Stem cell detection system and method based on magnetic particle balance modulation

Abstract

The invention belongs to the field of magnetic nanoparticle detection, particularly relates to a stem cell detection system and method based on magnetic particle balance modulation, and aims to solve the problem that in the prior art, the sensitivity is not high enough when tracing detection is carried out on stem cells by utilizing an MPI technology. The system comprises a coil balance assembly and a signal modulation module, the coil balance assembly comprises a first receiving coil, a second receiving coil and a compensation coil, and the signal modulation module comprises a signal modulation circuit and a gain adjustment resistor. Based on the system, the coil balance assembly and the signal modulation module are utilized to ensure that noise interference is reduced from a hardware system, and signals from stem cells are extracted as much as possible under the condition of low noise, so that the sensitivity of stem cell detection is improved, and hundreds of levels of stem cells can be detected.

Description

Technical Field

[0001] The invention belongs to the field of magnetic nanoparticle detection, and specifically relates to a stem cell detection system and method based on magnetic particle balance modulation. Background Art

[0002] Stem cell-based cell therapy has great potential in the treatment of a variety of diseases, including tumors, stroke, liver disease, etc. However, after the stem cells are injected into the body, how to migrate to the diseased tissue and achieve in vivo stem cell tracking is still a challenging problem. At present, a series of stem cell tracking studies have been carried out based on different imaging technologies such as optical imaging, radionuclide imaging, and magnetic resonance imaging, but the process of stem cell migration, proliferation, and differentiation has not been fully elucidated, which limits the further clinical transformation of stem cell tracking.

[0003] Magnetic Particle Imaging (MPI) technology is a new type of molecular imaging technology that is non-invasive, quantitative, radiation-free, nanomolar-level sensitive, and has no penetration depth limitation. It has been initially applied in the field of stem cell tracing and has shown great potential.

[0004] At present, the application of MPI for high-sensitivity stem cell tracing is limited due to the insufficient sensitivity of MPI in the in vivo microenvironment. In the existing technology, MPI can detect a minimum of 2,500 cell clusters composed of in vivo stem cells. During the stem cell tracing process, as the stem cells migrate, proliferate and differentiate, the SPIO that marks the stem cells is diluted, and MPI cannot detect a lower number of stem cells, making it difficult to track stem cells in the process of proliferation and differentiation, and difficult to determine whether the stem cells are still retained in the body or have been eliminated. Summary of the invention

[0005] In order to solve the above-mentioned problem in the prior art, that is, the problem that the prior art is not sensitive enough when using MPI to trace and detect stem cells, the present invention, in a first aspect, proposes a stem cell detection system based on magnetic particle balance modulation, including: a coil balance component, a signal modulation module; The coil balance component comprises a first receiving coil, a second receiving coil and a compensation coil, wherein the first receiving coil, the second receiving coil and the compensation coil are arranged in parallel and coaxially; the coil balance component is used to collect magnetic signals generated by the alternating magnetic field of the magnetic particles, and convert the magnetic signals into electrical signals, and transmit them to the signal modulation module; The signal modulation module includes a signal modulation circuit and a gain adjustment resistor; one end of the gain adjustment resistor is connected to the input end of the signal modulation circuit, and the other end is connected to the output end of the signal modulation circuit; the compensation coil is connected to the input end of the signal modulation circuit, and the first receiving coil and the second receiving coil are connected in reverse series and connected to the output end of the signal modulation circuit; the signal modulation circuit is used to gain the voltage signal output by the compensation coil; the gain adjustment resistor is used to control the gain coefficient of the signal modulation circuit by adjusting the resistance value.

[0006] In some preferred embodiments, the first receiving coil and the second receiving coil have the same size and number of turns, and the compensation coil has a smaller size and number of turns than the first receiving coil and the second receiving coil.

[0007] In some preferred embodiments, the spatial positions of the first receiving coil and the second receiving coil are uniformly symmetrical, so that the output terminal voltage of the signal modulation circuit reaches a preset minimum value in the case of empty measurement, and the spatial positions of the first receiving coil and the second receiving coil satisfy: ; In the formula, V is the output voltage of the signal modulation circuit, V1 is the voltage signal of the first receiving coil, V2 is the voltage signal of the second receiving coil, D is the spatial distance between the first receiving coil and the second receiving coil, and min is the preset minimum value of the output voltage of the signal modulation circuit.

[0008] In some preferred embodiments, the compensation coil is disposed inside the alternating magnetic field generated by the magnetic particles, and the parameter setting of the compensation coil satisfies: ; Wherein, V is the voltage at the output end of the signal modulation circuit, Vc is the voltage signal of the compensation coil, N is the number of turns of the compensation coil, P is the spatial position of the compensation coil inside the alternating magnetic field, and min is the preset minimum value of the voltage at the output end of the signal modulation circuit.

[0009] In some preferred embodiments, the parameter setting of the gain adjustment resistor satisfies: ; Wherein, V is the voltage at the output end of the signal modulation circuit, K is the gain of the signal modulation circuit, Rg is the resistance value of the gain adjustment resistor, and min is the preset minimum value of the voltage at the output end of the signal modulation circuit.

[0010] In some preferred embodiments, the voltage at the output end of the signal modulation circuit is: ; Where V is the output voltage of the signal modulation circuit, V1 is the voltage signal of the first receiving coil, V2 is the voltage signal of the second receiving coil, K is the gain coefficient of the signal modulation circuit, V c is the voltage signal of the compensation coil, D is the spatial distance between the first receiving coil and the second receiving coil, N is the number of turns of the compensation coil, P is the spatial position of the compensation coil inside the alternating magnetic field, Rg is the resistance of the gain adjustment resistor, and min is the preset minimum value of the output voltage of the signal modulation circuit.

[0011] In a second aspect, the present invention provides a stem cell detection method based on magnetic particle balance modulation. The method is based on the stem cell detection system based on magnetic particle balance modulation as described in the first aspect, and the method comprises: The stem cell detection system is used to detect a stem cell sample to be detected, and a voltage signal output by a signal modulation circuit is obtained, wherein the stem cell sample is a stem cell incubated with magnetic particles; Performing Fourier transform on the voltage signal to obtain frequency distribution characteristics of the voltage signal; Based on the frequency distribution characteristics, the voltage signal is screened to obtain a target signal; MPI reconstruction is performed based on the target signal to obtain stem cell detection results.

[0012] In some preferred embodiments, the screening of the voltage signal based on the frequency distribution characteristics comprises: Performing frequency screening on the voltage signal according to the frequency distribution characteristics to obtain a first signal; Performing frequency screening on the first signal according to a preset first signal-to-noise ratio threshold to obtain a second signal; Calculating the energy density of each frequency point in the second signal, and performing frequency screening on the second signal according to the energy density and a preset energy density threshold to obtain a third signal; The target signal is determined according to the third signal.

[0013] In some preferred embodiments, the first signal is composed of frequency points where signals exist in the voltage signal, the second signal is composed of frequency points where the signal-to-noise ratio in the first signal is higher than a preset first signal-to-noise ratio threshold, and the third signal is composed of frequency points where the energy density in the second signal is higher than a preset energy density threshold.

[0014] In some preferred embodiments, determining the target signal according to the third signal includes: Determining whether the signal-to-noise ratio of the third signal is higher than a preset second signal-to-noise ratio threshold; If the signal-to-noise ratio of the third signal is higher than a preset second signal-to-noise ratio threshold, re-screening the voltage signal based on the frequency distribution characteristics; If the signal-to-noise ratio is not higher than a preset second signal-to-noise ratio threshold, the third signal is determined to be a target signal.

[0015] Beneficial effects of the present invention: (1) The present invention proposes a high-sensitivity stem cell detection system and method based on magnetic particle balance modulation. The coil balance component and signal modulation module are constructed, and then combined with the signal processing method of stem cell signal characteristics, the detection of dozens to hundreds of stem cells can be achieved.

[0016] (2) The present invention uses a coil balance component and a signal modulation module to ensure that noise interference is reduced from the hardware system; at the same time, through the balance modulation of the coil balance component and the further processing method of the output signal, as much signal from the stem cell as possible is extracted under low noise conditions, thereby achieving the sensitivity of stem cell detection, and can detect hundreds of stem cells. The present invention is of great significance for predicting the effect of cell therapy, evaluating potential risks of treatment, and optimizing treatment strategies, and provides new technologies and methods for the study of stem cell migration mechanisms and new mechanisms of cancer biology. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 It is a structural schematic diagram of a stem cell detection system based on magnetic particle balance modulation proposed in an embodiment of the present invention; Figure 2 It is a schematic flow chart of a stem cell detection method based on magnetic particle balance modulation proposed in an embodiment of the present invention; Figure 3 It is a structural diagram of a computer system proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the relevant invention are shown in the accompanying drawings.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] Reference Figure 1 ,like Figure 1As shown, the present invention provides a stem cell detection system based on magnetic particle balance modulation, the system comprising: The coil balance component comprises a first receiving coil, a second receiving coil and a compensation coil, wherein the first receiving coil, the second receiving coil and the compensation coil are arranged in parallel and coaxially; the coil balance component is used to collect magnetic signals generated by the alternating magnetic field of the magnetic particles, and convert the magnetic signals into electrical signals, and transmit them to the signal modulation module; The signal modulation module includes a signal modulation circuit and a gain adjustment resistor; one end of the gain adjustment resistor is connected to the input end of the signal modulation circuit, and the other end is connected to the output end of the signal modulation circuit; the compensation coil is connected to the input end of the signal modulation circuit, and the first receiving coil and the second receiving coil are connected in reverse series and connected to the output end of the signal modulation circuit; the signal modulation circuit is used to gain the voltage signal output by the compensation coil; the gain adjustment resistor is used to control the gain coefficient of the signal modulation circuit by adjusting the resistance value.

[0021] In this embodiment, the function of the compensation coil is to compensate for the interference magnetic field in the entire system or the magnetic field inhomogeneity caused by environmental factors, thereby improving the sensitivity of the entire detection system.

[0022] In this embodiment, for the specific implementation of the signal modulation circuit, a dedicated integrated operational amplifier chip (such as OP07, etc.) can be used to build a basic signal amplification and modulation circuit. Generally speaking, the circuit includes at least a preamplifier, a filter, and a post-amplifier. The preamplifier is used to preliminarily amplify the input weak electrical signal, the filter is used to remove noise and clutter in the signal, and the post-amplifier further amplifies the signal to meet the requirements of subsequent processing.

[0023] In this embodiment, for the specific implementation of the gain adjustment resistor, a variable resistor (such as a potentiometer, a sliding resistor, etc.) can be selected, which has a certain resistance range (preferably, 1kΩ-10kΩ), connected between the input and output ends of the signal modulation circuit. Then, the amplification factor of the voltage signal generated by the compensation coil by the signal modulation circuit can be accurately controlled by adjusting its resistance.

[0024] Based on the system proposed in this embodiment, when the magnetic particles generate an alternating magnetic field under the action of an external alternating magnetic field, the first receiving coil and the second receiving coil will simultaneously sense the magnetic signal of the alternating magnetic field and convert the magnetic signal into an electrical signal according to the law of electromagnetic induction. The compensation coil will also sense the alternating magnetic field generated by the magnetic particles and other interfering magnetic fields in the environment, and the voltage signal generated by it will be input to the input end of the signal modulation circuit, and by adjusting the resistance value of the gain adjustment resistor, the signal modulation circuit can further accurately control the amplification factor of the compensation coil voltage signal. The amplified compensation signal is then superimposed or subtracted from the signals of the first receiving coil and the second receiving coil (the specific processing method is determined according to the actual signal modulation requirements) to offset the signal imbalance caused by environmental interference or coil differences.

[0025] It is easy to understand that the electrical signal processed by the signal modulation module will eventually be output to a possible signal processing unit (such as a spectrum analyzer, a data acquisition card, a microcontroller, etc., which are not used as examples in this system) for further analysis, processing and display, thereby ultimately achieving accurate detection and analysis of the alternating magnetic field of the magnetic particles.

[0026] It should be noted that the system provided in the above embodiment is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the modules or steps in the embodiments of the present invention can be decomposed or combined. For example, the modules in the above embodiments can be combined into one module, or further divided into multiple sub-modules to complete all or part of the functions described above. The names of the modules and steps involved in this embodiment and subsequent embodiments are only for distinguishing the modules or steps and are not regarded as improper limitations of the present invention.

[0027] Further, in this embodiment, the size and number of turns of the first receiving coil are equal to those of the second receiving coil, and the size and number of turns of the compensation coil are smaller than those of the first receiving coil and the second receiving coil.

[0028] The size and number of turns of the first receiving coil and the second receiving coil are equal, and the specific values ​​can be determined according to the actual detection sensitivity requirements. For example, the first receiving coil and the second receiving coil can be made of coils with 500 turns and a wire diameter of 0.2 mm, which can effectively receive the magnetic signal of the alternating magnetic field generated by the magnetic particles. Correspondingly, the size and number of turns of the compensation coil are smaller than the first receiving coil or the second receiving coil. For example, it can be made of a coil with 200 turns and a wire diameter of 0.2 mm.

[0029] Furthermore, in this embodiment, the first receiving coil and the second receiving coil are connected in reverse series and connected to the output end of the signal circuit.

[0030] Furthermore, in this embodiment, the spatial positions of the first receiving coil and the second receiving coil are uniformly symmetrical, so that the output terminal voltage of the signal modulation circuit reaches a preset minimum value in the case of empty measurement, and the spatial positions of the first receiving coil and the second receiving coil satisfy: ; In the formula, V is the output terminal voltage of the signal modulation circuit, V1 is the first receiving coil, V2 is the second receiving coil, and D is the spatial distance between the first receiving coil and the second receiving coil.

[0031] In this embodiment, by adjusting the relative spatial distance D between the receiving coil 1 and the receiving coil 2, the positions of the two in the alternating magnetic field space are ensured to be uniform and symmetrical as much as possible. The voltage signal V1 of the receiving coil 1 and the voltage signal V2 of the receiving coil 2 are connected in series in reverse order into the signal modulation circuit. By adjusting the relative spatial position of the receiving coil 1 and the receiving coil 2, the voltage V at the signal output end is made as small as possible in the case of empty measurement (no magnetic particles), that is, the noise is made as small as possible.

[0032] Furthermore, in this embodiment, the compensation coil is disposed inside the alternating magnetic field, and the parameter setting of the compensation coil satisfies: ; Where, V is the voltage at the signal output terminal, V c is the output voltage of the compensation coil, N is the number of turns of the compensation coil, and P is the spatial position of the compensation coil inside the alternating magnetic field.

[0033] It is easy to understand that in this embodiment, the output voltage Vc of the compensation coil is adjusted by adjusting the number of turns N and the spatial position P of the compensation coil, so that the voltage V at the signal output end is further reduced. Compared with the adjustment of the receiving coil 1 and the receiving coil 2, the ability of the compensation coil to adjust noise is relatively small, which belongs to fine-tuning noise.

[0034] Furthermore, in this embodiment, the parameter setting of the gain adjustment resistor satisfies: ; Wherein, V is the voltage at the signal output terminal, K is the gain of the signal modulation circuit, R g is the resistance value of the gain adjustment resistor.

[0035] It is easy to understand that since the compensation coil still reduces the noise at the signal output end by adjusting the magnetic field, the accuracy of its adjustment ability is still limited, so it is necessary to cooperate with the gain adjustment resistor to further fine-tune the noise level at the circuit level.

[0036] Furthermore, in this embodiment, the voltage of the signal output terminal is: ; In the formula, V is the output voltage of the signal modulation circuit, V1 is the voltage signal of the first receiving coil, V2 is the voltage signal of the second receiving coil, K is the gain of the signal modulation circuit generated by the gain adjustment resistor, Vc is the voltage signal of the compensation coil, D is the spatial distance between the first receiving coil and the second receiving coil, N is the number of turns of the compensation coil, P is the spatial position of the compensation coil inside the alternating magnetic field, and Rg is the resistance value of the gain adjustment resistor. Based on this, through the common restrictions and constraints of multiple parameters, when no magnetic particles are put in (empty measurement), the voltage at the signal output end is as small as possible to meet the requirements of high-sensitivity detection.

[0037] Based on the system proposed in the above embodiment, the method of the present application is further introduced.

[0038] Based on the above system, the second embodiment of the present invention proposes a stem cell detection method based on magnetic particle balance modulation, such as Figure 2 As shown, the method includes: Step S10, using the stem cell detection system to detect a stem cell sample to be detected, and obtaining a voltage signal output by a signal modulation circuit, wherein the stem cell sample is a stem cell incubated with magnetic particles; One purpose of this embodiment is to screen out the signals generated by magnetic particles in stem cells. In this embodiment, the stem cell sample to be detected is incubated with magnetic particles for a fixed period of time (preferably 24 hours) and then washed to wash away the magnetic particles that have not entered the stem cells, and then an ultra-high number of stem cells (10 to the sixth power or the seventh power level) is measured to detect obvious frequency distribution characteristics of magnetic particles in the stem cells.

[0039] Step S20, performing Fourier transform on the voltage signal to obtain frequency distribution characteristics; It is easy to understand that performing frequency domain analysis on a signal through Fourier transform and then extracting corresponding frequency distribution characteristics is a common technical means used by those skilled in the art, and therefore this embodiment does not impose too many limitations on this.

[0040] Step S30, screening the voltage signal based on the frequency distribution characteristics to obtain a target signal; Among them, based on the frequency distribution characteristics, the voltage signal is screened, specifically including: According to the frequency distribution characteristics, the voltage signal is frequency-filtered to obtain a first signal, and the first signal is composed of frequency points of signals existing in the voltage signal; according to a preset first signal-to-noise ratio threshold, the first signal is frequency-filtered to obtain a second signal, and the second signal is composed of frequency points in the first signal whose signal-to-noise ratio is higher than the preset first signal-to-noise ratio threshold; the energy density of each frequency point in the second signal is calculated, and according to the energy density and the preset energy density threshold, the second signal is frequency-filtered to obtain a third signal, and the third signal is composed of frequency points in the second signal whose energy density is higher than the preset energy density threshold.

[0041] In this embodiment, millions of stem cells incubated with magnetic particles are first placed in a magnetic particle spectrometer to test the signal, and then the signal is transformed into the frequency domain through Fourier transform to save the frequency point information of the stem cell signal, that is, the frequency distribution characteristics.

[0042] Frequency screening is performed based on the frequency distribution characteristics, and only the frequency points with signals in stem cells are retained, that is, the first signal is obtained; Calculate the signal-to-noise ratio of the frequency points filtered in the first step, set a signal-to-noise ratio threshold (generally, the threshold can be set to 1), retain the frequency points above the threshold, and remove the frequency points below the threshold, thus obtaining the second signal; Calculate the energy density of the frequency points in the second signal retained in the previous step, that is, calculate the square of the signal amplitude at each frequency point, and similarly retain the signal frequency points with energy density higher than a certain threshold, and you will get the third signal.

[0043] After obtaining the third signal, determine whether the signal-to-noise ratio of the third signal is higher than a preset second signal-to-noise ratio threshold; if the signal-to-noise ratio of the third signal is higher than the preset second signal-to-noise ratio threshold, re-screen the voltage signal based on the frequency distribution characteristics; if the signal-to-noise ratio is not higher than the preset second signal-to-noise ratio threshold, determine that the third signal is a target signal.

[0044] In this embodiment, if it is detected that the signal-to-noise ratio is higher than the second signal-to-noise ratio threshold, the whole process is repeated until the signal-to-noise ratio of the third signal finally obtained is less than the second signal-to-noise ratio threshold, and the final target signal is obtained, which is used for MPI reconstruction.

[0045] Step S40: Perform MPI reconstruction based on the target signal to obtain a stem cell detection result.

[0046] The specific process of MPI reconstruction is common knowledge that can be understood by those skilled in the art, and this embodiment does not improve it. Those skilled in the art can implement it by themselves according to the existing technology, and this embodiment will not be repeated here.

[0047] Reference below Figure 3 , which shows a schematic diagram of the structure of a computer system of a server suitable for implementing an embodiment of the method of the present application. Figure 3 The server shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0048] like Figure 3 As shown, the computer system includes a central processing unit (CPU) 301, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 302 or the program loaded from the storage part 308 to the random access memory (RAM) 303. Various programs and data required for system operation are also stored in the RAM 303. The CPU 301, ROM 302 and RAM 303 are connected to each other through a bus 304. An input / output (I / O) interface 305 is also connected to the bus 304.

[0049] The following components are connected to the I / O interface 305: an input section 306 including a keyboard, a mouse, etc.; an output section 307 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker; a storage section 303 including a hard disk, etc.; and a communication section 309 including a network interface card such as a LAN (Local Area Network) card, a modem, etc. The communication section 309 performs communication processing via a network such as the Internet. A drive 310 is also connected to the I / O interface 305 as needed. A removable medium 311, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 310 as needed so that a computer program read therefrom is installed into the storage section 308 as needed.

[0050] In particular, according to an embodiment of the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 309, and / or installed from the removable medium 311. When the computer program is executed by the central processing unit (CPU) 301, the above-mentioned functions defined in the method of the present application are executed. It should be noted that the above-mentioned computer-readable medium of the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium can be, for example, - but not limited to - a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above.

[0051] More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection with one or more conductors, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, an apparatus or a device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in combination with an instruction execution system, an apparatus or a device. The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, RF, etc., or any suitable combination of the above.

[0052] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0053] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0054] The terms "first", "second", etc. are used to distinguish similar objects rather than to describe or indicate a particular order or sequence.

[0055] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0056] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the drawings.

[0057] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A stem cell detection system based on magnetic particle equilibrium modulation, characterized in that: include: Coil balancing components, signal modulation modules; The coil balance component comprises a first receiving coil, a second receiving coil and a compensation coil, wherein the first receiving coil, the second receiving coil and the compensation coil are arranged in parallel and coaxially; the coil balance component is used to collect magnetic signals generated by the alternating magnetic field of the magnetic particles, and convert the magnetic signals into electrical signals, and transmit them to the signal modulation module; The signal modulation module includes a signal modulation circuit and a gain adjustment resistor; one end of the gain adjustment resistor is connected to the input end of the signal modulation circuit, and the other end is connected to the output end of the signal modulation circuit; the compensation coil is connected to the input end of the signal modulation circuit, and the first receiving coil and the second receiving coil are connected in reverse series and connected to the output end of the signal modulation circuit; the signal modulation circuit is used to gain the voltage signal output by the compensation coil; the gain adjustment resistor is used to control the gain coefficient of the signal modulation circuit by adjusting the resistance value.

2. The stem cell detection system based on magnetic particle equilibrium modulation according to claim 1, characterized in that: The size and number of turns of the first receiving coil are equal to those of the second receiving coil, and the size and number of turns of the compensation coil are smaller than those of the first receiving coil and the second receiving coil.

3. The stem cell detection system based on magnetic particle equilibrium modulation according to claim 1, characterized in that: The spatial positions of the first receiving coil and the second receiving coil are uniformly symmetrical, so that the output terminal voltage of the signal modulation circuit reaches a preset minimum value in the case of empty measurement, and the spatial positions of the first receiving coil and the second receiving coil satisfy: ； In the formula, V is the output voltage of the signal modulation circuit, V1 is the voltage signal of the first receiving coil, V2 is the voltage signal of the second receiving coil, D is the spatial distance between the first receiving coil and the second receiving coil, and min is the preset minimum value of the output voltage of the signal modulation circuit.

4. The stem cell detection system based on magnetic particle equilibrium modulation according to claim 1, characterized in that: The compensation coil is disposed inside the alternating magnetic field generated by the magnetic particles, and the parameter setting of the compensation coil satisfies: ； Where V is the voltage at the output of the signal modulation circuit, V c is the voltage signal of the compensation coil, N is the number of turns of the compensation coil, P is the spatial position of the compensation coil inside the alternating magnetic field, and min is the preset minimum value of the output voltage of the signal modulation circuit.

5. The stem cell detection system based on magnetic particle equilibrium modulation according to claim 1, characterized in that: The parameter setting of the gain adjustment resistor satisfies: ； In the formula, V is the voltage at the output of the signal modulation circuit, K is the gain coefficient of the signal modulation circuit, and R g is the resistance value of the gain adjustment resistor, and min is the preset minimum value of the output voltage of the signal modulation circuit.

6. The stem cell detection system based on magnetic particle equilibrium modulation according to claim 1, characterized in that: The voltage at the output end of the signal modulation circuit is: ； Where V is the output voltage of the signal modulation circuit, V1 is the voltage signal of the first receiving coil, V2 is the voltage signal of the second receiving coil, K is the gain coefficient of the signal modulation circuit, V c is the voltage signal of the compensation coil, D is the spatial distance between the first receiving coil and the second receiving coil, N is the number of turns of the compensation coil, P is the spatial position of the compensation coil inside the alternating magnetic field, R g is the resistance value of the gain adjustment resistor, and min is the preset minimum value of the output voltage of the signal modulation circuit.

7. A stem cell detection method based on magnetic particle equilibrium modulation, characterized in that: Based on the stem cell detection system based on magnetic particle balance modulation according to any one of claims 1 to 6, the method comprises: The stem cell detection system based on magnetic particle balance modulation is used to detect the stem cell sample to be detected, and a voltage signal output by the signal modulation circuit is obtained, wherein the stem cell sample is a stem cell incubated with magnetic particles; Performing Fourier transform on the voltage signal to obtain frequency distribution characteristics of the voltage signal; Based on the frequency distribution characteristics, frequency screening is performed on the voltage signal to obtain a target signal; MPI reconstruction is performed based on the target signal to obtain stem cell detection results.

8. The stem cell detection method based on magnetic particle equilibrium modulation according to claim 7, characterized in that: The frequency screening of the voltage signal based on the frequency distribution characteristics includes: Performing frequency screening on the voltage signal according to the frequency distribution characteristics to obtain a first signal; Performing frequency screening on the first signal according to a preset first signal-to-noise ratio threshold to obtain a second signal; Calculating the energy density of each frequency point in the second signal, and performing frequency screening on the second signal according to the energy density and a preset energy density threshold to obtain a third signal; The target signal is determined according to the third signal.

9. The stem cell detection method based on magnetic particle equilibrium modulation according to claim 8, characterized in that: The first signal is composed of frequency points where signals exist in the voltage signal, the second signal is composed of frequency points where the signal-to-noise ratio in the first signal is higher than a preset first signal-to-noise ratio threshold, and the third signal is composed of frequency points where the energy density in the second signal is higher than a preset energy density threshold.

10. The stem cell detection method based on magnetic particle equilibrium modulation according to claim 8, characterized in that: The step of determining the target signal according to the third signal includes: Determining whether the signal-to-noise ratio of the third signal is higher than a preset second signal-to-noise ratio threshold; If the signal-to-noise ratio of the third signal is higher than a preset second signal-to-noise ratio threshold, re-performing frequency screening on the voltage signal; If the signal-to-noise ratio is not higher than a preset second signal-to-noise ratio threshold, the third signal is determined to be the target signal.

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