Micro-fluidic chip for detecting various solutes in solution based on terahertz metasurface sensing

Abstract

The invention relates to a micro-fluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing. The micro-fluidic chip comprises a packaging shell, a terahertz metasurface sensor, a hydrogel layer and an electrode assembly, a groove is formed in the hydrogel layer; the terahertz metasurface sensor is arranged in the packaging shell, and the hydrogel layer is located on the upper surface of the terahertz metasurface sensor and attached to the terahertz metasurface sensor. The electrode assemblies are arranged on the two sides of the hydrogel layer, one end of each electrode assembly is connected with the hydrogel layer, and the other side of each electrode assembly extends out of the packaging shell; the micro-fluidic chip can provide a good containing carrier for subsequent solution sensing detection, the technical problems that in solution sensing detection in the prior art, the concentration of solute is difficult to distinguish, and accurate sensing cannot be achieved are solved, and the technical problems that samples are polluted, and time and labor are wasted are solved; the solute separation efficiency of a multi-solute solution is greatly improved, and the solute detection efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of terahertz metasurface sensing technology, specifically to a microfluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing. Background Technology

[0002] Terahertz waves are electromagnetic waves with wavelengths between microwaves and infrared, and frequencies ranging from 100 GHz to 10 THz. Due to their high penetration, broadband nature, and low photon energy, terahertz waves have received widespread attention and research in the past 20 years. Terahertz time-domain spectrometry (TDMA) is often used to analyze the terahertz spectral properties of materials, providing information on the vibration and rotation of molecules across a wide spectrum. However, TDMA has limited resolution, and its sensitivity is insufficient to detect differences in the spectral properties of minute samples. To meet the sensing requirements of minute samples, the intensity of the terahertz wave needs to be locally enhanced to reduce the sample quantity required. Magnetic metasurfaces are composed of periodically arranged subwavelength unit cells. The unique response of a metasurface to electromagnetic waves is determined by the geometry of its unit cell structure; we can design resonant characteristic peaks with different responses by optimizing the structural shape. Using this material, which is sensitive to changes in the local electric field environment, as a sensor in conjunction with a TDMA can significantly improve detection sensitivity without requiring sample labeling. This method has immense value for biomedical and chemical analysis.

[0003] Terahertz metasurface sensors have achieved excellent sensing sensitivity and stability in solid powder testing and biochemical tissue culture testing, but they remain challenging in solution sensing. This is because the chemical bond perturbation frequency of water molecules in the terahertz band is highly absorbed by aqueous solutions, making it difficult to distinguish solute concentrations and accurately sense terahertz waves in solution-containing tests. Furthermore, current liquid detection technologies rely on drying, which is susceptible to sample contamination during drying. Separating multiple solutes within the solution requires additional steps, and pre-detection separation takes extra time, resulting in sample contamination and significant time and labor costs.

[0004] Therefore, avoiding interference from water in the solution and achieving faster separation and detection of multiple solutes in the solution are important steps to promote the application and marketization of terahertz metasurface sensors. Summary of the Invention

[0005] The purpose of this application is to provide a microfluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing. This chip can provide a good container for subsequent solution sensing and detection, which not only solves the technical problems of difficulty in distinguishing solute concentration and inaccurate sensing in the prior art, but also solves the technical problems of sample contamination and time-consuming and labor-intensive processes. It significantly improves the solute separation efficiency of multi-solute solutions and enhances the solute detection efficiency.

[0006] To achieve the above objectives, this application provides a microfluidic chip for detecting multiple solutes in a solution based on a terahertz metasurface sensor. The microfluidic chip includes: a packaging shell, a terahertz metasurface sensor, a hydrogel layer, and an electrode assembly. Further, the hydrogel layer is a porous hydrogel layer; grooves for accommodating the target solution are formed on the hydrogel layer; the terahertz metasurface sensor is disposed inside the packaging shell, and the hydrogel layer is located on the upper surface of the terahertz metasurface sensor and is in contact with it; the electrode assembly is disposed on both sides of the hydrogel layer, one end of the electrode assembly is connected to the hydrogel layer, and the other side of the electrode assembly extends to the outside of the packaging shell.

[0007] Furthermore, the encapsulation housing includes an insulating fixing frame and a pressing plate, wherein the insulating fixing frame has a through hole and the pressing plate is disposed inside the insulating fixing frame.

[0008] Furthermore, the pressing plate includes: a first pressing plate and a second pressing plate, the first pressing plate and the second pressing plate are disposed opposite to each other, one side of the first pressing plate is in contact with one side of the hydrogel layer, and one side of the second pressing plate is in contact with one side of the terahertz metasurface sensor.

[0009] Furthermore, the first pressing plate has a length of 40-60mm, a width of 40-60mm, and a height of 3-4mm; the second pressing plate has the same length, height, and width as the first pressing plate.

[0010] Furthermore, the insulating fixing frame includes: a first insulating fixing frame and a second insulating fixing frame; the second insulating fixing frame has a limiting boss on one side relative to the first insulating fixing frame; the first insulating fixing frame is connected to the limiting boss of the second insulating fixing frame by a fixing member, and a placement cavity is formed between the first insulating fixing frame and the first insulating fixing frame.

[0011] Furthermore, the length of the first insulating bracket is 50-70 mm and the width is 50-70 mm; the height of the limiting boss of the second insulating bracket is 8-12 mm; the length and width of the second insulating bracket are the same as those of the first insulating bracket.

[0012] Furthermore, the electrode assembly includes: a first electrode plate and a second electrode plate, the first electrode plate and the second electrode plate being symmetrically disposed on both sides of the hydrogel layer; the transverse cross-section of the first electrode plate and the second electrode plate is T-shaped.

[0013] Furthermore, the first electrode plate and the second motor plate have the same structure; the first electrode plate has a length of 30-50mm, a width of 8-12mm, and a thickness of 2-4mm.

[0014] Furthermore, a set of baffles is provided between the first electrode plate and the second electrode plate. The set of baffles, together with the first electrode plate and the second electrode plate, forms a limiting groove whose size is adapted to the hydrogel layer. The hydrogel layer is located within the limiting groove.

[0015] Furthermore, the length of the enclosure panel is 40-60mm, the width is 8-10mm, and the height is 2.5-3.5mm.

[0016] Furthermore, the substrate layer of the terahertz metasurface sensor is made of fused silica material.

[0017] Furthermore, the terahertz metasurface sensor has a length of 30-50 mm, a width of 30-50 mm, and a thickness of 450-550 μm.

[0018] Furthermore, let the length of the groove on the hydrogel layer be L1, the width of the groove on the hydrogel layer be W1, and the height of the groove on the hydrogel layer be H1; the length L1, width W1, and height H1 of the groove on the hydrogel layer satisfy the following relationships: 3mm≤L1≤7mm, 3mm≤W1≤7mm, 1mm≤H1≤2mm.

[0019] Furthermore, the hydrogel layer has a length of 30-50 mm, a width of 30-50 mm, and a thickness of 2-3 mm.

[0020] Furthermore, let the length of the first pressing plate be L2 and the width of the first pressing plate be W2; let the length of the second pressing plate be L3 and the width of the second pressing plate be W3; let the length of the hydrogel layer be L4 and the width of the hydrogel layer be W4; the first pressing plate and the second pressing plate satisfy the following relationship: L2=L3 and W21=W3; the first pressing plate and the hydrogel layer satisfy the following relationship: L2>L4 and W2>W4.

[0021] The solution provided in this application has at least the following beneficial effects: By using the encapsulation shell, terahertz metasurface sensor, hydrogel layer, and electrode assembly in combination, the microfluidic chip can achieve rapid separation and detection of complex samples through electrophoresis when performing multi-solute solution sensing and detection. Specifically, the terahertz metasurface sensor and hydrogel layer are first sequentially placed inside the encapsulation shell, and then the electrode assembly is placed at both ends of the hydrogel layer. Next, the encapsulation shell is sealed and fixed, and a bias voltage is applied to both ends of the electrode assembly for electrophoresis. After electrophoresis, the top cover of the encapsulation shell and the electrode assembly are removed, and the chip is dried in a constant temperature drying oven. The multi-solute solution can then be separated, and a suitable amount of precipitate appears at the junction of the hydrogel layer and the terahertz metasurface sensor. This structure not only enables multi-solute solution sensing and detection, solving the technical problems of difficulty in distinguishing solute concentrations and inaccurate sensing in existing solutions, but also solves the problems of sample contamination and time-consuming and labor-intensive processes. It significantly improves the solute separation efficiency of multi-solute solutions and enhances solute detection efficiency.

[0022] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings: Figure 1 An exploded view of the microfluidic chip in the embodiment is shown schematically.

[0024] Figure 2 A perspective view of the microfluidic chip in the embodiment is shown schematically.

[0025] Figure 3 A top view of the microfluidic chip in the embodiment is shown schematically.

[0026] Figure 4 Schematic illustration Figure 3 Cross-sectional view of section AA.

[0027] Figure 5 Schematic illustration Figure 3 Cross-sectional view of section BB in the middle.

[0028] Explanation of reference numerals in the attached figures Encapsulation shell 01, insulating fixing frame 011, first insulating fixing frame 0111, second insulating fixing frame 0112, pressing plate 012, first pressing plate 0121, second pressing plate 0122, limiting boss 0113, terahertz metasurface sensor 02, hydrogel layer 03, groove 031, electrode assembly 04, first electrode plate 041, second electrode plate 042, enclosure plate 05. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0030] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0031] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0032] like Figure 1-3As shown, this embodiment provides a microfluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing. The microfluidic chip includes: a packaging shell 01, a terahertz metasurface sensor 02, a hydrogel layer 03, and an electrode assembly 04. Further, the hydrogel layer 03 is a porous hydrogel layer 03. The hydrogel layer 03 has grooves 031 for accommodating the target solution. The terahertz metasurface sensor 02 is disposed inside the packaging shell 01, and the hydrogel layer 03 is located on the upper surface of the terahertz metasurface sensor 02 and is in contact with it. The electrode assembly 04 is disposed on both sides of the hydrogel layer 03, one end of the electrode assembly 04 is connected to the hydrogel layer 03, and the other side of the electrode assembly 04 extends to the outside of the packaging shell 01.

[0033] By using the encapsulation shell 01, terahertz metasurface sensor 02, hydrogel layer 03, and electrode assembly 04 in combination, this microfluidic chip can achieve rapid separation and detection of complex samples through electrophoresis in the sensing and detection of multi-solute solutions. Specifically, the terahertz metasurface sensor 02 and hydrogel layer 03 are first sequentially placed inside the encapsulation shell 01, and then the electrode assembly 04 is placed at both ends of the hydrogel layer 03. Next, the encapsulation shell 01 is sealed and fixed, and a bias voltage is applied across the electrode assembly 04 for electrophoresis. After electrophoresis, the top cover of the encapsulation shell and the electrode assembly are removed, and the chip is dried in a constant temperature drying oven. The multi-solute solution can then be separated, and a suitable amount of precipitation occurs at the junction of the hydrogel layer and the terahertz metasurface sensor. This structure not only enables the sensing and detection of multi-solute solutions, solving the technical problems of difficulty in distinguishing solute concentrations and inaccurate sensing in existing solution sensing technologies, but also solves the problems of sample contamination and time-consuming and labor-intensive processes. It significantly improves the solute separation efficiency and solute detection efficiency of multi-solute solutions.

[0034] The principle behind solute separation in the mixed solution during the electrophoresis process described above is as follows: Different solute molecules have different molecular masses and charge characteristics. Substances with larger molecular masses pass through the pores of the hydrogel more slowly than those with smaller molecular masses under the same bias voltage. Different substances possess different charge characteristics, and under the influence of the voltage across the two sides, the substances will move to either side according to their own charge characteristics. Through the combined effect of these two factors, substances with different molecular masses and charge characteristics can be separated.

[0035] In a preferred embodiment, the encapsulation housing 01 includes an insulating fixing frame 011 and a pressing plate 012. The insulating fixing frame 011 has a through hole 013, and the pressing plate 012 is disposed inside the insulating fixing frame 011.

[0036] In a preferred embodiment, the pressing plate 012 includes: a first pressing plate 0121 and a second pressing plate 0122, the first pressing plate 0121 and the second pressing plate 0122 are disposed opposite to each other, one side of the first pressing plate 0121 is in contact with one side of the hydrogel layer 03, and one side of the second pressing plate 0122 is in contact with one side of the terahertz metasurface sensor 02.

[0037] Specifically, the first pressing plate 0121 and the second pressing plate 0122 are made of TPX material; TPX material has high transmittance in the terahertz band, which allows terahertz waves to effectively penetrate the pressing plate 012 without affecting the sensing and detection of multi-solute solutions in the experiment.

[0038] Furthermore, the first pressing plate has a length of 40-60mm, a width of 40-60mm, and a height of 3-4mm; the second pressing plate has the same length, height, and width as the first pressing plate.

[0039] In a preferred embodiment, the insulating bracket 011 includes: a first insulating bracket 0111 and a second insulating bracket 0112; the second insulating bracket 0112 is provided with a limiting boss 0113 on one side relative to the first insulating bracket 0112; the first insulating bracket 0111 is connected to the limiting boss 0113 of the second insulating bracket 0112 by a fastener, and a placement cavity is formed between the first insulating bracket 0111 and the second insulating bracket 0112; the first insulating bracket 0111 and the second insulating bracket 0112 are connected by a fastener (e.g., screw).

[0040] Furthermore, the length and width of the first insulating bracket are 50-70 mm; the height of the limiting boss of the first insulating bracket is 8-12 mm; the length and width of the second insulating bracket are the same as those of the first insulating bracket.

[0041] In a preferred embodiment, the electrode assembly 04 includes a first electrode plate 041 and a second electrode plate 042, which are symmetrically arranged on both sides of the hydrogel layer 03; the transverse cross-section of the first electrode plate 041 and the second electrode plate 042 is T-shaped.

[0042] Furthermore, the first electrode plate and the second motor plate have the same structure and are both T-shaped; the first electrode plate has a length of 30-50mm, a width of 8-12mm, and a thickness of 2-4mm.

[0043] In a preferred embodiment, a set of baffles 05 is further provided between the first electrode plate 041 and the second electrode plate 042. The set of baffles 05, together with the first electrode plate 041 and the second electrode plate 042, forms a limiting groove whose size is adapted to the hydrogel layer 03. The hydrogel layer 03 is located in the limiting groove.

[0044] Furthermore, the length of the enclosure panel is 40-60mm, the width is 8-10mm, and the height is 2.5-3.5mm.

[0045] In a preferred embodiment, the base layer of the terahertz metasurface sensor 02 is made of fused silica material.

[0046] Furthermore, the terahertz metasurface sensor has a length of 30-50 mm, a width of 30-50 mm, and a thickness of 450-550 μm.

[0047] Specifically, fused silica exhibits extremely low absorption loss and very high transmittance in the terahertz band (typically 0.1 THz to 10 THz). Its absorption coefficient is very small in the terahertz range, allowing terahertz waves to effectively penetrate the substrate, thus enabling sensor structures (such as antennas and resonators) to interact efficiently with terahertz waves.

[0048] like Figure 4-5 As shown, in a preferred embodiment, the length of the groove 031 on the hydrogel layer 03 is L1, the width of the groove 031 on the hydrogel layer 03 is W1, and the height of the groove 031 on the hydrogel layer 03 is H1; the length L1, width W1, and height H1 of the groove 031 on the hydrogel layer 03 satisfy the following relationships: 3mm≤L1≤7mm, 3mm≤W1≤7mm, 1mm≤H1≤2mm.

[0049] Furthermore, the hydrogel layer has a length of 30-50 mm, a width of 30-50 mm, and a thickness of 2-3 mm.

[0050] like Figure 4-5 As shown, in a preferred embodiment, the length of the first pressing plate 0121 is L2, and the width of the first pressing plate 0121 is W2; the length of the second pressing plate 0122 is L3, and the width of the second pressing plate 0122 is W3; the length of the hydrogel layer 03 is L4, and the width of the hydrogel layer 03 is W4; the first pressing plate 0121 and the second pressing plate 0122 satisfy the following relationship: L2=L3 and W21=W3; the first pressing plate 0121 and the hydrogel layer 03 satisfy the following relationship: L2>L4 and W2>W4.

[0051] Specifically, because the length and width of the hydrogel layer are smaller than those of the first and second pressing plates, leakage of liquid from the grooves in the hydrogel layer can be prevented.

[0052] like Figure 4-5 As shown, in a preferred embodiment, the thickness of the length of the enclosure 05 is H2, the thickness of the terahertz metasurface sensor 02 is H3, and the thickness of the hydrogel layer 03 is H4. The enclosure 05, the terahertz metasurface sensor 02, and the hydrogel layer 03 satisfy the following relationship: H2 = H3 + H4.

[0053] Specifically, since the thickness of the enclosure plate 05 is equal to the sum of the thickness of the terahertz metasurface sensor 02 and the thickness of the hydrogel layer 03, it can effectively enclose the terahertz metasurface sensor 02 and the hydrogel layer 03, preventing external impurities from penetrating into the hydrogel layer 03 and affecting the experimental test.

[0054] In this embodiment, the microfluidic chip is installed as follows: from top to bottom, the hydrogel layer 03, the terahertz metasurface sensor 02, and the second pressing plate 0122 are placed inside the second insulating fixing frame 0112 so that their surfaces are in contact with each other. Then, the first electrode plate 041 and the second electrode plate 042 are placed on both sides of the hydrogel layer 03 and the terahertz metasurface sensor 02 so that their sidewalls are in contact with each other. Next, a baffle is placed between the first electrode plate 041 and the second electrode plate 042. Then, various solute solutions are added into the groove of the hydrogel layer 03. Then, the first pressing plate 0121 and the first insulating fixing frame 0111 are placed on top of each other. Finally, the first insulating fixing frame 0111 and the second insulating fixing frame 0112 are fixed by bolts to obtain the microfluidic chip, which is ready for subsequent testing.

[0055] Example 1: This embodiment provides a microfluidic chip for detecting multiple solutes in a solution based on a terahertz metasurface sensor. The microfluidic chip includes, from top to bottom: a first insulating bracket 0111, a first pressing plate 0121, a hydrogel layer 03, a terahertz metasurface sensor 02, a baffle plate 05, a first electrode plate 041, a second electrode plate 042, a second pressing plate 0122, and a second insulating bracket 0112.

[0056] Specifically, the length of the first insulating fixing bracket 0111 and the second insulating fixing bracket 0112 are both 60mm and 60mm; the length of the first pressing plate 0121 and the second pressing plate are both 50mm and 50mm, and the height is 3.5mm; the length of the hydrogel layer 03 is 40mm, the width is 40mm, and the height is 2.5mm; the length of the groove on the hydrogel layer 03 is 5mm, the width is 5mm, and the height is 1.5mm; the length of the terahertz metasurface sensor 02 is 40mm, the width is 40mm, and the height is 0.5mm; the length of the enclosure plate 05 is 50mm, the width is 10mm, and the height is 3mm; the length of the first electrode plate 041 and the second electrode plate 042 are 40mm, the width is 10mm, and the height is 3mm.

[0057] Example 2 This embodiment provides a microfluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing. The structure is identical to the microfluidic chip provided in Embodiment 1, except that the thicknesses of the first pressing plate 0121, the second pressing plate, the hydrogel layer 03, the terahertz metasurface sensor 02, the enclosure plate 05, the first electrode plate 041, and the second electrode plate 042 are inconsistent. Details are as follows: In this embodiment, the thickness of the second pressing plate of the first pressing plate 0121 is 3.3 mm; the thickness of the hydrogel layer 03 is 3 mm; the thickness of the terahertz metasurface sensor 02 is 0.4 mm; the thickness of the enclosure plate 05 is 3.4 mm; and the thickness of the first electrode plate 041 and the second electrode plate 042 is 3.4 mm.

[0058] Example 3 This embodiment provides a microfluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing. The microfluidic chip structure is identical to that provided in Embodiment 1, except that the thicknesses of the first pressing plate 0121, the second pressing plate, the hydrogel layer 03, the terahertz metasurface sensor 02 enclosure plate 05, the first electrode plate 041, and the second electrode plate 042 are inconsistent; details are as follows: In this embodiment, the thickness of the second pressing plate of the first pressing plate 0121 is 3.75 mm; the thickness of the hydrogel layer 03 is 2 mm; the thickness of the terahertz metasurface sensor 02 is 0.5 mm; the thickness of the enclosure plate 05 is 2.5 mm; and the thickness of the first electrode plate 041 and the second electrode plate 042 is 2.5 mm.

[0059] Example 4 This embodiment provides a detection method for multiple solutes in a solution using a microfluidic chip based on terahertz metasurface sensing: S1. Preparation of the encapsulation shell 01: First, the structural drawing of the encapsulation shell 01 is obtained using 3D drawing software, and then the encapsulation shell 01 is obtained using 3D printing technology; S2. Fabrication of terahertz metasurface sensor 02: The designed metasurface pattern is formed on the substrate using photolithography to obtain terahertz metasurface sensor 02; S3. Preparation of hydrogel layer 03: Pour the hydrogel into a mold to form a layered precursor, then freeze the layered precursor at low temperature to crystallize the water in the solution, and finally thaw at low temperature to obtain hydrogel layer 03. S4. Preparation of electrode assembly 04: The conductive metal plate is placed in a stamping machine and stamped to obtain electrode assembly 04; S5. Prepare the mixed solution to be tested: Prepare 90-100 μL of the mixed solution for later use; S6. Electrophoretic solute separation: Place the terahertz metasurface sensor from step S2, the hydrogel layer from step S3, and the electrode assembly from step S4 into the encapsulation shell; then take an appropriate amount of the mixed solution from step S5 and place it into the groove 031 of the hydrogel layer 03, and fix the encapsulation shell 01; finally, apply a bias voltage to the electrode assembly 04 at both ends of the hydrogel layer 03 and continue electrophoresis for a first preset time. S7. Sensing and Detection: After electrophoresis, firstly, part of the insulating fixture 011 and electrode assembly 04 are removed. Then, the insulating fixture 011 with terahertz metasurface sensor 02 and hydrogel layer 03 is placed in a constant temperature drying oven and dried continuously at a preset temperature for a second preset time until various solutes are appropriately precipitated at the junction of porous hydrogel and terahertz metasurface sensor 02. Finally, the precipitated solutes are sequentially sensed and tested using a terahertz time-domain spectrometer.

[0060] Furthermore, in step S6, applying the bias voltage specifically involves setting the voltage difference between the two sides to 30-50V and the first preset electrophoresis time to 8-12 minutes.

[0061] Furthermore, in step S7, the drying temperature of the constant temperature drying oven is set to 30-50℃; the second preset drying time is 8-12 minutes.

[0062] Step S6 is implemented as follows: First, drop 35 μL of the test mixture solution into the center of the hydrogel layer (groove 11) (the drop volume should be the same as or slightly less than the groove volume). Cover with the first pressing plate and the second insulating fixing frame, and press them tightly to prevent leakage. Apply a bias voltage to both ends of the electrode assembly, setting the voltage difference between the two sides to 40V (10V per centimeter; the specific voltage difference may need to be adjusted according to the specific solute). Electrophoresis continues for 10 minutes (the specific electrophoresis time may also need to be adjusted according to the specific solute).

[0063] The specific steps of step S7 are as follows: Remove the first insulating bracket and the electrode part, and place the insulating bracket 011 with the terahertz metasurface sensor 02 and the hydrogel layer 03 into the constant temperature drying oven and dry it at 40 degrees for 10 minutes. After drying, the various solutes have been separated and a suitable amount of precipitation appears at the junction of the hydrogel layer and the terahertz metasurface sensor. This indicates that the solute separation is complete. Finally, place the insulating bracket 011 with the terahertz metasurface sensor 02 and the hydrogel layer 03 according to the position of the central spot of the terahertz time-domain spectrometer, and perform sensing tests on the separated points in sequence.

[0064] In a preferred embodiment, step S1: preparing the encapsulation shell 01 includes the following sub-steps: S11. Use SolidWorks or UG drawing software to obtain the model drawings of the first insulating fixing frame 0111, the second insulating fixing frame 0112, the first pressing plate 0121, the second pressing plate 0122 and the enclosure plate 05 in sequence. S12. Convert the model diagrams in step S11 into STL or OBJ format diagrams in sequence; S13. Import the format diagram from step S12 into slicing software: Cura or Simplify3D, then adjust the position and set the size and fill parameters to generate G-code; S14. Transfer the G code from step S13 to the 3D printer via USB, SD card, or Wi-Fi; S15. On the control panel of the 3D printer, select the G-code file uploaded in step S14, click Start Printing, and you will get the structural products of the first insulating bracket 0111, the second insulating bracket 0112, the first pressing plate 0121, the second pressing plate 0122, and the enclosure plate 05.

[0065] Furthermore, in step S11 above, the length of the first pressing plate 0121 is 40-60mm, the width is 40-60mm, and the height is 3-4mm; the length, height, and width of the second pressing plate 0122 are the same as those of the first pressing plate 0121; the length of the first insulating fixing frame 0111 is 50-70mm, and the width is 50-70mm; the height of the limiting boss 0113 of the first insulating fixing frame 0111 is 8-12mm; the length and width of the second insulating fixing frame 0112 are the same as those of the first insulating fixing frame 0111; and the length of the enclosure plate 05 is 40-60mm, the width is 8-10mm, and the height is 2.5-3.5mm.

[0066] Furthermore, in step S15 above, the 3D printer uses any one of the following raw materials when printing the first insulating fixture 0111 and the second insulating fixture 0112: PLA (polylactic acid), ABS (acrylonitrile-butadiene-styrene copolymer), PETG (polyethylene terephthalate-1,4-cyclohexanediol ester), and PEI (polyetherimide); the 3D printer uses TPX (4-methyl-1-pentene) when printing the lamination plate 012.

[0067] In a preferred embodiment, step S2, preparing the terahertz metasurface sensor O2, includes the following sub-steps: S21. Design the structure of a terahertz metasurface using electromagnetic simulation software (CST); S22. Select fused silica as the substrate material, and then clean the substrate to remove impurities and oil stains from the surface; S23. Coat the substrate surface with photoresist, then cover the photoresist with a mask, expose the photoresist with ultraviolet light to cause a photochemical reaction, and then remove the unexposed photoresist after development to form a photoresist pattern of metasurface structure on the substrate. S24. A metal thin film is deposited on the substrate surface by electron beam evaporation, and then the metal part not protected by photoresist is removed by etching process to form a metal metasurface structure. Finally, the photoresist is removed to obtain the terahertz metasurface sensor 02.

[0068] In a preferred embodiment, S3. Preparing the hydrogel layer 03 includes the following sub-steps. S31: Select gelatin and / or polyvinyl alcohol, dissolve them in water, stir evenly to prepare a solution of a certain concentration, and set aside for later use; S32: The solution prepared in step S31 is used to prepare a mixed solution containing bubbles using the modified Tessari method; S33: Transfer the mixed solution containing air bubbles from step S32 into a mold, place it in a refrigerator and freeze for a certain period of time to allow the solvent water to crystallize into ice crystals, forming a porous layered structure; S34: Place the porous layered structure from step S33 into a freeze dryer for freeze drying, and then soak it in TBE buffer solution to obtain hydrogel layer 03 with bubble structure.

[0069] Further, S4. Prepare electrode assembly 04; including the following sub-steps: S41: Select a conductive metal plate; S42: Place the metal sheet from step S41 into the mold positioning area; S43: Start the stamping machine, press down the punch, so that the sheet metal in step S42 is plastically deformed in the mold cavity to obtain a semi-finished product; S44: Deburr and clean the semi-finished product from step S43 to obtain the first electrode plate 041 and the second electrode plate 042.

[0070] This embodiment presents a novel method for detecting multi-solute mixed solutions, overcoming the limitation of existing terahertz sensing methods for detecting multi-solute solutions. It achieves rapid separation of multiple solutes through electrophoresis, and subsequent drying avoids direct detection of the solvent fraction. Furthermore, compared to traditional methods that require separation before detection, this method is faster and simplifies concentration testing. The microfluidic chip required for this method is also inexpensive and easy to fabricate. The details are as follows: The principle of this method for rapid solute separation is the same as that of electrophoresis, but it requires less time compared to conventional electrophoresis. This is because the resolution of a terahertz time-domain spectrometer can reach 1 mm, and the periodic structure of a terahertz metasurface sensor is only about 100 μm. As long as the separation distance between the two substances exceeds 1 mm, only one substance will exist within the spectrometer's detection point, and at least one periodic metasurface structure will enhance the terahertz light. Therefore, the voltage can be appropriately set according to the molecular weight of the analyte to further accelerate the testing speed. This method also has higher efficiency than solid-phase extraction and liquid-phase extraction techniques. These two common extraction techniques require selecting multiple extraction columns based on the various physicochemical properties of the substances to separate each substance sequentially, and each pass through an extraction column also requires a certain amount of time (generally more than 5 minutes per column). The entire extraction process requires conversion of sample concentration and final comparative analysis, making the analysis difficult.

[0071] The microfluidic chips required for this solution do not have high precision requirements; they can be machined at the millimeter level using lathes or rapidly fabricated using additive manufacturing methods such as 3D printing. The chip structures are reusable and have a long lifespan.

[0072] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0073] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A microfluidic chip for detecting multiple solutes in a solution based on terahertz metasurface sensing, characterized in that, The microfluidic chip includes: a package shell, a terahertz metasurface sensor, a hydrogel layer, and an electrode assembly; the hydrogel layer has grooves formed on it; the terahertz metasurface sensor is disposed inside the package shell, the hydrogel layer is located on the upper surface of the terahertz metasurface sensor, and is in contact with the terahertz metasurface sensor; the electrode assembly is disposed on both sides of the hydrogel layer, one end of the electrode assembly is connected to the hydrogel layer, and the other side of the electrode assembly extends to the outside of the package shell.

2. The microfluidic chip according to claim 1, characterized in that, The encapsulation housing includes an insulating fixing frame and a pressing plate. The insulating fixing frame has a through hole, and the pressing plate is disposed inside the insulating fixing frame.

3. The microfluidic chip according to claim 2, characterized in that, The pressing plate includes a first pressing plate and a second pressing plate, the first pressing plate and the second pressing plate are disposed opposite to each other, one side of the first pressing plate is in contact with one side of the hydrogel layer, and one side of the second pressing plate is in contact with one side of the terahertz metasurface sensor.

4. The microfluidic chip according to claim 3, characterized in that, The insulating fixing frame includes: a first insulating fixing frame and a second insulating fixing frame; the second insulating fixing frame is provided with a limiting boss on one side relative to the first insulating fixing frame; the first insulating fixing frame is connected to the limiting boss of the second insulating fixing frame by a fixing member, and a placement cavity is formed between the first insulating fixing frame and the first insulating fixing frame.

5. The microfluidic chip according to claim 1, characterized in that, The electrode assembly includes a first electrode plate and a second electrode plate, which are symmetrically arranged on both sides of the hydrogel layer; the transverse cross-section of the first electrode plate and the second electrode plate is T-shaped.

6. The microfluidic chip according to claim 5, characterized in that, A set of baffles is also provided between the first electrode plate and the second electrode plate. The set of baffles, together with the first electrode plate and the second electrode plate, forms a limiting groove whose size is adapted to the hydrogel layer. The hydrogel layer is located in the limiting groove.

7. The microfluidic chip according to any one of claims 1-6, characterized in that, The base layer of the terahertz metasurface sensor is made of fused silica material.

8. The microfluidic chip according to claim 1, characterized in that, Let the length of the groove on the hydrogel layer be L1, the width of the groove on the hydrogel layer be W1, and the height of the groove on the hydrogel layer be H1; the length L1, width W1 and height H1 of the groove on the hydrogel layer satisfy the following relationship: 3 mm≤L1≤7 mm, 3 mm≤W1≤7 mm, 1 mm≤H1≤2 mm.

9. The microfluidic chip according to claim 2, characterized in that, it is provided that... The length of the first pressing plate is L2, and the width of the first pressing plate is W2; the length of the second pressing plate is L3, and the width of the second pressing plate is W3; the length of the hydrogel layer is L4, and the width of the hydrogel layer is W4; the first pressing plate and the second pressing plate satisfy the following relationship: L2=L3 and W21=W3; the first pressing plate and the hydrogel layer satisfy the following relationship: L2>L4 and W2>W4.

10. The microfluidic chip according to claim 2, characterized in that, Let the thickness of the enclosure be H2, the thickness of the terahertz metasurface sensor be H3, and the thickness of the hydrogel layer be H4. The enclosure, the terahertz metasurface sensor, and the hydrogel layer satisfy the following relationship: H2 = H3 + H4.

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