System and method for controlling liposome drug targeted delivery based on spectral spatial phase gradient light field

Abstract

The application discloses a system and method for controlling liposome drug directional delivery based on a spectrum space phase gradient light field, and belongs to the technical field of light field regulation of biological cells; in the application, quasi-plane waves are irradiated onto a spatial light modulator, the amplitude of a target light field is embedded into a phase by using Fourier expansion, and then a holographic template of the reconstructed light field is generated; the holographic template is loaded onto the spatial light modulator, and after filtering through a 4f system, the light beam is projected to an objective lens; on the focal plane of the objective lens, with the help of the existence of the phase gradient, the drug-loaded liposome is transported along a preset track in a directional manner, and is captured by an intensity gradient optical trap at the end of the track; the application can design any drug delivery track according to requirements, and without moving the equipment platform, the two manipulations of any track delivery and target capture can be realized through a single light beam, and the convenience and efficiency of drug directional delivery are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of light field regulation of biological cells, and particularly relates to a system and method for controlling directional delivery of liposome drugs based on a spectral spatial phase gradient light field. BACKGROUND

[0002] With the continuous development of modern drug treatment technology, how to realize the directional delivery of drugs and improve the effectiveness of drugs in specific cells or tissues has become an important research direction in the field of biomedicine. Liposomes, as an effective drug carrier, are widely used in drug delivery systems because they can encapsulate various drugs and have biocompatibility. However, how to simultaneously control the directional delivery of liposomes and fix the position of liposomes is still a major technical challenge currently faced.

[0003] In recent years, optical technology, especially optical tweezers technology, has provided a new idea for solving this problem. Optical tweezers technology can capture and manipulate small particles through the radiation pressure and gradient force of laser beams, realizing accurate manipulation of drug carriers such as liposomes. However, existing optical tweezers technology is usually limited to static capture or simple straight-line motion, making it difficult to achieve precise delivery on complex paths and simultaneous manipulation in multiple forms. Therefore, how to use light field design to achieve precise and complex trajectory transportation and effective capture at the target position has become a problem to be solved. SUMMARY

[0004] In view of the problems existing in the prior art, the application provides a system and method for controlling directional delivery of liposome drugs based on a spectral spatial phase gradient light field,

[0005] According to a first aspect of the technical scheme of the application, the application provides a method for controlling directional delivery of liposome drugs based on a spectral spatial phase gradient light field, which includes the following steps:

[0006] Step S1: building an optical system;

[0007] Step S2: checking whether the position of the objective lens entrance pupil in the optical system built in step S1 is located at the focal length of the second lens of the 4f system;

[0008] Step S3: starting the laser, and the laser emitted by the laser passes through the collimation, and then passes through the spatial filter and the first double-cement achromatic lens to form an approximate plane wave through the beam expansion system;

[0009] Step S4: designing the target light field beam shape and phase gradient.

[0010] Further, the following steps are included:

[0011] Step S5: calculating the phase template of the complex amplitude mode of the light field;

[0012] Step S6: load the phase template on the liquid crystal panel of the spatial light modulator, check whether the shape of the light field is consistent with the preset shape from the camera;

[0013] Step S7: prepare drug-loaded liposomes by using the secondary emulsification method, so that the internal refractive index is greater than the external refractive index;

[0014] Step S8: prepare a sample chamber containing drug-loaded liposomes and target cells, encapsulate and place it on the stage, open the illumination light path, adjust the distance between the sample chamber and the objective lens, so that it is located on the focal plane of the objective lens, and ensure that the imaging is clear in the camera;

[0015] Step S9: in the light field, the drug-loaded liposomes are targeted on the trajectory with a phase gradient and move to the endpoint target cells, and are captured by the high light intensity area at the endpoint of the light beam trajectory path.

[0016] In step S5, the phase template of the complex amplitude pattern of the light field is calculated based on MATLAB software, the light field has a certain intensity distribution and phase distribution in the frequency spectrum space, the gradient of the phase distribution can make the liposome particles transport along the preset trajectory, and the gradient of the intensity distribution can make the liposome particles be captured at the endpoint of the trajectory.

[0017] Further, the intensity distribution and phase distribution of the light field in step S4 are precisely controlled by the phase template, the phase template in step S5 is generated by MATLAB software, the trajectory superposition meets the requirements of the intensity distribution and the phase distribution of the light field, and is used to generate the shape and phase gradient required by the user.

[0018] Further, the light beam in step S3 passes through a spatial filter and a double cemented achromatic lens to improve the uniformity of the light beam, so that the light beam irradiated on the spatial light modulator is more similar to a plane wave, so as to generate more accurate phase gradient and light intensity distribution of the light field.

[0019] Preferably, the phase and light intensity of the target light field are superimposed on the phase of the blazed grating with an order of 270, which is used to filter out 0-order light, and subsequent 1-order light is used to realize the capture and transport of the liposomes.

[0020] More preferably, the light field design can realize both arbitrary trajectory transport and targeted capture of the liposome drug by a single beam of light without moving the equipment platform. The phase template is dynamically adjusted according to different drug delivery requirements, and different light field shapes and light intensity distributions are generated to realize the directional delivery of liposomes at different positions.

[0021] Preferably, the light field system has the function of regulating the speed, and the speed of liposome transportation is regulated by adjusting the size of the designed light field phase gradient, that is, the larger the phase gradient, the faster the liposome transportation speed, and the smaller the phase gradient, the smaller the liposome transportation speed. Further, the internal refractive index of the drug-loaded liposome prepared by the secondary emulsification method in step S7 is 1.40, and the external refractive index is 1.34, that is, the internal refractive index is greater than the external refractive index, which provides conditions for light tweezers capture and transportation.

[0022] According to the second aspect of the technical scheme of the present application, the present application provides a system for controlling liposome drug directional delivery based on a frequency spectrum space phase gradient, which uses a pure phase space light modulator to simultaneously regulate the phase and amplitude information of a light beam based on a frequency spectrum space, accurately designs a phase template, generates an arbitrary trajectory phase gradient light field to transport drug-loaded liposome particles, and captures liposomes at a target position, thereby providing a basis for further promoting the combination of drugs and target cells; the optical system of the system for controlling liposome drug directional delivery based on a frequency spectrum space phase gradient includes a laser, a half-plate, an attenuation plate, a spatial filter, a first lens, a beam splitter prism, a spatial light modulator, a second lens, a pinhole, a third lens, a beam splitter plate, an objective lens, a stage, an illumination light source, a fourth lens, and a camera.

[0023] Compared with the prior art, the system and method for controlling liposome drug directional delivery based on a frequency spectrum space phase gradient have the following beneficial effects:

[0024] (1) Efficient and accurate liposome drug delivery: The present application realizes accurate control and delivery of liposome drugs by designing the phase gradient and light intensity distribution of the light field. Compared with existing light tweezers technology, the present application can directionally deliver drug-loaded liposomes on a complex path, thereby improving delivery efficiency and target position accuracy.

[0025] (2) No platform movement, more flexible: The light field designed by the present application can realize the directional delivery and capture of liposomes without moving the equipment platform, thereby breaking through the limitation of the existing technology that requires mechanical movement of the equipment platform, simplifying the system structure and improving the flexibility of the system.

[0026] (3) Single-beam light can complete capture and delivery: Compared with existing multi-beam light control systems, the present application can simultaneously realize the capture and delivery of liposomes by a single beam of light, thereby greatly simplifying the optical path design, reducing system complexity and cost.

[0027] (4) Trajectory controllable, strong adaptability: The present application can design various drug delivery trajectories by generating a special phase template through MATLAB, thereby meeting the complex transportation requirements in different application scenarios. The flexibility, adaptability and operability of the system under different conditions are significantly improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the method and technical solutions of the present application, the drawings required to be used in the examples will be briefly introduced as follows, and the drawings described below are only one embodiment of the present application, and other drawings can be obtained according to the method without creative labor for those skilled in the art.

[0029] Figure 1 The optical path schematic diagram used for the system for controlling the targeted delivery of liposome drugs based on the phase gradient of the spectral space according to the present application;

[0030] Figure 2a And Figure 2b The light intensity and phase information diagrams of the example target light field being an "s-shaped" trajectory drawn on the MATLAB software according to the present application; wherein Figure 2a The light intensity schematic diagram of the example target light field being an "s-shaped" trajectory drawn on the MATLAB software according to the present application; Figure 2b The phase information diagram of the example target light field being an "s-shaped" trajectory drawn on the MATLAB software according to the present application;

[0031] Figure 3 The method for generating the phase template loaded onto the pure phase type spatial light modulator by using the Fourier transform;

[0032] Figure 4 The light field observed according to step S4 according to the present application, which is consistent with the target light field. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the present application will be clearly and completely described below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application. In addition, the protection scope of the present application should not be limited to the following specific experimental methods or specific parameters.

[0034] In addition, it should be further pointed out that only the parts related to the present application are shown in the drawings for convenience of description. The embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0035] It should be noted that the concepts of "first", "second" and the like mentioned in the present application are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0036] It should be noted that the modification of "one", "a plurality of" mentioned in the present application is illustrative but not restrictive, and those skilled in the art should understand that unless the context clearly indicates otherwise, it should be understood as "one or more".

[0037] The application discloses a system and method for controlling liposome drug directional delivery based on a spectral spatial phase gradient light field, and belongs to the technical field of light field regulation of biological cells. The application irradiates a quasi-non-diffracting light beam onto a spatial light modulator, embeds an amplitude into a phase by using Fourier expansion, generates a holographic template of a reconstructed light field, projects the light beam to an objective lens (preferably a 100 times objective lens) after filtering through a 4f system, and captures the drug-loaded liposome along a preset trajectory by means of the existence of a phase gradient on the focal plane of the objective lens, and captures the drug-loaded liposome at the end of the trajectory by an intensity gradient optical trap. The application can design an arbitrary drug delivery trajectory according to requirements, and can realize two kinds of manipulations of arbitrary trajectory delivery and target capture by a single light beam without moving the equipment platform, thereby improving the convenience and efficiency of drug directional delivery.

[0038] The application is based on the technology of controlling liposome drug directional delivery by a phase gradient light field based on a spectral spatial phase gradient light field.

[0039] The application is based on the technology of controlling liposome drug directional delivery by a phase gradient light field based on a spectral spatial phase gradient light field.

[0040] In order to make the above-mentioned purposes, features and advantages of the present application more obvious, the present application will be further described in detail below in combination with the drawings and specific examples.

[0041] As shown in the drawings, Figure 1 The application is based on the technology of controlling liposome drug directional delivery by a phase gradient light field based on a spectral spatial phase gradient light field. Figure 1The light path system shown is the light path system of the present application based on the spectral space phase gradient light field control liposome drug targeted delivery system, which comprises a laser, a half glass, an attenuation sheet, a spatial filter, a first lens (preferably with a focal length of 250 mm), a light splitting prism, a spatial light modulator, a second lens (preferably with a focal length of 200 mm), a small hole, a third lens (preferably with a focal length of 200 mm), a light splitting flat sheet, an objective lens (preferably with a magnification of 100 times, and the objective lens uses an oil lens), a stage, an illumination light source (preferably an LED light source with a power of 3 W), a fourth lens (preferably with a focal length of 150 mm), and a camera;

[0042] a laser for emitting laser light, in the present preferred embodiment, a 532 nm solid-state laser is used;

[0043] a half glass for adjusting the polarization direction of the laser light emitted from the laser;

[0044] an attenuation sheet for adjusting the power of the laser light emitted from the laser;

[0045] The spatial filter and the first lens are combined to convert the laser beam into a quasi-plane wave, so as to ensure that the equal phase of the light beam is a parallel plane, and facilitate the phase modulation of the light beam by the spatial light modulator in the later stage. In an embodiment, the focal length of the first lens is preferably 200 mm; the first lens uses a double-cemented achromatic lens. The laser, the half glass, the attenuation sheet, the spatial filter, and the first lens are arranged in a straight line light path in sequence, the laser is at the front end of the half glass, the half glass is located 10 cm behind the laser, for adjusting the polarization direction of the laser, the attenuation sheet is placed at a position 10 cm behind the half glass, for facilitating the adjustment of the power of the laser. The spatial filter is placed at a position 10 cm behind the attenuation sheet, the spatial filter is internally composed of an objective lens with a magnification of 40 times and a small hole with an aperture of 20 μm, the laser passes through the objective lens and the small hole in sequence, and the distance between the objective lens and the small hole needs to be carefully adjusted, and the standard is that the cross-sectional intensity of the laser spot after passing through the small hole is uniform. The first lens is placed at a position 200 mm (this distance is the focal length of the first lens) behind the small hole of the spatial filter, and a quasi-plane wave can be obtained.

[0046] a light splitting prism located at the intersection of the light path of the laser and the light path of the spatial light modulator, for separating the light beams with equal energy; the separated light beams are respectively the light beam along the laser and the light beam along the spatial light modulator; the light path of the laser and the light path of the spatial light modulator are in a perpendicular relationship.

[0047] A spatial light modulator is located at the leftmost end of the vertical direction of the optical path where the laser is located, which is used to modulate the phase of the light source from the laser to generate a target light field; further, in the preferred embodiment, the spatial light modulator adopts a reflective pure phase spatial light modulator. When the light wave passes through the spatial light modulator, the optical function and signal are loaded on the liquid crystal panel, and the voltage on each pixel point is modulated to generate wavefront phase modulation of light. The optical function and signal can be directly displayed by the computer, transmitted by the DVI or HDMI (HDMI is preferred in the present application) signal output by the image card, and the signal is adjusted by electrical addressing to realize the regulation of the light intensity and phase of the light field. Further, in the preferred embodiment, the pixel size of the spatial light modulator panel is 8μm, and the phase size is 15.36mm×8.64mm. The phase template loaded on the spatial light modulator is obtained by Fourier transform of the target light field in MATLAB software; the target light field has a special intensity distribution and phase distribution in the frequency spectrum space, and in an embodiment, the intensity distribution and phase distribution of the target light field are characterized in that: the light intensity of the light field has an "S-shaped" shape distribution, and has an intensity "bright spot" at the end, and the phase of the light field is characterized in that: along the "S-shaped" trajectory, the phase gradient changes uniformly in the angular direction, and the phase increases continuously along the trajectory. In such a special light field, there is an intensity gradient force in the direction perpendicular to the trajectory, which can attract the liposome particles to the "S-shaped" trajectory, and there is a phase gradient force in the direction along the trajectory, which can transport the liposome particles along the preset trajectory ("S-shaped"), and the strong intensity gradient force at the position of the "bright spot" at the end of the trajectory captures the liposome particles.

[0048] The phase gradient force makes the liposome particles transport along the preset trajectory, and the intensity gradient force makes the liposome particles be captured at the end of the trajectory, providing conditions for subsequent combination with target cells.

[0049] A second lens, preferably a double cemented achromatic lens, is located behind the beam splitter prism (along the optical path where the spatial light modulator is located), which is used to convert the light beam passing through the spatial light modulator to the frequency spectrum space, and the focal length thereof is preferably 250mm;

[0050] A pinhole is located at the focal point of the second lens, which is used for filtering and selecting the modulated light beam; the position of the pinhole is the Fourier plane; since a part of the light beam reflected by the spatial light modulator is not modulated, the present application superimposes a phase template of a blazed grating with an order of 270 on the phase template loaded on the spatial light modulator, which is used to filter out the 0th order light; the present application uses the +1st order diffracted light, which is the completely modulated part. The function of the pinhole is to make the +1st order diffracted light pass through completely, and other order light beams cannot pass through.

[0051] A third lens, preferably a doublet achromatic lens, is located behind the pinhole and forms a 4F system with the second lens, which is used to reduce the size of the light beam, and preferably has a focal length of 200 mm; the focal lengths of the second and third lenses are both f, and they are separated by 2f, and the object distance is f, and the separation is f.

[0052] A beam splitter is used to split the light beam passing through the third lens into two beams, one of which passes through the beam splitter to the objective lens, and the other of which is reflected by the beam splitter to a vertical light path (the vertical light path axis formed by the fourth lens and the central axis of the camera) to image the target light field. Preferably, the beam splitter has a splitting ratio of T / R = 50 / 50, and the working wavelength is 450-650 nm.

[0053] An objective lens is located at the focal length of the third lens, and focuses the modulated light beam; and provides sufficient intensity gradient and phase gradient to capture the liposome.

[0054] A stage is placed at the focal length of the objective lens, and can be finely adjusted up, down, left and right to move the sample chamber; the sample chamber is placed on the stage;

[0055] An illumination light source is placed above the stage and is separated from the stage by 5 cm, and emits illumination light to illuminate the liposome for subsequent imaging; the illumination light source is an LED light source with a power of 3 W and a wavelength band of white light (440-670 nm).

[0056] The spatial light modulator, the beam splitter prism, the second lens, the pinhole, the third lens, the beam splitter, the objective lens, the stage and the illumination light source are arranged in the light path of the spatial light modulator in sequence.

[0057] A fourth lens, preferably a doublet achromatic lens, is used to image the liposome and the light field to the camera, and preferably has a focal length of 150 mm;

[0058] A camera is located at the end of the camera light path, and is used to collect imaging information of the liposome particles and the phase gradient light field intensity.

[0059] The components and parameters in the optical path system as shown in Figure 1 may be preferred parameters, and can also be adjusted according to actual conditions.

[0060] The second lens and the third lens form a 4F system, which has the functions of expanding and reducing the light beam in addition to filtering, and the focal lengths are selected so that the size of the light beam is slightly larger than the size of the objective lens back pupil, which is done to allow the objective lens to obtain higher gradient force. In the present example, the focal lengths of the second lens and the third lens are 250 mm and 200 mm respectively, i.e. the light beam is reduced to 0.8 times.

[0061] The objective is an Olympus flat-field semi-apochromatic oil objective, and the magnification of the oil objective used in the examples of the present application is 100 times, which needs to be matched with the Olympus microscope oil. The fourth lens and the camera form an imaging system, and the fourth lens and the camera position should be linearly moved so that the liposome particles in the focal plane of the objective in the sample chamber can be clearly imaged.

[0062] If laser filtering is needed in front of the camera, a filter should be added in front of the camera to filter out the 532nm laser beam.

[0063] Combined Figure 1 The light path system, specifically as shown in Figure 2a and Figure 2b The "S-shaped" target light field is a practical case. A method for controlling the targeted delivery of liposome drugs based on the phase gradient of the spectral space of the present application comprises the following steps:

[0064] Step S1: build the light path system as shown in Figure 1 .

[0065] Step S2: check whether the position of the objective entrance pupil in the light path system built in step S1 is located at the focal length of the second lens of the 4f system; when the focal length of the second lens is 200mm, whether the distance between the second lens and the objective entrance pupil is 200mm.

[0066] Step S3: start the laser, the laser emitted by the laser passes through the collimation and then through the beam expander system composed of the spatial filter and the first lens to generate an approximate plane wave; turn on the control of the spatial light modulator, load the blank template on the spatial light modulator, then superimpose the blazed grating with an order of 270, slightly rotate the spatial light modulator so that the +1 order light passes through the pinhole, check whether the collimated beam is on the center of the objective; wherein turning on the control of the spatial light modulator mainly refers to turning on the software (preferably HOLOEYE software in this embodiment) of the control of the spatial light modulator.

[0067] Step S4: design the beam shape and phase gradient along the curve of the target light field; we give the specific examples of the beam intensity distribution and phase distribution of the "S-shaped" target light field, as shown in Figure 2a and

[0068] Figure 2b .

[0069] Step S5: calculate the phase template of the complex amplitude pattern of the light field; specifically, the phase template of the target light field is calculated based on the MATLAB software, and the method for calculating the phase template of the target light field based on the MATLAB software comprises:

[0070] The curve of the target light field is formed by coherent superposition of plane waves, such as the example "S-shaped" light field (as shown in Figure 3The expression of the curve is

[0071]

[0072] y0(t) = Rsin(t), t∈[0, T];

[0073] Where x0(t), y0(t) are used to describe the coordinates of each point on the curve, T = (2.01π) is the upper limit of integration, and R is the diameter of the semicircle, in this embodiment, R = 0.1 μm.

[0074] The phase gradient of the light field is expressed by the following formula:

[0075]

[0076] Where r = (x, y), t∈[0, t], τ∈[0, 2π]; x ′ 0(τ), y0 ′ (τ) are the derivatives of x0(τ), y0(τ), and the size of the phase gradient along the curve is regulated by the parameter σ, in this case, σ = 2, and ω0 is the beam waist.

[0077] Therefore, the complex amplitude form of the light field can be expressed as:

[0078]

[0079] Where L is the length of the trajectory. In MATLAB, a two-dimensional fast Fourier transform (fft) is performed on the complex amplitude light field to convert it from the spatial domain to the frequency domain, and the frequency shift transform fftshift is used for spectral centering. The specific operation is:

[0080] F(U, V) = fftshift(fft(fftshift(E(x, y))),

[0081] Taking the phase of F(U, V) is the required phase template.

[0082] The intensity distribution and phase distribution of the light field are precisely controlled by the phase template, which is generated by MATLAB software. The method of trajectory superposition used can meet both the intensity distribution requirements of the light field and the phase distribution requirements, and is used to generate the shape and phase gradient required by the user. The phase of the target light field and the light intensity are reproduced by superimposing a phase of a blazed grating with an order of 270 on the generated phase template, which is used to filter out 0-order light, and subsequent 1-order light is used to realize the capture and transport of liposomes.

[0083] Step S6: load the phase template of the complex amplitude mode obtained in step S5 on the liquid crystal panel of the spatial light modulator, and check whether the shape of the light field is consistent with the preset shape from the camera; in the example of the "S-shaped light field" given in the present application, the light beam imaged onto the camera is as shown in FIG. 6; in another embodiment, further quality check steps S5 and S6, the cover glass of the sample chamber will reflect the light beam, and the shape thereof is checked by the camera to see whether it conforms to the target light field. Figure 3

[0084] Step S7: drug-loaded liposomes are prepared by using the double emulsion method, the internal solution of the drug-loaded liposomes is a 1.5 mol / L sucrose solution, and the external solution is a 0.75 mol / L sodium chloride solution, and the drug-loaded liposomes with a particle size of about 1.5 microns are prepared; the drug-loaded liposomes prepared by using the double emulsion method have an internal refractive index of 1.40 and an external refractive index of 1.34, that is, the internal refractive index is greater than the external refractive index, which provides conditions for optical tweezer capture and transportation. Preferably, the specific operation steps of step S7 are as follows:

[0085] Step S71: add 10 mg of lipid POPC to 1 mL of liquid paraffin, heat and vortex for 30 minutes to dissolve;

[0086] Step S72: ultrasonically treat the mixture in step S71 for 90 minutes to make the dissolution more sufficient, and cool to room temperature;

[0087] Step S73: take 200 microliters of the mixture into a 1.5 mL sample tube, and cool on ice for 15 minutes;

[0088] Step S74: take 200 microliters of 1.5 mol / L sucrose and add it to the sample tube, gently stir for 30 seconds, and cool on ice for 5 minutes to form an emulsion;

[0089] Step S75: take a new sample tube, add 250 microliters of 0.75 mol / L sodium chloride solution, and gently place 250 microliters of the emulsion on top

[0090] Step S76: centrifuge for 30 minutes (centrifugal speed is 11000 x g), and remove the oil phase;

[0091] Step S77: preferably, ultrasonically treat for 10 minutes to obtain liposomes with a particle size of about 1.5 microns.

[0092] Step S8: prepare a sample chamber containing drug-loaded liposomes, encapsulate and place it on the stage, open the illumination light path, adjust the distance between the sample chamber and the objective lens, so that it is located on the focal plane of the objective lens, and ensure that the imaging is clear in the camera;

[0093] Preferably, the specific operation steps of preparing the sample chamber containing drug-loaded liposomes in step S8 are as follows: ​

[0094] Step S81, take a clean glass slide, and stick two 5mm wide tapes on the upper and lower edges of the center position;

[0095] Step S82, stick a clean cover glass on the tapes to form a sample chamber, and inject liposomes into the sample chamber with a needle tube, making sure there are no air bubbles;

[0096] Step S83, seal the sample chamber with transparent nail polish on both sides, and wait for it to dry naturally.

[0097] Step S9: In the light field, the drug-loaded liposomes are on a trajectory with a phase gradient and move to a target position at the end of the light beam trajectory path, which is captured by a high light intensity area.

[0098] The light field design described in the present application can simultaneously achieve both arbitrary trajectory transport and target capture of liposome drugs without moving the device platform. The phase gradient design of the light field ensures accurate control during the delivery of drug-loaded liposomes. The phase template can be dynamically adjusted according to different drug delivery needs, and by generating different light field shapes and light intensity distributions, directional delivery of liposomes to different positions can be achieved. The light field system has the function of regulating speed, and by adjusting the size of the designed light field phase gradient, the speed of liposome transport can be regulated, that is, the larger the phase gradient, the faster the liposome transport speed, and the smaller the phase gradient, the slower the liposome transport speed.

[0099] The above-described embodiments are only used to help understand the core idea of the present application and its specific applications, and are not used to limit the scope of the present application. The core of the present application is a drug directional delivery method based on a frequency spectrum space phase gradient light field design, and its application is not limited to the specific steps or parameters of the above-described embodiments.

[0100] For those skilled in the art, various modifications and improvements can be made to the design of the system, the shape of the light field, and the generation method of the phase template, etc. without departing from the core idea and technical essence of the present application, according to actual needs. These improvements or modifications, if they do not exceed the protection scope of the claims of the present application, should be considered as belonging to the protection scope of the present application. Therefore, the protection scope of the present application should be defined by the appended claims and their equivalent forms, and not just limited to the above-described specific embodiments. Any modification, equivalent replacement or improvement made according to the content of the claims of the present application should be covered within the protection scope of the present application.

Claims

1. A method for targeted delivery of liposomal drugs based on a spectral spatial phase gradient optical field, characterized in that, The method includes the following steps: Step S1: Build the optical path system; Step S2: Check whether the objective lens entrance pupil position in the optical path system built in step S1 is located at the focal length of the second lens in the 4f system. Step S3: Start the laser. The laser emitted by the laser is collimated and then passes through a beam expansion system consisting of a spatial filter and the first cemented doublet achromatic lens to generate an approximate plane wave. Step S4: Design the target light field beam shape and phase gradient; calculate the phase template of the complex amplitude mode of the light field using MATLAB software. The method for calculating the target light field phase template using MATLAB software includes: The target light field curve is formed by the coherent superposition of plane waves, and the expression for the S-shaped light field curve is: ， in Used to describe the coordinates of points on the curve, T is the upper limit of integration, and R is the diameter of the semicircle of the curve; The phase gradient of the target light field is expressed by the following formula: ， in ; , for , The derivative of the phase gradient along the curve is given by the parameter. To regulate, For waist cinching; Step S5: Calculate the phase template of the complex amplitude mode of the light field; The complex amplitude of the light field is expressed as: ， Where L is the length of the trajectory; in MATLAB, a two-dimensional fast Fourier transform (fft) is performed on the complex amplitude light field to transform it from the spatial domain to the spectral domain, and the frequency shift transform (fftshift) is used to center the spectrum and obtain the required phase template. Step S6: Load the phase template onto the liquid crystal panel of the spatial light modulator and check from the camera whether the shape of the light field is consistent with the preset shape; Step S7: Prepare drug-loaded liposomes using a secondary emulsification method, making their internal refractive index greater than their external refractive index; Step S8: Prepare a sample chamber containing drug-loaded liposomes and target cells, encapsulate it and place it on the stage, turn on the illumination path, adjust the distance between the sample chamber and the objective lens so that it is located on the focal plane of the objective lens, and ensure that the image is clear in the camera. In step S9, the drug-loaded liposome moves along a trajectory with a phase gradient to the target cell in the light field and is captured by a high-intensity region at the end of the beam trajectory path.

2. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient light field control according to claim 1, characterized in that, Step S5 calculates the phase template of the complex amplitude mode of the light field. Specifically, the phase template of the complex amplitude mode of the light field is calculated using MATLAB software. The light field has a certain intensity distribution and phase distribution in the spectral space. The gradient of the phase distribution enables the liposome particles to be transported along a preset trajectory, and the gradient of the intensity distribution enables the liposome particles to be captured at the end of the trajectory.

3. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient light field control according to claim 2, characterized in that, In step S4, the intensity and phase distribution of the light field are precisely controlled by a phase template. In step S5, the phase template is generated by MATLAB software. The trajectory superposition used satisfies both the intensity and phase distribution requirements of the light field and is used to generate the shape and phase gradient required by the user.

4. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient light field control according to claim 1, characterized in that, In step S3, the beam passes through a spatial filter and a cemented doublet achromatic lens to improve the uniformity of the beam, making the beam illuminating the spatial light modulator more approximate a plane wave, thereby generating a more accurate phase gradient and intensity distribution of the light field.

5. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient light field control according to claim 1, characterized in that, The phase and intensity of the target light field are reproduced by superimposing the phase of a blazed grating of order 270 onto the generated phase template to filter out the 0th order light. The 1st order light is then used to capture and transport the liposomes.

6. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient optical field control according to claim 5, characterized in that, The light field design enables both arbitrary trajectory transport and targeted capture of liposomal drugs to be achieved simultaneously using a single beam of light without moving the mobile device platform.

7. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient light field control according to claim 6, characterized in that, The phase template is dynamically adjusted according to different drug delivery requirements, and the targeted delivery of liposomes at different locations is achieved by generating different light field shapes and light intensity distributions.

8. The method for targeted delivery of liposome drugs based on spectral spatial phase gradient light field control according to claim 7, characterized in that, The optical field system has the function of speed regulation. By adjusting the magnitude of the designed optical field phase gradient, the speed of liposome transport can be controlled. That is, the larger the phase gradient, the faster the liposome transport speed, and the smaller the phase gradient, the slower the liposome transport speed.

9. A system for targeted delivery of liposomal drugs based on a spectral spatial phase gradient optical field, comprising using the method for targeted delivery of liposomal drugs based on a spectral spatial phase gradient optical field as described in claim 1, characterized in that... Based on the use of a pure phase-type spatial light modulator to simultaneously control the phase and amplitude information of the light beam, a phase template is precisely designed to generate an arbitrary trajectory phase gradient light field to transport drug-loaded liposome particles and capture liposomes at the target location, providing a basis for further promoting the binding of drugs to target cells. The optical path system of the liposome drug delivery system controlled by the phase gradient light field in the spectral space includes a laser, a half glass slide, an attenuator, a spatial filter, a first lens, a beam splitter, a spatial light modulator, a second lens, a pinhole, a third lens, a beam splitter, an objective lens, a stage, an illumination source, a fourth lens, and a camera.

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