Method for rapidly detecting heavy metal pollution by utilizing microalgae based on terahertz metamaterial sensor
By using terahertz metamaterial sensors to rapidly detect heavy metal pollution from microalgae, the problems of high cost, long processing time, and limited sensitivity in existing technologies have been solved, enabling rapid and non-destructive detection of heavy metal pollution and characterization of aquatic organism response features.
Patent Information
- Application Number
- CN202511818258.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-02-27
AI Technical Summary
Existing methods for detecting heavy metal pollution are costly, time-consuming, and difficult to directly reflect the toxic effects on aquatic organisms. Traditional terahertz detection technology has limited sensitivity when detecting low concentrations of substances.
A terahertz metamaterial sensor was used to rapidly detect heavy metal pollution using microalgae. The sensor consists of a PET substrate and a gold-plated film on the surface. The metal microstructure is a symmetrical open ring, which is periodically arranged and the concentration relationship curve is established by combining the transmission peak frequency shift.
It enables rapid, non-destructive, and sensitive detection of heavy metal pollution, characterizes the response features of aquatic organisms, and assists in assessing the pollution status of water bodies.
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Figure CN121577573A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of biosensing, and particularly relates to a method for rapidly detecting heavy metal pollution based on a terahertz metamaterial sensor and microalgae BACKGROUND
[0002] Heavy metal pollution has become one of the important global environmental problems, and its high toxicity, non-degradability and characteristics of enrichment in aquatic organisms pose a continuous threat to the ecosystem and human health. At present, the detection of heavy metals in water mainly relies on analytical techniques such as atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). These methods have high sensitivity and accuracy, but AAS has low multi-element measurement efficiency, ICP-AES and ICP-MS are strongly dependent on instruments, and these methods also have limitations such as high cost, destructiveness and long time-consuming. In addition, traditional physicochemical detection only reflects the metal content, and it is difficult to directly reflect the real toxic effects of heavy metals on aquatic organisms. Therefore, a new detection strategy that can be rapid, non-destructive, sensitive and can characterize the response characteristics of aquatic organisms is urgently needed to assist in evaluating the pollution status of water bodies.
[0003] Microalgae, as an important primary producer in aquatic ecosystems, are extremely sensitive to changes in heavy metals in water, and thus are often used as ideal biological indicator materials for monitoring water pollution. Microalgae adsorption of heavy metals can be divided into two categories: biosorption and bioaccumulation; biosorption is a passive process that does not depend on cell metabolism, the process is very fast, and is mainly completed by the cell wall and its related parts. Bioaccumulation is an active process that depends on cell metabolism, the process is slow, and requires heavy metal ions to pass through the cell membrane into the cell interior.
[0004] Terahertz waves (THz) are located in the transition region of the microwave and infrared region of the electromagnetic spectrum, with a frequency band of 0.1-10 THz, and have a significant material fingerprint recognition capability. This characteristic enables terahertz waves to detect the characteristic spectrum of many biological macromolecules and other substances. However, traditional terahertz detection technology still faces great challenges in detecting low-concentration substances, mainly because most substances have weak electromagnetic responses to terahertz waves, which limits the detection sensitivity. Metamaterials are periodic arrays of artificial electromagnetic materials with unit sizes much smaller than the incident wavelength. By optimizing the unit size, shape, size and arrangement, the electromagnetic properties can be macroscopically controlled. Therefore, terahertz metamaterial sensors can achieve high-sensitivity sensing and identification in biological detection. SUMMARY
[0005] Therefore, the purpose of the present application is to provide a method for rapidly detecting heavy metal pollution based on a terahertz metamaterial sensor and microalgae.
[0006] The application provides a method for rapidly detecting heavy metal pollution based on a terahertz metamaterial sensor, characterized in that the terahertz metamaterial sensor adopts a PET substrate and a gold film on the surface, and the terahertz metamaterial sensor is composed of a plurality of periodic structures, wherein the periodic structure is composed of a symmetric split ring.
[0007] The detection method comprises the following steps:
[0008] (1) A certain amount of microalgae is taken into a reagent tube for centrifugation, and the bottom algal mud is washed with ultrapure water for standby;
[0009] (2) Different kinds and different concentrations of heavy metal solutions are prepared, the prepared solution is poured into the harvested algal mud reagent tube for stress, and then the reagent tube is placed in a centrifuge for centrifugation, and the bottom algal mud is washed with ultrapure water to harvest the stressed algal mud;
[0010] (3) The algal mud in the reagent tube is added with ultrapure water to a specified position, and a small amount of microalgae is evenly dropped on the surface of the terahertz metamaterial sensor after shaking;
[0011] (4) The dried terahertz metamaterial sensor is placed in a terahertz system for measurement, and the terahertz spectrum information of the corresponding sample is collected;
[0012] (5) The spectrum data is smoothed, and the transmission peak frequency is extracted;
[0013] (6) The frequency shift amount in the spectrum data is fitted, and a transmission peak frequency shift-heavy metal concentration relationship curve is established.
[0014] Further, the method for rapidly detecting heavy metal pollution based on the terahertz metamaterial sensor utilizes microalgae, characterized in that the metal microstructure of the terahertz metamaterial sensor is a symmetric split ring combined in a periodic arrangement mode in an xy two-dimensional plane.
[0015] Further, the method for rapidly detecting heavy metal pollution based on the terahertz metamaterial sensor utilizes microalgae, characterized in that the substrate of the terahertz metamaterial sensor is PET material.
[0016] Further, the method for rapidly detecting heavy metal pollution based on the terahertz metamaterial sensor utilizes microalgae, characterized in that the metal microstructure of the terahertz metamaterial sensor is gold material, and the conductivity is 4.561e+07 S / m.
[0017] Further, the method for rapid detection of heavy metal pollution based on the terahertz metamaterial sensor and microalgae has the characteristics that the long dimension of the metal microstructure of the terahertz metamaterial sensor is S=38µm, the wide dimension is L=33µm, the metal microstructure width is W=5µm, the metal microstructure opening ring width is O=10µm, the symmetric opening ring is apart from g=10µm in the y-axis direction, the metal microstructure thickness is d=200nm, and the chip substrate thickness is h1=100µm.
[0018] Further, the method for rapid detection of heavy metal pollution based on the terahertz metamaterial sensor and microalgae has the characteristics that 20nm Ti is arranged as a bonding layer between the Au layer and the PET substrate.
[0019] Further, the method for rapid detection of heavy metal pollution based on the terahertz metamaterial sensor and microalgae has the characteristics that the sensor has a clear transmission peak in the 1.6-2.1THz frequency band range, and can sensitively perceive spectral movement changes.
[0020] Further, the method for rapid detection of heavy metal pollution based on the terahertz metamaterial sensor and microalgae has the characteristics that the step (1) specifically includes:
[0021] According to the preset proportioning scheme, equal amounts of microalgae are taken into reagent tubes, the microalgae in the reagent tubes are centrifuged at a speed of 8000r / min, the supernatant after centrifugation is poured out, the bottom algal mud is washed twice with ultrapure water, and the algal mud after removal of the culture medium is harvested;
[0022] Further, the method for rapid detection of heavy metal pollution based on the terahertz metamaterial sensor and microalgae has the characteristics that the step (2) specifically includes:
[0023] The concentrations of Cu, Cr, and As three kinds of heavy metal solutions are prepared as 1mg / L, 0.7mg / L, 0.5mg / L, 0.3mg / L, 0.1mg / L, 0.05mg / L, 0.01mg / L, 0.005mg / L, and 0.001mg / L, the prepared solution is poured into the harvested algal mud reagent tube for stress for ten minutes, then the microalgae in the reagent tube are centrifuged at a speed of 8000r / min, the supernatant after centrifugation is poured out, the bottom algal mud is washed twice with ultrapure water, and the algal mud after stress is harvested;
[0024] Further, the method for rapid detection of heavy metal pollution based on the terahertz metamaterial sensor and microalgae has the characteristics that the step (3) specifically includes:
[0025] The algal mud in the reagent tube is added with ultrapure water to the specified position, then the reagent tube is placed in a vortex shaker to shake the microalgae, 10 μL of microalgae is taken from high to low heavy metal concentration in turn and dropped uniformly on the surface of the metamaterial sensor by using a precision pipette, and after each sample test, the sensor is placed in a beaker for shaking and sent to a drying oven for drying treatment for 15 min, and the temperature of the drying oven is controlled at 50℃;
[0026] Further, the method for rapidly detecting heavy metal pollution based on the terahertz metamaterial sensor utilizes microalgae, and the step (4) specifically comprises:
[0027] Before the experiment, the system is dehumidified by an air dryer, and dry nitrogen is continuously filled into the system, which is detected by a hygrometer to keep the humidity below 3% and the temperature constant at 25±0.5℃. During the experiment, each sample is measured three times, and the average value of three times is taken for each spectrum. BRIEF DESCRIPTION OF DRAWINGS
[0028] Figure 1 (a) is a structural schematic diagram of the terahertz metamaterial sensor in the embodiment of the present application, Figure 1 (b) is a unit structure diagram of the terahertz metamaterial sensor under an electron microscope in the embodiment of the present application;
[0029] Figure 2 is a transmission curve diagram of the terahertz metamaterial sensor in the embodiment of the present application;
[0030] Figure 3 (a) is a transmission spectrum diagram of the terahertz metamaterial sensor in the embodiment of the present application after measuring microalgae stressed by different Cu ion solution concentrations, Figure 3 (b) is a transmission spectrum diagram of the terahertz metamaterial sensor in the embodiment of the present application after measuring microalgae stressed by different Cr ion solution concentrations, Figure 3 (c) is a transmission spectrum diagram of the terahertz metamaterial sensor in the embodiment of the present application after measuring microalgae stressed by different As ion solution concentrations;
[0031] Figure 4 (a) is a fitting curve diagram of the transmission peak frequency shift amount and the Cu solution concentration measured after Cu stress in the embodiment of the present application, Figure 4 (b) is a fitting curve diagram of the transmission peak frequency shift amount and the Cr solution concentration measured after Cr stress in the embodiment of the present application, Figure 4 (c) is a fitting curve diagram of the transmission peak frequency shift amount and the As solution concentration measured after As stress in the embodiment of the present application; DETAILED DESCRIPTION
[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the preferred embodiments of the present invention will be described in detail below. However, the following embodiments do not limit the scope of protection of the present invention.
[0033] In the embodiments of the present invention, unless otherwise described, conventional experimental methods are used. The processes involved in the embodiments are those that can be understood and easily implemented by those skilled in the art based on the product manual or basic knowledge in the field. Unless otherwise specified, the experimental materials, carriers and reagents involved in the following embodiments can be obtained from commercial sources, and therefore will not be described in detail.
[0034] Sample Preparation: The experiment used *Scenedesmus obliquus* (strain 276) purchased from the Wild Species Germplasm Bank - Freshwater Algae Bank of the Chinese Academy of Sciences. BG11 medium, suitable for the growth of *Scenedesmus obliquus*, was selected as the culture medium. 1L Erlenmeyer flasks were used for culturing the microalgae. After high-temperature sterilization, 600ml of BG11 medium solution was added to each flask. An appropriate amount of algae was placed in the flask, covered with non-woven fabric, and secured with rubber bands to prevent dust contamination. The flasks containing the microalgae were placed under a full-spectrum plant growth lamp, providing 12 hours of illumination daily to simulate natural growth. The flasks were shaken twice daily until stable growth was achieved after two months. During the cultivation period, the growth morphology of *Scenedesmus obliquus* was regularly observed using a cell counting chamber and microscope, and the cell density of the microalgae was estimated to ensure the stability of the microalgae throughout the experiment.
[0035] Example 1: Terahertz metamaterial sensor for rapid detection of heavy metal pollution in microalgae
[0036] like Figure 1 As shown in (a) and 1(b), the terahertz metamaterial sensor includes a PET substrate and a metal microstructure. The PET substrate is preferably 100µm thick, and the metal microstructure is preferably made of gold. The metal microstructure has a length S = 38µm, a width L = 33µm, a width W = 5µm, an opening ring width O = 10µm, symmetrical opening rings spaced g = 10µm apart along the y-axis, and a thickness d = 200nm. A 20nm Ti layer is placed between the metal layer and the PET substrate layer as an adhesive layer. Figure 2 This is the transmission spectrum of this structure obtained by a terahertz time-domain spectrometer.
[0037] Example 2: Stress on microalgae under different concentrations of three heavy metals, Cu, Cr, and As
[0038] The conical flask of Scenedesmus obliquus which has been stably grown for 2 months is placed on the clean bench, and a few drops of the microalgae suspension are taken with a disposable rubber head dropper and placed on a glass slide. The morphology and density of the Scenedesmus obliquus are observed under a microscope with a cover glass. An equal amount of microalgae is taken and placed in a reagent tube, and the reagent tube is centrifuged at a speed of 8000 r / min for 5 minutes. After centrifugation, the supernatant is removed, and the bottom algae mud is washed twice with ultrapure water to remove impurities, and the bottom algae mud is reserved for use.
[0039] The standard Cu, Cr, and As heavy metal solutions are prepared according to the proportion, and the concentrations are 1 mg / L, 0.7 mg / L, 0.5 mg / L, 0.3 mg / L, 0.1 mg / L, 0.05 mg / L, 0.01 mg / L, 0.005 mg / L, and 0.001 mg / L. The prepared solution is poured into the harvested algae mud reagent tube and stressed for ten minutes. Then the microalgae in the reagent tube are centrifuged at a speed of 8000 r / min, and the supernatant after centrifugation is poured out. The bottom algae mud is washed twice with ultrapure water, and the stressed algae mud is harvested.
[0040] Example 3: Rapid detection of heavy metal pollution of microalgae based on terahertz metamaterial sensor
[0041] The algae mud in the reagent tube is added with ultrapure water to the specified position, and then the reagent tube is placed in a vortex shaker to shake the microalgae. 10 μL of microalgae is taken from the heavy metal concentration from high to low in turn and uniformly dropped onto the surface of the metamaterial sensor, and after each sample test, the sensor is placed in a beaker for shaking and sent to a drying oven for drying treatment for 15 min. The temperature of the drying oven is controlled at 50℃. Before each experiment, the microalgae density is measured with a cell counter to ensure that the amount of microalgae dropped onto the metamaterial sensor is consistent.
[0042] The dried terahertz metamaterial sensor is placed between the terahertz source and the terahertz detection module to measure the transmission spectrum. Before the experiment, the system is dehumidified by an air dryer, and dry nitrogen is continuously filled into the system. The humidity is detected by a hygrometer to keep it below 3%, and the temperature is kept constant at 25±0.5℃. During the experiment, each sample is measured three times, and the average value of each spectrum is taken three times.
[0043] As Figure 3 (a), Figure 3 (b), Figure 3 (c) are the transmission spectrum graphs of the microalgae stressed by Cu, Cr, and As three kinds of heavy metal ions measured by the terahertz metamaterial sensor. As can be seen from the figure, with the increase of the concentration of heavy metals, the transmission peak will gradually red shift.
[0044] As Figure 4 (a), Figure 4 (b), Figure 4(c) The fitting curve diagram of the transmission peak frequency shift amount measured after the microalgae were stressed by Cu, Cr and As three heavy metals and the concentration of the heavy metal solution, from the diagram, it can be seen that the determination coefficient R of the fitting curve of As is 0.983, the second is 0.931 of Cu, and the last is 0.795 of Cr. 2 The results show that the present application provides a kind of terahertz metamaterial sensor based on microalgae, which has superior detection capability for rapid detection of heavy metal pollution, especially in detecting As and Cu heavy metals.
[0045] The above-described embodiments only express several embodiments of the present application, which are described in detail, but cannot be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.
Claims
1. A method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensors, characterized by, The terahertz metamaterial sensor adopts a PET substrate and a gold film plated on the surface, and is composed of a plurality of periodic structures, wherein the periodic structure is composed of a symmetric split ring. The detection method comprises the following steps: (1) A certain amount of microalgae is placed in a reagent tube for centrifugation, and the bottom algal mud is washed with ultrapure water for standby; (2) Prepare different kinds and different concentrations of heavy metal solutions, pour the prepared solution into the harvested algal mud reagent tube for stress, then put it into the centrifuge for centrifugation, and wash the bottom algal mud with ultrapure water to harvest the stressed algal mud; (3) Add ultrapure water to the algal mud in the reagent tube to the specified position, shake well, and then drop a small amount of microalgae evenly onto the surface of the terahertz metamaterial sensor; (4) The dried terahertz metamaterial sensor is placed in the terahertz detection system for measurement, and the terahertz spectrum information of the corresponding sample is collected; (5) Smooth the spectrum data and extract the transmission peak frequency; (6) Based on the frequency shift amount in the spectrum data, a fitting is performed to establish a transmission peak frequency shift-heavy metal concentration relationship curve.
2. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The metal microstructure of the terahertz metamaterial sensor is a symmetric split ring arranged periodically in an xy two-dimensional plane.
3. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The substrate of the terahertz metamaterial sensor is PET material.
4. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The metal microstructure of the terahertz metamaterial sensor is gold material, and the conductivity is 4.561e+07 S / m.
5. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The length of the metal microstructure of the terahertz metamaterial sensor is S=38µm, the width is L=33µm, the width of the metal microstructure is W=5µm, the width of the split ring of the metal microstructure is O=10µm, the symmetric split ring is spaced apart by g=10µm in the y-axis direction, the thickness of the metal microstructure is d=200nm, and the thickness of the chip substrate is h1=100µm.
6. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, A 20nm Ti bonding layer is arranged between the Au layer and the PET substrate.
7. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The sensor has a distinct transmission peak in the 1.6-2.1THz frequency band range, and can sensitively perceive spectral shift changes.
8. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The step (1) specifically comprises: According to a predetermined proportioning scheme, an equal amount of microalgae is placed in a reagent tube, and the microalgae in the reagent tube is centrifuged at a speed of 8000r / min, the supernatant after centrifugation is poured out, and the bottom algal mud is washed twice with ultrapure water to harvest the algal mud after removing the culture medium.
9. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The step (2) specifically comprises: Prepare Cu, Cr, As three kinds of heavy metal solution concentration: 1mg / L, 0.7 mg / L, 0.5 mg / L, 0.3 mg / L, 0.1 mg / L, 0.05 mg / L, 0.01 mg / L, 0.005 mg / L, 0.001 mg / L, pour the prepared solution into the harvested algal mud reagent tube for stress for ten minutes, then centrifuge the microalgae in the reagent tube at a speed of 8000r / min, pour out the supernatant after centrifugation, wash the bottom algal mud twice with ultrapure water, and harvest the stressed algal mud.
10. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The step (3) specifically comprises: The algal mud in the reagent tube is added with ultrapure water to the specified position, and then the reagent tube is placed in a vortex shaker to shake the microalgae. A precision pipette gun is used to take 10 μL of microalgae from high to low in heavy metal concentration and drop them uniformly on the surface of the metamaterial sensor. After each sample test, the sensor is placed in a beaker for shaking and sent to a drying oven for drying treatment for 15 min, with the temperature of the drying oven controlled at 50°C.
11. The method for rapid detection of heavy metal pollution using microalgae based on terahertz metamaterial sensor according to claim 1, characterized in that, The step (4) specifically comprises: Before the experiment, the system is dehumidified by an air dryer, and dry nitrogen is continuously filled into the system. The humidity is detected by a hygrometer to keep the humidity below 3%, and the temperature is kept constant at 25±0.5℃. During the experiment, each sample is measured three times, and the average value of three times is taken for each spectrum.