Optical microscopy method, system and device for positioning magnetic nanoparticles

Abstract

The invention discloses an optical microscopy method, system and device for positioning magnetic nanoparticles, and the method comprises the steps: obtaining an interference pattern generated when laser passes through a to-be-detected sample, and distributing the magnetic nanoparticles in the to-be-detected sample; the interference pattern is formed by interference of incident laser and scattered light of the magnetic nanoparticles; determining a distribution function of the interference pattern, and determining the central position of the magnetic nanoparticle according to the interference pattern and the distribution function; the device comprises a laser, an amplification objective lens, a focusing lens, an imaging unit and a processor, light emitted by the laser passes through a to-be-detected sample to generate an interference pattern, the interference pattern is amplified by the amplification objective lens and focused by the focusing lens to be imaged in the imaging unit, and magnetic nanoparticles are distributed in the to-be-detected sample. According to the embodiment of the invention, micron-sized space positioning of the magnetic nanoparticles can be realized, and the method can be widely applied to the technical field of optical positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of optical positioning, and in particular, to an optical microscopy method, system and device for magnetic nanoparticle positioning. Background Art

[0002] Magnetic nanoparticles have important application prospects in the fields of multimodal in vivo bioimaging, cell tracking, precise magnetic hyperthermia, targeted drug delivery, nanomaterials, etc. The spatial positioning resolution of existing magnetic particle imaging technology depends on the magnetic properties of magnetic nanoparticles and the gradient of the external magnetic field, and currently it is at the sub-millimeter level. Therefore, it is necessary to develop a magnetic nanoparticle positioning technology with higher spatial resolution. Summary of the Invention

[0003] In view of this, to solve one of the above problems, an object of an embodiment of the present invention is to provide an optical microscopy method, system and device for magnetic nanoparticle positioning, which can achieve micron-level spatial positioning of magnetic nanoparticles.

[0004] On the one hand, an embodiment of the present invention provides an optical microscopy method for magnetic nanoparticle positioning, including:

[0005] Obtaining an interference pattern generated by laser passing through a sample to be measured, wherein magnetic nanoparticles are distributed in the sample to be measured; the interference pattern is formed by the interference of incident laser light and scattered light of the magnetic nanoparticles;

[0006] Determining a distribution function of the interference pattern, and determining the central position of the magnetic nanoparticles according to the interference pattern and the distribution function.

[0007] Optionally, the determining the central position of the magnetic nanoparticles according to the interference pattern and the distribution function includes:

[0008] Performing a cross-correlation operation on the interference pattern and the distribution function to determine the central position of the magnetic nanoparticles.

[0009] Optionally, the method further includes:

[0010] Performing peak fitting on the central position to determine the spatial coordinates of the magnetic nanoparticles.

[0011] Optionally, if multiple magnetic nanoparticles are included within the field of view of the interference pattern, the method further includes:

[0012] Obtaining a complete interference pattern region of the magnetic nanoparticles for magnetic nanoparticle positioning.

[0013] On the other hand, an embodiment of the present invention provides an optical microscopy system for magnetic nanoparticle positioning, including:

[0014] The first module is configured to obtain an interference pattern generated by laser passing through a sample to be measured, wherein magnetic nanoparticles are distributed in the sample to be measured;

[0015] The second module is configured to determine a distribution function of the interference pattern, and determine a central position of the magnetic nanoparticles according to the interference pattern and the distribution function.

[0016] On the other hand, an embodiment of the present invention provides an optical microscopy device for positioning magnetic nanoparticles, including:

[0017] At least one processor;

[0018] At least one memory for storing at least one program;

[0019] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0020] On the other hand, an embodiment of the present invention provides an optical microscopy device for positioning magnetic nanoparticles, including a laser, a magnifying objective lens, a focusing lens, an imaging unit, and a processor. The light emitted by the laser passes through the sample to be measured to generate an interference pattern. The interference pattern is magnified by the magnifying objective lens and focused by the focusing lens to be imaged on the imaging unit. Magnetic nanoparticles are distributed in the sample to be measured, and the processor is configured to execute the above method.

[0021] Optionally, the optical positioning microscopy device further includes a collimating unit configured to collimate the light emitted by the laser.

[0022] Optionally, the optical positioning microscopy device further includes a first mirror configured to reflect the light emitted by the laser to the sample to be measured.

[0023] Optionally, the optical positioning microscopy device further includes a second mirror configured to reflect the light magnified by the magnifying objective lens to the focusing lens.

[0024] Implementing the embodiments of the present invention includes the following beneficial effects: In this embodiment, the incident laser is scattered at the magnetic nanoparticles in the sample to be measured. The scattered light of the magnetic nanoparticles and the incident laser interfere to form an interference pattern, so as to enhance the scattering characteristic signal of the magnetic nanoparticles, and determine the central position of the magnetic nanoparticles according to the interference pattern and its distribution function, thereby realizing the micron-level spatial positioning of the magnetic nanoparticles and providing a powerful tool for observing the microscopic behavior of magnetic nanoparticles in a biological living environment. Description of the Drawings

[0025] Figure 1It is an optical path diagram for generating an interference pattern by magnetic nanoparticles provided by an embodiment of the present invention;

[0026] Figure 2 It is a schematic flow chart of steps of an optical microscopy method for magnetic nanoparticle positioning provided by an embodiment of the present invention;

[0027] Figure 3 It is a schematic distribution diagram of the scattering intensity of magnetic nanoparticles provided by an embodiment of the present invention;

[0028] Figure 4 It is a schematic intensity distribution diagram of the interference pattern of magnetic nanoparticles provided by an embodiment of the present invention;

[0029] Figure 5 It is a flow chart for determining the central position of magnetic nanoparticles provided by an embodiment of the present invention;

[0030] Figure 6 It is a structural block diagram of an optical microscopy system for magnetic nanoparticle positioning provided by an embodiment of the present invention;

[0031] Figure 7 It is a structural block diagram of an optical microscopy device for magnetic nanoparticle positioning provided by an embodiment of the present invention;

[0032] Figure 8 It is a structural block diagram of another optical microscopy device for magnetic nanoparticle positioning provided by an embodiment of the present invention;

[0033] Figure 9 It is a structural block diagram of another optical microscopy device for magnetic nanoparticle positioning provided by an embodiment of the present invention;

[0034] Figure 10 It is an interference pattern based on magnetic nanoparticles provided by an embodiment of the present invention. Specific embodiments

[0035] The following further elaborates the present invention in detail in conjunction with the accompanying drawings and specific embodiments. For the step numbers in the following embodiments, they are only set for the convenience of elaboration and explanation, and no limitation is imposed on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0036] Magnetic nanoparticles (Magnetic Particle) include nanoparticles formed by superparamagnetic iron oxide (SuperParamagnetic Iron Oxide) and are used in various magnetic imaging and treatment technologies.

[0037] Interference: When two or more waves meet in space, they superpose or cancel each other out, thus forming a new waveform.

[0038] Optical microscopy refers to a technique where visible light passing through or reflected from a sample, after passing through one or more lenses, can obtain an enlarged image of a microscopic sample; the obtained image can be directly observed with the naked eye through an eyepiece, or recorded using a photographic plate or a digital image detector (such as CCD, CMOS), and can also be displayed and analyzed on a computer.

[0039] Magnetic Particle Imaging (MPI) is a new type of biological metabolic imaging technique. It injects superparamagnetic iron oxide nanoparticles as tracers into a living organism and uses the non-linear magnetization response of the superparamagnetic nanoparticles under a DC gradient magnetic field and an alternating magnetic field to achieve spatial encoding and imaging. This method applies a gradient magnetic field to the imaging region through a pair of reverse permanent magnets, and this pair of reverse permanent magnets will form a Field-Free Region at the center position. The magnetic nanoparticles in the free region will generate a non-linear response to the applied alternating magnetic field. Based on this non-linear response signal, the spatial position and concentration information of the magnetic nanoparticles can be marked. When the Field-Free Region moves, the spatial positioning and concentration information acquisition of magnetic nanoparticles in the entire region can be achieved.

[0040] Since magnetic nanoparticles operate in a living biological environment and the surrounding medium is mainly water. When coherent light irradiates the water body containing magnetic nanoparticles, due to the significant difference in refractive index between magnetic nanoparticles and water, the magnetic nanoparticles will scatter the incident coherent light. Since the scattered light is coherent with the incident light at the same frequency, interference will occur, thus forming an interference pattern. The center point of the interference pattern is the spatial position where the magnetic nanoparticles are located. By collecting and calculating this interference pattern through a microscopic optical path, the positioning of magnetic nanoparticles can be achieved.

[0041] As Figure 2 shown, an embodiment of the present invention provides an optical microscopy method for magnetic nanoparticle positioning, including:

[0042] S100. Obtain the interference pattern generated by the laser passing through the sample to be measured, where magnetic nanoparticles are distributed in the sample to be measured; the interference pattern is formed by the interference between the incident laser and the scattered light of the magnetic nanoparticles;

[0043] S200. Determine the distribution function of the interference pattern, and determine the central position of the magnetic nanoparticles based on the interference pattern and the distribution function.

[0044] Refer to Figure 3, according to Rayleigh scattering theory, when the particle size is much smaller than the wavelength of the incident light, elastic scattering of light will occur, and the scattering intensity in each direction is inconsistent. The distribution of its scattering intensity at various angles in space is as Figure 3 shown.

[0045] Based on the characteristics of the scattered light signal, it can be inferred that the interference scattering pattern generated by the interference of the forward-propagating scattered light and the incident light is a concentric circle with central symmetry, and the center of the concentric circle is the region where the magnetic nanoparticles are located. Based on the intensity and angle characteristics of Rayleigh scattering, it can be inferred that the shape of the ideal interference scattering pattern is as Figure 4 shown, which can be regarded as the "point spread function" of the magnetic nanoparticles.

[0046] To extract the spatial coordinates of the magnetic nanoparticles, using the intensity distribution map in the X-Y direction of the ideal interference scattering pattern as a template, the center position of the "point spread function" is found by performing shift and fitting calculations on the photographed interference pattern photo of the magnetic nanoparticles.

[0047] Optionally, determining the center position of the magnetic nanoparticles according to the interference pattern and the distribution function includes:

[0048] Performing a cross-correlation operation on the interference pattern and the distribution function to determine the center position of the magnetic nanoparticles.

[0049] Cross-correlation is a mathematical operation that measures the similarity between two signals. Using the Figure 4 pattern shown as the point spread function, denoted as PSF(x,y), and then using the imaging to obtain the interference pattern of the magnetic nanoparticles, denoted as M(x,y), performing a cross-correlation operation on the two to obtain the cross-correlation map C(x,y). The specific calculation formula is as follows:

[0050] C(x,y) = PSF(x,y) * M(x,y) = ΣPSF(x,y)M(x - u, y - v)

[0051] where x and u represent the spatial abscissa, and y and v represent the spatial ordinate.

[0052] Referring to Figure 5 , the maximum value of the cross-correlation map within the target area is the center point of the magnetic nanoparticles, such as the Figure 5 red triangle in.

[0053] Optionally, the method further includes:

[0054] Performing peak fitting on the center position to determine the spatial coordinates of the magnetic nanoparticles.

[0055] Furthermore, two-dimensional Gaussian fitting method is used to finely locate the peak center point, and this center position is the spatial coordinates of the magnetic nanoparticles.

[0056] Optionally, a plurality of magnetic nanoparticles are included within the field of view of several interference patterns, and the method further includes:

[0057] Obtaining the complete interference pattern region of the magnetic nanoparticles for magnetic nanoparticle positioning.

[0058] If there are multiple magnetic nanoparticles within the field of view of the imaging picture, the magnetic nanoparticles with a complete circular interference scattering pattern can be located first, and then the spatial positioning or position estimation of other magnetic nanoparticles can be performed.

[0059] Implementing the embodiments of the present invention includes the following beneficial effects: In this embodiment, the incident laser is scattered at the magnetic nanoparticles of the sample to be measured, and the scattered light of the magnetic nanoparticles interferes with the incident laser to form an interference pattern, so as to enhance the scattering characteristic signal of the magnetic nanoparticles, and determine the center position of the magnetic nanoparticles according to the interference pattern and its distribution function, thereby realizing the micron-level spatial positioning of the magnetic nanoparticles, providing a powerful tool for observing the microscopic behavior of magnetic nanoparticles in the biological living environment.

[0060] Referring to Figure 6 , the embodiments of the present invention provide an optical microscopy system for magnetic nanoparticle positioning, including:

[0061] A first module for obtaining the interference pattern generated by the laser passing through the sample to be measured, where magnetic nanoparticles are distributed in the sample to be measured;

[0062] A second module for determining the distribution function of the interference pattern and determining the center position of the magnetic nanoparticles according to the interference pattern and the distribution function.

[0063] It can be seen that the content in the above method embodiments is applicable to the system embodiments of the present invention. The functions specifically implemented by the system embodiments of the present invention are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0064] Referring to Figure 7 , the embodiments of the present invention provide an optical microscopy device for magnetic nanoparticle positioning, including:

[0065] At least one processor;

[0066] At least one memory for storing at least one program;

[0067] When at least one program is executed by at least one processor, at least one processor implements the above method.

[0068] Among them, the memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. The memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory optionally includes a remote memory remotely disposed relative to the processor, and these remote memories can be connected to the processor through a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0069] It can be seen that the content in the above method embodiments is applicable to the device embodiments of the present invention. The functions specifically implemented in the device embodiments of the present invention are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0070] In addition, the embodiments of the present application also disclose a computer program product or a computer program. The computer program product or the computer program is stored in a computer-readable storage medium. The processor of the computer device can read the computer program from the computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the above method.

[0071] The embodiments of the present invention also provide a computer-readable storage medium. The computer-readable storage medium stores a program executable by a processor, and the program executable by the processor is used to implement the above method when executed by the processor. Similarly, the content in the above method embodiments is applicable to the storage medium embodiments of the present invention. The functions specifically implemented in the storage medium embodiments of the present invention are the same as those in the above method embodiments, and the beneficial effects achieved are also the same as those achieved in the above method embodiments.

[0072] It can be understood that all or some of the steps and systems disclosed in the above methods can be implemented as software, firmware, hardware, and their appropriate combinations. Some physical components or all physical components can be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those of ordinary skill in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory, or other memory technologies, CD-ROM, digital versatile disk (DVD), or other optical disk storage, magnetic cartridges, tapes, magnetic disk storage, or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that a communication medium typically contains computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transmission mechanism, and can include any information delivery medium.

[0073] Refer to Figure 8 , an optical microscopy device for magnetic nanoparticle localization according to an embodiment of the present invention includes a laser, a magnifying objective lens, a focusing lens, an imaging unit, and a processor. The light emitted by the laser passes through the sample to be measured to generate an interference pattern. The interference pattern is magnified by the magnifying objective lens and focused by the focusing lens to form an image on the imaging unit. Magnetic nanoparticles are distributed in the sample to be measured, and the processor is used to execute the above method.

[0074] The sample to be measured is determined according to the actual measurement application. For example, the sample to be measured is a thin cuvette filled with pure water, and the magnetic nanoparticles are put into the pure water. The magnification of the magnifying objective lens is determined according to the actual application, such as 100 times. The imaging unit is determined according to the actual application, such as CMOS / CCD, etc.

[0075] Optionally, the optical positioning microscopy device further includes a collimating unit, and the collimating unit is used to collimate the light emitted by the laser.

[0076] Optionally, the optical positioning microscopy device further includes a first mirror, and the first mirror is used to reflect the light emitted by the laser to the sample to be measured.

[0077] Optionally, the optical positioning microscopy device further includes a second mirror, and the second mirror is used to reflect the light magnified by the magnifying objective lens to the focusing lens.

[0078] Refer toFigure 9 , the optical positioning microscope device may further include any one or more of a collimation unit, a first mirror, and a second mirror. The collimation unit is used to collimate the light emitted by the laser to improve the correlation; the first mirror and the second mirror are used to change the propagation direction of the light to facilitate the layout of the optical positioning microscope device.

[0079] In a specific embodiment, refer to Figure 10 , an experimental system is built according to the system optical path shown in the present invention. Pure water is contained in a cuvette, and superparamagnetic iron oxide nanoparticles with a size of 50 nm are put into the pure water, and then irradiated with a continuous laser of 632 nm, and then the CMOS camera is controlled to record the relevant circular interference pattern.

[0080] It can be seen that the content in the above method embodiments is applicable to the present system embodiment. The functions specifically implemented by the present system embodiment are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those of the above method embodiments.

[0081] The above is a specific description of the preferred embodiment of the present invention, but the present invention is not limited to the described embodiment. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. An optical microscopy method for localizing magnetic nanoparticles, characterized in that: include: Obtaining an interference pattern generated by laser passing through a sample to be tested, wherein magnetic nanoparticles are distributed in the sample to be tested; The interference pattern is formed by the interference of incident laser light and scattered light of the magnetic nanoparticles; The distribution function of the interference pattern is determined, and the center position of the magnetic nanoparticle is determined according to the interference pattern and the distribution function.

2. The optical localization microscopy method according to claim 1, characterized in that: Determining the center position of the magnetic nanoparticles according to the interference pattern and the distribution function comprises: The interference pattern and the distribution function are cross-correlated to determine the center position of the magnetic nanoparticles.

3. The optical localization microscopy method according to claim 2, characterized in that: The method further comprises: Peak fitting is performed on the central position to determine the spatial coordinates of the magnetic nanoparticles.

4. The optical localization microscopy method according to claim 1, characterized in that: If the interference pattern includes a plurality of magnetic nanoparticles within the field of view, the method further comprises: The complete interference pattern area of ​​the magnetic nanoparticles is obtained to locate the magnetic nanoparticles.

5. An optical microscopy system for positioning magnetic nanoparticles, characterized in that: include: The first module is used to obtain the interference pattern generated by the laser passing through the sample to be tested, wherein the sample to be tested has magnetic nanoparticles distributed therein; The second module is used to determine the distribution function of the interference pattern, and determine the center position of the magnetic nanoparticles according to the interference pattern and the distribution function.

6. An optical microscopy device for positioning magnetic nanoparticles, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 4.

7. An optical microscopy device for positioning magnetic nanoparticles, characterized in that: The method comprises a laser, a magnifying objective lens, a focusing lens, an imaging unit and a processor. The light emitted by the laser generates an interference pattern when passing through a sample to be tested. The interference pattern is magnified by the magnifying objective lens and focused by the focusing lens to form an image in the imaging unit. Magnetic nanoparticles are distributed in the sample to be tested. The processor is used to execute the method according to any one of claims 1 to 4.

8. The optical positioning microscope device according to claim 7, characterized in that: The optical positioning microscope device also includes a collimating unit, which is used to collimate the light emitted by the laser.

9. The optical positioning microscope device according to claim 7, characterized in that: The optical positioning microscope device also includes a first reflector, which is used to reflect the light emitted by the laser to the sample to be measured.

10. The optical positioning microscope device according to claim 7, characterized in that: The optical positioning microscope device also includes a second reflector, which is used to reflect the light magnified by the magnifying objective lens to the focusing lens.

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