A terahertz spectroscopy detection device for liquid biological samples

Abstract

The utility model discloses a kind of for liquid biological sample terahertz spectrum detection device, belong to liquid biological sample detection field including terahertz wave laser system, microchannel component and terahertz wave detector, terahertz wave laser system is used to form terahertz wave, microchannel component includes reflecting window piece, sample plate, cooling assembly and temperature sensor, microflow passage structure is equipped on sample plate, terahertz wave laser system is oppositely arranged with reflecting window piece, terahertz wave detector is oppositely arranged with sample plate, temperature sensor and cooling assembly are all set on sample plate;Microflow passage structure is equipped on sample plate, and microflow passage structure is serpentine groove;Liquid biological sample is equipped in microflow passage structure, terahertz wave is transmitted to liquid biological sample in microflow passage structure on reflecting window piece, after transmission or reflection of liquid biological sample, into terahertz wave detector, to improve the stability when liquid biological sample carries out terahertz spectrum detection.

Description

Technical Field

[0001] This invention belongs to the field of liquid biological sample detection technology, specifically relating to a terahertz spectroscopy detection device for liquid biological samples. Background Technology

[0002] Terahertz (THz) waves are electromagnetic waves with frequencies ranging from 0.1 to 10 THz, occupying most of the electromagnetic spectrum between microwaves and infrared light. Their high penetrating power and low ionization energy allow for direct detection of biological samples without damaging their structure. Many biomolecules with vibrational and rotational energy level jumps exist in the THz band, each possessing a unique spectral fingerprint that can be used to identify amino acids, carbohydrates, proteins, nucleic acids, and other biochemical substances. Terahertz spectroscopy is becoming an effective tool for studying biological samples and has enormous application potential in the biomedical field.

[0003] Currently, common terahertz spectroscopy detection devices for liquid biological samples include a terahertz wave emitter, a microfluidic structure, and a terahertz wave detector. The microfluidic structure consists of multiple parallel linear grooves. Using this structure, the liquid biological sample is added into the microfluidic structure during detection. The terahertz waves emitted by the emitter enter the microfluidic structure and are transmitted or reflected by the liquid biological sample to the terahertz wave detector, thus enabling terahertz spectroscopy detection of the liquid biological sample. However, liquid biological samples are quite sensitive to temperature, and the aforementioned devices are easily affected by fluctuations in ambient temperature, which in turn affects the stability of terahertz spectroscopy detection of liquid biological samples. Utility Model Content

[0004] To address the aforementioned problems in the existing technology, this invention provides a terahertz spectroscopy detection device for liquid biological samples. The technical problem to be solved by this invention is achieved through the following technical solution: In a first aspect, this utility model provides a terahertz spectroscopy detection device for liquid biological samples, including a terahertz laser system, a microfluidic assembly, and a terahertz detector. The terahertz laser system is used to generate terahertz waves. The microfluidic assembly includes a reflective window, a sample plate, a cooling assembly, and a temperature sensor. The sample plate is provided with a microfluidic channel structure. The terahertz laser system is arranged opposite to the reflective window, and the terahertz detector is arranged opposite to the sample plate. The temperature sensor and the cooling assembly are both arranged on the sample plate. The sample plate is equipped with a microfluidic channel structure, which is a serpentine groove. The microfluidic channel structure contains a liquid biological sample. Terahertz waves are transmitted through a reflective window to the liquid biological sample within the microfluidic channel structure, and then enter the terahertz wave detector after being transmitted or reflected by the liquid biological sample.

[0005] In one embodiment of this utility model, the cooling component is a Peltier element; There are two temperature sensors, which are respectively located on both sides of the sample plate.

[0006] In one embodiment of this invention, the refractive index of the reflective window is greater than that of the liquid biological sample.

[0007] In one embodiment of this invention, the refractive index of the sample plate is greater than that of the liquid biological sample.

[0008] In one embodiment of this utility model, the thickness of the reflective window is 0.14mm ± 0.03k, where k is a positive integer.

[0009] In one embodiment of this utility model, the depth of the microfluidic channel structure is greater than 300 nm, and the aspect ratio of the microfluidic channel structure is 1:20.

[0010] In one embodiment of this utility model, the serpentine groove includes 5 to 7 arc-shaped curved segments, and the radius of each arc-shaped curved segment is 200μm to 400μm.

[0011] In one embodiment of the present invention, the terahertz wave laser system includes a terahertz wave emitter, a beam splitter, a mirror group, a first off-axis parabolic mirror group, and a second off-axis parabolic mirror group. The terahertz wave detector is provided in two parts, namely the first detector and the second detector. The terahertz wave transmitter is used to emit terahertz waves. The terahertz waves are split into a first beam and a second beam by a beam splitter. The first beam enters the first detector, and the second beam is reflected by a mirror group to a first off-axis parabolic mirror group, and then reflected by the first off-axis parabolic mirror group to a microfluidic assembly. The terahertz waves entering the microfluidic assembly are reflected by the liquid biological sample to a second off-axis parabolic mirror group, and then reflected by the second off-axis parabolic mirror group to a second detector.

[0012] In one embodiment of this utility model, the reflector group includes a first reflector and a second reflector arranged along a first direction; the first off-axis parabolic reflector group includes a first off-axis parabolic reflector and a second off-axis parabolic reflector arranged along the first direction; and the second off-axis parabolic reflector group includes a third off-axis parabolic reflector and a fourth off-axis parabolic reflector arranged along the first direction. The first direction is perpendicular to the emission direction of the terahertz wave transmitter. The second beam is reflected by the first mirror to the second mirror, then by the second mirror to the first off-axis parabolic mirror, then by the first off-axis parabolic mirror to the second off-axis parabolic mirror, and finally by the second off-axis parabolic mirror to the microchannel assembly. The light beam reflected from the liquid biological sample enters the third off-axis parabolic mirror, and is reflected by the third off-axis parabolic mirror to the fourth off-axis parabolic mirror, and then reflected by the fourth off-axis parabolic mirror to the second detector.

[0013] In one embodiment of the present invention, the terahertz laser system further includes a chopper located between the terahertz wave transmitter and the beam splitter.

[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: In the above-mentioned scheme of this application, the terahertz spectroscopy detection device includes a terahertz laser system, a microfluidic assembly, and a terahertz detector. The terahertz laser system is used to generate terahertz waves. The microfluidic assembly includes a reflective window, a sample plate, a cooling assembly, and a temperature sensor. The sample plate is provided with a microfluidic channel structure. The terahertz laser system is positioned opposite to the reflective window, and the terahertz detector is positioned opposite to the sample plate. The temperature sensor and the cooling assembly are both located on the sample plate. The sample plate is provided with a microfluidic channel structure, which is a serpentine groove. A liquid biological sample is placed inside the microfluidic channel structure. The terahertz waves are transmitted through the reflective window to the liquid biological sample inside the microfluidic channel structure, and then enter the terahertz detector after being transmitted or reflected by the liquid biological sample. This structure allows for several key improvements. First, the terahertz laser system emits terahertz waves that irradiate the liquid biological sample within the microfluidic assembly. The waves are then transmitted or reflected by the sample to the terahertz detector, enabling terahertz spectral detection of the liquid biological sample when the laser, microfluidic assembly, and detector work together. Second, a temperature sensor detects the temperature of the sample plate, and subsequently the temperature of the liquid biological sample within it. A cooling assembly cools the sample plate, reducing the impact of temperature fluctuations on the device and improving the stability of terahertz spectral detection. Furthermore, a serpentine microfluidic channel structure extends the sample flow path, enhancing signal strength while reducing turbulence and ensuring signal detection stability. Additionally, the reflective window reduces evaporation and humidity disturbances during sample detection, further enhancing the stability of terahertz spectral detection.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the terahertz spectrum detection device provided in this embodiment of the present invention; Figure 2 This is a schematic diagram of the microfluidic channel structure in an embodiment of this utility model; Figure 3This is an optical path diagram of the terahertz wave on the microfluidic component in an embodiment of this utility model; Figure 4 This is a schematic diagram showing the variation of the reflectivity of terahertz waves with the thickness of the reflective window in an embodiment of this utility model. Figure 5 This is a schematic diagram of terahertz wave irradiation on the surface of a plasma sample in an embodiment of this utility model; Figure 6 This is a schematic diagram of the terahertz wave reflectivity corresponding to reflective windows with different refractive indices in this embodiment of the present invention; Figure 7 This is a schematic diagram of the terahertz laser system in an embodiment of this utility model; Figure 8 This is a schematic diagram of the terahertz wave reflection parameters in an embodiment of this utility model.

[0017] Reference numerals: 1-Reflective window, 2-Sample plate, 3-Microfluidic channel structure, 4-Temperature sensor, 5-Terahertz wave emitter, 6-Chopper, 7-Beam splitter, 8-First reflector, 9-Second reflector, 10-First off-axis parabolic reflector, 11-Second off-axis parabolic reflector, 12-Third off-axis parabolic reflector, 13-Fourth off-axis parabolic reflector, 14-First detector, 15-Second detector. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0019] Terahertz (THz) waves are electromagnetic waves with frequencies ranging from 0.1 to 10 THz, occupying most of the electromagnetic spectrum between microwaves and infrared light. Their high penetrating power and low ionization energy allow for direct detection of biological samples without damaging their structure. Many biomolecules with vibrational and rotational energy level jumps exist in the THz band, each possessing a unique spectral fingerprint that can be used to identify amino acids, carbohydrates, proteins, nucleic acids, and other biochemical substances. Terahertz spectroscopy is becoming an effective tool for studying biological samples and has enormous application potential in the biomedical field.

[0020] Currently, common terahertz spectroscopy detection devices for liquid biological samples include a terahertz wave emitter, a microfluidic structure, and a terahertz wave detector. The microfluidic structure consists of multiple parallel linear grooves. Using this structure, the liquid biological sample is added into the microfluidic structure during detection. The terahertz waves emitted by the emitter enter the microfluidic structure and are transmitted or reflected by the liquid biological sample to the terahertz wave detector, thus enabling terahertz spectroscopy detection of the liquid biological sample. However, liquid biological samples are quite sensitive to temperature, and the aforementioned devices are easily affected by fluctuations in ambient temperature, which in turn affects the stability of terahertz spectroscopy detection of liquid biological samples.

[0021] Currently, terahertz spectroscopy detection of liquid samples typically involves drying (milk, cells) or lyophilizing (plasma, blood) the sample before detection, or using attenuated total reflectance detection mode (cells, serum, cerebrospinal fluid) and microfluidic chip sample cells (liquid cells). Drying and lyophilizing samples can achieve high signal-to-noise ratio detection by reducing terahertz wave absorption, but this method is time-consuming and risks damaging the sample's inherent properties. Attenuated reflectance mode can achieve high signal-to-noise ratio detection, but its penetration depth is limited, making it difficult to detect deeper information, leading to low interface coupling efficiency and large fluctuations in the detection signal intensity. While microfluidic chip samples offer high-speed, high-throughput sample detection with precise control and high repeatability, they are technically complex, have high development costs, and poor long-term stability and durability. In particular, the refractive index of liquids is temperature-sensitive (e.g., the temperature coefficient of refractive index of water is approximately -4 × 10⁻⁴). The current detection method (at / ℃) is easily affected by fluctuations in ambient temperature, which may cause spectral shifts. Therefore, there is an urgent need to optimize the detection method to improve the stability and signal-to-noise ratio of terahertz spectroscopy detection of liquid biological samples.

[0022] Based on the above issues, please refer to Figure 1 , Figure 2 and Figure 3 This utility model provides a terahertz spectroscopy detection device for liquid biological samples, including a terahertz laser system, a microfluidic assembly, and a terahertz detector. The terahertz laser system is used to generate terahertz waves. The microfluidic assembly includes a reflective window 1, a sample plate 2, a cooling assembly, and a temperature sensor 4. The sample plate 2 is provided with a microfluidic channel structure 3. The terahertz laser system is positioned opposite to the reflective window 1, and the terahertz detector is positioned opposite to the sample plate 2. The temperature sensor 4 and the cooling assembly are both located on the sample plate 2. The microfluidic channel structure 3 is a serpentine groove. A liquid biological sample is placed inside the microfluidic channel structure 3. The terahertz waves are transmitted through the reflective window 1 to the liquid biological sample inside the microfluidic channel structure 3, and then enter the terahertz detector after being transmitted or reflected by the liquid biological sample.

[0023] In some embodiments of this application, a terahertz wave detector is a device for detecting and measuring electromagnetic waves in the terahertz frequency band (0.1~10THz), and its core function is to convert terahertz signals into quantifiable electrical or optical signals.

[0024] In some embodiments of this application, the reflective window 1 has high transmittance for terahertz waves, which is used to reduce evaporation and humidity disturbances during liquid sample detection.

[0025] In some embodiments of this application, the temperature sensor 4 can be a commonly used temperature sensor, such as a thermocouple sensor, a resistance temperature detector (RTD) sensor, etc.

[0026] In some embodiments of this application, the cooling component is a commonly used existing cooling component, such as a thermoelectric cooler or a heat pipe.

[0027] In some embodiments of this application, such as Figure 1 and Figure 2 As shown, a and b are the thicknesses of the reflective window layer 1 and the microfluidic channel layer, respectively; c and d are the length and width of the microfluidic channel layer, respectively.

[0028] In some embodiments of this application, the microchannel component can be made of a material that is highly transparent to terahertz waves, such as TPX (polymethylpentene), PE (polyethylene), HRFZ-Si (high-resistance floating zone silicon), etc.

[0029] In some embodiments of this application, liquid biological samples can be dripped into a serpentine trough using a dropper.

[0030] In the above-mentioned scheme of this application, the terahertz spectroscopy detection device includes a terahertz laser system, a microfluidic assembly, and a terahertz detector. The terahertz laser system is used to generate terahertz waves. The microfluidic assembly includes a reflective window 1, a sample plate 2, a cooling assembly, and a temperature sensor 4. The sample plate 2 is provided with a microfluidic channel structure 3. The terahertz laser system is arranged opposite to the reflective window 1, and the terahertz detector is arranged opposite to the sample plate 2. The temperature sensor 4 and the cooling assembly are both arranged on the sample plate 2. The sample plate 2 is provided with a microfluidic channel structure 3, which is a serpentine groove. A liquid biological sample is placed inside the microfluidic channel structure 3. The terahertz waves are transmitted through the reflective window 1 to the liquid biological sample inside the microfluidic channel structure 3, and enter the terahertz detector after being transmitted or reflected by the liquid biological sample. This structure allows for several key improvements. First, the terahertz laser system emits terahertz waves that irradiate the liquid biological sample within the microfluidic assembly. The waves are then transmitted or reflected by the sample to the terahertz detector, enabling terahertz spectral detection of the liquid biological sample when the laser, microfluidic assembly, and detector work together. Second, the temperature of the sample plate 2 is detected by the temperature sensor 4, which in turn detects the temperature of the liquid biological sample within it. Cooling the sample plate 2 by the cooling assembly reduces the temperature fluctuations and thus minimizes the impact of temperature fluctuations on the device, improving the stability of terahertz spectral detection. Furthermore, when the microfluidic channel structure 3 is a serpentine groove, it extends the sample flow path, enhances signal strength, and reduces turbulence, ensuring signal detection stability. Additionally, the reflective window 1 reduces evaporation and humidity disturbances during liquid sample detection, further enhancing the stability of terahertz spectral detection.

[0031] Understandably, current experiments use off-axis parabolic mirrors for focusing. However, when an off-axis parabolic mirror is used to focus parallel light to a focal point, all reflected light converges at the focal point. The outgoing light is not strictly parallel but rather a diverging beam centered on the focal point. When two light waves meet, if their phase difference is an integer multiple of the wavelength, constructive interference (enhancing reflected light) occurs; if the phase difference is an odd multiple of half the wavelength, destructive interference (enhancing transmitted light) occurs, resulting in a series of bright and dark fringes. Interference theory, through precise manipulation of light waves, has achieved groundbreaking applications in measurement, imaging, and communication. In the field of artificial structure interference manipulation, researchers utilize subwavelength-scale structural interference to achieve novel optical effects such as negative refractive index and superlenses, driving the development of new optical devices. To enhance the detection of reflected (or transmitted) terahertz spectra of liquid biological samples, this application applies the interference principle to terahertz spectra detection by optimizing the microfluidic channel structure 3.

[0032] In some embodiments of this application, the cooling component is a Peltier element; two temperature sensors 4 are provided, with the two temperature sensors 4 respectively disposed on both sides of the sample plate 2. Using this structure, the sample plate 2 can be cooled using the Peltier element; and, by detecting the temperature using the temperature sensors 4 disposed on both sides, the temperature of the liquid biological sample on the sample plate 2 can be accurately detected.

[0033] In some embodiments of this application, the Peltier element, also known as a thermoelectric cooler, is an existing solid-state heat pump device based on the Peltier effect. It achieves precise heating or cooling through direct current drive without the need for traditional refrigerants or mechanical compression components.

[0034] In some embodiments of this application, the refractive index of the reflective window 1 is greater than that of the liquid biological sample. This structure reduces the impact of half-wave loss and improves the accuracy of biological sample detection.

[0035] In some embodiments of this application, the refractive index of sample plate 2 is greater than that of the liquid biological sample. This structure reduces the impact of half-wave loss and improves the accuracy of biological sample detection.

[0036] In some embodiments of this application, the depth of the microfluidic channel structure 3 is greater than 300 nm, and the aspect ratio of the microfluidic channel structure 3 is 1:20. Using this structure, when the depth of the microfluidic channel structure 3 is greater than 300 nm, the influence of the double relaxation phenomenon can be reduced, and its thickness satisfies interference subtraction. When the aspect ratio of the microfluidic channel structure 3 is 1:20, complete capture of the relaxation process can be ensured.

[0037] In some embodiments of this application, the thickness of the reflective window 1 is 0.14 mm ± 0.03 k, where k is a positive integer. This structure allows the thickness of the reflective window 1 to satisfy the interference subtraction condition, thereby improving signal strength.

[0038] In one embodiment of this invention, the serpentine groove includes 5 to 7 arc-shaped curved segments, each with a radius of 200 μm to 400 μm. This structure utilizes multiple consecutive arc-shaped curved segments to focus particles of different sizes at a stable, off-center position, improving the accuracy of biological sample detection.

[0039] In some embodiments of this application, considering that interference occurs when the thickness of the reflective window 1 is an integer multiple of half the wavelength of the incident optical path difference, the incident light will undergo multiple reflections (and transmissions) within the reflective window 1 of a certain thickness, resulting in a decrease in signal intensity, and the light intensity follows the multi-beam interference theory. Using the multi-beam interference theory, the reflectivity and transmittance of the incident light after passing through the reflective window 1 of a certain thickness can be calculated; here, reflectivity is taken as an example. The multi-beam interference formula is as follows: ; in, R The reflectivity of a terahertz wave after multiple reflections through a reflection window of a certain thickness. It is a phase shift. and These are the Fresnel coefficients of the terahertz wave on the front and back surfaces of the reflection window. The Fresnel coefficients of the terahertz wave under different polarization states (p-polarized and s-polarized) can be expressed as: ; Based on the above formula, the change in reflectivity of the tested sample with the thickness of the reflection window can be obtained, such as... Figure 4 As shown. Considering that terahertz spectroscopy detection of biological samples typically occurs in the range of 0.3-3.5 THz (0.03-3 mm), and that lower reflectivity window thickness results in less absorption of terahertz waves, the change in reflectivity of the sample after reflection of terahertz waves through the reflectivity window was calculated for a thickness of 0.1-0.7 mm. Figure 4 It can be seen that when the thickness of the reflection window satisfies the interference subtraction condition (i.e. When the reflectivity is at its lowest (assuming attenuation is not considered, since the sum of reflectivity and transmittance is 1), the reflectivity is at its lowest. Therefore, in order for terahertz waves to have high transmittance after passing through the reflection window, the thickness of the reflection window should satisfy the interference subtraction condition, such as 0.14 mm and 0.32 mm.

[0040] In some embodiments of this application, considering that the transmittance of incident light through the sample is maximized when the thickness satisfies the subtractive interference condition, thus maximizing the acquisition of sample information, the microfluidic channel depth should satisfy the subtractive interference condition, such as 0.52 mm. Additionally, liquid samples exhibit a double relaxation process (…). ≈0.2ps When d > 100 μm, the high-frequency relaxation signal is strongly absorbed by water molecules, and the low-frequency relaxation is interfered with by boundary effects. When d ≈ 1000 times the Debye length (0.3 nm), the protein adsorption rate decreases to 0.2 μg / cm². Therefore, the microfluidic channel depth should be greater than 300 nm. The dual relaxation process describes the phenomenon that a microscopic system recovers its equilibrium state through two relaxation mechanisms with different time scales under external perturbations (such as electromagnetic fields and temperature fields).

[0041] In some embodiments of this application, according to the half-wave loss principle, when a terahertz wave enters an optically denser medium (with a higher refractive index) from an optically less dense medium, the reflected light will experience half-wave loss. Therefore, when the refractive index of the reflection window is less than the refractive index of the sample, half-wave loss will occur, which will affect the power of the terahertz wave irradiating the sample, and thus affect the detection accuracy. Figure 5This is a simulation of terahertz wave irradiation on a plasma sample, using one protein as an example. The dashed circles represent a portion of the terahertz light spot (in actual detection, the terahertz light spot completely covers the sample; however, even with complete coverage, there is still a certain angle between the light spot and the sample, such as...). Figure 5 As shown, The angle between the terahertz spot and the boundary line between the protein and plasma samples (i.e., the angle between the dashed lines CO1 and DO1).

[0042] In some embodiments of this application, based on the above formula, using reflective windows made of materials with refractive indices n2=3.42 and n2=1.5 respectively, the terahertz wave reflectivity at the interface between protein (n1=2) and plasma (n1=1.7) samples was calculated. Figure 6 As shown. By Figure 6 It is known that when the refractive index of the reflection window (n2) is less than the refractive index of the sample (n1), terahertz waves at different angles will produce indentations. Therefore, when terahertz waves irradiate the sample at angles of 0-360°, if the plasma sample from a brain injury model contains multiple factors (such as electrolytes, proteins, and brain injury markers) and the dielectric constants of different factors differ in the terahertz band, multiple indentations will appear in the terahertz wave detection results of the plasma sample, thus affecting the accuracy of the detection results. Conversely, when the refractive index of the reflection window (n2) is greater than the refractive index of the sample (n1), no indentation appears in the reflectivity value of the sample, and sample information can be accurately obtained. Therefore, in order to reduce the influence of the reflection window material on the detection results of brain injury plasma samples, the refractive index of the reflection window should be greater than that of the sample being detected. According to previous literature, in the terahertz range of 0.3-3.5 THz, the refractive indices of electrolytes, proteins, and brain injury markers in brain injury model plasma samples are typically between 1.2 and 2.8. Therefore, in order to improve the accuracy of plasma sample testing for brain trauma, the refractive index of the reflective window 1 and the sample plate 2 should be greater than 2.8.

[0043] In some embodiments of this application, such as Figure 7As shown, the terahertz laser system includes a terahertz wave emitter 5, a beam splitter 7, a mirror assembly, a first off-axis parabolic mirror assembly, and a second off-axis parabolic mirror assembly. Two terahertz wave detectors are provided, designated as a first detector 14 and a second detector 15. The terahertz wave emitter 5 emits terahertz waves, which are split into a first beam and a second beam by the beam splitter 7. The first beam enters the first detector 14, and the second beam is reflected by the mirror assembly to the first off-axis parabolic mirror assembly, and then reflected again by the first off-axis parabolic mirror assembly to the microfluidic assembly. The terahertz wave entering the microfluidic assembly is reflected by the liquid biological sample to the second off-axis parabolic mirror assembly, and then reflected again by the second off-axis parabolic mirror assembly to the second detector 15. This structure enables the emission and reception of terahertz waves, thereby achieving terahertz spectral detection of liquid biological samples. Meanwhile, the first beam serves as the reference beam, and the second beam serves as the signal beam. By comparing the signals from the two beams, the noise caused by small power fluctuations can be reduced, thereby improving the accuracy of the detection.

[0044] In some embodiments of this application, such as Figure 7 As shown, the reflector group includes a first reflector 8 and a second reflector 9 arranged along a first direction; the first off-axis parabolic reflector group includes a first off-axis parabolic reflector 10 and a second off-axis parabolic reflector 11 arranged along the first direction; the second off-axis parabolic reflector group includes a third off-axis parabolic reflector 12 and a fourth off-axis parabolic reflector 13 arranged along the first direction; the first direction is perpendicular to the emission direction of the terahertz wave transmitter 5; the second beam is reflected by the first reflector 8 to the second reflector 9, then by the second reflector 9 to the first off-axis parabolic reflector 10, then by the first off-axis parabolic reflector 10 to the second off-axis parabolic reflector 11, and finally by the second off-axis parabolic reflector 11 to the microfluidic assembly; the beam reflected from the liquid biological sample enters the third off-axis parabolic reflector 12, and is reflected by the third off-axis parabolic reflector 12 to the fourth off-axis parabolic reflector 13, and finally by the fourth off-axis parabolic reflector 13 to the second detector 15. This structure ensures that terahertz waves can propagate into the second detector 15.

[0045] In some embodiments of this application, the terahertz laser system further includes a chopper 6 located between the terahertz wave transmitter 5 and the beam splitter 7. Using this structure, the signal-to-noise ratio of the terahertz wave can be improved by modulating the terahertz wave with the chopper 6, thereby enhancing the performance of the terahertz wave.

[0046] In some embodiments of this application, the chopper 6 is an existing electronic device capable of switching or modulating electrical signals.

[0047] Example 1: In this example, the thickness of the reflection window satisfies the subtractive interference condition, and the refractive indices of the reflection window are n2=2.12 and n2=1.5, respectively, which are used to detect samples with refractive indices between the two (n1=2.05). This verifies that using a material with a refractive index higher than that of the sample being tested can improve the signal-to-noise ratio and accuracy of the test.

[0048] Terahertz wave transmitter 5 emits terahertz waves, which are split into a first beam and a second beam by beam splitter 7. The first beam enters the first detector 14, and the second beam is reflected by a mirror group to a first off-axis parabolic mirror group, and then reflected by the first off-axis parabolic mirror group to a microfluidic assembly. The terahertz waves entering the microfluidic assembly are reflected by the liquid biological sample to a second off-axis parabolic mirror group, and then reflected by the second off-axis parabolic mirror group to a second detector 15.

[0049] Liquid biological samples are dropped into the microfluidic channel structure 3 of sample plate 2, such as... Figure 8 As shown in (a) of the diagram. Figure 8 In the diagram, (b) and (c) are obtained when the reflection window is n2=1.5 and n2=2.12, respectively. Figure 8 (a) Terahertz spectral data at the dashed line. (From...) Figure 8 As shown in (b), when the refractive index of the reflection window is less than that of the sample, a depression appears at the sample boundary (reflectivity decreases from 0.93 to 0.65), and the reflection signal fluctuates significantly at the uniform sample area (reflectivity fluctuation range: 0.93-0.87). The reflectivity of the reflection window and the uniform sample area at n²=1.5, calculated using the above formula, are 96% and 89%, respectively. Although the theoretical and experimental results are consistent, the depression at the sample boundary due to half-wave loss in the experiment severely affects the accuracy of the detection results. Figure 8 As shown in (c), when the refractive index of the reflection window is greater than that of the sample, no depression appears at the sample boundary (the theoretical reflectivities at the reflection window and the sample, calculated by the above formula, are 0.92 and 0.66, respectively), and the reflection signal fluctuation at the uniform part of the sample is small (reflectivity fluctuation range: 0.65-0.66). Therefore, when the refractive index of the reflection window is greater than that of the sample, lower parameter fluctuations can be obtained without being affected by half-wave loss, thus improving both the signal-to-noise ratio and detection accuracy. Furthermore, from... Figure 8 As shown in (b), the reflected signal at a uniform point in the sample differs little from the background, making it difficult to extract accurate sample signals; while Figure 8 In (b) of the sample, the reflected signal at the uniform point of the sample is significantly different from the background, making it less susceptible to noise and easier to extract the sample signal, thereby improving the accuracy of sample detection.

[0050] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0053] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A terahertz spectroscopy detection device for liquid biological samples, characterized in that, The device includes a terahertz laser system, a microfluidic assembly, and a terahertz detector. The terahertz laser system is used to generate terahertz waves. The microfluidic assembly includes a reflective window, a sample plate, a cooling assembly, and a temperature sensor. The sample plate is provided with a microfluidic channel structure. The terahertz laser system is disposed opposite to the reflective window, and the terahertz detector is disposed opposite to the sample plate. The temperature sensor and the cooling assembly are both disposed on the sample plate. The sample plate is provided with a microfluidic channel structure, which is a serpentine groove. The microfluidic channel structure contains a liquid biological sample. Terahertz waves are transmitted through the reflective window to the liquid biological sample within the microfluidic channel structure, and then enter the terahertz wave detector after being transmitted or reflected by the liquid biological sample.

2. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The cooling component is a Peltier element; The sample plate is provided with two temperature sensors, which are respectively located on both sides of the sample plate.

3. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The refractive index of the reflective window is greater than that of the liquid biological sample.

4. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The refractive index of the sample plate is greater than that of the liquid biological sample.

5. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The thickness of the reflective window is 0.14mm ± 0.03k, where k is a positive integer.

6. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The depth of the microfluidic channel structure is greater than 300 nm, and the aspect ratio of the microfluidic channel structure is 1:

20.

7. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The serpentine groove includes 5 to 7 arc-shaped bends, and the radius of each arc-shaped bend is 200 μm to 400 μm.

8. The terahertz spectroscopy detection device for liquid biological samples according to claim 1, characterized in that, The terahertz wave laser system includes a terahertz wave emitter, a beam splitter, a mirror group, a first off-axis parabolic mirror group, and a second off-axis parabolic mirror group. The terahertz wave detector has two components, namely the first detector and the second detector. The terahertz wave transmitter is used to emit terahertz waves. The terahertz waves are split into a first beam and a second beam by the beam splitter. The first beam enters the first detector, and the second beam is reflected by the mirror group to the first off-axis parabolic mirror group, and then reflected by the first off-axis parabolic mirror group to the microfluidic assembly. The terahertz waves entering the microfluidic assembly are reflected by the liquid biological sample to the second off-axis parabolic mirror group, and then reflected by the second off-axis parabolic mirror group to the second detector.

9. The terahertz spectroscopy detection device for liquid biological samples according to claim 8, characterized in that, The reflector group includes a first reflector and a second reflector arranged along a first direction. The first off-axis parabolic reflector group includes a first off-axis parabolic reflector and a second off-axis parabolic reflector arranged along the first direction. The second off-axis parabolic reflector group includes a third off-axis parabolic reflector and a fourth off-axis parabolic reflector arranged along the first direction. The first direction is perpendicular to the emission direction of the terahertz wave transmitter. The second beam is reflected by the first reflector to the second reflector, then by the second reflector to the first off-axis parabolic reflector, then by the first off-axis parabolic reflector to the second off-axis parabolic reflector, and finally by the second off-axis parabolic reflector to the microchannel assembly. The light beam reflected from the liquid biological sample enters the third off-axis parabolic mirror, and is reflected by the third off-axis parabolic mirror to the fourth off-axis parabolic mirror, and then reflected by the fourth off-axis parabolic mirror to the second detector.

10. The terahertz spectroscopy detection device for liquid biological samples according to claim 8, characterized in that, The terahertz laser system also includes a chopper located between the terahertz wave transmitter and the beam splitter.

Images