the type and number of plankton through the tracking and counting function. The tracking, counting and analysis results of the plankton are then sent to laboratory researchers to facilitate the researchers to further calculate parameters such as the planktonic cell concentration.

[0022] The device is powered by a combination of batteries and electricity from the offshore platform. An internal power supply unit is connected to each device and to an external power source via wires. Under normal circumstances, this power supply provides power to the devices, while the batteries provide power under special circumstances. The sealed cabin adopts a watertight structure, ensuring that all devices can operate normally even in inclement weather.

[0023] The present invention customizes the design of the imaging module. Compared with the imaging device of the existing floating detection equipment, the microscopic imaging device of the present invention removes multiple duplicate cameras and circulation slides, and only retains one lens and one camera to achieve multi-angle shooting and alleviate the problem of slide clogging, which greatly compresses the overall space of the equipment and makes it possible to be portable. For microfluidic observation of planktonic cells, the circulation slide is embedded in the imaging module to ensure the quality of the observed planktonic cells. In addition, by flexibly rotating the imaging module, dual-angle observation in the horizontal and vertical directions can be achieved to obtain the characteristics of planktonic cells from different perspectives. In addition, in view of the existing technologies such as 2019106547768,

[0024] This invention simultaneously accomplishes both planktonic data collection and monitoring. Firstly, a microfluidics-based automated sampling system and a rotating dual-view microscopy module are used to collect high-quality planktonic cell images and construct a dataset for deep learning model training. Secondly, this system is combined with existing deep learning-based multi-target real-time tracking models for monitoring and analysis.

[0025] This invention proposes a portable plankton monitoring device based on microfluidic sampling and multi-view microscopic imaging. This device utilizes a microfluidic, integrated microscopic imaging device to achieve efficient plankton sample collection, full-view imaging, and intelligent identification and analysis. Through its integrated design, it can be deployed in field marine environments to enable in-situ monitoring of plankton, dynamic tracking and counting of multiple targets, and real-time transmission of detection data to laboratory terminals via wireless or wired networks. This effectively overcomes the shortcomings of existing technologies in terms of intelligence, precision, and adaptability, and enhances the technical level and application breadth of marine ecological monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall appearance structure of the circulation slide of the present invention when it is turned to a horizontal state.

[0027] Figure 2 It is a schematic diagram of the overall appearance structure of the circulation glass of the present invention when it is rotated to a vertical state.

[0028] Figure 3 It is a stereoscopic diagram of the microscopic imaging device of the present invention when the observation direction is horizontal.

[0029] Figure 4It is a stereoscopic diagram of the microscopic imaging device of the present invention when it is in a vertical observation direction.

[0030] Figure 5 It is a schematic diagram of the internal structure of the microscopic imaging device of the present invention.

[0031] Figure 6 It is a schematic diagram of a microscopic imaging device with a partial cross-section.

[0032] Among them, 1 is a hose, 2 is a pumping device, 3 is a water storage tank, 4 is a rotating motor, 5 is a global motion camera, 6 is a biological microscope lens, 7 is a circulation slide, 8 is a light source, 9 is a C-shaped frame, 10 is a syringe pump, 11 is a control circuit, 12 is a frame, 13 is a sealed cabin, 14 is a microscopic imaging device, 15 is an electric lifting platform, 16 is a light source driving power supply, and A is a circulation slide installation position. DETAILED DESCRIPTION

[0033] like Figure 1-6 As shown, a portable plankton monitoring device based on microfluidic sampling and multi-view imaging includes a sealed cabin 13 with a water inlet and a drain on the cabin body, and a microscopic imaging device 14, a rotating motor 4, a pumping device 2, a water storage tank 3, an injection pump 10, a control circuit 11 containing a data transmission module, and a transmission line are installed in the sealed cabin 13.

[0034] The sealed chamber 13 is a watertight structure. It is connected to the outside world via a power transmission line for power supply, transmits data to the outside world via a data transmission module, and collects and discharges sample liquids through a water inlet and outlet. The sealed chamber 13 is divided into three spaces: the top is the water pumping and storage area, the middle area is the microscopic imaging device area, and the bottom area is where the syringe pump 10, control circuit 11, and power supply module are located.

[0035] The pumping device 2 can be equipped with a filter screen, and the water storage tank 3 has a capacity of 1-2L and is connected to the pumping device 2 through a hose 1. A solenoid valve is connected below the water storage tank 3, and water storage and drainage are controlled by controlling the switch of the solenoid valve.

[0036] A high-precision syringe pump 10 is used to precisely control the flow rate of the cell suspension. An ultra-macro biological microscope lens 6 is used in conjunction with an ultra-thin flow slide 7 at close range to clearly capture multiple layers of cells, ensuring stable, clear flow cytometric images within the slide channel. The water inlet of the flow chip 7 is connected to the outlet of the water storage tank 3 via a flexible connecting hose 1, and the syringe pump 10 is connected to the outlet of the flow slide 7. The flow slide 7 utilizes a 48×0.8×0.4 mm microfluidic channel structure made of a square-cross-section transparent material, exhibiting excellent optical imaging performance and fluid stability. This slide structure can be modularly adjusted based on the camera's depth of field and the observation requirements of different cell particle sizes, supporting the rapid replacement of channel sizes of different specifications, taking into account the imaging requirements of both tiny cells and large microorganisms. This flow control scheme not only achieves high-precision control of cell movement but also provides a stable and reliable fluid foundation for subsequent multi-view imaging and intelligent recognition.

[0037] like Figure 3-6 As shown, the microscopic imaging device 14 integrates key components such as optical illumination, focusing, and microscopic imaging. The optical illumination utilizes a high-power LED light source as the primary illumination component, with the center point of the LED light source adjustable to accommodate varying field of view requirements. The light source 8 is driven by an independent power supply (light source driver 16) and supports dynamic brightness control by a host computer program, enabling multi-level brightness adjustment and significantly improving image quality and contrast. The focusing device is equipped with a motorized lift 15 to control the distance between the biological microscope lens 6 and the flow slide 7. Its repeatability is better than 0.001mm, with a maximum spacing of 26.1mm. It supports computer-controlled autofocus, enabling fast response and stable imaging, meeting the high-precision requirements of long-term continuous operation and automatic recognition processes. To further reduce the size of the imaging device, the camera can be directly embedded in the base of the C-shaped frame 9. It supports image sensors up to 2 / 3 inches in size, and the interface utilizes a standardized C-Mount thread structure, allowing for replacement and expansion. The microscopic imaging device 14 features a built-in center calibration mechanism and establishes a stable connection with the model computing device via a high-speed data transmission line, ensuring efficient transmission and synchronous processing of image data. Microscopic imaging device 14 utilizes an inverted microscope structure, offering excellent sample compatibility and supporting a variety of objective lens specifications (including but not limited to 4X, 10X, 20X, and 40X). These lenses can be flexibly changed based on the target cell type, meeting observation requirements of varying resolutions and fields of view. The aforementioned functional modules are encapsulated and secured within sealed chamber 13 via a highly integrated mechanical structure. The entire device is equipped with an automated rotary drive structure, primarily driven by a rotary motor 4. This allows for multi-angle rotation of the flow-through chip without compromising imaging stability, thereby capturing multi-view image features of the target cells.

[0038] The microscopic imaging device 14 is embedded in the customized flow glass slide 7 and integrated with it to realize the flow observation of floating cells. This device can change the observation angle by automatic rotation, and flexibly realize the horizontal or vertical shooting of cells. The imaging effect is better under the horizontal flow state, but a certain degree of blockage will occur. The present invention solves this problem well, taking into account the needs of multi-angle shooting and anti-blocking. On the one hand, this multi-angle rotation design can capture the morphological characteristics of floating cells from multiple angles; on the other hand, the use of vertical observation combined with high-speed flushing of the injection pump can also alleviate the problem of liquid blockage. By automatically alternating sampling and observation in the horizontal and vertical directions, long-term unattended observation can be achieved. In addition, compared with previous imaging devices, this miniaturized single camera and glass slide packaging combination can also reduce the volume of the microscopic imaging device to 1 / 3 of the traditional microscope system, thereby compressing the overall volume of the equipment, facilitating portable multi-scene applications.

[0039] The host computer controls the status of all devices and deploys a deep learning model. Camera images are used to identify the species and abundance of plankton in the host computer using a plankton detection, tracking, and counting algorithm. The host computer can be located on an offshore platform or on land, or installed in a sealed cabin 13. Monitoring results are transmitted in real time via the Beidou short message transmitter 1 within the data transmission device.

[0040] The device is powered by a battery or connected to an external power source through a power supply line. Under normal circumstances, the external power source is used to power the device first, and the battery provides power to the device under special circumstances.

[0041] like Figure 1 、 2 The sealed cabin 13 is a watertight structure, and the external frame 12 is used to construct the required shape and size and is sealed with a baffle.

[0042] The pumping device 2 includes a pump connected to the water inlet via a hose 1. Seawater is first pumped into a water storage tank 3, which has a filter screen and a solenoid valve and a capacity of 1 to 2 L for storing sample liquid after impurities are filtered out.

[0043] The water storage tank 3 is connected to the inlet end of the circulation slide 7 through a hose 1, and the outlet end of the circulation slide 7 is connected to the injection pump 10 through a hose 1. A drain pipe is connected below the injection pump 10, and the tested seawater sample is discharged through the drain port.

[0044] To address depth of field issues and observe clear laminar cells, depth of field calculations must consider the entire imaging system, including the microscope lens and camera. For example, a 500-pixel 1 / 3-inch CCD / CMOS camera has a minimum resolution of d = (4.8 * 3.6 / 5,000,000)^0.5 = 0.001859mm = 1.859 microns. Compared to previous equipment, to further reduce the size of the flow slide, a global motion camera is used in conjunction with an ultra-macro microscope lens for close-up observation of the slide. Based on the camera's depth of field requirements, the slide's width and thickness are designed to fit within the camera's depth of field. Testing has shown that a cube slide with an inner diameter of 48*0.8*0.4mm, when paired with a 10x lens, can capture clear images of multilayered cells.

[0045] Syringe pump 10 uses a 1.25ml syringe with a fixed speed of 6.25ul / min per step, allowing for a range of speeds from 1 to 300. Testing has shown that a rate of 25ul / min provides optimal extraction results, with a cycle lasting approximately 30 minutes, allowing 36ml of liquid to be extracted per day. Syringe pump 10 also provides both pumping and drainage functions, pumping the filtered sample solution obtained in the previous step onto the flow slide 7. Adjusting the speed of syringe pump 10 controls the flow rate of the planktonic cells, ensuring clear capture of the planktonic cells by the camera. The flow rate of syringe pump 10 is adjusted based on the specifications of the flow slide and the size of the planktonic organisms.

[0046] The control circuit is connected to the injection pump, the electromagnetic valve, and the microscopic imaging device 14 through a transmission line, controls each device through serial communication, and is connected to the power supply device through an electric energy transmission line.

[0047] The power supply can be a combination of batteries and external power supply. Under normal circumstances, the external power supply is preferred to power the equipment; the battery provides power for the equipment under special circumstances.

[0048] The working process of the present invention is as follows:

[0049] (1) After connecting the sealed cabin 13 to the external power supply, turn on the equipment switch.

[0050] (2) Put the pumping pipe into the water to prepare for collecting seawater, and make the following operations fully automated.

[0051] (3) The pumping device 2 extracts a certain amount of seawater and sends it into the water storage tank 3.

[0052] (4) The seawater is filtered through a 200 μm filter to remove impurities and allowed to stand for a period of time.

[0053] (5) The syringe pump 10 draws the filtered seawater sample into the cubic flow glass slide 7 with an inner diameter of 48*0.8*0.4 mm.

[0054] (6) The global motion camera 5 in the microscopic imaging device 14 starts to capture images of the circulation slide 7 in the horizontal flow state.

[0055] (7) After a period of time, the microscope imaging device 14 is automatically rotated by the rotating motor 4 to observe the image in the circulation slide 7 under the horizontal flow state.

[0056] (8) The image is transmitted to the host computer, and the AI edge computing module in the model computing device embedded in the host computer runs a detection, tracking and counting model on the plankton image to obtain the species and quantity of plankton and the data analysis visualization results.

[0057] (9) Send the types and quantities of plankton and the analysis results to the researchers in the laboratory in the form of short messages.

[0058] (10) Open the solenoid valve, and the injection pump 10 will drain all the water in the water storage tank 3 and flush the circulation glass slide 7 in the vertical state.

[0059] The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. A portable plankton monitoring device based on microfluidic sampling and multi-view imaging, characterized by The sealed cabin (13) includes a water inlet and a water outlet provided on the cabin body, wherein the sealed cabin (13) is provided with a microscopic imaging device (14), a rotating motor (4), a water pumping device (2), a water storage tank (3), an injection pump (10), and a control circuit (11) including a data transmission module; The microscopic imaging device (14) integrates optical illumination, automatic focusing, microscopy, and imaging, and includes a C-shaped frame (9) on which a global motion camera (5) is installed. A light source (8) is installed at one end of the C-shaped frame (9), and a detachable circulation glass slide (7) and a detachable biological microscope head (6) are installed at the other end. The circulation glass slide (7) is located between the light source (8) and the biological microscope head (6) and is perpendicular to the emission direction of the light source (8). The biological microscope head (6) is directly facing the emission direction of the light source (8). The focusing method is to control the distance between the biological microscope head (6) and the circulation glass slide (7) by an electric lifting platform (15). The optical path of the global motion camera (5) is perpendicular to the optical path of the biological microscope head (6), and imaging is performed in a reflection manner. The rotating shaft of the rotating motor (4) is connected to the middle of the outer side of the C-shaped frame (9), and drives the microscopic imaging device (14) to make the circulating glass slide (7) circulate in two ways: vertically and horizontally; The pumping device (2) pumps seawater from the water inlet to the water storage tank (3), and the injection pump (10) pumps water in the water storage tank (3) to the circulation glass (7) and then discharges the water through the drain outlet. The injection pump (10) and the circulation glass (7), as well as the circulation glass (7) and the drain outlet are connected by a hose (1); The control circuit (11) uses the data transmission module to transmit the image captured by the microscopic imaging device (14) to the host computer.

2. The device according to claim 1, characterized in that The biological microscope lens (6) of the microscopic imaging device (14) is equipped with four groups of microscope lenses: 4x, 10x, 20x, and 40x.

3. The device according to claim 1, characterized in that The inner diameter width and depth of the circulation glass slide (7) are designed according to the depth of field of the global motion camera (5), that is, the width and depth are within the camera field of view and depth of field.

4. The device according to claim 3, characterized in that it is combined with When using a 10x lens, a cubic quartz glass tube with an inner diameter, length, width and height of 48*0.8*0.4mm is designed to capture clear multi-layered cells.

5. The device according to claim 1, characterized in that The water inlet is provided with a filter screen, and a solenoid valve is provided between the water inlet and the pumping device (2).

6. The device according to claim 1, characterized in that The injection volume of the injection pump (10) is 1.25 ml, the fixed speed of each step is 6.25 ul / min, and the speed switching of 1-300 steps can be achieved.

7. The device according to claim 6, characterized in that The injection pump (10) has the best extraction effect when the rate is set to 25ul / min. One cycle takes 30 minutes, and 36 ml of liquid can be extracted per day.

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