Blood viscosity sensor based on dual-mode surface acoustic wave and detection system

Abstract

The invention relates to the technical field of blood coagulation detection, and provides a blood viscosity sensor and detection system based on dual-mode surface acoustic waves, the blood viscosity sensor at least comprises: a substrate base; the first interdigital transducer group is arranged on the substrate base, and the first interdigital transducer group comprises two first interdigital transducers which are arranged at an interval along a first direction; and the second interdigital transducer group is arranged on the substrate base, and the second interdigital transducer group at least comprises two second interdigital transducers which are arranged at intervals along the second direction. According to the blood viscosity sensor based on the dual-mode surface acoustic waves, on the same substrate, through the first interdigital transducer group and the second interdigital transducer group which are arranged in two different directions, Rayleigh waves and shear horizontal surface acoustic waves can be excited at the same time, and by utilizing the complementary characteristic of the two-mode surface acoustic waves, the blood viscosity of the blood viscosity sensor based on the dual-mode surface acoustic waves can be measured. Unification of high sensitivity and wide detection range is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of coagulation detection, and particularly to a blood viscosity sensor and a detection system based on dual-mode surface acoustic waves. Background Art

[0002] Blood coagulation is a complex physiological process involving a series of biochemical reactions and cell activities, including the liquid phase, gel phase, and blood clot formation phase. Timely detection of blood viscosity changes is of great significance for guiding clinicians to evaluate the bleeding and thrombosis risks of patients, preventing and treating cardiovascular diseases, etc. Currently, the main methods for blood viscosity detection on the market include electrochemical methods, pressure sensor measurement methods, optical turbidimetry, magnetic bead methods, etc., but they generally have defects such as a small detection range, low accuracy, large volume, complex operation, high cost, and slow detection speed. Therefore, there is an urgent need to develop a new type of blood viscosity sensor that can achieve whole blood detection, requires a small blood sample volume, has a wide detection range, high accuracy, low cost, and is portable. Surface acoustic wave sensors have the advantages of high sensitivity, fast response, and easy integration, and can be miniaturized based on microelectromechanical system processes. Applying them to blood viscosity detection is expected to overcome the deficiencies of traditional methods. The existing surface acoustic wave sensors for blood viscosity detection are single-mode surface acoustic waves, which are difficult to balance high sensitivity and a wide detection range. Summary of the Invention

[0003] Therefore, the present invention aims to solve the problem that the existing surface acoustic wave sensors for blood viscosity detection are single-mode surface acoustic waves, which are difficult to balance high sensitivity and a wide detection range, and thus provides a blood viscosity sensor and a detection system based on dual-mode surface acoustic waves.

[0004] To solve the above technical problems, the technical solution of the present invention is as follows:

[0005] On the one hand, the present invention provides a blood viscosity sensor based on dual-mode surface acoustic waves, which at least includes: a substrate; a first interdigital transducer group disposed on the substrate, the first interdigital transducer group including two first interdigital transducers spaced apart along a first direction; one of the first interdigital transducers is used to excite Rayleigh waves, and the other first interdigital transducer is used to receive Rayleigh waves; a second interdigital transducer group disposed on the substrate, the second interdigital transducer group at least including two second interdigital transducers spaced apart along a second direction; one of the second interdigital transducers is used to excite shear horizontal surface acoustic waves, and the other second interdigital transducer is used to receive shear horizontal surface acoustic waves; wherein, the first direction and the second direction are two different directions.

[0006] Further, the blood viscosity sensor based on dual-mode surface acoustic wave further includes a first sample reservoir, which is arranged on the substrate base and located between two adjacent first interdigital transducers.

[0007] Further, a waveguide layer is deposited on the region of the substrate base for propagating shear horizontal surface acoustic waves, and the shear wave velocity of the waveguide layer is less than that of the substrate base to convert the shear horizontal surface acoustic wave into a Love wave.

[0008] Further, the blood viscosity sensor based on dual-mode surface acoustic wave further includes a second sample reservoir, which is arranged on the substrate base and covers the region where the second interdigital transducer and the waveguide layer are located.

[0009] Further, a sensitive material is modified on the waveguide layer, and the sensitive material realizes selective detection of specific components in blood through specific binding; the waveguide layer is a waveguide layer formed of a corrosion-resistant material.

[0010] Further, the angle range between the projections of the first direction and the second direction in the same plane is 15° - 90°.

[0011] Further, the material of the substrate base is selected from 36° - 42° YX lithium tantalate, 41° YX lithium niobate, ST quartz, AT quartz, oriented zinc oxide or aluminum nitride thin film.

[0012] Further, one first interdigital transducer group and one second interdigital transducer group form a sensor unit, and a plurality of the sensor units are integrally arranged in an array on the substrate base.

[0013] Further, among them, the attenuation coefficient of the Rayleigh wave is:

[0014]

[0015] Among them, the frequency change of the Love wave is:

[0016]

[0017] In the expression:

[0018] λ is the wavelength of the Rayleigh wave; ρ L is the density of the liquid; ρ S is the solid density; ω is the angular frequency; η is the viscosity of the liquid; f0 is the natural frequency of the Love wave without the influence of the liquid; μ S is the shear modulus of the solid;

[0019] Then, the output of the blood viscosity sensor is:

[0020] C(t) = αΔαR (t) + βΔf SH (t) + γT(t);

[0021] Wherein, α and β are weighting coefficients, γ is a temperature compensation coefficient, and T(t) is a temperature function.

[0022] On the other hand, the present invention provides a blood viscosity detection system, which includes the dual-mode surface acoustic wave-based blood viscosity sensor described in any one of the above, and further includes a microfluidic unit, a signal processing circuit, and a packaging housing; the blood viscosity sensor, the microfluidic unit, and the signal processing circuit are integrated in the packaging housing.

[0023] The technical solution of the present invention has the following advantages:

[0024] The dual-mode surface acoustic wave-based blood viscosity sensor provided by the present invention can simultaneously excite Rayleigh waves and shear horizontal surface acoustic waves on the same substrate by arranging a first interdigital transducer group and a second interdigital transducer group in two different directions. Utilizing the complementary characteristics of the two-mode surface acoustic waves, the unity of high sensitivity and wide detection range is achieved. Because Rayleigh waves are vertically polarized surface acoustic waves with a large contact area with the liquid to be measured. When the blood viscosity changes slightly, the propagation characteristics of Rayleigh waves, such as velocity, attenuation, etc., will produce obvious responses. Therefore, the sensitivity to blood viscosity is very high, and it is particularly suitable for detecting low-viscosity or slightly changing blood samples, especially for the real-time and immediate inspection of the change from fluid blood to the gel phase. Shear horizontal surface acoustic waves are a horizontally polarized guided wave mode, and their response to liquid viscosity is more linear than that of Rayleigh waves. Therefore, it is suitable for detecting blood samples with a large viscosity change range, especially for the real-time monitoring of the change from the coagulation phase to blood clot formation. By setting it like this, the high sensitivity of the Rayleigh wave mode is suitable for low-viscosity blood detection and rapid response, and the wide detection range and high resolution of the shear horizontal surface acoustic wave mode are suitable for blood analysis at different viscosity levels. Combining the two can achieve comprehensive, accurate, and real-time blood viscosity monitoring to meet the needs of clinical diagnosis and treatment monitoring. Description of the Drawings

[0025] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a schematic diagram of a dual-mode surface acoustic wave-based blood viscosity sensor in an embodiment of the present invention;

[0027] Figure 2 Schematic diagram of a blood viscosity sensor based on dual-mode surface acoustic wave in another embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the propagation characteristic curve of Rayleigh wave;

[0029] Figure 4 Schematic diagram of the propagation characteristics of Rayleigh wave;

[0030] Figure 5 Schematic diagram of the propagation characteristic curve of Love wave;

[0031] Figure 6 Schematic diagram of the propagation characteristics of Love wave.

[0032] Explanation of reference numerals:

[0033] 1. Substrate base; 2. Waveguide layer; 3. First interdigital transducer; 4. Second interdigital transducer; 5. First sample reservoir; 6. Rayleigh wave; 7. Love wave. Detailed implementation manners

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0035] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0037] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0038] As Figure 1 shown, this embodiment provides a blood viscosity sensor based on dual-mode surface acoustic waves, which at least includes: a substrate base 1; a first interdigital transducer group disposed on the substrate base 1, the first interdigital transducer group includes two first interdigital transducers 3 spaced along a first direction; one of the first interdigital transducers 3 is used to excite Rayleigh waves, and the other first interdigital transducer 3 is used to receive Rayleigh waves; a second interdigital transducer group disposed on the substrate base 1, the second interdigital transducer group at least includes two second interdigital transducers 4 spaced along a second direction; one of the second interdigital transducers 4 is used to excite shear horizontal surface acoustic waves, and the other second interdigital transducer 4 is used to receive shear horizontal surface acoustic waves; wherein, the parameters of the first interdigital transducer 3 and the second interdigital transducer 4 can be optimized according to the detection requirements, for example, wavelength, logarithm, bandwidth, etc., to obtain ideal transmission characteristics. Wherein, the first direction and the second direction are two different directions. Wherein, the first interdigital transducer and the second interdigital transducer can be coplanarly arranged, and the angle range between the first direction and the second direction can be 15° - 90°, for example, it can be 38°. Wherein, the first interdigital transducer and the second interdigital transducer can also be non-coplanarly arranged. When the two are non-coplanar, the angle range between the projections of the first direction and the second direction in the same plane can be 15° - 90°, for example, it can be 38°. With such an arrangement, the first interdigital transducer 3 and the second interdigital transducer 4 have a certain angle in space, which can maximize the suppression of crosstalk and achieve independent control. During operation, Rayleigh waves and Love waves propagate in their respective directions at different frequencies, attenuate after interacting with the blood, and the remaining energy is received by the output transducer. The blood viscosity can be obtained according to the change in signal intensity.

[0039] The blood viscosity sensor based on dual-mode surface acoustic waves provided by this embodiment can simultaneously excite Rayleigh waves and shear horizontal surface acoustic waves on the same substrate base 1 by arranging three groups of first interdigital transducers and four groups of second interdigital transducers in two different directions. Utilizing the complementary characteristics of the two-mode surface acoustic waves, the unity of high sensitivity and wide detection range is achieved. Because Rayleigh waves are vertically polarized surface acoustic waves with a large contact area with the liquid to be measured. When there are slight changes in blood viscosity, the propagation characteristics of Rayleigh waves, such as velocity and attenuation, will produce obvious responses. Therefore, the sensitivity to blood viscosity is very high, and it is especially suitable for detecting blood samples with low viscosity or small viscosity changes, especially for the real-time immediate detection of the change from fluid blood to the gel phase. Shear horizontal surface acoustic waves are a horizontally polarized guided wave mode, and their response to liquid viscosity is more linear than that of Rayleigh waves. Therefore, they are suitable for detecting blood samples with a large range of viscosity changes, especially for the real-time monitoring of the change from the coagulation phase to blood clot formation in blood. With such a setting, the high sensitivity of the Rayleigh wave mode is suitable for low-viscosity blood detection and rapid response, and the wide detection range and high resolution of the shear horizontal surface acoustic wave mode are suitable for blood analysis at different viscosity levels. Combining the two can achieve comprehensive, accurate, and real-time blood viscosity monitoring to meet the needs of clinical diagnosis and treatment monitoring.

[0040] Among them, the blood viscosity sensor based on dual-mode surface acoustic waves further includes a first sample reservoir 5, which is arranged on the substrate base 1. The size of the first sample reservoir 5 is small and can be located between two adjacent first interdigital transducers 3. During use, the blood to be measured is dropped into the first sample reservoir 5. When a Rayleigh wave is excited by one of the first interdigital transducers 3 and passes through the first sample reservoir 5, the energy of the Rayleigh wave changes and is then received by another first interdigital transducer 3. According to the change in the energy of the Rayleigh wave before and after, the viscosity information of the blood in the first sample reservoir 5 can be obtained.

[0041] Among them, a waveguide layer 2 is deposited on the area of the substrate base 1 for propagating shear horizontal surface acoustic waves. For example, the material of the waveguide layer 2 can be selected from organic or inorganic dielectrics. The shear wave velocity of the waveguide layer 2 is less than the shear wave velocity of the substrate base 1 to achieve the energy confinement and propagation of shear horizontal surface acoustic waves, convert shear horizontal surface acoustic waves into Love waves 7, and improve the sensitivity. Among them, the waveguide layer 2 can be a waveguide layer 2 formed of a corrosion-resistant material. For example, the material of the waveguide layer 2 can be selected as SiO2, ZnO, etc., and the thickness range can be from several hundred nanometers to several micrometers. The optimized design of the waveguide layer 2 can significantly improve the sensitivity and signal-to-noise ratio of Love waves. Moreover, the existence of the waveguide layer 2 can make the energy of Love waves mainly confined in the interface between the substrate base 1 and the waveguide layer 2, with less dependence on the material of the substrate base 1. The corrosion-resistant waveguide layer 2 material can withstand long-term immersion of blood samples without easy degradation, which is beneficial to extending the service life of the device.

[0042] Among them, the blood viscosity sensor based on dual-mode surface acoustic wave further includes a second sample reservoir, which is arranged on the substrate base 1. The size of the second sample reservoir is relatively large and can cover the area where the second interdigital transducer 4 and the waveguide layer 2 are located. During use, the blood to be measured is dropped into the second sample reservoir. When the Love wave is excited by one of the second interdigital transducers 4 and is affected by the blood in the second sample reservoir during the propagation process, the frequency of the Love wave changes, and then it is received by the other second interdigital transducer 4. According to the change in the frequency of the Love wave before and after, the viscosity information of the blood in the second sample reservoir can be obtained. Since the Love wave cannot propagate in liquid, therefore, only when the size of the second sample reservoir is designed to be relatively large so that it covers the area where the second interdigital transducer 4 and the waveguide layer 2 are located, can the viscosity of the blood in the second sample reservoir be measured by using the change in the frequency of the Love wave before and after. With such a setting, according to the different characteristics of the Rayleigh wave 6 and the Love wave 7, reasonably designing the positions and sizes of the first sample reservoir 5 and the second sample reservoir helps to improve the detection sensitivity and reduce the sample consumption.

[0043] Among them, a sensitive material is modified on the waveguide layer 2, and the sensitive material realizes the selective detection of specific components in the blood through specific binding. For example, the sensitive material can be biomolecules such as antibodies and aptamers, and through specific binding, the selective detection of specific components in the blood, such as coagulation factors and fibrinogen, is realized, expanding the dimension of blood analysis. Among them, in order to facilitate rapid detection, blood coagulation promoting reagents are usually required. For example, the blood coagulation promoting reagent can be added after adding the blood sample. Another example is that the blood coagulation promoting reagent can also be doped in the sensitive material, and during use, only the blood sample needs to be added.

[0044] Among them, the material of the substrate base 1 can be selected as a piezoelectric material compatible with the Rayleigh wave 6 and the Love wave 7. For example, lithium tantalate in the range of 36°YX to 42°YX can be selected, or lithium niobate of 41°YX can be selected, or it can also be ST quartz, or it can also be AT quartz, or it can also be

[1120] -oriented zinc oxide or aluminum nitride thin film. These materials can support the propagation of the Rayleigh wave and can also excite surface acoustic waves as the basis of the Love wave in specific crystal orientations.

[0045] It should be noted that the surface acoustic wave mode on the piezoelectric substrate is related to the propagation direction. The crystal structure of the piezoelectric material determines the anisotropy of its elastic, piezoelectric, and dielectric properties. Substrate bases 1 cut in different crystal orientations will exhibit different coupling coefficients and wave propagation characteristics. In practical applications, crystals have different symmetry types, and in some cases, there will be special cases of wave decoupling. It is necessary to distinguish and examine the symmetry type of the crystal, the decoupling of the two displacement components and the electric potential from the horizontal displacement component. In this way, a piezoelectrically coupled Rayleigh wave can exist in the material. For example, a pure Rayleigh wave without piezoelectric coupling and a Love wave with piezoelectric coupling can exist in the crystal. Since surface acoustic wave sensors utilize the piezoelectric effect, waves decoupled from the electric potential are meaningless. Therefore, both the Love wave and the Rayleigh wave applied here must be modes coupled with the electric potential. As Figures 3 - 6 shown, both the Rayleigh wave and the Love wave modes calculated on the selected substrate base 1 are coupled with the electric potential. To achieve a dual-mode design on the substrate, the wave propagation characteristics must be considered first.

[0046] Among them, for the Rayleigh wave, the Rayleigh wave is a surface wave whose energy is mainly concentrated on the material surface and decays with depth. The propagation direction is along the x-axis, but its displacement components U1, U2, and U3 simultaneously include vibrations in the vertical direction (z-axis) and the propagation direction (x-axis).

[0047] As Figure 3 shown, the U1, U2, and U3 components of the Rayleigh wave indicate that U1 (blue curve) represents the displacement along the x direction. U2 (red curve) indicates that the displacement along the y direction is almost 0.

[0048] U3 (green curve) represents the displacement along the z direction. V (purple curve) represents the energy distribution or normalization parameter. Due to the characteristics of the Rayleigh wave, its vertical displacement is the largest at the surface and decays exponentially with depth. As Figure 4 shown, it can be seen that the surface fluctuations are large, and elliptical trajectories (red and blue regions) appear near the material surface. This indicates that the particle motion of the Rayleigh wave is an elliptical trajectory, that is, the Rayleigh wave has a combination of vertical and horizontal displacements.

[0049] For the Love wave, the Love wave is a surface wave of pure shear mode, that is, its displacement mainly occurs in the horizontal direction and does not involve vertical vibrations. Its propagation direction is along the x-axis, but the displacement direction is completely along the y-axis (perpendicular to the propagation direction). As Figure 5 shown, U1 (blue) is close to 0 in the Love wave, indicating no displacement in the x direction. U2 (red) exhibits significant shear displacement, indicating that the Love wave mainly vibrates along the y direction. U3 (green) is basically 0, indicating no vertical vibration. V (purple) represents the energy distribution or wave characteristics. As Figure 6As shown, only red and blue regions appear near the material surface, indicating that the wave motion is confined to the surface. Since Love waves vibrate only in the horizontal direction (y-axis), their energy is more easily coupled with the liquid through shear, resulting in higher sensitivity.

[0050] Principle of dual-mode collaborative detection:

[0051] The core of the dual-mode detection strategy is to utilize the different mechanisms of Rayleigh waves and Love waves when interacting with liquids to achieve a comprehensive characterization of liquid properties. Rayleigh waves have a displacement component perpendicular to the propagation direction. When in contact with a liquid, energy is dissipated into the liquid through acoustic wave radiation. By measuring the attenuation characteristics of Rayleigh waves, information about the viscosity parameter of the sample liquid can be obtained. Love waves, on the other hand, have a displacement direction parallel to the substrate surface and perpendicular to the propagation direction, and their interaction with the liquid is mainly achieved through shear coupling. When a liquid is loaded onto the sensor surface, it causes a change in the frequency of Love waves: this frequency change is closely related to the viscosity characteristics of the sample liquid.

[0052] Interaction between Rayleigh waves and liquid:

[0053] When Rayleigh waves come into contact with a liquid, due to their vertical displacement component, energy is radiated into the sample liquid, and the attenuation coefficient is:

[0054]

[0055] This formula describes the attenuation coefficient α of Rayleigh waves when in contact with a liquid R , that is, the energy lost by the wave during propagation due to the influence of the liquid. In the expression: λ is the wavelength of Rayleigh waves; ρ L is the density of the liquid; ρ S is the solid density; ω is the angular frequency; η is the viscosity of the liquid.

[0056] Physical meaning: Rayleigh waves have a vertical displacement component, that is, when propagating, they not only move along the material surface but also vibrate in the vertical direction. When a liquid contacts the solid surface where Rayleigh waves propagate, part of the wave energy is absorbed by the liquid through viscous shear, resulting in attenuation. The attenuation coefficient α R reflects the degree of this energy loss. It increases with the increase of liquid density and viscosity, indicating that the properties of the liquid have a significant impact on the propagation of Rayleigh waves.

[0057] Interaction between Love waves and liquid: Love waves mainly interact with the sample liquid through shear coupling, and the relationship between frequency change and liquid properties:

[0058]

[0059] This formula describes the frequency change Δf of Love waves under the influence of a liquid SH, that is, the frequency shift generated when the wave interacts with the liquid. In the expression: ρ L is the density of the liquid; ρ S is the solid density; ω is the angular frequency; η is the viscosity of the liquid; f0 is the natural frequency of the Love wave without the influence of the liquid; μ S is the shear modulus of the solid.

[0060] Physical meaning:

[0061] The Love wave mainly interacts with the liquid through shear coupling, which means it is more sensitive to changes in the viscosity and density of the liquid. The frequency change Δf SH is determined by both the density and viscosity of the liquid. When the liquid contacts the sensor surface, the shear effect changes the wave propagation characteristics, resulting in a decrease in its resonance frequency. The frequency shift Δf SH increases with the increase of the liquid density ρ L and viscosity η, which enables the Love wave to be used as a sensor for detecting liquid properties. Since shear waves cannot propagate in liquids, the signal change of the Love wave is mainly related to the adhesion characteristics of the liquid surface, rather than directly attenuating like Rayleigh waves.

[0062] Then, the output of the blood viscosity sensor is:

[0063] C(t) = αΔα R (t) + βΔf SH (t) + γT(t);

[0064] where α and β are weighting coefficients, γ is the temperature compensation coefficient, and T(t) is the temperature function. In terms of signal processing, an innovative data fusion algorithm is used to detect the output, that is, based on the input quantities of the Love wave, Rayleigh wave, and temperature, and finally an output quantity is output. This algorithm makes full use of the complementary characteristics of the two wave modes, significantly improving the measurement accuracy and reliability.

[0065] Among them, the first interdigital transducer 3 operates at a lower frequency band, and the frequency range can be 100 MHz - 150 MHz, mainly considering its easy attenuation characteristics; the second interdigital transducer 4 operates at a higher frequency band, and the frequency range can be 200 MHz - 250 MHz to obtain higher mass sensitivity. The reasonable separation of the two frequency bands ensures the effective separation and processing of the signals. For example, the operating frequency of the first interdigital transducer 3 can be 155 MHz, with a periodic structure of 25 μm, containing 50 pairs of finger bars; the second interdigital transducer 4 can operate at 245 MHz, with a period of 20 μm, containing 60 pairs of finger bars. Through reasonable spatial layout and isolation design, the minimum mutual interference is achieved.

[0066] Meanwhile, the device performance can be further optimized by introducing a reflection grating and an acoustic absorption structure. For example, the device size can be 10mm * 5mm, the channel spacing can be 1mm, the effective detection area can be 2mm * 2mm, and the height of the microfluidic channel can be 100μm.

[0067] As Figure 2 shown, among which, 3 groups of one of the first interdigital transducers and 4 groups of one of the second interdigital transducers form a sensor unit, and a plurality of the sensor units are integrally arrayed on the substrate base 1.

[0068] Another embodiment provides a blood viscosity detection system, including the blood viscosity sensor based on dual-mode surface acoustic wave according to any one of the above, and further including a microfluidic unit, a signal processing circuit, and a packaging shell; the blood viscosity sensor, the microfluidic unit, and the signal processing circuit are integrated in the packaging shell. With such a setting, the blood viscosity sensor, the microfluidic unit, the signal processing circuit, etc. are integrated in a miniature packaging shell to form a complete blood viscosity detection system. The integrated design can reduce the volume, lower the power consumption, improve the reliability and usability of the system, and is conducive to realizing the rapid and portable detection of blood viscosity.

[0069] The blood viscosity sensor based on dual-mode surface acoustic wave in this application has a low cost, which is mainly reflected in the following aspects:

[0070] Simple manufacturing process: The manufacturing of surface acoustic wave sensors mainly relies on standard microelectronics and microelectromechanical system processes, such as photolithography, thin film deposition, etching, etc. These processes have a high maturity level and can be mass-produced, thus reducing the manufacturing cost of a single device.

[0071] Low material cost: The substrates of surface acoustic wave sensors are mostly common piezoelectric materials such as quartz, zinc oxide, aluminum nitride, etc., and the prices are relatively low. The metal interdigital transducers are usually prepared with materials such as aluminum and gold that have good conductivity and moderate prices. Therefore, the material cost is relatively low.

[0072] High integration level: Surface acoustic wave sensors are small in size and light in weight, and can be conveniently integrated with other electronic components on the same chip to form an integrated sensing system. High integration not only reduces the device size and material usage, but also simplifies the packaging and assembly processes, further reducing the cost.

[0073] No need for a complex signal processing circuit: The working principle of surface acoustic wave sensors is simple, and the output signal is directly related to the measured quantity. Compared with other types of sensors, surface acoustic wave sensors do not require complex signal conversion and amplification circuits, reducing the use of supporting electronic components, thus reducing the overall cost.

[0074] The miniaturization feature of surface acoustic wave sensors stems from their unique working principle and advanced manufacturing processes. The device structure at the micron level, chip packaging, array integration, and integration with microfluidic units and radio electronic circuits together construct a miniaturized, integrated, and intelligent sensor platform. This miniaturization feature enables surface acoustic wave sensors to be widely applied in fields such as environmental monitoring, medical diagnosis, and food safety.

[0075] The blood viscosity sensor based on dual-mode surface acoustic wave in this application is small in size and light in weight, with a high degree of miniaturization, which is mainly reflected in the following aspects:

[0076] Device structure at the micron level: The core structure of a surface acoustic wave sensor is the interdigital transducer fabricated on the surface of a piezoelectric substrate. Thanks to the progress of microelectronics and microelectromechanical system processing technologies, the characteristic size of the interdigital transducer can reach the micron level or even the sub-micron level. For example, for a surface acoustic wave sensor with an operating frequency of several hundred megahertz, the period of the interdigital transducer is usually on the order of microns. This tiny device structure makes the overall size of the surface acoustic wave sensor very small.

[0077] Chip packaging: Surface acoustic wave sensors usually adopt the form of chip packaging. Integrating the tiny sensor chip with electronic circuits, packaging housings, etc. forms a complete sensor component. Chip packaging can not only protect the sensor from external environmental interference but also significantly reduce the volume and weight of the sensor. Currently, the packaging size of surface acoustic wave sensors can be in the range of millimeters to centimeters, and the weight can be below the gram level.

[0078] Array integration: Thanks to the tiny size of surface acoustic wave sensors, multiple sensor units can be conveniently integrated on the same substrate 1 to form a sensor array. The array design can achieve multi-parameter and multi-channel parallel detection without significantly increasing the device size, improving the functional density of the sensor.

[0079] Integration with microfluidic units: The miniaturization feature of surface acoustic wave sensors makes it easy to integrate with microfluidic units to construct a micro total analysis system or a lab-on-a-chip. By integrating miniaturized fluid channels, sample processing chambers, etc. with the surface acoustic wave sensor on the same chip, functions such as automatic sample transportation, reaction, and detection can be realized, greatly simplifying the usage process of the sensor and achieving the miniaturization and intelligence of the sensor.

[0080] The blood viscosity sensor based on dual-mode surface acoustic wave in this application is different from traditional analysis methods. When detecting a sample liquid, surface acoustic wave sensors usually require only a very small amount of sample, which is mainly reflected in the following aspects:

[0081] Tiny Sensing Area: The sensitive area of the surface acoustic wave sensor, i.e., the area where the surface acoustic wave interacts with the sample to be measured, is usually only a few square millimeters to dozens of square millimeters. This tiny sensitive area determines that the required sample volume is very small. For example, for a typical delay-line surface acoustic wave sensor, the area of its sensitive area is about 1mm 2 , and the corresponding sample volume can be as low as the microliter level.

[0082] High Sensitivity: The surface acoustic wave sensor has a very high response sensitivity to small changes in the properties of the sample. When the surface acoustic wave contacts the sample to be measured, small changes in the properties of the sample, such as mass, viscoelasticity, conductivity, etc., will cause obvious changes in the propagation characteristics of the surface acoustic wave, such as phase velocity, amplitude, phase, etc. Thanks to this high sensitivity, even if the sample usage is very small, the surface acoustic wave sensor can generate a detectable signal response to achieve accurate measurement of the sample properties.

[0083] Microfluidic Technology: Integrating the surface acoustic wave sensor with a microfluidic unit can precisely control the delivery and reaction of the sample, minimizing sample consumption. The size of the fluid channels on the microfluidic chip is usually on the micron scale, and the volume of a single reaction chamber can be as low as the nanoliter level. Injecting the sample to be measured into the microfluidic chip and then guiding it to the surface of the surface acoustic wave sensor can realize the automated analysis of the sample, and the sample usage can be controlled at the microliter level.

[0084] In summary, the blood viscosity sensor based on dual-mode surface acoustic waves in this application, the single-chip dual-mode sensor scheme cleverly combines Rayleigh waves and Love waves, not only retains the high sensitivity of Rayleigh waves but also inherits the wide detection range of Love waves, while simplifying the device structure and reducing the manufacturing cost. This novel design is expected to promote the progress of blood viscosity sensing technology and provide a more optimized solution for clinical diagnosis and disease monitoring. With the in-depth research and the improvement of the process, the single-chip dual-mode sensor is expected to be widely used in the field of blood analysis.

[0085] The blood viscosity sensor based on dual-mode surface acoustic waves in this application, the interdigital transducer is arranged according to the maximum energy flow angle, with high flexibility; the dual-mode operating frequencies are different and do not interfere with each other; a waveguide layer 2 can be optionally added to further improve the sensitivity; a multi-parameter fusion algorithm is used to process the signals of the two modes, with high accuracy. Therefore, this application realizes a novel blood viscosity sensor with whole blood detection, small blood collection volume, wide detection range, high accuracy, low cost, short time consumption, and portability, and is expected to be applied to clinical coagulation function evaluation and home health monitoring.

[0086] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or alterations can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or alterations derived therefrom still fall within the protection scope of this invention.

Claims

1. A blood viscosity sensor based on dual-mode surface acoustic wave, characterized in that, Comprising at least: Substrate base (1); A first interdigital transducer group, disposed on the substrate base (1), the first interdigital transducer group including two first interdigital transducers (3) spaced apart in a first direction; one of the first interdigital transducers (3) is used to excite Rayleigh waves, and the other first interdigital transducer (3) is used to receive Rayleigh waves; A second interdigital transducer group, disposed on the substrate base (1), the second interdigital transducer group including at least two second interdigital transducers (4) spaced apart in a second direction; one of the second interdigital transducers (4) is used to excite shear horizontal surface acoustic waves, and the other second interdigital transducer (4) is used to receive shear horizontal surface acoustic waves; Wherein, the first direction and the second direction are two different directions.

2. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 1, wherein It further includes a first sample reservoir (5), disposed on the substrate base (1) and located between two adjacent first interdigital transducers (3).

3. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 1, wherein A waveguide layer (2) is deposited on the area of the substrate base (1) for propagating shear horizontal surface acoustic waves, and the shear wave velocity of the waveguide layer (2) is less than the shear wave velocity of the substrate base (1) to convert shear horizontal surface acoustic waves into Love waves.

4. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 3, wherein It further includes a second sample reservoir, disposed on the substrate base (1) and covering the area where the second interdigital transducer (4) and the waveguide layer (2) are located.

5. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 3, wherein The waveguide layer (2) is modified with a sensitive material, and the sensitive material realizes selective detection of specific components in blood through specific binding; The waveguide layer (2) is a waveguide layer (2) formed of a corrosion-resistant material.

6. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 1, wherein The angle range between the projections of the first direction and the second direction in the same plane is 15° - 90°.

7. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 1, wherein The material of the substrate base (1) is selected from 36° - 42° YX lithium tantalate, 41° YX lithium niobate, ST quartz, AT quartz, [1120] - oriented zinc oxide or aluminum nitride thin film.

8. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 1, wherein One first interdigital transducer group and one second interdigital transducer group form a sensor unit, and a plurality of the sensor units are integrally arrayed on the substrate base (1).

9. The blood viscosity sensor based on dual-mode surface acoustic wave according to claim 1, wherein Among them, The attenuation coefficient of Rayleigh waves is: Wherein, the frequency change of Love waves is: In the expression: λ is the wavelength of the Rayleigh wave; ρ L is the density of the liquid; ρ S is the solid density; ω is the angular frequency; η is the viscosity of the liquid; f0 is the natural frequency of the Love wave without the influence of the liquid; μ S is the shear modulus of the solid; Then, the output of the blood viscosity sensor is: C(t) = αΔα R (t) + βΔf SH (t) + γT(t); where α and β are weight coefficients, γ is a temperature compensation coefficient, and T(t) is a temperature function.

10. A blood viscosity detection system, comprising the dual-mode surface acoustic wave-based blood viscosity sensor according to any one of claims 1-9, characterized in that, It also includes a microfluidic unit, a signal processing circuit, and a packaging housing; the blood viscosity sensor, the microfluidic unit, and the signal processing circuit are integrated within the packaging housing.

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