Monitoring device for simultaneously monitoring multiple pollutants in water environment based on whispering gallery mode liquid crystal microcavity and control method thereof

Abstract

The invention provides a monitoring device for simultaneously monitoring multiple pollutants in a water environment based on an echo wall mode liquid crystal microcavity and a control method thereof, and belongs to the technical field of optical microsensing. Cholesteric liquid crystal solution doped with fluorescent dye DCM is injected into liquid to be detected through a conical capillary microtube to form a plurality of liquid microsphere cavities; the fluorescent dye DCM in the liquid crystal microspheres emits fluorescence under the excitation of 532 nm laser pulse, high-quality echo wall mode laser emission is generated under the limiting action of the microcavity, and a spectrograph is used for recording a laser spectrum; when the concentration of pollutants in a water environment slightly changes, the change of the refractive index of the liquid crystal causes the change of the wavelength of the laser, so that the spectrum drifts, and high-sensitivity sensing is realized; the invention designs a real-time, quantitative and visual water environment pollutant detection sensor which has a wide application prospect in the field of water environment protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical microsensors, and in particular, relates to a monitoring device for simultaneously monitoring multiple pollutants in a water environment based on a whispering gallery mode liquid crystal microcavity and a control method thereof. Background Art

[0002] Water is the source of life and is essential to all aspects of human production and life. However, freshwater resources are limited worldwide. Especially with the economic globalization and the exponential growth of population, conventional water supply is gradually unable to meet people's growing water needs. The resulting contradiction will restrict social and economic development and bring new difficulties and challenges to global water use.

[0003] In today's society, the emission of heavy metal ions has become a serious environmental challenge. These heavy metal ions, such as lead, mercury, and cadmium, pose a potential threat to the environment and human health, so efficient detection methods are needed to monitor their presence and concentration. Traditional heavy metal ion detection methods often require expensive instruments, complex sample preparation, and long detection times, so there is an urgent need to develop a faster and more sensitive detection technology.

[0004] Organophosphorus and carbamate pesticides, as acetylcholinesterase inhibitors, have become widely used pesticides in human agricultural production due to their low cost and high insecticide effect. However, due to the irregular use of pesticides and the lack of environmental protection awareness, excessive pesticide residues are constantly found in soil, river water, and groundwater. Therefore, in order to avoid the possible harm of residual pesticides to humans, animals and plants, it is particularly important to accurately and quickly detect pesticides. At present, the conventional detection methods for pesticides mainly include fluorescence determination, electrochemical method, chromatography, colorimetry, etc. Although they are helpful for the detection of pesticides, these detection systems have the disadvantages of being expensive, complicated to operate, and taking too long to detect while relying on human resources. Therefore, it is urgent to develop a high-sensitivity pesticide detection system that is simple to operate and low in cost.

[0005] Since feces are intestinal secretions of the human body, it includes feces of healthy people and feces of intestinal patients or bacteria, so in addition to normal bacteria, feces usually contain intestinal pathogens. If the water environment is contaminated by Escherichia coli, it will cause diarrhea, gastrointestinal infections, etc., and can also cause neonatal encephalitis and sepsis, as well as abscesses in multiple organs. For adults, it can cause urinary tract infections, such as urethritis, cystitis and other diseases, and even peritonitis, cholecystitis, appendicitis, etc. Therefore, water contaminated by animal feces also poses a risk to human health. Therefore, when water sources or food are contaminated by feces, it should be considered whether there is the possibility of intestinal pathogen contamination and the threat of potential food poisoning and epidemics. Therefore, it is urgent to develop a highly sensitive aquatic microbial detection system that is simple to operate and low in cost.

[0006] In this context, liquid crystal microcavity sensors, as an emerging detection technology, provide a potential solution. The uniqueness of liquid crystal microcavity sensors lies in their high-sensitivity detection based on changes in optical properties within the microcavity. For pollutant detection in water environments, the specific responsiveness of liquid crystals can be utilized, making it an ideal sensing material. Traditional liquid crystal sensors are usually based on external triggers, while liquid crystal microcavity sensors use the liquid crystal response within the microcavity to achieve detection. When exposed to a water environment, the refractive index inside the liquid crystal may change, causing the pattern within the microcavity to change. This change can be used to detect pollutants in water environments by monitoring the frequency or wavelength of the optical signal. Summary of the invention

[0007] In view of the fact that the prior art cannot simultaneously monitor multiple pollutants in the water environment, the present invention proposes a monitoring device and a control method for simultaneously monitoring multiple pollutants in the water environment based on a whispering gallery mode liquid crystal microcavity. Three liquid crystal microspheres doped with different substances are generated in the solution to be tested using a micro-pressure control system to simultaneously monitor pollutants in the water environment: Escherichia coli, pesticides and heavy metal ions. The microspheres have a nearly perfect spherical structure and an extremely smooth surface morphology, which reduces surface scattering losses, so that the stimulated whispering gallery mode laser has an extremely high Q value and an ultra-low laser threshold, thereby greatly improving the detection sensitivity of pollutants.

[0008] The present invention is achieved through the following technical solutions:

[0009] A monitoring device for simultaneously monitoring multiple pollutants in water environment based on whispering gallery mode liquid crystal microcavity:

[0010] The monitoring device comprises a 532nm pump pulse laser, a first half-reflecting half-mirror, a liquid crystal droplet, a 10x optical objective lens, a second half-reflecting half-mirror, a beam splitter, a 532nm filter, a charge coupled device (CCD), a spectrum analyzer, a solution to be tested, a temperature controller, a micro-heating stage, a PMMA substrate, a quartz capillary, a micro-injector, a three-dimensional section frame and a 4x optical objective lens;

[0011] The light emitted by the 532nm pump pulse laser passes through the first semi-reflective and semi-mirror lens, is focused by the 4x optical objective lens onto the surface of the liquid crystal droplet and excites the fluorescent dye DCM to produce fluorescence. The generated fluorescence is totally internally reflected and amplified at the interface between the liquid crystal droplet resonant cavity and the surrounding test solution environment, and finally produces whispering gallery mode laser emission. The whispering gallery mode laser is collected by the 10x optical objective lens and passes through the second semi-reflective and semi-mirror lens and the beam splitter in sequence. One beam of light is filtered by a 532nm filter and transmitted to the spectrometer to record the spectrum, and the other beam of light enters the charge-coupled device CCD for droplet imaging; the data obtained by the spectrometer and the charge-coupled device CCD are transmitted to the computer for information processing and display.

[0012] Further, the 532nm pump pulse laser emits a pulse laser with a wavelength of 532nm as an excitation source to excite the fluorescent dye DCM in the liquid crystal droplet to produce fluorescence;

[0013] The charge coupled device CCD is used for droplet imaging, for capturing and recording images of liquid crystal droplets, and for assisting in the detection and analysis of pollutants;

[0014] The spectrum analyzer is used to record and analyze the spectrum characteristics of the whispering gallery mode laser generated by the liquid crystal droplet, and detect and quantify the target pollutant by analyzing the changes in the spectrum.

[0015] Furthermore, the liquid crystal droplets are tiny droplets formed by liquid crystal materials doped with 0.01wt.% fluorescent dye DCM and other specific substances, and are generated in the solution to be detected through a tapered quartz capillary. Each liquid crystal droplet is designed to be sensitive to a specific type of pollutant, and the optical changes of the liquid crystal droplet are monitored by fluorescence characteristics.

[0016] The other specific substances include pH-sensitive molecule stearic acid, surfactant Myr and acetylcholinesterase (AChE), cetyltrimethylammonium bromide (CTAB) and aptamer.

[0017] Furthermore, the liquid crystal droplets are at least three, which are doped with pH-sensitive molecule stearic acid to detect pH changes, doped with surfactant Myr and acetylcholinesterase (AChE) for detecting pesticide residues, and doped with cetyltrimethylammonium bromide (CTAB) and aptamer for specific identification of microorganisms.

[0018] Further, the monitoring device includes a 532nm pump pulse laser, a first half-reflecting half-mirror, a liquid crystal droplet, a 10x optical objective lens, a second half-reflecting half-mirror, a beam splitter, a 532nm filter, a charge coupled device CCD, a spectrum analyzer, a solution to be tested, a temperature controller, a micro-heating stage, a PMMA substrate, a quartz capillary, a micro-injector, a three-dimensional section frame and a 4x optical objective lens;

[0019] The solution to be tested is placed on a PMMA substrate with a micro-heating stage at the bottom;

[0020] The temperature change of the micro heating platform is regulated by a temperature controller.

[0021] Furthermore, the micro-injector and the liquid crystal droplet are precisely position-controlled by a three-dimensional electric adjustment frame, and the diameter of the liquid crystal droplet generated by the micro-injector is controlled within 50 microns.

[0022] Furthermore, liquid crystal droplets are prepared by means of a three-dimensional electric adjustment frame: first, the unstretched end of the quartz capillary is connected to the micro-injection syringe using ultraviolet curing glue; secondly, the stretched end of the quartz capillary is fixed on the optical fiber clip of the three-dimensional frame, and the position of the quartz capillary is precisely controlled by adjusting the three-dimensional adjustment frame; then, the three-dimensional adjustment frame is moved to immerse the tip of the quartz capillary in the liquid crystal solution to extract a small amount of the liquid crystal solution; finally, the three-dimensional adjustment frame is moved to immerse the tip of the quartz capillary in the solution to be tested, and liquid crystal droplets are formed by controlling the injection speed of the micro-injection syringe.

[0023] A control method for a sensing device for simultaneously monitoring multiple pollutants in a water environment based on a whispering gallery mode liquid crystal microcavity: the control method specifically comprises the following steps:

[0024] Step 1: 3 portions of 1 mL nematic liquid crystal 5CB were doped with: 0.05 wt% of stearic acid and 0.01 wt% of fluorescent dye DCM, 0.05 wt% of surfactant Myr and 0.05 wt% of acetylcholinesterase (AChE) and 0.01 wt% of fluorescent dye DCM, 0.05 wt% of hexadecyltrimethylammonium bromide (CTAB) and 0.05 wt% of aptamer and 0.01 wt% of fluorescent dye DCM;

[0025] Step 2: Place the three mixed solutions in an ultrasonic machine for 30 minutes to make them fully mixed and uniform. The working temperature of the ultrasonic machine is set to 25°C.

[0026] Step 3: Using the flame heating taper method, a quartz capillary with an outer diameter of 162 μm and an inner diameter of 100 μm is pulled into a capillary microtube with an inner diameter of 5 μm; the other end of the capillary microtube is connected to a laboratory-made micro-syringe;

[0027] Step 4: By controlling the injection rate of the micro-injector, three liquid crystal droplets with a diameter of 50 μm are generated in the reaction solution;

[0028] Step 5: The temperature of the solution to be tested is monitored in real time using a micro temperature probe of a temperature controller, and the temperature is kept constant at 25°C through a feedback adjustment device;

[0029] Step 6: The light emitted by the 532nm pump pulse laser passes through the first half-reflecting half-mirror and is finally focused by the 4x optical objective lens onto the surface of the liquid crystal droplet and excites the dye DCM to produce fluorescence;

[0030] Step 7: The test solution contains the liquid to be tested, and the heavy metal ions in the water environment pollutants will have an electrostatic interaction with stearic acid, causing the spatial arrangement order of the liquid crystal molecules to change; the acetylcholinesterase inhibitor (AChEI) in the pesticide residue compounds in the water environment pollutants will inhibit the activity of acetylcholinesterase (AChE), and thus cannot hydrolyze Myr. Due to the hydrophobic effect of the long chain tail of Myr, the spatial arrangement order of the liquid crystal molecules will change; the Escherichia coli in the water environment pollutants will specifically bind to the aptamer, destroying the electrostatic interaction between the aptamer and CTAB, and the released CTAB molecules have amphiphilicity, causing the spatial arrangement order of the liquid crystal molecules to change;

[0031] Step 8: The whispering gallery mode laser generated by the liquid crystal droplet is collected by a 10x optical objective lens and passes through a second semi-reflective mirror and a beam splitter in sequence. One beam of light is filtered by a 532nm filter and transmitted to a spectrometer for spectral analysis; the other beam of light enters a charge-coupled device (CCD) for droplet imaging, and the data obtained are transmitted to a computer for information processing and display.

[0032] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0033] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are implemented.

[0034] Beneficial effects of the present invention

[0035] (1) The sensor device of the present invention can be used to simultaneously detect different pollutants in water environments: heavy metal ions, pesticides, and E. coli, greatly shortening the detection time and saving the detection cost.

[0036] (2) The liquid crystal droplet resonant cavity formed by surface tension has a nearly perfect spherical structure and an extremely smooth surface morphology, which greatly reduces the surface scattering loss, making the excited whispering gallery mode laser have an extremely high Q value and an ultra-low laser threshold, thereby greatly improving the detection sensitivity of pollutants in the water environment.

[0037] (3) Liquid crystal droplets have a large specific surface area, and the overall arrangement of liquid crystal molecules is highly sensitive to the strength and type of biochemical molecular anchoring at the liquid crystal / water interface. Slight changes in the anchoring state of liquid crystal molecules will be amplified by orders of magnitude in real time by the whispering gallery mode.

[0038] (4) It has high sensitivity in detecting pollutant concentration. When the pollutant concentration in the water environment changes slightly, it will cause the refractive index of the liquid crystal to change, which in turn causes the laser wavelength to change, resulting in drift in the spectrum, achieving high-sensitivity sensing.

[0039] (5) Liquid crystal sensing technology based on whispering gallery mode lasers can convert the concentration change process of pollutants in the water environment into spectral information in real time, allowing the entire detection process to be accurately quantified and monitored in real time. This completely overcomes the disadvantage that traditional liquid crystal sensors can only perform rough assessments through optical patterns.

[0040] (6) The sensing device of the present invention has a complete temperature monitoring system, which ensures the constant temperature of the reaction solution through a micro-heating table and a temperature controller, avoids errors caused by temperature changes, and effectively avoids disturbance errors caused by changes in the operating environment temperature, making the detection results more accurate and reliable.

[0041] An XYZ three-dimensional electric adjustment frame is also used to precisely control the position of the micro-injection syringe and liquid crystal droplet to ensure the accuracy of the experiment.

[0042] In summary, the present invention provides a real-time, quantitative and visual water environment pollutant detection sensor, which has broad application prospects in the field of water environment protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of the water environment pollution sensor based on whispering gallery mode laser.

[0044] The invention comprises a 532nm pump pulse laser (1), a first semi-reflective and semi-transparent mirror (2), a liquid crystal droplet (3), a 10x optical objective lens (4), a second semi-reflective and semi-transparent mirror (5), a beam splitter (6), a 532nm filter (7), a charge coupled device (CCD) (8), a spectrometer (9), a solution to be tested (10), a temperature controller (11), a micro heating table (12), a PMMA substrate (13), a quartz capillary (14), a micro syringe (15), a three-dimensional section frame (16), and a 4x optical objective lens (17).

[0045] Figure 2 Schematic diagram of the structure of liquid crystal droplets doped with fluorescent dye DCM in an aqueous environment.

[0046] Among them are Escherichia coli (18), acetylcholinesterase inhibitor (AChEI) (19), heavy metal ions (20), liquid crystal molecules (21), stearic acid (22), Myr (23), acetylcholinesterase (AChE) (24), CTAB (25), and aptamer (26).

[0047] Figure 3 This is the wavelength shift diagram of the whispering gallery mode laser spectrum of liquid crystal droplets in an aqueous environment containing pesticide residues. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained through commercial channels by those skilled in the art.

[0050] like Figure 1 , 2 As shown, the present invention proposes a monitoring device for simultaneously monitoring multiple pollutants in the water environment based on a whispering gallery mode liquid crystal microcavity:

[0051] The monitoring device comprises a 532nm pump pulse laser 1, a first semi-reflective and semi-mirror 2, a liquid crystal droplet 3, a 10x optical objective lens 4, a second semi-reflective and semi-mirror 5, a beam splitter 6, a 532nm filter 7, a charge coupled device CCD 8, a spectrum analyzer 9, a solution to be tested 10, a temperature controller 11, a micro-heating table 12, a PMMA substrate 13, a quartz capillary 14, a micro-injector 15, a three-dimensional section frame 16 and a 4x optical objective lens 17;

[0052] Preparation of liquid crystal droplets: First, use ultraviolet curing glue to connect the unstretched end of the quartz capillary 14 to the micro-injection syringe 15; secondly, the stretched end (tapered micro-tube end) of the quartz capillary 14 is fixed on the optical fiber buckle of the three-dimensional section frame 16, and the position of the quartz capillary 14 is accurately controlled by adjusting the three-dimensional adjustment frame 16; then, the three-dimensional adjustment frame 16 is moved to immerse the tip of the quartz capillary 14 in the liquid crystal solution to extract a small amount of liquid crystal solution; finally, the three-dimensional adjustment frame 16 is moved to immerse the tip of the quartz capillary 14 in the solution to be tested 10, and the liquid crystal droplet 3 is formed by controlling the injection speed of the micro-injection syringe 15.

[0053] The light emitted by the 532nm pump pulse laser 1 passes through the first semi-reflective half-mirror 2, and is focused by the 4x optical objective lens 17 onto the surface of the (functionalized 5CB microdroplet) liquid crystal microdroplet 3 and excites the fluorescent dye DCM to produce fluorescence. Since the effective refractive index of the microdroplet is higher than that of the solution to be tested 10, the generated fluorescence is totally internally reflected and amplified at the interface between the resonant cavity of the liquid crystal microdroplet 3 and the surrounding environment of the solution to be tested 10, and finally generates whispering gallery mode laser emission.

[0054] The whispering gallery mode laser generated by the 5CB droplet is collected by the 10x optical objective lens 4, and sequentially passes through the second semi-reflective mirror 5 and the beam splitter 6. One beam of light is filtered by the 532nm filter 7 and transmitted to the spectrum analyzer 9 to record the spectrum, and the other beam of light enters the charge coupled device CCD8 to image the droplet. The obtained data are all transmitted to the computer for information processing and display.

[0055] The 532nm pump pulse laser 1 emits a pulse laser with a wavelength of 532nm as an excitation source to excite the fluorescent dye DCM in the liquid crystal droplet 3 to generate fluorescence;

[0056] The charge coupled device CCD8 is a photoelectric sensor used for droplet imaging, for capturing and recording images of the liquid crystal droplet 3, and assisting in the detection and analysis of pollutants;

[0057] The spectrum analyzer 9 is used to record and analyze the spectrum characteristics of the whispering gallery mode laser generated by the liquid crystal droplet 3, and detect and quantify the target pollutants by analyzing the changes in the spectrum.

[0058] The liquid crystal droplet 3 is a tiny droplet formed by a liquid crystal material doped with fluorescent dye DCM and other specific substances, and is generated in a solution to be detected through a tapered quartz capillary 14. Each liquid crystal droplet 3 is designed to be sensitive to a specific type of pollutant, and the optical change of the liquid crystal droplet 3 is monitored by fluorescence characteristics;

[0059] The liquid crystal droplet 3 is doped with 0.01 wt.% of fluorescent dye DCM, and the diameter of the liquid crystal droplet 3 is controlled to be 50 microns by a self-made micro-injector 15;

[0060] When the fluorescent dye DCM is excited by light of a specific wavelength, it can emit light of another wavelength (usually a color in the visible light range). That is, DCM is used as a fluorescent marker, and its fluorescence properties are used to monitor the optical changes of liquid crystal droplets. When these liquid crystal droplets are exposed to the sample to be tested, if the target contaminants are present, they will interact with the doping substances, causing the optical properties of the DCM fluorescent dye inside the liquid crystal droplets to change. This change can be detected by a spectrometer, thereby achieving high-sensitivity detection of pollutants.

[0061] The liquid crystal droplets 3 are at least 3, which are doped with pH sensitive molecule stearic acid to detect pH changes, doped with surfactant Myr and acetylcholinesterase (AChE) for detecting pesticide residues, and doped with hexadecyltrimethylammonium bromide CTAB and aptamer for specific recognition of microorganisms such as Escherichia coli.

[0062] The solution to be tested 10 is placed on a PMMA substrate 13 , and a micro-heating platform 12 is installed at the bottom. The temperature of the micro-heating platform 12 is adjusted by a temperature controller 11 .

[0063] The micro-injection syringe 15 and the liquid crystal droplet 3 are precisely controlled in position by an XYZ three-dimensional electric adjustment frame 16 .

[0064] In the embodiment, the method for preparing the liquid crystal droplet 3 is specifically as follows:

[0065] First, the unstretched end of the quartz capillary 14 is connected to the micro-injector 15 using ultraviolet curing glue; secondly, the stretched end of the quartz capillary 14 is fixed on the optical fiber buckle of the three-dimensional adjustment frame 16, and the position of the quartz capillary 14 is accurately controlled by adjusting the three-dimensional adjustment frame 16; then, the three-dimensional adjustment frame 16 is moved to immerse the tip of the quartz capillary 14 in the liquid crystal solution to extract a small amount of liquid crystal solution; finally, the three-dimensional adjustment frame 16 is moved to immerse the tip of the quartz capillary 14 in the solution to be tested 10, and the liquid crystal droplet 3 is formed by controlling the injection speed of the micro-injector 15.

[0066] A control method for a sensing device for simultaneously monitoring multiple pollutants in a water environment based on a whispering gallery mode liquid crystal microcavity: the method specifically comprises the following steps:

[0067] Step 1: 3 portions of 1 mL of nematic liquid crystal 5CB were doped with: 0.05 wt% of stearic acid and 0.01 wt% of fluorescent dye DCM, 0.05 wt% of surfactant Myr and 0.05 wt% of acetylcholinesterase (AChE) and 0.01 wt% of fluorescent dye DCM, 0.05 wt% of hexadecyltrimethylammonium bromide CTAB and 0.05 wt% of aptamer and 0.01 wt% of fluorescent dye DCM;

[0068] Step 2: Place the three mixed solutions in an ultrasonic machine for 30 minutes to make them fully mixed and uniform. The working temperature of the ultrasonic machine is set to 25°C.

[0069] Step 3: Using the flame heating taper method, the quartz capillary 14 with an outer diameter of 162 μm and an inner diameter of 100 μm is pulled into a capillary microtube with an inner diameter of 5 μm; the other end of the capillary microtube is connected to a laboratory-made micro-injection syringe 15;

[0070] Step 4: by controlling the injection rate of the micro-injector 15, three liquid crystal droplets 3 with a diameter of 50 μm are generated in the reaction (to be tested) solution 10;

[0071] Step 5: The temperature of the reaction (to be tested) solution 10 is monitored in real time by a micro temperature probe of a temperature controller 11, and the temperature is ensured to be constant at 25°C by a feedback regulating device;

[0072] Step 6: The light emitted by the 532nm pump pulse laser 1 passes through the first semi-reflective semi-mirror 2, and is finally focused by the 4x optical objective lens 17 onto the surface of the liquid crystal droplet 3 and excites the dye DCM to produce fluorescence;

[0073] Step 7: The reaction (to be tested) solution 10 contains the liquid to be tested, and the heavy metal ions in the water environment pollutants will have an electrostatic interaction with stearic acid, so that the spatial arrangement order of the liquid crystal molecules changes; the acetylcholinesterase inhibitor (AChEI) in the pesticide residue compounds in the water environment pollutants will inhibit the activity of acetylcholinesterase (AChE), and thus cannot hydrolyze Myr. Due to the hydrophobic effect of the long chain tail of Myr, the spatial arrangement order of the liquid crystal molecules changes; the Escherichia coli in the water environment pollutants will specifically bind to the aptamer, destroying the electrostatic interaction between the aptamer and CTAB, and the released CTAB molecules have amphiphilicity, which causes the spatial arrangement order of the liquid crystal molecules to change;

[0074] Step 8: The whispering gallery mode laser generated by the liquid crystal droplet 3 is collected by a 10x optical objective lens 4, and passes through a second semi-reflective mirror 5 and a beam splitter 6 in sequence. One beam of light is filtered by a 532nm filter and transmitted to a spectrometer 9 for spectral analysis; the other beam of light enters a charge-coupled device CCD8 for droplet imaging, and the data obtained are transmitted to a computer for information processing and display.

[0075] like Figure 3 When stearic acid 22 is present in the reaction solution, the liquid crystal molecules 21 in the droplets are arranged perpendicular to the surface of the droplets. When heavy metal ions 20 are added to the reaction solution to be tested, there is electrostatic adsorption between the heavy metal ions 20 and stearic acid 22, thereby inducing the liquid crystal molecules 21 to change their arrangement from perpendicular to parallel to the surface. When the concentration of the heavy metal ions 20 being detected is low, the liquid crystal molecules 21 may undergo a slight deflection that is undetectable to the naked eye. At this time, this change is keenly captured by the whispering gallery laser. The wavelength drift of the whispering gallery laser can quantitatively characterize the adsorption of heavy metal ions 20, making the detection process more reliable.

[0076] When acetylcholinesterase (AChE) 24 and Myr23 are present in the reaction solution, the anchoring of Myr23 to the liquid crystal molecule 21 will be destroyed due to the efficient hydrolysis of Myr23 by (AChE) 24, resulting in the change of the arrangement of the liquid crystal molecule 21 from perpendicular to parallel to the surface. However, the acetylcholinesterase inhibitor (AChEI) 19 in the pesticide residue compounds in the water environment pollutants will inhibit the activity of acetylcholinesterase (AChE) 24, so acetylcholinesterase (AChE) 24 cannot hydrolyze Myr23. Due to the hydrophobic effect of the long chain tail of Myr23, the spatial arrangement order of the liquid crystal molecules changes. When the conformation of the liquid crystal droplets changes, a resonance shift of the whispering gallery spectrum will occur. When the concentration of the detected pesticide residue compound is low, the liquid crystal molecules 21 inside the microspheres may still be undergoing slight deflections during the hydrolysis reaction, and this effect can no longer be reflected by the POM image. However, it can be detected using the whispering gallery excitation spectrum, indicating that the detection sensitivity is higher than that of naked eye detection.

[0077] When aptamer 26 and CTAB25 are present in the reaction solution, the electrostatic interaction between cationic CTAB25 and anionic aptamer 26 causes the liquid crystal molecule 21 to change its arrangement from parallel to perpendicular to the surface. However, when E. coli 18 is added, the molecular structure of E. coli 18 consists of an inner lipid bilayer membrane, exoplasm, outer lipid membrane and LPS. The specific binding between aptamer 26 and lipopolysaccharide LPS destroys the electrostatic interaction between aptamer 26 and CTAB25, resulting in the release of CTAB molecule 25. Since CTAB molecule 25 is amphiphilic, it induces the structure of liquid crystal molecule 21 to change from perpendicular to parallel. This liquid crystal sensing technology based on the whispering gallery mode is a promising platform for specific, sensitive, rapid and label-free detection of E. coli 18.

[0078] The above-mentioned specific embodiments further illustrate the specific preparation method of the present invention. The present invention converts the reaction process into spectral information in real time, so that the entire detection process can be accurately quantified and monitored in real time, ensuring the accuracy and reliability of the results.

[0079] In summary, the design of the present invention belongs to the field of optical microsensing, and specifically relates to a sensing method for simultaneously monitoring multiple pollutants in a water environment based on a whispering gallery mode liquid crystal microcavity. pH-sensitive molecules stearic acid, surfactant Myr, acetylcholinesterase (AChE), hexadecyltrimethylammonium bromide CTAB, aptamers and fluorescent dye DCM are co-doped into liquid crystal molecules to functionalize them. By precisely controlling the injection rate of a micro-syringe, micron-sized liquid crystal droplets are prepared, which serve as both an optical resonant microcavity and a biosensor probe. The heavy metal ions and stearic acid contained in the reaction solution have electrostatic mutual adsorption, the hydrophobic effect of Myr, and the amphiphilicity of CTAB molecules will induce 5CB molecules to change their arrangement state. These changes are sensitively captured by the whispering gallery mode laser excited in the droplets, and are accurately characterized in real time by spectral shift, thereby achieving high-sensitivity, low-detection-limit detection of pollutants in water environments.

[0080] An electronic device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0081] A computer-readable storage medium is used to store computer instructions, and when the computer instructions are executed by a processor, the steps of the above method are implemented.

[0082] The memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory, ROM, a programmable read-only memory, PROM, an erasable programmable read-only memory, EPROM, an electrically erasable programmable read-only memory, EEPROM, or a flash memory. The volatile memory may be a random access memory, RAM, which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory static RAM, SRAM, dynamic random access memory dynamic RAM, DRAM, synchronous dynamic random access memory synchronous DRAM, SDRAM, double data rate synchronous dynamic random access memory double data rate SDRAM, DDR SDRAM, enhanced synchronous dynamic random access memory enhanced SDRAM, ESDRAM, synchronous link dynamic random access memory synchlink DRAM, SLDRAM, and direct memory bus random access memory direct rambus RAM, DR RAM. It should be noted that memory of the methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0083] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center through a wired method such as coaxial cable, optical fiber, digital subscriber line digital subscriber line, DSL or wireless such as infrared, wireless, microwave, etc. to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium such as a floppy disk, a hard disk, a tape, an optical medium such as a high-density digital video disc digital video disc, DVD, or a semiconductor medium such as a solid state hard disk solid state disc, SSD, etc.

[0084] In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in a processor or an instruction in the form of software. The steps of the method disclosed in conjunction with the embodiment of the present application can be directly embodied as a hardware processor for execution, or a combination of hardware and software modules in a processor for execution. The software module can be located in a storage medium mature in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware. To avoid repetition, it is not described in detail here.

[0085] It should be noted that the processor in the embodiment of the present application can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, a digital signal processor DSP, an application-specific integrated circuit ASIC, a field programmable gate array FPGA or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined to perform. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0086] The above is a detailed introduction to the monitoring device and control method for simultaneously monitoring multiple pollutants in the water environment based on the whispering gallery mode liquid crystal microcavity proposed in the present invention, and the principle and implementation mode of the present invention are explained. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A monitoring device for simultaneously monitoring multiple pollutants in water environment based on whispering gallery mode liquid crystal microcavity, characterized by: The monitoring device comprises a 532nm pump pulse laser (1), a first semi-reflective and semi-mirror lens (2), a liquid crystal droplet (3), a 10x optical objective lens (4), a second semi-reflective and semi-mirror lens (5), a beam splitter (6), a 532nm filter (7), a charge coupled device (CCD) (8), a spectrum analyzer (9), a solution to be tested (10), a temperature controller (11), a micro-heating platform (12), a PMMA substrate (13), a quartz capillary (14), a micro-injector (15), a three-dimensional section frame (16) and a 4x optical objective lens (17); Light emitted by a 532nm pump pulse laser (1) passes through a first semi-reflecting and semi-mirror lens (2), is focused by a 4x optical objective lens (17) onto the surface of a liquid crystal droplet (3), and excites a fluorescent dye DCM to generate fluorescence. The generated fluorescence is totally internally reflected and amplified at the interface between the liquid crystal droplet (3) resonant cavity and the surrounding test solution (10) environment, and finally generates a whispering gallery mode laser emission. The whispering gallery mode laser is collected by a 10x optical objective lens (4), and sequentially passes through a second semi-reflecting and semi-mirror lens (5) and a beam splitter (6). One beam of light is filtered by a 532nm filter (7) and transmitted to a spectrometer (9) to record a spectrum, and the other beam of light enters a charge coupled device (CCD) (8) to perform droplet imaging. The data obtained by the spectrometer (9) and the charge coupled device (CCD) (8) are transmitted to a computer for information processing and display.

2. The monitoring device according to claim 1, characterized in that: The 532nm pump pulse laser (1) emits a pulse laser with a wavelength of 532nm, which serves as an excitation source and is used to excite the fluorescent dye DCM in the liquid crystal droplet (3) to generate fluorescence; The charge coupled device CCD (8) is used for droplet imaging, for capturing and recording images of the liquid crystal droplets (3), and for assisting in the detection and analysis of pollutants; The spectrum analyzer (9) is used to record and analyze the spectrum characteristics of the whispering gallery mode laser generated by the liquid crystal droplet (3), and detect and quantify the target pollutant by analyzing the changes in the spectrum.

3. The monitoring device according to claim 2, characterized in that: The liquid crystal droplets (3) are tiny droplets formed by liquid crystal materials doped with 0.01 wt.% of fluorescent dye DCM and other specific substances, and are generated in a solution to be detected through a tapered quartz capillary (14). Each liquid crystal droplet (3) is designed to be sensitive to a specific type of pollutant, and the optical changes of the liquid crystal droplet (3) are monitored through fluorescence characteristics. The other specific substances include pH-sensitive molecule stearic acid, surfactant Myr and acetylcholinesterase (AChE), cetyltrimethylammonium bromide (CTAB) and aptamer.

4. The monitoring device according to claim 3, characterized in that: The liquid crystal droplets (3) are at least three, and are doped with pH-sensitive molecule stearic acid to detect pH changes, doped with surfactant Myr and acetylcholinesterase (AChE) to detect pesticide residues, and doped with cetyltrimethylammonium bromide (CTAB) and aptamers to specifically identify microorganisms.

5. The monitoring device according to claim 4, characterized in that: The monitoring device comprises a 532nm pump pulse laser (1), a first semi-reflective and semi-mirror lens (2), a liquid crystal droplet (3), a 10x optical objective lens (4), a second semi-reflective and semi-mirror lens (5), a beam splitter (6), a 532nm filter (7), a charge coupled device (CCD) (8), a spectrum analyzer (9), a solution to be tested (10), a temperature controller (11), a micro-heating platform (12), a PMMA substrate (13), a quartz capillary (14), a micro-injector (15), a three-dimensional section frame (16) and a 4x optical objective lens (17); The solution to be tested (10) is placed on a PMMA substrate (13), and a micro-heating platform (12) is installed at the bottom; The temperature change of the micro heating platform (12) is regulated by a temperature controller (11).

6. The monitoring device according to claim 5, characterized in that: The micro-injector (15) and the liquid crystal micro-droplet (3) are precisely position-controlled by a three-dimensional electric adjustment frame (16), and the diameter of the liquid crystal micro-droplet (3) generated by the micro-injector (15) is controlled within 50 microns.

7. The monitoring device according to claim 6, characterized in that: Liquid crystal droplets (3) are prepared by a three-dimensional electric adjustment frame (16): first, an unstretched end of a quartz capillary (14) is connected to a micro-injection syringe (15) using ultraviolet curing glue; second, the stretched end of the quartz capillary (14) is fixed to the optical fiber clip of the three-dimensional adjustment frame (16), and the position of the quartz capillary (14) is accurately controlled by adjusting the three-dimensional adjustment frame (16); then, the three-dimensional adjustment frame (16) is moved to immerse the tip of the quartz capillary (14) in a liquid crystal solution to extract a small amount of the liquid crystal solution; finally, the three-dimensional adjustment frame (16) is moved to immerse the tip of the quartz capillary (14) in a solution to be tested (10), and the liquid crystal droplets (3) are formed by controlling the injection speed of the micro-injection syringe (15).

8. A control method for a sensing device for simultaneously monitoring multiple pollutants in a water environment based on a whispering gallery mode liquid crystal microcavity according to any one of claims 1 to 7, characterized in that: The control method specifically comprises the following steps: Step 1: 3 portions of 1 mL nematic liquid crystal 5CB were doped with: 0.05 wt% of stearic acid and 0.01 wt% of fluorescent dye DCM, 0.05 wt% of surfactant Myr and 0.05 wt% of acetylcholinesterase (AChE) and 0.01 wt% of fluorescent dye DCM, 0.05 wt% of hexadecyltrimethylammonium bromide (CTAB) and 0.05 wt% of aptamer and 0.01 wt% of fluorescent dye DCM; Step 2: Place the three mixed solutions in an ultrasonic machine for 30 minutes to make them fully mixed and uniform. The working temperature of the ultrasonic machine is set to 25°C. Step 3: Using flame heating taper method, a quartz capillary (14) with an outer diameter of 162 μm and an inner diameter of 100 μm is drawn into a capillary microtube with an inner diameter of 5 μm; the other end of the capillary microtube is connected to a laboratory-made micro-injection syringe (15); Step 4: by controlling the injection rate of the micro-injector (15), three liquid crystal droplets (3) with a diameter of 50 μm are generated in the reaction solution; Step 5: The temperature of the solution to be tested (10) is monitored in real time by a micro temperature probe of a temperature controller (11), and the temperature is ensured to be constant at 25°C by a feedback regulating device; Step 6: The light emitted by the 532nm pump pulse laser (1) passes through the first semi-reflective semi-mirror (2), and is finally focused by the 4x optical objective lens (17) onto the surface of the liquid crystal droplet (3) and excites the dye DCM to produce fluorescence; Step 7: The test solution (10) contains the liquid to be tested, and the heavy metal ions in the water environment pollutants will have an electrostatic interaction with stearic acid, so that the spatial arrangement order of the liquid crystal molecules changes; the acetylcholinesterase inhibitor (AChEI) in the pesticide residue compounds in the water environment pollutants will inhibit the activity of acetylcholinesterase (AChE), and thus cannot hydrolyze Myr. Due to the hydrophobic effect of the long chain tail of Myr, the spatial arrangement order of the liquid crystal molecules changes; the Escherichia coli in the water environment pollutants will specifically bind to the aptamer, destroying the electrostatic interaction between the aptamer and CTAB, and the released CTAB molecules have amphiphilicity, which causes the spatial arrangement order of the liquid crystal molecules to change; Step 8: The whispering gallery mode laser generated by the liquid crystal droplet (3) is collected by a 10x optical objective lens (4) and sequentially passes through a second semi-reflective mirror (5) and a beam splitter (6). One beam of light is filtered by a 532nm filter and transmitted to a spectrometer (9) for spectral analysis; the other beam of light enters a charge coupled device (CCD) (8) for droplet imaging, and the obtained data is transmitted to a computer for information processing and display.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method described in claim 8 are implemented.

10. A computer-readable storage medium for storing computer instructions, characterized in that: When the computer instructions are executed by a processor, the steps of the method described in claim 8 are implemented.

Images