Terahertz biosensor chip based on MXene / variable polymer composite metamaterial

Abstract

The invention belongs to the technical field of medical engineering crossing and terahertz, and provides an MXene / variable polymer composite metamaterial-based terahertz biosensor chip, which comprises a silicon-based metamaterial chip and an MXene / variable polymer composite metamaterial layer formed on the surface of the silicon-based metamaterial chip, a variable polymer chain segment serving as a receptor in a biomedical sensing process is connected between the MXene nanosheets through chemical bonds; when a solution containing a ligand (namely a substance to be detected) passes through the terahertz sensing chip, the ligand can induce a high polymer material serving as an acceptor to generate conformational change, so that the orientation, interlayer spacing and other microstructures of the MXene nanosheet compounded with the high polymer material are changed, the conductivity of the metamaterial is changed, and the detection sensitivity is improved. The absorption characteristic of terahertz waves continuously irradiated on the chip is changed, and biomedical detection is realized by detecting the change of the terahertz absorption frequency; in conclusion, the high resolution ratio is guaranteed, meanwhile, the detection cost is lower, and the structure is light and simple.

Description

Technical Field

[0001] The present invention belongs to the fields of medical engineering intersection and terahertz technology, and specifically provides a terahertz biosensing chip based on MXene / variable polymer composite metamaterials. Background Art

[0002] Biomedical detection refers to the process of quantitatively or qualitatively analyzing the human body and its biological signs through biological, medical, and technical means to diagnose diseases, monitor health conditions, or guide treatment decisions; with the continuous progress of technology, biomedical detection technology has become an important part of modern medicine and plays a key role in clinical diagnosis, disease prevention, drug research and development, and health management. In recent years, the development of biomedical detection has shown a rapid trend, especially driven by genomics, molecular biology, and bioinformatics; traditional detection methods, such as blood tests, imaging examinations, and physiological monitoring, have gradually been combined with new technologies such as high-throughput screening, molecular biomarker detection, and artificial intelligence-assisted analysis. These emerging technologies not only improve the sensitivity and specificity of detection but also provide a theoretical basis and technical support for personalized medicine and precision treatment. Despite the rapid development of biomedical detection technology, it still faces a series of challenges, such as detection accuracy, cost control, convenience and compliance of sample collection, etc.

[0003] In recent years, terahertz spectroscopy technology can achieve high-time-resolution measurements without the need for biohazard labels or reagents, and has become increasingly prominent due to its fast and label-free measurement capabilities, making it very suitable for biomedical detection. Since the energy of terahertz waves is relatively low, different from the commonly used laser and photoelectric detection technologies in the infrared and visible light bands, the detection of terahertz waves often requires special materials and technologies; especially the lack of natural condensed matter materials with energy band gaps corresponding to terahertz wave energy is one of the bottlenecks restricting the wide application of terahertz technology.

[0004] MXene, as an emerging two-dimensional material, has characteristics such as good mechanical flexibility, good electrical conductivity, large specific surface area, and certain biocompatibility, and has attracted much attention in recent years; it is worth noting that due to its high electrical conductivity and special structure, it exhibits strong absorption of terahertz waves, making it possible to make a sensing chip for biomedical detection by combining MXene with a variable polymer material sensitive to biomolecules. Summary of the Invention

[0005] The purpose of the present invention is to provide a terahertz biosensing chip based on MXene / variable polymer composite metamaterials to achieve various biomedical detections.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A terahertz biosensing chip based on MXene / variable polymer composite metamaterials, characterized in that it includes: a silicon-based metamaterial chip and an MXene / variable polymer composite metamaterial layer formed on its surface, wherein the MXene / variable polymer composite metamaterial layer is composed of MXene nanosheets and variable polymers, the MXene nanosheets are formed on the surface of the silicon-based metamaterial chip by self-assembly, and both ends of the variable polymer chain segments are connected between the MXene nanosheets by chemical bonds.

[0008] Further, the Mxene material is Ti3C2Tx (T: surface-modified group), Ti2C or Ti3CN x 。

[0009] Further, the variable polymer is silk fibroin, polycaprolactone, polylactic acid, polyurethane, silk fibroin, polydopamine, chitosan or polyethylene glycol.

[0010] Further, the working process of the terahertz biosensing chip based on the MXene / variable polymer composite metamaterial is as follows: integrate the terahertz biosensing chip into a microfluidic system, then continuously irradiate the surface of the terahertz sensing chip with terahertz waves, and detect the terahertz transmission spectrum, and realize biomedical detection through the characterization of the terahertz wave absorption frequency.

[0011] Furthermore, the microfluidic control system includes: a circulation pump, a heat exchanger and pipelines. After the system is started, the circulation pump sequentially guides the solution containing the substance to be detected through the heat exchanger and the terahertz sensing chip, and then sends it back into the circulation pump to realize circulation.

[0012] Based on the above technical solutions, the beneficial effects of the present invention are as follows:

[0013] This embodiment provides a terahertz biosensing chip based on MXene / variable polymer composite metamaterials, including: a silicon-based metamaterial chip and an MXene / variable polymer composite metamaterial layer formed on its surface. The variable polymer chain segments serving as receptors in the biomedical sensing process are connected between MXene nanosheets through chemical bonds. When a solution containing a ligand (i.e., the substance to be detected) passes through the terahertz sensing chip, the ligand can induce a conformational change in the polymer material serving as the receptor, resulting in changes in the microstructure such as the orientation and layer spacing of the MXene nanosheets complexed therewith, thereby changing the conductivity of the metamaterial and causing a change in its terahertz wave absorption characteristics for the continuous irradiation on the chip. By detecting the change in the terahertz absorption frequency, the biomedical detection is realized. Compared with traditional biomedical testing technologies and chips, the terahertz biosensing chip provided by the present invention has a lower detection cost while ensuring a high resolution, and has a light and simple structure. In addition, the present invention has the ability of fast and label-free measurement, and does not require biohazard labels or reagents. Description of the Drawings

[0014] Figure 1 It is a schematic structural diagram of the terahertz biosensing chip based on MXene / variable polymer composite metamaterials in the present invention.

[0015] Figure 2 It is a schematic surface structural diagram of the terahertz biosensing chip based on MXene / variable polymer composite metamaterials in the present invention.

[0016] Figure 3 It is an XPS characterization result diagram of MXene binding multiple substances in the terahertz biosensing chip based on MXene / variable polymer composite metamaterials in the present invention. Detailed Embodiments

[0017] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and the drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0018] This embodiment proposes a terahertz biosensing chip based on MXene / variable polymer composite metamaterials for biomedical detection, and its structure is as Figure 1As shown in the figure, it includes: a silicon-based metamaterial chip and an MXene / variable polymer composite metamaterial layer formed on its surface. Among them, the MXene / variable polymer composite metamaterial layer is composed of MXene nanosheets and variable polymer segments. The MXene nanosheets are formed on the surface of the silicon-based metamaterial chip by self-assembly, and the two ends of the variable polymer segments are connected between the MXene nanosheets through chemical bonds. Specifically, driven by the Marangoni effect, MXene forms nanosheets on the surface of the bare metamaterial chip by self-assembly, and then the functional groups on the surface of MXene are modified to combine with the variable polymer sensitive to biomolecules to form a composite metamaterial. The two ends of the variable polymer segments are respectively connected between the MXene nanosheets through chemical bonds; the chip is integrated into a microfluidic system, and terahertz waves are vertically irradiated on the top of the chip. When biomolecules as ligands pass through the chip, they can induce conformational changes in the polymer material as the receptor, resulting in changes in the microstructure such as the orientation and layer spacing of the MXene nanosheets combined with it, thereby changing the conductivity of the metamaterial and changing its absorption characteristics of the terahertz waves continuously irradiated on the chip. By detecting the change in the terahertz absorption frequency, the biomedical detection is realized.

[0019] Furthermore, in this embodiment, the Mxene material is specifically selected as Ti3C2Tx, where T is the surface-modified group, and the Ti3C2Tx monolayer nanosheets are obtained by selective etching (etching off the Al atomic layer) and intercalation of the precursor Ti3AlC2.

[0020] Furthermore, in this embodiment, the variable polymer substance is specifically selected as silk fibroin. The Ti3C2Tx monolayer nanosheets are surface-modified so that the two ends of the silk fibroin are connected between the MXene nanosheets through chemical bonds. The connection process is specifically as follows

[0021] (1) Surface modification of MXene: Anchoring of silane coupling agent;

[0022] The surface of MXene is rich in hydroxyl groups (-OH). The silane coupling agent (such as amino silane APTES) first hydrolyzes to generate silanol (-Si-OH): Si-O-R + H2O → Si-OH + ROH. Subsequently, the silanol undergoes a condensation reaction with the hydroxyl groups of MXene to form a stable Si-O-Ti (or Si-O-M, M is the metal in MXene) covalent bond, fixing the silane coupling agent on the surface of MXene: Si-OH + Ti-OH → Si-O-Ti + H2O;

[0023] (2) Bonding of the organic end of the silane coupling agent with silk fibroin

[0024] The organic functional groups of the silane coupling agent (such as amino group, -NH2) react with the hydroxyl groups in the active groups of silk fibroin: SF-OH + NH2-Si-MXene → SF-O-NH-Si-MXene + H2O, forming ether bonds or condensation products;

[0025] Through the above chemical reactions, the combination of silk fibroin and MXene nanosheets is achieved.

[0026] Furthermore, in this embodiment, the silicon-based metamaterial chip is as Figure 1 shown, and is prepared through processes such as silicon wafer cleaning, gold film deposition, coating with ultraviolet photoresist, etching to form an array, ion beam etching and polishing, and metamaterial chip cleaning. Specifically, it includes: a silicon-based substrate and a resonant ring array on its upper surface. The resonant units in the resonant ring array are composed of concentric squares symmetrically connected by four sides. The sides of the inner square are connected to the sides of the outer square in the direction of the axis of symmetry, and openings are etched at the four corners of the inner square along the diagonal direction, as Figure 2 shown. The side length f of the outer square is 45 μm, the frame width w is 5 μm, the side length d2 of the inner square is 16 μm, the frame width is (d2 - d1) / 2 (5.5 μm), the connection side width g between the inner square and the outer square is 5 μm, and openings with an etching width l of 2 μm are etched at the four corners of the inner square. The thickness of the gold film (the thickness of the resonant ring array) is 50 nm to 100 nm.

[0027] Furthermore, the above terahertz biosensing chip based on MXene / variable polymer composite metamaterials is prepared by the following steps:

[0028] Step 1: Configure Mxene (Ti3C2Tx monolayer nanosheets) into a Mxene solution with a concentration of 3.75 μg / ml. Slowly add ethyl acetate solution to extract MXene to the surface of the solution. Place the metamaterial chip flat and quickly in contact with the surface of the solution. Through the Marangoni effect, self-assemble it on the metamaterial chip to form MXene nanosheets. Clean the surface with deionized water and dry it to obtain a MXene-metamaterial chip;

[0029] Step 2: Immerse the MXene-metamaterial chip in a silane coupling agent solution and let it stand for 2 h to 48 h. Then wash the MXene-metamaterial chip soaked in the silane coupling agent solution clean with deionized water and place it in the air to dry naturally to obtain a modified MXene-metamaterial chip, which is convenient for combining with various variable polymer substances to form a composite; as Figure 3 shown in the XPS characterization of modified MXene combined with different substances. It can be seen that there are obvious differences in the XPS curves of modified MXene combined with different substances, thus proving that the modification has a greater impact on the properties of MXene;

[0030] Step 3: Immerse the modified MXene-metamaterial chip in the silk fibroin solution and let it stand for 30 min to allow them to fully combine into MXene / silk fibroin composite metamaterial. Rinse the unbound silk fibroin with deionized water, and air-dry it to obtain a terahertz biosensing chip based on MXene / variable polymer composite metamaterial.

[0031] Next, integrate the terahertz biosensing chip based on MXene / variable polymer composite metamaterial in this embodiment onto a microfluidic system for biomedical detection. The microfluidic system includes: a circulation pump, a heat exchanger, and pipelines; an aptamer (a single-stranded nucleic acid or peptide chain that can specifically bind to specific target molecules such as proteins, nucleic acids, or small molecules) is selected as the biological sample to be detected, which can specifically bind to the composite metamaterial in the chip; integrate the terahertz biosensing chip based on MXene / variable polymer composite metamaterial into the microfluidic system containing the aptamer solution, and realize biomedical detection by detecting the change in terahertz absorption frequency.

[0032] As described above, it is only the specific implementation manner of the present invention. Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features; all the disclosed features, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A terahertz biosensing chip based on MXene / variable polymer composite metamaterials, characterized in that, Including: A silicon-based metamaterial chip and an MXene / variable polymer composite metamaterial layer formed on its surface. Among them, the MXene / variable polymer composite metamaterial layer is composed of MXene nanosheets and variable polymers. The MXene nanosheets are formed on the surface of the silicon-based metamaterial chip by self-assembly, and both ends of the variable polymer chain segments are connected between the MXene nanosheets through chemical bonds.

2. The terahertz biosensing chip based on MXene / variable polymer composite metamaterials according to claim 1, characterized in that, The Mxene material uses Ti3C2Tx (T: surface-modified group), Ti2C or Ti3CN x .

3. The terahertz biosensing chip based on MXene / variable polymer composite metamaterials according to claim 1, wherein The variable polymer is silk fibroin, polycaprolactone, polylactic acid, polyurethane, silk fibroin, polydopamine, chitosan or polyethylene glycol.

4. The terahertz biosensing chip based on the MXene / variable polymer composite metamaterial according to claim 1, characterized in that, The working process of the terahertz biosensing chip based on the MXene / variable polymer composite metamaterial is as follows: Integrate the terahertz biosensing chip into the microfluidic system, then continuously irradiate the surface of the terahertz sensing chip with terahertz waves, and detect the terahertz transmission spectrum to achieve biomedical detection through the characterization of the terahertz wave absorption frequency.

5. The terahertz biosensing chip based on the MXene / variable polymer composite metamaterial according to claim 4, characterized in that, The microfluidic control system includes: a circulation pump, a heat exchanger and pipelines. After the system is started, the circulation pump successively guides the solution containing the substance to be detected through the heat exchanger and the terahertz sensing chip, and then sends it back into the circulation pump for circulation.

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