Magnetic detection nucleic acid recognition method and device
Through the SOT-based magnetic detection nucleic acid recognition method, combined with the spin Hall effect and microfluidic channels, the sensitivity and integration problems of magnetic signal detection in existing technologies are solved, and high-sensitivity and low-cost nucleic acid detection is achieved, which is suitable for scenarios such as virus detection and early tumor screening.
Patent Information
- Application Number
- CN202510974550.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-15
- Publication Date
- 2025-10-17
AI Technical Summary
Existing nucleic acid detection technology has problems such as complex instruments, high costs, long response cycles, low sensitivity in weak magnetic field detection, low signal-to-noise ratio, and size redundancy and integration difficulties caused by the split structure. It is difficult to meet the needs of low-cost, high-throughput and rapid diagnosis.
A SOT-based magnetic detection nucleic acid recognition method is adopted, and the sensor is constructed using the spin Hall effect and silicon dioxide layer. Combined with microfluidic channels, high-sensitivity magnetic signal detection and integrated structure are achieved, and target molecules are detected through the local magnetic field disturbance caused by the aggregation of magnetic nanoparticles.
It achieves highly sensitive detection of weak magnetic signals, supports batch integration and low-cost preparation of sensors, is suitable for scenarios such as virus detection and early cancer screening, and has miniaturized and low-power portable detection capabilities.
Smart Images
Figure CN120801485A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of nucleic acid recognition, and particularly relates to a magnetic detection nucleic acid recognition method based on SOT (spin orbit coupling) and a magnetic detection nucleic acid recognition device based on SOT. BACKGROUND
[0002] With the continuous development of precision medicine and point-of-care testing (POCT), disease early screening and virus detection based on DNA molecular recognition are becoming the core technology in the field of life science and public health. Although traditional detection methods such as PCR or fluorescently labeled probes have high sensitivity, they generally have problems such as complex instruments, high cost, long response period, and are difficult to meet the actual needs of low cost, high throughput and rapid diagnosis. In recent years, magnetic particle labeling methods have gradually been applied to nucleic acid detection systems due to their good biocompatibility and easy manipulation in a magnetic field. This method uses magnetic nanoparticles to modify DNA probes, which are fixed on the sensing area after specific complementary pairing with the target sequence, thereby realizing recognition through magnetic response changes. Although this technology has made some progress in specific recognition, the performance of the magnetic signal detection device is still limited. The widely used Hall devices and magnetoresistance devices (such as GMR, TMR, etc.) have limitations in terms of weak magnetic field response sensitivity, noise control, size integration and manufacturing cost, especially in the detection of local magnetic fields in the pT~nT level, it is difficult to achieve high signal-to-noise ratio output. In addition, most of the existing nucleic acid magnetic detection systems use a split structure, with the microfluidic channel and the magnetic sensor arranged independently, resulting in size redundancy, low signal coupling efficiency, difficulty in batch integration, and difficulty in meeting the needs of high throughput and portable integration.
[0003] Under this background, a new detection method with high sensitivity magnetic detection capability, no fluorescent label reading mechanism and sensor-microfluidic integrated structure needs to be developed to effectively improve the weak magnetic signal response capability and meet the comprehensive requirements of the next generation of biological detection platform in terms of miniaturization, low power consumption and integrability. SUMMARY
[0004] The main purpose of the present application is to provide a magnetic detection nucleic acid recognition method and device, which uses a heterogeneous spin orbit material to construct the core sensing unit and utilizes the spin Hall effect to realize the response and conversion of weak magnetic signals. In terms of structural design, the sensor surface is covered with a dense and uniform silicon dioxide (SiO2) insulating layer, which not only serves as an electrical insulator, but also has good chemical stability and biocompatibility.
[0005] Microfluidic channels are constructed on the surface of the silicon dioxide layer, and a high-precision microchannel array is formed by photolithography and plasma or wet etching technology to guide the flow of the biological sample to be tested (such as a solution containing biomarkers) in the region. When the magnetic nanoparticles or the magnetically labeled nucleic acid molecules in the sample to be tested flow in the microchannel with the inner surface functionalized, they are paired with the template chain DNA, thereby being fixed in the microchannel. The aggregation of the magnetic nanoparticles produces local magnetic field disturbance, thereby causing a change in the output signal of the SOT sensor, and high-sensitivity detection of the target molecules is realized.
[0006] Another object of the present application is to provide a magnetic detection nucleic acid recognition method and device. The present application scheme has the advantages of high precision of magnetic detection and high throughput of microfluidics, is beneficial to batch integration and low-cost preparation of the sensor chip in terms of structural design, is suitable for various scenes such as virus detection, tumor early screening, and pathogen recognition, and has wide application prospects and industrial value in the field of fusion of new magnetic sensors and biological detection.
[0007] To achieve the above objects, the present application provides a magnetic detection nucleic acid recognition method, comprising the following steps: Step S1: preparing a magnetic detection nucleic acid recognition device based on SOT, including substrate preparation, SOT structure deposition, patterning process, insulating layer deposition, microfluidic channel construction, microfluidic channel inner wall functionalization, packaging and electrode leading-out; Step S2: preparing and testing the nucleic acid sample to be tested; Step S3: signal processing to obtain the nucleic acid concentration value.
[0008] As a further preferred technical solution of the above technical solution, step S1 is specifically implemented as: Step S1.1: substrate preparation, selecting a high-resistance silicon wafer or a silicon wafer with a surface thermal oxide, cleaning and then treating with oxygen plasma to improve the surface adhesion; Step S1.2: SOT structure deposition, depositing a multi-layer structure by sputtering process to form a transverse current response structure; Step S1.3: patterning process, defining the sensor pattern area by using photolithography and ion etching technology to form an array of sensing units, thereby obtaining an SOT magnetic sensor; Step S1.4: insulating layer deposition, depositing a silicon dioxide layer on the surface of the SOT magnetic sensor, and using PECVD or PVD method to ensure uniform coverage; Step S1.5: microfluidic channel construction, constructing microfluidic channels on the surface of the silicon dioxide layer by photolithography and plasma or wet etching technology, and the inlet and outlet of the microfluidic channels are located above the sensor pattern area; Step S1.6: Microfluidic channel inner wall functionalization, hydroxylation of the inner wall silicon dioxide surface of the microfluidic channel structure by plasma activation and hydrogen peroxide chemical treatment, followed by the APTES / Glu method to introduce template single-stranded DNA; Step S1.7: Packaging and electrode lead-out, soft packaging using polyimide or PDMS, and reserving liquid inlet and outlet holes and electrode pad areas at both ends, and lead connection to the PCB detection system.
[0009] As a further preferred technical solution of the above technical solution, in step S1.4, the thickness of the silicon dioxide layer is 10-50 µm; in step S1.5, the height of the microfluidic channel is 9–49 µm, and the width is 50-200 µm.
[0010] As a further preferred technical solution of the above technical solution, step S2 is specifically implemented as the following steps: Step S2.1: Introduce the sample to be tested into the microfluidic channel, which contains target nucleic acid molecules; the inner wall of the microfluidic channel has been modified with single-stranded DNA probes complementary to the target nucleic acid, and the target nucleic acid is fixed on the wall; Step S2.2: Inject magnetic nanoballs modified with complementary single-stranded DNA on the surface, which bind to the other end of the target nucleic acid molecule, forming a probe-target nucleic acid-magnetic ball structure; Step S2.3: Introduce buffer for cleaning to remove unbound magnetic balls; Step S2.4: Under the action of an externally applied varying magnetic field, the resistance value of the SOT magnetic sensor increases compared to the change in resistance value before the introduction of complementary single-stranded DNA modified magnetic nanoparticles, and a constant current Io is applied to the SOT magnetic sensor, the change in resistance value causes the voltage value of the SOT magnetic sensor to change, and by measuring the change in voltage value of the SOT magnetic sensor, quantitative detection of the target nucleic acid molecule is achieved.
[0011] As a further preferred technical solution of the above technical solution, for step S3, replace ΔR with ΔR / Ro and the concentration of the detected nucleic acid to establish a linear mapping relationship, where Ro is the resistance value of the SOT sensor measured before the introduction of complementary single-stranded DNA modified magnetic nanoparticles; Under the action of a fixed varying magnetic field H and a constant current Io applied to the SOT sensor, a series of standard samples of target nucleic acid molecules with known concentrations are used to calibrate the SOT sensor to establish a sample concentration linear formula, and then according to the linear mapping relationship between the voltage change value and the nucleic acid concentration, the measured voltage voltage change is converted into the concentration value of the test substance.
[0012] As a further preferred technical solution of the above technical solution, in step S3, the nucleic acid concentration value is calculated by the following formula: ; wherein, is the voltage value difference of the SOT sensor measured in the range of fixed changing magnetic field after introducing the magnetic nanoparticles modified by the complementary single-stranded DNA; is the voltage value of the SOT sensor before introducing the magnetic nanoparticles modified by the complementary single-stranded DNA; a and b are constants obtained when the SOT sensor is calibrated to establish the sample concentration linear formula by using a series of standard samples of the nucleic acid molecules to be detected with known concentrations. .
[0013] To achieve the above purposes, the application further provides a magnetic detection nucleic acid recognition device applied to the magnetic detection nucleic acid recognition method.
[0014] The application has the following beneficial effects: 1. High sensitivity: the SOT magnetic sensor has a detection capability of approximately pico Tesla (pT) level, and can detect extremely low concentration target nucleic acids.
[0015] 2. Chip integration: the sensor structure is compatible with the CMOS process, facilitating batch production and system integration.
[0016] 3. High specificity: through the "sandwich type" recognition mechanism of the magnetic nanoballs, the non-specific binding background is effectively reduced.
[0017] 4. Label-free fluorescence: avoiding the traditional fluorescence labeling step, the system simplicity and stability are improved.
[0018] 5. Suitable for on-site detection: small size and low power consumption, which can be integrated into portable nucleic acid rapid detection equipment. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 is a preparation schematic diagram of the magnetic detection nucleic acid recognition device of the application.
[0020] Figure 2 is a preparation and test flowchart of the nucleic acid sample to be detected of the application.
[0021] Figure 3 is a graph showing that the resistance value of the SOT sensor shows different change ranges (R-H curve) with the applied magnetic field in the presence of magnetic nanoballs (with MNP) and the absence of magnetic nanoballs (W / O MNP).
[0022] Figure 4 is a graph showing that the voltage change value of the SOT sensor and the detection nucleic acid concentration have a linear mapping relationship in the presence of magnetic nanoballs (with MNP) and the absence of magnetic nanoballs (W / O MNP). DETAILED DESCRIPTION
[0023] The following description is presented to enable any person skilled in the art to practice the application as claimed. The preferred embodiments disclosed herein are only examples of the many possible variations of the present application. Other variations of the present application are possible and will be apparent to those skilled in the art upon reading the description of the preferred embodiments. The basic principles of the present application defined in the following description are applicable to other embodiments, variations, modifications, equivalents, and other implementations of the present application without departing from the spirit and scope of the present application.
[0024] In the preferred embodiments of the present application, those skilled in the art should note that the sample to be tested and the like involved in the present application can be regarded as prior art.
[0025] Preferred embodiments.
[0026] As Figures 1-4 shown, the present application discloses a magnetic detection nucleic acid recognition method, comprising the following steps: Step S1: preparation of a magnetic detection nucleic acid recognition device based on SOT (spin orbit coupling), including substrate preparation, SOT structure deposition, patterning process, insulating layer deposition, microfluidic channel construction, microfluidic channel inner wall functionalization, packaging and electrode lead-out; Step S2: preparation and testing process of the nucleic acid sample to be tested; Step S3: signal processing, thereby obtaining the nucleic acid concentration value.
[0027] Specifically, step S1 is specifically implemented as: Step S1.1: substrate preparation, high resistance silicon wafer or surface thermal oxidation silicon wafer is selected, and after cleaning, oxygen plasma treatment is used to improve the surface adhesion; Step S1.2: SOT structure deposition, a sputtering process is used to deposit a multi-layer structure (generally including Pt / CoFeB / MgO / Ta and the like hetero material stack), thereby forming a transverse current response structure; Step S1.3: patterning process, using photolithography and ion etching technology to define the sensor pattern area, forming a sensor unit array (up to 10^3-10^5 units per unit area), thereby obtaining an SOT magnetic sensor; Step S1.4: insulating layer deposition, depositing a silicon dioxide layer on the surface of the SOT magnetic sensor, using PECVD or PVD method to ensure uniform coverage (avoiding Pin-hole problem); Step S1.5: microfluidic channel construction, through (SU-8) photolithography and plasma or wet etching technology, a microfluidic channel is constructed on the surface of the silicon dioxide layer, and the inlet and outlet of the microfluidic channel are located above the sensor pattern area; Step S1.6: Functionalization of the inner wall of the microfluidic channel: hydroxylation of the silica surface of the inner wall of the microfluidic channel structure by plasma activation and hydrogen peroxide chemical treatment, followed by incorporation of template single-stranded DNA via the APTES / Glu method; Step S1.7: Encapsulation and electrode lead-out: Use polyimide or PDMS for soft encapsulation, reserve liquid inlet and outlet holes and electrode pad areas at both ends, and connect the leads to the PCB detection system.
[0028] More specifically, in step S1.4, the thickness of the silicon dioxide layer is 10-50 µm; and in step S1.5, the height of the microfluidic channel is 9-49 µm and the width is 50-200 µm.
[0029] Furthermore, step S2 is specifically implemented as the following steps: Step S2.1: Introducing a sample to be tested, which contains a target nucleic acid molecule, into a microfluidic channel; the inner wall of the microfluidic channel has been modified with a single-stranded DNA probe complementary to the target nucleic acid, and the target nucleic acid is fixed to the wall; Step S2.2: Injecting magnetic nanospheres modified with complementary single-stranded DNA to bind to the other end of the target nucleic acid molecule, forming a probe-target nucleic acid-magnetic nanosphere structure; Step S2.3: Introduce buffer for washing to remove unbound magnetic beads; Step S2.4: Figure 3 As shown in the figure, under an externally applied changing excitation magnetic field (H), the resistance value change (ΔRw) of the SOT magnetic sensor caused by the aggregation of magnetic nanoparticles increases compared with the resistance value change before the introduction of magnetic nanoparticles modified with complementary single-stranded DNA (ΔRwo<ΔRw). When a constant current Io is applied to the SOT magnetic sensor, the resistance value change causes the voltage value of the SOT magnetic sensor to change accordingly (ΔV). By measuring the voltage value change (ΔV) of the SOT magnetic sensor, quantitative detection of target nucleic acid molecules is achieved. Figure 3 In the figure, ΔRw corresponds to the change in the resistance of the SOT sensor during an external magnetic field sweep (-1 to 1 Oe) after the introduction of magnetic nanoparticles modified with complementary single-stranded DNA. This change is recorded as ΔRw (w represents with MNP); ΔRwo represents the change in the resistance of the SOT sensor during an external magnetic field sweep (-1 to 1 Oe) without the introduction of magnetic nanoparticles modified with single-stranded DNA (or before the introduction of a reagent containing magnetic nanoparticles). Wo represents the change in the resistance of the SOT sensor during an external magnetic field sweep (-1 to 1 Oe).
[0030] Furthermore, for step S3, (in actual measurement, the resistances of different SOT sensors are not completely consistent. During calculation, in order to eliminate the error caused by the inconsistency of resistance values between different sensors), ΔR / Ro is used instead of ΔR (ΔR refers to the change in the resistance of the SOT sensor during an external magnetic field sweep (-1 to 1 Oe), including the case where magnetic nanoparticles are introduced or not. Simply put, ΔR includes ΔRw and ΔRwo). A linear mapping relationship is established with the concentration of the nucleic acid being detected, and Ro is the resistance value of the SOT sensor measured before the introduction of complementary single-stranded DNA-modified magnetic nanoparticles (Ro represents the inherent resistance of the SOT in the absence of an external magnetic field change and is independent of the external magnetic field. ΔRwo represents the change in the resistance of the SOT sensor during an external magnetic field sweep (-1 to 1 Oe) without the introduction of single-stranded DNA-modified magnetic nanoparticles (or before the introduction of a reagent containing magnetic nanoparticles); When a fixed magnetic field H (e.g. -1 1Oe) and a constant current Io, a series of target nucleic acid molecule standard samples with known concentrations were used to calibrate the SOT sensor to establish The linear formula of sample concentration is then used, and the linear mapping relationship between voltage change value and nucleic acid concentration is established (such as Figure 4 As shown in the figure, the measured voltage change is converted into the concentration value of the analyte. Combined with the phase-locked amplifier or low-frequency noise filtering technology, the signal-to-noise ratio is further improved, achieving reliable identification of extremely small amounts of target molecules.
[0031] Preferably, in step S3, the nucleic acid concentration value is calculated by the following formula: ; in, The voltage difference is the voltage value difference measured by the SOT sensor in a fixed magnetic field range after the introduction of complementary single-stranded DNA modified magnetic nanoparticles; is the voltage value of the SOT sensor before the introduction of complementary single-stranded DNA modified magnetic nanoparticles; a and b are the voltage values of the SOT sensor established by calibrating a series of standard samples of nucleic acid molecules with known concentrations. The constant obtained when the linear equation of sample concentration is used.
[0032] The present invention also discloses a magnetic detection nucleic acid identification device, comprising a SOT magnetic sensor and a silicon dioxide layer, wherein the SOT magnetic sensor uses photolithography and ion etching technology to define a sensor pattern area to form a sensing unit array; The silicon dioxide layer is deposited on the surface of the SOT magnetic sensor, and a microfluidic channel is constructed on the surface of the silicon dioxide layer by photolithography and plasma or wet etching technology, with the inlet and outlet of the microfluidic channel located above the sensor pattern area.
[0033] It is worth mentioning that the technical features of the sample to be measured and the like involved in the present patent application should be regarded as the prior art, and the specific structure, working principle and possible control mode and spatial arrangement mode thereof can be selected according to the conventional selection in the field, and should not be regarded as the invention point of the present patent, and the present patent will not be further specifically expanded and described.
[0034] For those skilled in the art, the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features thereof can be replaced by equivalents, and any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims
1. A magnetic detection nucleic acid identification method, characterized in that: The following steps are involved: Step S1: Preparation of a magnetic detection nucleic acid recognition device based on SOT, including substrate preparation, SOT structure deposition, patterning process, insulating layer deposition, microfluidic channel construction, microfluidic channel inner wall functionalization, packaging and electrode extraction; Step S2: preparing and testing the nucleic acid sample to be tested; Step S3: Perform signal processing to obtain a nucleic acid concentration value.
2. A magnetic detection nucleic acid identification method according to claim 1, characterized in that: Step S1 is specifically implemented as follows: Step S1.1: Substrate preparation: Use a high-resistance silicon wafer or a thermally oxidized silicon wafer, clean it, and then treat it with oxygen plasma to improve surface adhesion; Step S1.2: SOT structure deposition, using a sputtering process to deposit a multilayer structure to form a lateral current response structure; Step S1.3: Patterning process, using photolithography and ion etching technology to define the sensor pattern area, forming a sensing unit array, thereby obtaining a SOT magnetic sensor; Step S1.4: Deposition of an insulating layer: Deposit a silicon dioxide layer on the surface of the SOT magnetic sensor using PECVD or PVD to ensure uniform coverage. Step S1.5: Microfluidic channel construction: constructing a microfluidic channel on the surface of the silicon dioxide layer by photolithography and plasma or wet etching techniques, with the inlet and outlet of the microfluidic channel located above the sensor pattern area; Step S1.6: Functionalization of the inner wall of the microfluidic channel: hydroxylation of the silica surface of the inner wall of the microfluidic channel structure by plasma activation and hydrogen peroxide chemical treatment, followed by incorporation of template single-stranded DNA via the APTES / Glu method; Step S1.7: Encapsulation and electrode lead-out: Use polyimide or PDMS for soft encapsulation, reserve liquid inlet and outlet holes and electrode pad areas at both ends, and connect the leads to the PCB detection system.
3. A magnetic detection nucleic acid identification method according to claim 2, characterized in that: In step S1.4, the thickness of the silica layer is 10–50 µm; in step S1.5, the height of the microfluidic channel is 9–49 µm and the width is 50–200 µm.
4. A magnetic detection nucleic acid identification method according to claim 3, characterized in that: Step S2 is specifically implemented as follows: Step S2.1: Introducing a sample to be tested, which contains a target nucleic acid molecule, into a microfluidic channel; the inner wall of the microfluidic channel has been modified with a single-stranded DNA probe complementary to the target nucleic acid, and the target nucleic acid is fixed to the wall; Step S2.2: Injecting magnetic nanospheres modified with complementary single-stranded DNA to bind to the other end of the target nucleic acid molecule, forming a probe-target nucleic acid-magnetic nanosphere structure; Step S2.3: Introduce buffer for washing to remove unbound magnetic beads; Step S2.4: Under an externally applied changing excitation magnetic field, the resistance value of the SOT magnetic sensor changes due to the aggregation of magnetic nanoparticles, which increases compared to the resistance value change before the introduction of complementary single-stranded DNA-modified magnetic nanoparticles. A constant current Io is applied to the SOT magnetic sensor, and the resistance value change causes the voltage value of the SOT magnetic sensor to change accordingly. By measuring the change in the voltage value of the SOT magnetic sensor, quantitative detection of the target nucleic acid molecule is achieved.
5. A magnetic detection nucleic acid identification method according to claim 4, characterized in that: For step S3, ΔR / Ro is used instead of ΔR to establish a linear mapping relationship with the concentration of the detected nucleic acid, where Ro is the resistance value of the SOT sensor measured before the introduction of the complementary single-stranded DNA-modified magnetic nanoparticles; When a fixed magnetic field H and a constant current Io are applied to the SOT sensor, a series of target nucleic acid molecule standard samples with known concentrations are used to calibrate the SOT sensor to establish a linear formula for sample concentration. Then, based on the established linear mapping relationship between the voltage change value and the nucleic acid concentration, the measured voltage change is converted into the concentration value of the analyte.
6. A magnetic detection nucleic acid identification method according to claim 5, characterized in that: In step S3, the nucleic acid concentration value is calculated using the following formula: ； in, The voltage difference is the voltage value difference measured by the SOT sensor in a fixed magnetic field range after the introduction of complementary single-stranded DNA modified magnetic nanoparticles; is the voltage value of the SOT sensor before the introduction of complementary single-stranded DNA modified magnetic nanoparticles; a and b are the voltage values of the SOT sensor established by calibrating a series of standard samples of nucleic acid molecules with known concentrations. The constant obtained when the linear equation of sample concentration is used.
7. A magnetic detection nucleic acid identification device, characterized in that: A magnetic detection nucleic acid recognition method applied to any one of claims 1-6.