A bioaerosol automated monitoring detection cascade control system

Abstract

This invention discloses an automated monitoring and detection cascade control system for bioaerosols, comprising a cascaded monitoring and detection unit and an automatic control unit. The cascaded monitoring and detection unit includes: a first-level monitoring module, a bioaerosol monitor based on laser-induced fluorescence technology (aerosol fluorescent particle monitor); a second-level monitoring module, a bioaerosol live-cell monitor based on ATP fluorescence detection technology (aerosol live-cell ATP monitor); and a third-level detection module, a bioaerosol nucleic acid detector based on microfluidic PCR technology (an integrated bioaerosol detection and nucleic acid detection system). The automatic control unit uses high and low level switching signals to achieve sequential instantaneous triggering of the three levels of equipment, completing automated hierarchical monitoring and early warning of "broad-spectrum monitoring → biological confirmation → specific detection". This invention solves the problem in existing bioaerosol monitoring technologies that cannot simultaneously achieve broad-spectrum, real-time, accurate, and automated monitoring.

Description

Technical Field

[0001] This invention discloses an automated monitoring and detection cascade control system and method for bioaerosols, belonging to the field of infectious disease biosafety monitoring technology. Background Technology

[0002] Bioaerosols are aerosols containing biological particles such as bacteria and viruses suspended in the air. Their transmission is a major route for outbreaks of respiratory infectious diseases and bioterrorism attacks. Therefore, achieving real-time, broad-spectrum, specific, and automated monitoring and early warning of bioaerosols in ambient air is of great significance for safeguarding public health and national defense security.

[0003] Currently, existing bioaerosol monitoring technologies mainly suffer from the following technical shortcomings: First, the monitoring technologies are isolated, failing to balance timeliness and accuracy. Laser-induced fluorescence (LAF) monitoring technology offers fast response (seconds) and long-term operation without consumables, but its principle involves detecting all fluorescent particles (including fluorescent substances in pollen and dust), making it susceptible to interference from many non-biological fluorescent particles in the air, resulting in a high false alarm rate. It also cannot distinguish between dead and live bacteria, let alone identify specific pathogens. ATP-based bioluminescence monitoring technology can effectively detect live microorganisms (because ATP exists only in living cells), but it requires reagents (lysis buffer, luciferase, etc.), making long-term continuous operation difficult, and similarly unable to identify specific species. Current technologies lack automated solutions that combine the advantages of both, leaving users either burdened by high false alarm rates or unable to achieve continuous monitoring.

[0004] Second, the testing process is cumbersome and lacks automation. While polymerase chain reaction (PCR)-based nucleic acid detection is the gold standard for pathogen-specific identification, boasting high sensitivity and specificity, traditional methods require manual sampling (e.g., collecting aerosols into a liquid using a sampler), manual nucleic acid extraction (lysis, binding, washing, elution), manual preparation of the PCR reaction system, and manual instrument testing. The entire process typically requires over two hours of operation by professionals, and the repeated opening of the container greatly increases the risk of aerosol contamination, leading to false positives. Even with some automated nucleic acid extraction instruments, manual transfer of samples and reagents is still necessary, making a fully automated, integrated process from air to result impossible.

[0005] Third, the lack of system cascading makes it difficult to achieve tiered early warning. Existing products are mostly single-function devices (individual fluorescence early warning devices, individual ATP detectors, or individual detection analyzers), each operating independently without a unified logical system that can automatically initiate different levels of detection based on monitoring results. In practical applications, continuous nucleic acid testing leads to high reagent consumption and costs; while activating only fluorescence early warning results in frequent false alarms, requiring manual intervention for sampling and testing after each false alarm. Therefore, existing technologies cannot guarantee both real-time monitoring and specificity and accuracy, nor can they achieve tiered automated early warning from "routine broad-spectrum monitoring → abnormal biological confirmation → pathogen identification." Therefore, the purpose of this invention is to provide a bioaerosol monitoring and early warning system capable of achieving automatic cascading monitoring of broad spectrum and specificity, integrating the entire process to solve the technical challenges in this field. Summary of the Invention

[0006] To achieve the above objectives, the present invention first provides a bioaerosol monitoring, detection and early warning system based on multi-technology automatic cascading, the system comprising: a cascaded monitoring and detection unit and an automatic control unit.

[0007] The cascaded monitoring and detection unit includes: Level 1 monitoring module: Bioaerosol fluorescent particle monitor based on laser-induced fluorescence technology (aerosol fluorescent particle monitor). Second-level monitoring module: Bioaerosol live cell monitor based on ATP fluorescence detection technology (aerosol live cell ATP monitor). The third-level detection module: a bioaerosol nucleic acid detector based on microfluidic PCR technology (an integrated bioaerosol detection and sampling nucleic acid detection system).

[0008] The automatic control unit connects the first-level monitoring module, the second-level monitoring module, and the third-level detection module in sequence via high and low level switching signals to form a cascaded trigger network.

[0009] In a preferred embodiment, the aerosol fluorescent particle monitor includes a gas path unit and an optical detection unit. The gas path unit consists of a sampling inlet, a micro air pump, a flow sensor, and an exhaust port, used to draw ambient air into the detection chamber at a constant flow rate and to monitor and provide feedback on flow stability in real time via the flow sensor. The optical detection unit is used to monitor the concentration and fluorescence intensity of total aerosol particles in the air in real time. When the monitored value exceeds a preset threshold, a first low-level alarm signal is output. This signal consists of an ultraviolet laser, a beam-shaping lens group, an aerosol detection chamber, a photomultiplier tube, and a signal amplification circuit, used to focus the ultraviolet laser on the center of the detection chamber to excite aerosol particles to produce intrinsic fluorescence. The photomultiplier tube converts the fluorescence signal into an electrical signal and amplifies it. Its detection limit is 48 ACPLA (Aerosol Particle Fluorescence Count Level, representing the equivalent number of fluorescent particles detected per minute), and the alarm response time is ≤22 seconds. The intrinsic fluorescence refers to the fluorescence signal emitted by organic molecules contained in microorganisms under ultraviolet light excitation, and the intensity of this signal is positively correlated with the concentration of bioaerosol particles in the air.

[0010] In a preferred embodiment, the aerosol live-cell ATP monitor is used to collect live microorganisms in the air and detect their ATP concentration. When the detected value exceeds a preset threshold, a second low-level alarm signal is output. It includes a liquid phase sampling unit, a lysis buffer reagent unit, and a photoelectric detection unit. The liquid phase sampling unit includes a sampling inlet, a gas-liquid separator, a micro-liquid pump, and a sample collection tube, used to draw air into the cyclone separator at high speed, allowing the airborne bioaerosol particles to fully contact and be captured by the pre-placed lysis buffer to form a sample solution. The lysis buffer reagent unit includes an independently sealed reagent blister, a microfluidic channel, and an automatic sample dispensing valve, used to allow the lysis buffer to disrupt the cell membrane of live microorganisms and release intracellular ATP. Simultaneously, luciferase catalyzes the oxidation of luciferin to produce light in the presence of ATP and O2. The photoelectric detection unit consists of a high-sensitivity photomultiplier tube, a bandpass filter, and a signal processing circuit, used to collect the luminescence signal and convert its intensity into an ATP concentration value. Its detection limit is 46 ACPLA, and the alarm response time is ≤25 seconds.

[0011] In a preferred embodiment, the integrated bioaerosol detection and nucleic acid testing system includes an aerosol collection unit, an automated liquid processing unit, a microfluidic chip unit, and a temperature control and optical detection unit, wherein... The aerosol collection unit includes a high-speed centrifugal fan, a gas-liquid exchanger, and a gas-liquid separation membrane, with a sampling flow rate ≥400 L / min; The automatic liquid processing unit consists of a micro-injection pump, a multi-way rotary valve, a liquid level sensor, and a waste liquid collection bottle, and is used to collect aerosols into the sampling liquid. The microfluidic chip unit is a multilayer composite microfluidic chip, which includes, from bottom to top: a polycarbonate substrate layer, a microchannel layer (including a sample lysis chamber, a magnetic bead extraction chamber, and a PCR reaction chamber), a sealing elastic membrane layer, and a sample inlet layer. The chip is a disposable sealed chip, which is pre-encapsulated with nucleic acid extraction reagents and amplification detection reagents, and integrates reaction chambers for sample lysis, nucleic acid extraction, and product amplification. The temperature control and optical detection unit includes a Peltier heating module, a cooling fan, a temperature sensor (PT100), and a fluorescence detection module. It is used to control the temperature cycle required for PCR amplification (95℃ denaturation, 60℃ annealing and extension) through PID (Proportional-Integral-Derivative Control, a closed-loop feedback control algorithm in industrial automation, which is the core control logic for achieving precise temperature cycling) and to collect the fluorescence signal of each reaction well in real time. The positive and negative results are determined by the Ct value and the amplification curve.

[0012] In a more preferred embodiment, the microfluidic chip unit is a disposable sealed chip with multiple pre-set detection channels for detecting the nucleic acid sequences of influenza A virus, influenza B virus, adenovirus, novel coronavirus, respiratory syncytial virus, mycoplasma pneumoniae, Yersinia pestis, and anthrax bacillus; the detection reagents in the chip are pre-packaged in lyophilized powder form to meet the requirements for room temperature transportation and storage; the total time from starting sampling to outputting detection results for the third-level detection module does not exceed 40 minutes, and the detection sensitivity is ≤500 copies / mL.

[0013] In a preferred embodiment, the automatic control unit includes a relay and a data line. When the value monitored by the first-level monitoring module exceeds a preset first alarm threshold, its relay activates, sending a low-level trigger signal to the second-level monitoring module via the data line. When the value monitored by the second-level monitoring module exceeds a preset second alarm threshold, its relay activates, sending a low-level trigger signal to the third-level detection module via the data line. After transmission, the following tasks are performed: Upon receiving the low-level signal, the second-level module automatically powers on and starts the gas pump sampling and ATP detection process; upon receiving the low-level signal, the third-level module automatically starts the high-flow sampling pump, loads the microfluidic chip, and performs fully automated nucleic acid detection.

[0014] Secondly, the present invention also provides an automated monitoring, detection, and early warning method for bioaerosols based on the above system, comprising the following steps: Broad-spectrum monitoring step S1: Activate the first-level monitoring module to monitor the intrinsic fluorescence intensity of aerosol particles; when it exceeds the preset first alarm threshold, output the first trigger signal; Biological confirmation step S2: In response to the first trigger signal, the second-level monitoring module is instantly activated to perform ATP fluorescence detection, and a second trigger signal is output when the preset second threshold is exceeded; Specific identification step S3: In response to the second trigger signal, the third-level detection module is activated instantaneously to automatically complete aerosol liquid phase acquisition, microfluidic chip sample addition, nucleic acid amplification and fluorescence detection, and output the pathogen type detection results; Reset step S4: After the detection is completed, the system automatically cleans the sampling liquid path and automatically replaces the new microfluidic chip, so that the system returns to standby state and waits for the next round of monitoring to be triggered.

[0015] In a more preferred embodiment, the specific steps of the specific identification step include: S11. Collect aerosols in high-flow-rate mode and elute them into the liquid; S12. Liquid samples are quantitatively injected into the microfluidic chip through automatic control; S13. Start the nucleic acid extraction and amplification program in the microfluidic chip and complete the polymerase chain reaction within 40 minutes; S14. The detection results for specific pathogen types are output by interpreting the fluorescence signal.

[0016] In this invention, the total time from starting sampling to outputting the detection result in the specificity identification step does not exceed 40 minutes, and the detection sensitivity is ≤500 copies / mL.

[0017] The beneficial effects of this invention are as follows: First, it achieves automatic cascading and hierarchical early warning of multiple technologies. This invention utilizes high and low level switching signals to cascade three technologies: laser-induced fluorescence (rapid, broad-spectrum), ATP fluorescence (biological confirmation), and microfluidic PCR (specific identification). The system only triggers the next level after the previous level alarms, ensuring real-time monitoring (first-level alarm ≤ 22 seconds), significantly reducing the false alarm rate through cascading verification, and ultimately achieving accurate identification of pathogens.

[0018] Secondly, it achieves fully automated integration of the entire "sampling, detection, and testing" process. This invention integrates bioaerosol sampling, sample pretreatment, nucleic acid extraction, amplification, and detection into a single prototype and within a cascade system. Utilizing a microfluidic chip with pre-packaged reagents, this invention achieves automated detection with "sample in, result out," taking ≤40 minutes and achieving a detection sensitivity ≤500 copies / mL, far superior to the more than 2 hours required for traditional PCR detection, while also avoiding cross-contamination.

[0019] Third, it addresses the dual needs of broad-spectrum monitoring and specific detection. The first-level laser-induced fluorescence monitoring enables continuous broad-spectrum monitoring for 24 hours without the need for consumables; the second-level ATP detection for biological confirmation is triggered only when an abnormality is detected; and the third-level nucleic acid detection for species identification is triggered only when the biological confirmation is positive. This tiered design significantly reduces reagent consumption and the frequency of manual intervention, achieving an optimal balance between monitoring costs and monitoring efficiency.

[0020] Fourth, it improves the system's practicality and deployment flexibility. This invention enables unattended cascading operation of multiple devices through an automatic control unit. The system can complete the entire automated process of "routine broad-spectrum monitoring - abnormal biological confirmation - pathogen identification" without human intervention, making it suitable for biosafety protection in key areas such as airports, customs, large event venues, and sensitive locations. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of automatic cascading of multiple devices in an embodiment of the present invention; Figure 2 This is a schematic diagram of the automatic cascading circuit control for multiple devices in an embodiment of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result of the description. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of protection defined by the claims of the present invention.

[0023] Example 1: Constructing an Example 1. Construction of the first-level monitoring module (aerosol fluorescent particle monitor) In this embodiment, the first-level monitoring module employs an aerosol fluorescent particle monitor based on laser-induced fluorescence technology. This monitor continuously draws air at a constant flow rate. An internal ultraviolet laser irradiates aerosol particles, causing the organic components within the microorganisms to emit intrinsic fluorescence under ultraviolet light. The intensity of the fluorescence is detected by a photomultiplier tube. An alarm threshold is preset in the system. When a signal exceeding this threshold is detected, an alarm is triggered, with a response time ≤22 seconds. This monitor enables low-cost, rapid, and broad-spectrum monitoring, requires no consumables, and can operate continuously for extended periods.

[0024] In one specific embodiment of this example, the bioaerosol monitor based on laser-induced fluorescence technology includes a gas path unit and an optical detection unit. The gas path unit consists of a sampling inlet, a micro air pump, a flow sensor, and an exhaust port, used to draw ambient air into the detection chamber at a constant flow rate of 2.8 L / min, and monitors and provides feedback on flow stability in real time through an ultrasonic flow sensor. The optical detection unit is used to monitor the concentration and fluorescence intensity of total aerosol particles in the air in real time. When the monitored value exceeds a preset threshold (e.g., 100 ACPLA), a first low-level alarm signal is output. This signal consists of an ultraviolet laser, a beam-shaping lens group, an aerosol detection chamber, a photomultiplier tube, and a signal amplification circuit, used to focus the ultraviolet laser on the center of the detection chamber, exciting aerosol particles to produce intrinsic fluorescence. The photomultiplier tube converts the fluorescence signal into an electrical signal and amplifies it. Its detection limit is 48 ACPLA (Aerosol Particle Fluorescence Count Level, representing the equivalent number of fluorescent particles detected per minute), and the alarm response time is 22 seconds. The intrinsic fluorescence refers to the fluorescence signal emitted by organic molecules contained in microorganisms under ultraviolet light excitation, and the intensity of this signal is positively correlated with the concentration of bioaerosol particles in the air.

[0025] 2. Construction of the second-level monitoring module (aerosol live-cell ATP monitor) In this embodiment, the second-level monitoring module employs an aerosol live-cell ATP monitor based on ATP fluorescence detection technology. This monitor is normally in standby mode and is activated upon receiving a trigger signal from the automatic control unit. Its built-in liquid-phase sampling system draws air into a test tube containing lysis buffer. The lysis buffer disrupts the cell membranes of living microorganisms, releasing ATP which reacts with luciferin / luciferase to generate a light signal. A photomultiplier tube reads the light signal intensity, corresponding to the ATP concentration. When the detected value exceeds a preset alarm threshold, the alarm response time is ≤25 seconds. This monitor solves the problem of high-flow-rate monitoring through aerosol concentration technology, improving the detection limit, and automates the sampling process using microfluidic and automatic control technologies.

[0026] In one specific embodiment of this example, the bioaerosol monitor based on ATP fluorescence detection technology is used to collect live microorganisms in the air and detect their ATP concentration. When the detected value exceeds a preset threshold (e.g., 80 ACPLA), a second low-level alarm signal is output. It includes a liquid phase sampling unit, a lysis buffer reagent unit, and a photoelectric detection unit. The liquid phase sampling unit includes a sampling inlet, a gas-liquid separator, a micro-liquid pump, and a sample collection tube, used to draw air into the cyclone separator, allowing the bioaerosol particles in the air to fully contact and be captured by the pre-placed lysis buffer to form a sample solution. The lysis buffer reagent unit includes an independently sealed reagent blister, a microfluidic channel, and an automatic sample dispensing valve, used to dispense the lysis buffer (e.g., Triton X-100). The lysis buffer disrupts the cell membrane of living microorganisms, releasing intracellular ATP. Simultaneously, luciferase catalyzes the oxidation of luciferin to produce light in the presence of ATP and O2. The photoelectric detection unit comprises a high-sensitivity photomultiplier tube, a bandpass filter, and a signal processing circuit, used to collect the light emission signal and convert its intensity into an ATP concentration value. Its detection limit is 46 ACPLA, and the alarm response time is 25 seconds.

[0027] 3. Construction of the third-level detection module (integrated nucleic acid detection system for bioaerosol detection and collection) In this embodiment, the third-level detection module adopts a bio-aerosol detection and sampling integrated nucleic acid detection instrument based on microfluidic PCR technology. The instrument is normally in standby mode, and automatically starts the integrated "detection, sampling and detection" process after receiving a trigger signal through the automatic control unit.

[0028] In one specific embodiment of the present invention, the bioaerosol nucleic acid detector based on microfluidic PCR technology includes an aerosol acquisition unit, an automatic liquid processing unit, a microfluidic chip unit, and a temperature control and optical detection unit, wherein... The automatic liquid processing unit consists of a micro-injection pump, a multi-way rotary valve, a liquid level sensor, and a waste liquid collection bottle, and is used to collect aerosols into the sampling liquid. The microfluidic chip unit is a multilayer composite microfluidic chip, which includes, from bottom to top: a polycarbonate substrate layer, a microchannel layer (including a sample lysis chamber, a magnetic bead extraction chamber, and a PCR reaction chamber), a sealing elastic membrane layer, and a sample inlet layer. The chip is a disposable sealed chip, which is pre-encapsulated with nucleic acid extraction reagents and amplification detection reagents, and integrates reaction chambers for sample lysis, nucleic acid extraction, and product amplification. The temperature control and optical detection unit includes a Peltier heating module, a cooling fan, a temperature sensor (PT100), and a fluorescence detection module. It is used to control the temperature cycle required for PCR amplification (95℃ denaturation, 60℃ annealing and extension) through PID (Proportional-Integral-Derivative Control, a closed-loop feedback control algorithm in industrial automation, which is the core control logic for achieving precise temperature cycling) and to collect the fluorescence signal of each reaction well in real time. The positive and negative results are determined by the Ct value and the amplification curve.

[0029] In a more preferred embodiment, the microfluidic chip unit is a disposable sealed chip with eight pre-set detection channels for detecting the nucleic acid sequences of influenza A virus, influenza B virus, adenovirus, novel coronavirus, respiratory syncytial virus, mycoplasma pneumoniae, Yersinia pestis, and anthrax bacillus, respectively. The detection reagents in the chip are pre-packaged in lyophilized powder form to meet the requirements for room temperature transportation and storage. The total time from starting sampling to outputting detection results for the third-level detection module does not exceed 40 minutes, and the detection sensitivity is ≤500 copies / mL.

[0030] In one specific embodiment of the present invention, the specific workflow of the bioaerosol nucleic acid detection instrument based on microfluidic PCR technology is as follows: Sampling and liquid processing: First, start the high-flow sampling pump to draw in air, and enrich the aerosol particles into the buffer solution through the gas-liquid exchange device.

[0031] Chip loading: The automatic control unit picks up a new microfluidic chip from the chip compartment and pushes it into the testing station. The chip is pre-packaged with lyophilized PCR reagents for influenza A virus, influenza B virus, adenovirus, novel coronavirus respiratory syncytial virus, mycoplasma pneumoniae, Yersinia pestis, and anthrax bacillus. The reagents are pre-packaged in lyophilized powder form to meet the requirements for room temperature transportation and storage.

[0032] Sample addition and amplification: An automated pipette precisely injects the collected sample solution into the sample wells of the chip. Under the control of the microchannels and microvalve inside the chip, nucleic acid extraction, purification, and mixing of the PCR reaction solution are completed sequentially. Subsequently, the Peltier heating module at the bottom of the chip is activated to initiate the polymerase chain reaction.

[0033] Result Interpretation: Fluorescence signals from each channel are acquired in real time via the fluorescence detection module on top of the chip. Built-in software automatically determines whether the pathogen detection is negative or positive. The detection sensitivity is 500 copies / mL, and the entire process is completed within 40 minutes. Results are automatically uploaded to the terminal for display.

[0034] 4. Construction of the automatic control unit and cascading triggering mechanism This embodiment describes in detail the automatic cascading operation process of the three-level monitoring and detection system. Figure 1 An embodiment of the present invention illustrates an automatic cascading framework for multiple devices.

[0035] The cascaded automatic control system in this invention integrates the alarm and start-up functions of a three-stage prototype into a single unit via high and low level signal switches. The first-stage prototype is an aerosol fluorescent particle monitor that requires no reagents or consumables for continuous monitoring and can quickly identify abnormal biological fluorescent particles in the air, but it cannot determine whether these particles are biologically active. The second stage is an aerosol live-cell ATP monitor that can identify whether aerosols possess biological activity, but it cannot identify which pathogen is involved. The third stage is an aerosol detection and multiplex pathogen-specific detection system that can specifically identify specific pathogens, but it is relatively time-consuming and consumes reagents. By cascading the three-stage monitoring prototype, the requirements for long-term monitoring and rapid response in aerosol monitoring are met, while ensuring the specificity and accuracy of the monitoring.

[0036] Connection method: The aerosol fluorescent particle monitor, aerosol live cell ATP monitor, and bioaerosol detection and nucleic acid testing integrated system are connected in series via an aviation plug and a 3-core data cable.

[0037] Cascade Trigger Logic: The first-stage monitor (laser-induced fluorescence) has a built-in relay. In non-alarm mode, the signal receiver cannot receive a low-level signal and will not trigger the next cascaded detection. When the first-stage monitor alarms, the alarm signal causes its relay to engage, connecting the relay's C and NO ports. The data line connects the signal receiver to GND, placing the signal receiver at a low level and triggering the second-stage monitor (ATP fluorescence) to start operating. When the second-stage monitor alarms, the alarm signal causes its relay to engage, connecting the relay's C and NO ports. The data line connects the signal receiver in the third-stage detector to GND, placing the signal receiver at a low level and triggering the third-stage detection system (microfluidic PCR) to start operating.

[0038] Reset and continuous operation: After the third-level detection is completed, the system automatically cleans the sampling liquid path, automatically removes the used chip, loads a new chip, and the system returns to standby mode, waiting for the next round of monitoring to be triggered. Figure 2 A schematic diagram of the automatic cascading circuit control for multiple devices is shown in an embodiment of the present invention.

[0039] 5. Overall System Workflow In one application scenario, the system operates 24 / 7. The first-level aerosol fluorescent particle monitor continuously monitors the air. When a man-made release or natural eruption causes a sudden increase in the concentration of biological particles in the air, the first level alarms within 22 seconds. This signal automatically activates the second-level aerosol live-cell ATP monitor. The second level confirms the presence of live microorganisms within 25 seconds and outputs a signal to activate the third-level integrated nucleic acid detection system for bioaerosol detection and collection. The third level completes sample testing within 40 minutes and reports "positive for influenza A virus." Throughout the entire process, there is no human intervention, achieving automation, tiered early warning, and identification of results from airborne pathogens. After testing, the system automatically cleans the tubing, removes the used chip, loads a new chip, and automatically resets, ready for the next monitoring session.

[0040] Example 2 Application Example This example is applied to a biological laboratory simulation training. The application task simulates a novel coronavirus pathogen leak in a biological laboratory. It utilizes a graded monitoring and early warning system for bioaerosols to sequentially complete automated monitoring, detection, and alarm functions, addressing the challenges of traditional monitoring methods such as delayed response, high false alarm rates, and low automation.

[0041] The system, according to the scheme of this invention, completes the cascaded networking of three-level monitoring and detection instruments. The alarm thresholds of the first and second-level monitoring devices are set to 1 APCLA, far below the background background, to simulate natural triggering alarms, thus initiating the cascaded operation mode. Upon system startup, the first-level aerosol fluorescent particle monitor issues an alarm after approximately 20 seconds, simultaneously outputting a trigger signal to the second-level monitor. The second-level aerosol live-cell ATP monitor is instantaneously activated, issuing an alarm after approximately 25 seconds and simultaneously outputting a trigger signal to the third-level detection system. The integrated bioaerosol detection and nucleic acid testing system is instantaneously activated, completing aerosol sampling, pathogen nucleic acid detection, and result interpretation within 40 minutes, ultimately determining a negative result for novel coronavirus nucleic acid testing.

[0042] This invention not only meets the need for rapid response in aerosol risk monitoring in biological laboratories, but also ensures the specificity and accuracy of monitoring through three-level cascade detection, providing reliable technical support for monitoring the risk of pathogen bioaerosols in biological laboratories.

Claims

1. A cascaded control system for automated monitoring and detection of bioaerosols, characterized in that, The automated monitoring and detection cascade control system for bioaerosols includes a cascaded monitoring unit and an automatic control unit. The cascaded monitoring unit includes a first-level monitoring module, a second-level monitoring module, and a third-level detection module cascaded sequentially. The first-level monitoring module is an aerosol fluorescent particle monitor; the second-level monitoring module is an aerosol live-cell ATP monitor; and the third-level detection module is an integrated nucleic acid detection system for bioaerosols. The automatic control unit is used to receive alarm signals from the first-level monitoring module and the second-level monitoring module, and according to the preset cascading logic, to sequentially trigger the next-level module to start operation through high and low level switching signals.

2. The automated monitoring and detection cascade control system for bioaerosols according to claim 1, characterized in that, The aerosol fluorescent particle monitor includes a gas path unit and an optical detection unit. The gas path unit consists of a sampling inlet, a miniature air pump, a flow sensor, and an exhaust port, used to draw ambient air into the detection chamber at a constant flow rate and uniform speed. The flow sensor monitors and provides feedback on the flow stability in real time. The optical detection unit consists of an ultraviolet laser, a beam-shaping lens group, an aerosol detection chamber, a photomultiplier tube, and a signal amplification circuit, used to focus the ultraviolet laser at the center of the detection chamber to excite aerosol particles to produce intrinsic fluorescence. The photomultiplier tube converts the fluorescence signal into an electrical signal and amplifies it. Its detection limit is 48 ACPLA, and the alarm response time is ≤22 seconds.

3. The automated monitoring and detection cascade control system for bioaerosols according to claim 1, characterized in that, The aerosol live-cell ATP monitor includes a liquid phase sampling unit, a lysis buffer reagent unit, and a photoelectric detection unit. The liquid phase sampling unit includes a sampling inlet, a gas-liquid separator, a micro-liquid pump, and a sample collection tube, used to draw air into the cyclone separator at high speed, allowing the bioaerosol particles in the air to fully contact and be captured by the pre-placed lysis buffer to form a sample solution. The lysis buffer reagent unit includes an independently sealed reagent blister, a microfluidic channel, and an automatic sample dispensing valve, used to allow the lysis buffer to disrupt the cell membrane of living microorganisms and release intracellular ATP. Simultaneously, luciferase catalyzes the oxidation of luciferin to produce light in the presence of ATP and O2. The photoelectric detection unit consists of a high-sensitivity photomultiplier tube, a bandpass filter, and a signal processing circuit, used to collect the luminescence signal and convert its intensity into an ATP concentration value. Its detection limit is 46 ACPLA, and the alarm response time is ≤25 seconds.

4. The automated monitoring and detection cascade control system for bioaerosols according to claim 1, characterized in that, The integrated nucleic acid detection system for bioaerosol collection and testing includes an aerosol collection unit, an automatic liquid processing unit, a microfluidic chip unit, and a temperature control and optical detection unit. The aerosol collection unit includes a high-speed centrifugal fan, a gas-liquid exchanger, and a gas-liquid separation membrane, with a sampling flow rate ≥400L / min; The automatic liquid processing unit consists of a micro-injection pump, a multi-way rotary valve, a liquid level sensor, and a waste liquid collection bottle, and is used to collect aerosols into the sampling liquid. The microfluidic chip unit is a multilayer composite microfluidic chip, which includes, from bottom to top: a polycarbonate substrate layer, a microchannel layer, a sealing elastic membrane layer, and a sample inlet layer. The chip is a disposable sealed chip, which is pre-encapsulated with nucleic acid extraction reagents and amplification detection reagents, and integrates reaction chambers for sample lysis, nucleic acid extraction, and product amplification. The microchannel layer includes a sample lysis chamber, a magnetic bead extraction chamber, and a PCR reaction chamber. The temperature control and optical detection unit includes a Peltier heating module, a cooling fan, a temperature sensor, and a fluorescence detection module. It is used to achieve the temperature cycle required for PCR amplification through PID control and to collect the fluorescence signal of each reaction well in real time. The positive and negative results are determined by the Ct value and the amplification curve.

5. The automated monitoring and detection cascade control system for bioaerosols according to claim 1, characterized in that, The automatic control unit includes a relay and a data line. When the value monitored by the first-level monitoring module exceeds a preset first alarm threshold, its relay is activated, and a low-level trigger signal is sent to the second-level monitoring module via the data line. When the value monitored by the second-level monitoring module exceeds a preset second alarm threshold, its relay is activated, and a low-level trigger signal is instantaneously sent to the third-level detection module via the data line. After sending, the following tasks are performed: the second-level module automatically powers on upon receiving the low-level signal and starts the gas pump sampling and ATP detection process; the third-level module automatically starts the high-flow sampling pump, loads the microfluidic chip, and performs fully automated nucleic acid detection upon receiving the low-level signal.

6. The automated monitoring and detection cascade control system for bioaerosols according to claim 5, characterized in that, The microfluidic chip unit is equipped with a microbial detection channel, and the detection reagents inside the chip are pre-packaged in the form of lyophilized powder to meet the requirements for room temperature transportation and storage.

7. The automated monitoring and detection cascade control system for bioaerosols according to claim 6, characterized in that, The microbial detection channels include nucleic acid detection channels for influenza A virus, influenza B virus, adenovirus, novel coronavirus, respiratory syncytial virus, mycoplasma pneumoniae, Yersinia pestis, and anthrax bacillus.

8. The automated monitoring and detection cascade control system for bioaerosols according to claim 1, characterized in that, The integrated bioaerosol detection and nucleic acid testing system first mixes the aerosol liquid sample with a lysis buffer, lyses and releases nucleic acid, which is then specifically adsorbed by magnetic beads. Under magnetic force, the magnetic beads are transferred to a washing buffer to remove impurities, and then transferred to an elution buffer to release nucleic acid. Finally, the eluted nucleic acid is mixed with a pre-packaged PCR reaction solution containing specific primers, probes, Taq enzyme, and dNTPs. Real-time fluorescent PCR amplification is performed in the chip reaction chamber. The lyophilized powder is pre-packaged in the chip reaction chamber and reconstituted with a buffer solution pre-placed in the chip before use.

9. A method for automated monitoring and early warning of bioaerosols based on the automated monitoring and detection cascade control system for bioaerosols according to any one of claims 1 to 8, characterized in that, Includes the following steps: Broad-spectrum monitoring step S1: Activate the first-level monitoring module to monitor the intrinsic fluorescence intensity of aerosol particles; when it exceeds the preset first alarm threshold, output the first trigger signal; Biological confirmation step S2: In response to the first trigger signal, the second-level monitoring module is instantly activated to perform ATP fluorescence detection, and a second trigger signal is output when the preset second threshold is exceeded; Specific identification step S3: In response to the second trigger signal, the third-level detection module is activated instantaneously to automatically complete aerosol liquid phase acquisition, microfluidic chip sample addition, nucleic acid amplification and fluorescence detection, and output the pathogen type detection results; Reset step S4: After the detection is completed, the system automatically cleans the sampling liquid path and automatically replaces the new microfluidic chip, so that the system returns to standby state and waits for the next round of monitoring to be triggered.

10. The method according to claim 8, characterized in that, The specific steps of the specificity identification step include: S11: Collect aerosols in high-flow-rate mode and elute them into the liquid; S12: Quantitatively injects liquid samples into the microfluidic chip through automatic control; S13: Start the nucleic acid extraction and amplification program in the microfluidic chip and complete the polymerase chain reaction within 40 minutes; S14: Detection results for specific pathogen types are output by interpreting fluorescence signals.

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