All-hydroxyl group mxene-modified terahertz metamaterial chip for blood detection
By treating MXene with a NaOH/NaI molten salt system, fully hydroxyl-terminated MXene nanosheets were prepared for use in terahertz metamaterial chips. This solved the problems of unstable sensing signals and slow response speed, and enabled highly sensitive and rapid label-free blood detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2026-05-20
- Publication Date
- 2026-07-21
AI Technical Summary
Existing MXene-based terahertz sensing technologies suffer from problems such as unstable sensing signals, difficulty in controlling end-group hybridization, and sensing responses that are limited by polymer dynamics processes and have complex structures, making it difficult to meet the sensitivity and response speed requirements of blood testing.
The surface end groups of initial MXene were treated with a NaOH/NaI molten salt system to prepare fully hydroxyl-terminated MXene nanosheets, which were used to construct terahertz metamaterial chips to achieve highly sensitive and rapid label-free detection by directly interacting with biomolecules through hydrogen bonding or electrostatic interactions.
It achieves stability and repeatability of sensing signals, improves biomolecule binding efficiency, simplifies the structure, and enhances sensing sensitivity and response speed, making it suitable for the immediate detection of biomarkers in blood.
Smart Images
Figure CN122430278A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of terahertz biosensing technology, specifically providing a terahertz metamaterial chip based on MXene modified with all-hydroxyl end groups and its application in blood detection. Background Technology
[0002] Biomedical testing plays a crucial role in disease diagnosis, health monitoring, and treatment guidance. However, traditional methods such as blood biochemistry analysis and enzyme-linked immunosorbent assay (ELISA) are generally cumbersome to operate, have long testing cycles, and require labeling reagents, making it difficult to meet the urgent clinical demand for rapid, convenient, low-cost, and real-time testing.
[0003] Terahertz spectroscopy offers a new solution to the aforementioned problems due to its unique advantages. Terahertz waves have extremely low photon energy (on the order of millielectronvolts), which will not cause ionization damage to biomolecules. At the same time, the characteristic absorption of the collective motion modes of various biomolecules such as proteins and nucleic acids, such as skeletal vibrations and hydrogen bond stretching, happens to be located in the terahertz band. Based on these characteristics, terahertz technology can achieve label-free, non-destructive, and highly sensitive detection, and is especially suitable for the analysis of biological samples such as blood. In recent years, it has become a research hotspot in the medical-engineering interdisciplinary field.
[0004] To enhance the interaction between terahertz waves and biomolecules and improve sensing sensitivity, researchers have turned their attention to novel two-dimensional materials. Among them, MXene (two-dimensional transition metal carbides and / or nitrides) is considered an ideal sensitive material for constructing terahertz biosensor chips due to its high conductivity, large specific surface area, excellent hydrophilicity, and strong absorption capacity for terahertz waves. However, current MXene-based terahertz sensing technology still faces challenges: First, the MXene surface prepared by traditional fluorine etching methods has mixed end groups (-F, -OH, -O, -Cl, etc. coexist), making it difficult to precisely control properties such as conductivity and resulting in poor sensing signal stability. Second, existing end group control methods, such as alkaline treatment or high-temperature annealing, suffer from low substitution efficiency or are prone to material oxidation, making it difficult to obtain MXene with highly uniform end groups. Third, some schemes use MXene to combine with variable polymers to indirectly achieve sensing through polymer conformational changes, but the response is limited by polymer dynamics and the structure is complex. Therefore, there is an urgent need to develop an MXene-modified terahertz sensing chip with uniform surface end groups, stable structure, and direct response to biomolecules to meet the sensitivity and response speed requirements of blood detection applications. Summary of the Invention
[0005] The purpose of this invention is to provide a terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection, thereby overcoming many shortcomings of existing technologies. This invention uses MXene nanosheets with all-hydroxyl (-OH) end groups as the terahertz sensing layer. The highly uniform end group types effectively solve the problem of unstable sensing signals caused by mixed end groups in traditional MXene. Simultaneously, the all-hydroxyl end groups endow the chip with excellent hydrophilicity and direct response to biomolecules, achieving highly sensitive and rapid-response label-free terahertz biosensing detection without the need for intermediate sensing layers such as polymers.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] A terahertz metamaterial chip modified with MXene for blood detection is characterized by comprising: a silicon-based metamaterial chip substrate and a MXene-modified layer with hydroxyl end groups formed on the surface of the silicon-based metamaterial chip substrate; wherein the silicon-based metamaterial chip substrate is composed of a high-resistivity silicon substrate and a periodic superstructure metal thin film, and the MXene-modified layer with hydroxyl end groups is composed of two-dimensional MXene nanosheets with hydroxyl (-OH) end groups on the surface, and the MXene nanosheets with hydroxyl end groups are obtained by surface end group substitution treatment of initial MXene using a NaOH / NaI molten salt system.
[0008] Furthermore, in the NaOH / NaI molten salt system, the heteroterminal groups such as -F and / or -Cl on the initial MXene surface are converted by OH... - Complete ion substitution yields MXene nanosheets with fully hydroxyl-terminated ends.
[0009] Furthermore, the periodic superstructure metal thin film is a metal resonant ring array, which is composed of multiple resonant units arranged periodically. Each resonant unit consists of an inner square and an outer square arranged concentrically. The inner square and the outer square are connected by a connecting edge in the direction of the axis of symmetry. The four corners of the inner square are etched with openings along the diagonal direction.
[0010] Furthermore, the initial MXene material includes at least one of Ti3C2, Ti2C, Nb2C, V2C, Mo2C, Nb4C3, Ta4C3, Mo2TiC2, and Mo2Ti2C3.
[0011] Furthermore, the fully hydroxyl-terminated MXene modification layer is formed on the surface of the silicon-based metamaterial chip substrate through self-assembly. The fully hydroxyl-terminated MXene nanosheets are dispersed in a solvent to form a dispersion, and the silicon-based metamaterial chip substrate is immersed in the dispersion. The fully hydroxyl-terminated MXene nanosheets self-assemble on the surface of the silicon-based metamaterial chip substrate to form a uniform modification layer.
[0012] Furthermore, the working process of the terahertz metamaterial chip based on MXene modified with all-hydroxyl groups is as follows: the chip is integrated into a microfluidic system, and a blood sample solution containing the target biomolecule flows through the chip surface; the chip surface is continuously irradiated with terahertz waves, and the terahertz transmission or reflection spectrum is detected in real time; the target biomolecule directly changes the surface conductivity of the MXene-modified layer through hydrogen bonding or electrostatic interaction with the all-hydroxyl end groups on the MXene surface, thereby changing the terahertz absorption characteristics of the metamaterial; by monitoring the changes in terahertz absorption frequency or intensity, label-free quantitative detection of the target biomolecule is achieved.
[0013] Furthermore, the microfluidic system includes a circulation pump, a heat exchanger, and pipelines. After the system is started, the circulation pump guides the solution containing the analyte through the heat exchanger and the terahertz metamaterial chip, and then returns it to the circulation pump to achieve circulation.
[0014] Furthermore, the terahertz metamaterial chip based on MXene modified with all-hydroxyl groups is prepared by the following steps:
[0015] MAX phase ceramic powder was selectively etched with a fluorine-containing etching solution to obtain an initial MXene material, wherein the surface end groups of the initial MXene material contain -F and / or -Cl;
[0016] The initial MXene material was placed in a mixed molten salt system composed of NaOH and NaI, and heated under an inert atmosphere to react, allowing the OH groups in the molten salt to react. - Ions replace the -F and / or -Cl end groups on the surface of the initial MXene material to obtain fully hydroxyl-terminated MXene; the reaction product is washed, centrifuged, and dried to obtain fully hydroxyl-terminated MXene powder;
[0017] All-hydroxyl-terminated MXene powder is dispersed in a solvent, and an all-hydroxyl-terminated MXene modification layer is formed on the surface of a silicon-based metamaterial chip substrate by self-assembly or coating.
[0018] Furthermore, in the mixed molten salt system, the molar ratio of NaOH to NaI is 1:0.2 to 1:0.5.
[0019] Furthermore, the mass ratio of the initial MXene material to the mixed molten salt system was 1:14 to 1:16; the heating temperature was 200°C to 280°C, and the time was 30 min to 120 min.
[0020] Based on the above technical solution, the beneficial effect of the present invention is to provide a terahertz metamaterial chip modified with all-hydroxyl group MXene for blood detection, which has the following advantages:
[0021] 1. MXene nanosheets with all-hydroxyl end groups were prepared by using a NaOH / NaI molten salt system to treat the surface end groups of MXene. This method has extremely high end group substitution efficiency and can completely eliminate the -F, -Cl and other impure end groups introduced by traditional etching processes, thereby achieving a high degree of uniformity of end group types and ensuring the stability of the electrical properties of MXene and the repeatability of the sensing signal.
[0022] 2. The all-hydroxyl end groups endow MXene with excellent hydrophilicity, which is conducive to the uniform spreading and full contact of blood samples on the chip surface, and improves the binding efficiency of biomolecules and the sensitive layer.
[0023] 3. It abandons the indirect sensing mode of "MXene / variable polymer composite". The biomolecules to be tested directly bind to the all-hydroxyl end groups on the surface of MXene through hydrogen bonding or electrostatic interaction, which changes the surface conductivity of the MXene modified layer and thus causes changes in terahertz absorption characteristics. This direct action mechanism has a faster response speed and avoids the structural complexity and consistency deviation caused by the introduction of polymer layer.
[0024] 4. The resonant ring structure of silicon-based metamaterial chips can generate a strong local electromagnetic field enhancement effect in the terahertz band, which, in synergy with the high terahertz absorption characteristics of all-hydroxyl MXene, significantly improves the sensing sensitivity.
[0025] In summary, the terahertz metamaterial chip modified with all-hydroxyl groups MXene provided by this invention has advantages such as label-free, rapid detection, simple structure, and low cost. It is especially suitable for the point-of-care detection of biomarkers in blood and has broad prospects for clinical application. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the terahertz metamaterial chip based on the all-hydroxyl group MXene modified in this invention.
[0027] Figure 2 This is a schematic diagram of the surface structure of the terahertz metamaterial chip modified with MXene based on all-hydroxyl groups in this invention. Detailed Implementation
[0028] 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 accompanying drawings; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0029] This embodiment provides a terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection, the structure of which is as follows: Figure 1As shown, it includes: a silicon-based metamaterial chip substrate and a fully hydroxyl-terminated MXene modification layer formed on the surface of the substrate; wherein, the silicon-based metamaterial chip substrate is composed of a high-resistivity silicon substrate and a periodic superstructure metal thin film, the periodic superstructure metal thin film being a metal resonant ring array; the fully hydroxyl-terminated MXene modification layer is composed of two-dimensional MXene nanosheets with fully hydroxyl (-OH) end groups on the surface; the fully hydroxyl-terminated MXene nanosheets are obtained by surface end group substitution treatment of initial MXene using a NaOH / NaI molten salt system.
[0030] Furthermore, such as Figure 2 As shown, each resonant unit in the resonant ring array consists of concentric inner and outer squares. The inner and outer squares are connected by connecting edges along the four axes of symmetry, and the four corners of the inner square have openings etched along the diagonal direction. In this embodiment, the outer square has a side length of 45 μm and a border width of 5 μm; the inner square has a side length of 16 μm and a border width of 5.5 μm; the connecting edge width between the inner and outer squares is 5 μm; and the gap width of the openings at the four corners of the inner square is 2 μm. The metal resonant ring is made of gold with a thickness of 50 nm to 100 nm. This metamaterial structure can excite localized surface plasmon resonance in the terahertz band, generating strong electromagnetic field enhancement and providing a highly sensitive resonant response for terahertz sensing.
[0031] Furthermore, the MXene-modified layer with all-hydroxyl end groups is composed of Ti3C2(OH)2 nanosheets with all-hydroxyl (-OH) end groups on the surface, which are prepared by the following steps:
[0032] Step 1. Multilayer Ti3C2T x Preparation of MXene;
[0033] 1 g of Ti3AlC2 MAX phase ceramic powder was slowly added to 20 mL of etching solution, which was prepared by 12 mL of 9M hydrochloric acid, 2 mL of 49% hydrofluoric acid, and 6 mL of deionized water. The mixture was stirred at 400 rpm for 24 h at room temperature to selectively etch away the Al atomic layers in the MAX phase. After the reaction, the product was repeatedly washed with deionized water by centrifugation at 3500 rpm for 5 min each time, until the pH of the supernatant reached 6, thus obtaining multilayer Ti3C2T x MXene, the multilayer Ti3C2T x MXene was vacuum dried at 60°C for 8 hours to obtain multilayer MXene powder;
[0034] Step 2. Preparation of all-hydroxyl-terminated Ti3C2(OH)2 MXene by NaOH / NaI molten salt treatment;
[0035] Weigh 200mg of the above multilayer Ti3C2T x MXene powder was thoroughly mixed and ground with a mixed molten salt consisting of NaOH and NaI; the molar ratio of NaOH to NaI was 1:0.2 to 1:0.5, and the total amount of molten salt was approximately 3g. The mixture was placed in a graphite crucible and heated in a tube furnace under an argon atmosphere to 200-280℃ at a heating rate of 5℃ / min, and held at that temperature for 30-120min to allow the OH groups in the molten salt to react. - Ions will Ti3C2T x The surface heteroterminal groups such as -F and -Cl are completely replaced to obtain multilayer Ti3C2(OH)2 MXene with all-hydroxyl end groups. The reaction formula is: Ti3C2(F)2+2NaOH=Ti3C2(OH)2+2NaF (taking -F as an example).
[0036] Step 3. Preparation of monolayer all-hydroxyl-terminated MXene dispersion;
[0037] The all-hydroxyl-terminated multilayer Ti3C2(OH)2 MXene powder obtained in step 2 was added to deionized water and sonicated in an ice bath for 0.5-1 h to exfoliate the multilayer MXene into single-layer or few-layer nanosheets. After sonication, the nanosheets were centrifuged at 3500 rpm for 5 min and the supernatant was collected to obtain a dispersion of single-layer all-hydroxyl-terminated Ti3C2(OH)2 MXene nanosheets. The concentration of the dispersion was adjusted to 0.1-1.0 mg / mL for later use.
[0038] Step 4. Fabrication of silicon-based metamaterial chips;
[0039] A high-resistivity silicon wafer was selected as the substrate and subjected to standard cleaning and drying processes. A gold film with a thickness of 50-100 nm was deposited on the clean silicon substrate surface by electron beam evaporation. Ultraviolet photoresist was spin-coated on the gold film surface, and a resonant ring array pattern was patterned on the photoresist by electron beam lithography. After development, the pattern was transferred to the gold film layer by ion beam etching to form a resonant ring array structure. Finally, the residual photoresist was removed, the chip surface was cleaned with deionized water and dried to obtain a silicon-based metamaterial chip.
[0040] Step 5. Self-assembly of the all-hydroxyl-terminated MXene modified layer;
[0041] The silicon-based metamaterial chip prepared in step 4 was flatly immersed in the dispersion of all-hydroxyl-terminated Ti3C2(OH)2MXene nanosheets prepared in step 3. It was allowed to stand at room temperature for 15-30 minutes to self-assemble, allowing the MXene nanosheets to be uniformly adsorbed onto the surface of the metamaterial chip through van der Waals forces and hydrogen bonding. Then, the chip was slowly and vertically pulled out of the liquid surface, and the chip surface was gently rinsed with deionized water to remove excess MXene that was not firmly adsorbed. It was then dried with nitrogen gas, thus forming an all-hydroxyl-terminated MXene modification layer on the surface of the silicon-based metamaterial chip. Thus, an all-hydroxyl-terminated MXene-modified terahertz metamaterial chip for blood detection was obtained.
[0042] The terahertz metamaterial chip modified with all-hydroxyl groups MXene, prepared based on the above steps, was used for blood detection. The specific process is as follows:
[0043] The MXene-modified terahertz metamaterial chip with all-hydroxy groups prepared in Example 1 was integrated into a microfluidic system. The system includes a circulating pump, a heat exchanger, and connecting pipes. After the system is started, the circulating pump guides the blood sample solution containing the biomarker to be tested through the heat exchanger and the surface of the terahertz sensing chip in sequence, and then sends it back into the circulating pump to form a circulating flow.
[0044] During the detection process, a terahertz time-domain spectroscopy system is used to vertically irradiate terahertz waves from above the chip, and the terahertz transmission spectrum transmitted through the chip is acquired in real time. When the target biomolecules (such as specific proteins, nucleic acid fragments, etc.) in the blood sample flow through the chip surface, the biomolecules specifically bind to the all-hydroxyl end groups on the MXene surface through hydrogen bonds and electrostatic interactions. This binding directly changes the surface charge distribution and conductivity of the MXene-modified layer, thereby altering the resonance characteristics of the metamaterial resonant ring. This causes measurable changes in the resonant frequency and absorption intensity in the terahertz transmission spectrum. By analyzing the resonant frequency shift and the change in absorption intensity, label-free quantitative detection of the target biomolecules can be achieved.
[0045] In summary, this invention provides a terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection. Compared with the prior art using an MXene / variable polymer composite sensing layer, the all-hydroxyl-terminated MXene-modified layer of this invention interacts directly with biomolecules without relying on polymer conformational changes to transmit signals. Therefore, it has a faster response speed and better signal consistency. At the same time, the high uniformity of the all-hydroxyl end groups ensures the stability and repeatability of the sensing response.
[0046] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.
Claims
1. A terahertz metamaterial chip modified with MXene (a fully hydroxyl group) for blood detection, characterized in that, include: A silicon-based metamaterial chip substrate and a fully hydroxyl-terminated MXene modification layer formed on the surface of the silicon-based metamaterial chip substrate; wherein, the silicon-based metamaterial chip substrate is composed of a high-resistivity silicon substrate and a periodic superstructure metal thin film, and the fully hydroxyl-terminated MXene modification layer is composed of two-dimensional MXene nanosheets with fully hydroxyl (-OH) end groups on the surface, and the fully hydroxyl-terminated MXene nanosheets are obtained by surface end group substitution treatment of initial MXene using a NaOH / NaI molten salt system.
2. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, In the NaOH / NaI molten salt system, the -F and / or -Cl end groups on the initial MXene surface are converted by OH... - Complete ion substitution yields MXene nanosheets with fully hydroxyl-terminated ends.
3. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, The periodic superstructure metal thin film is a metal resonant ring array, which is composed of multiple resonant units arranged periodically. Each resonant unit consists of an inner square and an outer square arranged concentrically. The inner square and the outer square are connected by a connecting edge in the direction of the axis of symmetry. The four corners of the inner square are etched with openings along the diagonal direction.
4. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, The initial MXene material includes at least one of Ti3C2, Ti2C, Nb2C, V2C, Mo2C, Nb4C3, Ta4C3, Mo2TiC2, and Mo2Ti2C3.
5. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, The fully hydroxyl-terminated MXene modification layer is formed on the surface of the silicon-based metamaterial chip substrate by self-assembly. The fully hydroxyl-terminated MXene nanosheets are dispersed in a solvent to form a dispersion, and the silicon-based metamaterial chip substrate is immersed in the dispersion. The fully hydroxyl-terminated MXene nanosheets self-assemble on the surface of the silicon-based metamaterial chip substrate to form a uniform modification layer.
6. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, The working process of the terahertz metamaterial chip based on MXene modified with all-hydroxy groups is as follows: the chip is integrated into a microfluidic system, and a blood sample solution containing the biomolecules to be tested flows through the chip surface; the chip surface is continuously irradiated with terahertz waves, and the terahertz transmission or reflection spectrum is detected in real time. By monitoring the changes in the terahertz absorption frequency or intensity, label-free quantitative detection of the biomolecules to be tested is achieved.
7. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, The microfluidic system includes a circulation pump, a heat exchanger, and pipelines. After the system is started, the circulation pump guides the solution containing the analyte through the heat exchanger and the terahertz metamaterial chip, and then returns it to the circulation pump to achieve circulation.
8. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 1, characterized in that, The terahertz metamaterial chip is prepared by the following steps: MAX phase ceramic powder was selectively etched with a fluorine-containing etching solution to obtain an initial MXene material, wherein the surface end groups of the initial MXene material contain -F and / or -Cl; The initial MXene material was placed in a mixed molten salt system composed of NaOH and NaI, and heated under an inert atmosphere to react, allowing the OH groups in the molten salt to react. - Ions completely replace the -F and / or -Cl end groups on the surface of the initial MXene material to obtain fully hydroxyl-terminated MXene; the reaction product is washed, centrifuged, and dried to obtain fully hydroxyl-terminated MXene powder; All-hydroxyl-terminated MXene powder is dispersed in a solvent, and an all-hydroxyl-terminated MXene modification layer is formed on the surface of a silicon-based metamaterial chip substrate by self-assembly or coating.
9. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 8, characterized in that, In the mixed molten salt system, the molar ratio of NaOH to NaI is 1:0.2 to 1:0.
5.
10. The terahertz metamaterial chip modified with all-hydroxyl MXene for blood detection according to claim 8, characterized in that, The initial MXene material to the mixed molten salt system was in a mass ratio of 1:14 to 1:16; the heating temperature was 200℃ to 280℃, and the time was 30 min to 120 min.