阅读说明：本技术 一种微透镜及其应用 (Micro lens and application thereof ) 是由 李宇超 李宝军 张垚 陈熙熙 龚智勇 林承鸿 于 2021-08-06 设计创作，主要内容包括：本发明公开了一种微透镜及其应用,所述微透镜为脂质颗粒。本发明方案制备的微透镜制备、提取方法简单,不需要进行额外的加工,脂质颗粒能够作为细胞内部的光学元件发挥光学作用并具有完全生物兼容性；同时脂质颗粒天然生成于细胞内部,与细胞内部的微结构具有天然的位置靠近关系,可以在近场收集和重定位微结构的光学信号,有效的提高了光学显微镜的细胞微结构成像质量。(The invention discloses a micro lens and application thereof, wherein the micro lens is lipid particles. The method for preparing and extracting the micro-lens prepared by the scheme of the invention is simple, no additional processing is needed, and the lipid particles can be used as optical elements in cells to play an optical role and have complete biocompatibility; meanwhile, the lipid particles are naturally generated in the cells and have natural position close relationship with the microstructures in the cells, so that optical signals of the microstructures can be collected and repositioned in a near field, and the imaging quality of the cell microstructures of the optical microscope is effectively improved.)

1. Use of lipid particles for the manufacture of microlenses.

2. A microlens comprising lipid particles extracted from the interior of a cell.

3. The microlens of claim 2 wherein said cells are cells that produce micron-sized lipid particles.

4. The microlens of claim 3 wherein said cell is one of an adipocyte, a cone, and an stellate cell.

5. The microlens as claimed in claim 2, wherein the particle size of the lipid particle is 1 to 40 μm.

6. Use of a microlens according to any one of claims 2 to 5 for the production of a cellular micro-optical element.

7. Use of a microlens according to any of claims 2 to 5 in bioimaging, wherein said bioimaging comprises imaging of subcellular structures or imaging of cellular microenvironments.

8. A method of imaging a cell, the method comprising the steps of: internalizing the microlens of any one of claims 2-5 into a test cell, and using the microlens for cellular fluorescence imaging.

9. The method of claim 8, wherein the retention time of the microlens in the test cell is 12-96 h.

Technical Field

The invention belongs to the technical field of optics, and particularly relates to a micro lens and application thereof.

Background

The optical means is used for monitoring the change of the state inside and outside the cell in real time, and has important significance for understanding the physiological process and quickly diagnosing cytopathic effect. The microsphere auxiliary technology has application convenience and excellent optical performance, so that the microsphere auxiliary technology is widely applied to the exploration of optical experiments, the technology not only helps a traditional optical microscope to realize real-time unmarked super-resolution imaging in a visible light wave band, but also can collect and enhance various optical imaging signals.

However, as the requirements and standards for imaging and detection technology in biological environments have increased, the biocompatibility of microsphere-assisted technology in biological environments for long-term imaging and detection has become a challenge. In the prior microsphere auxiliary technology, the commonly used microsphere material is mostly solid medium microspheres (such as SiO)₂Polystyrene, BaTiO₃、TiO₂Etc.), the stable solid nature and low degradability of these microsphere materials, make them less biocompatible for biological sample observation, and may have an effect on biological activity during long-term use.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides the application of the lipid particles in the preparation of the micro-lens, has the advantage of complete biocompatibility, and can be directly applied to a biological environment for micro-structure imaging detection inside and outside cells.

The invention also provides a micro lens.

The invention also provides an application of the micro lens.

The invention also provides a cell imaging method.

According to one aspect of the invention, the use of lipid particles for the preparation of microlenses is proposed.

According to a second aspect of the present invention, a microlens is presented, the microlens comprising lipid particles extracted from the interior of a cell.

In some embodiments of the invention, the cell is a cell that can produce micron-sized lipid particles; preferably, the cell is one of an adipocyte, a cone cell, and a stellate cell.

In some embodiments of the invention, the lipid particles extracted from the interior of the cell specifically comprise the following steps: washing fat cells or cone cells with cell buffer solution, adding sterile water or sterile water containing 0.1-1% cell lysate (Triton-X100), and standing for 10-30 min.

In some embodiments of the present invention, the particle size of the microlens is 1 to 40 μm.

According to a third aspect of the present invention, there is provided the use of the above microlens, in the production of a cellular micro-optical element.

In some embodiments of the invention, the use of the above-described microlens in biological imaging.

A method of imaging cells, the method comprising the steps of: internalizing the micro lens into a cell to be detected, and performing fluorescence imaging by using the micro lens.

In some embodiments of the invention, the residence time of the microlenses in the cells is 12-96 h.

In some embodiments of the invention, the cellular structure comprises an inner and an outer microstructure.

According to the embodiment of the invention, at least the following beneficial effects are achieved: the lipid particle is used as the micro-optical element for preparing the micro-lens, is an endogenous organelle, has higher refractive index than the surrounding cytoplasm environment, is simple in preparation method, does not need to be additionally processed, can play an optical role as the optical element in the cell and has complete biocompatibility; meanwhile, the lipid particles are naturally generated in the cells and have natural position close relationship with microstructures (subcellular structures) in the cells, so that optical signals of the microstructures can be collected and repositioned in a near field, and the imaging quality of the cellular microstructures of the optical microscope is improved; the lipid particles can converge the incident exciting light beam to the external environment of the cell, and imaging observation of the external environment of the cell by the lipid particles in the cell can be realized by utilizing the effect; the lipid particles can also be combined with an optical tweezers manipulation technology to realize flexible lipid particle movement imaging in the cells. And the lipid particles can be extracted by a simple method and applied to other types of cells, so that the application range of the micro-lens is expanded.

Drawings

The invention is further described with reference to the following figures and examples, in which:

FIG. 1 is an optical microscopic image of lipid particles and mature adipocytes of example 1 of this invention, wherein a is an optical microscopic image of mature adipocytes; b is an optical microscopic image of lipid particles with different sizes extracted from mature adipocytes;

FIG. 2 is a transmitted light spectrum of a visible light to near infrared band (400nm-1000nm) of the lipid particle in example 1 of the present invention;

FIG. 3 is a diagram showing the observation result of fluorescence imaging of the fluorescent nanodiamond by the microlens in the test example of the present invention; a, superposing a bright field of an experimental sample and a fluorescence optical microscope; a1 is a bright field and fluorescence optical microscopic superposition image of the fluorescence nano diamond cluster on the glass slide; a2 is a superposition graph of bright field of lipid particles (diameter 9 μm) and fluorescence after signal enhancement of fluorescent nanodiamond cluster; b is a three-dimensional plot of the intensity of the fluorescence signal in plot a; b1 is a three-dimensional graph of the original fluorescence intensity of the fluorescent nanodiamond (corresponding to a 1); b2 is a three-dimensional graph of fluorescence intensity after the fluorescence nanodiamond is enhanced (corresponding to a 2); c is the plot of the reduction rate of the excitation light power of the microlens;

FIG. 4 is a view showing the observation of subcellular structures inside cells by the microlenses in the test example of the present invention, wherein a is a cellular microfilament fluorescence image of mature adipocytes; a1 is a fluorescence image of the target cell microfilament at the optimal focal plane; a2 is a fluorescence image of the target cell microfilament obtained on the virtual image surface of the microlens; b is the normalized curve of the intensity distribution of the target observed cellular microfilaments obtained in a; c is fluorescence and optical microscopy images of enhanced imaging of intracellular lysosomes by intracellular lipid particles; c1, c2 are fluorescence images focused on the cell surface and virtual image plane of the micro lens (diameter: 11.3 μm), respectively, c3 is bright field optical image focused on the virtual image plane of the micro lens (diameter: 11.3 μm);

FIG. 5 is a graph showing the enhancement of the fluorescence signal of leukemia cells in liquid by lipid particles inside mature adipocytes in the test example of the present invention, wherein a is a schematic diagram of the experimental Z-axis position, b is a bottom view of experimental observation, a1 is an observation diagram of leukemia cells in fluid in the range where no focused light beam enters the lipid particles, and b1 is a diagram of mitochondrial fluorescence imaging; a2 is an observation picture of leukemia cells gradually entering the imaging range of lipid particles; b2 is a fluorescence imaging graph when the fluorescence signal is collected by the lipid particle; a3 is an observation picture when leukemia cells completely enter the axial center of a focused light beam of the lipid particle, b3 is a fluorescence imaging picture when a fluorescence signal is collected by the lipid particle;

FIG. 6 is a graph showing the observation that lipid particles of different diameters are internalized into phagocytes and tumor cells by means of biological endocytosis in the test example of the present invention, wherein a1 and a2 are the observation that lipid particles enter phagocytes; b1 and b2 are graphs of observations of lipid particles entering tumor cells.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.

Example 1

The embodiment prepares a microlens, and specifically comprises the following steps:

1. culture of adipocytes

Culturing mature adipocytes: precursor liver adipocytes (precursor subcutaneous adipocytes) at 1X 10^3～4cell/cm²The density of (2) was inoculated on a glass-bottomed culture dish (35mm), and the culture was carried out by adding a precursor adipocyte complete medium and placing at 37 ℃ and 5% CO₂Was cultured in a cell culture chamber for 36 hours. Differentiation was induced when the pre-somatic adipocytes were 100% in contact with each other. Refining the precursor fatThe complete cell culture medium was replaced with the complete adipocyte-induced differentiation medium, and the complete cell culture medium was replaced once every 2 days. After 6 days, mature adipocytes in which differentiation was induced to be completed could be obtained (optical microscope image of mature adipocytes is shown in FIG. 1 a). Mature adipocytes can be cultured in a medium for complete fat culture for 5-8 days, whereas spherical lipid particles in mature adipocytes can exist inside cells for a long time (5-8 days), as well as cell growth cycle changes.

2. Extraction of lipid particles inside cells

The cell culture medium in the dish containing the mature adipocytes was removed, and washed 3 times with 3mL of cell buffer (DPBS), after which 1mL of sterile water or sterile water with 0.5% cell lysate (Triton-X100) was added thereto, and after standing for 20 minutes, floating lipid particles appeared in the solution. By extraction and resuspension of the supernatant, an aqueous solution of lipid particles was obtained (optical microscopy images of different size lipid particles extracted from mature adipocytes are shown in FIG. 1 b).

The prepared micro-lens and mature fat cells are detected by an optical microscope, and the results are shown in a figure a and a figure b, so that the micro-lens is successfully prepared by the scheme of the invention; the transmission spectrum from visible light to near infrared band (400nm-1000nm) of the microlens is shown in fig. 2, and it can be seen from the figure that the microlens prepared by the scheme of the invention has the maximum light transmittance at 500 nm.

Test example

1. In vitro optical imaging properties of lipid particles

The lipid particles extracted from example 1 were subjected to in vitro testing for optical imaging performance. The lipid particles were placed in a refractive index matching solution of glycerol solution and water (matching cytoplasmic refractive index of 1.36) for testing of optical imaging performance. In the experiment, an inverted microscopic imaging optical system is used for observation to be matched with an optical tweezers operation control system. A fluorescence sample (fluorescence nano diamond and quantum dot microspheres) which is not easy to generate fluorescence quenching is placed above a sample cavity, and the original brightness of the fluorescence sample and the brightness after lipid particle imaging are compared through the irradiation of excitation light with corresponding wavelengths (red: 590-650nm, green: 540-580nm and blue: 465-495nm) of a red-green-blue Light Emitting Diode (LED) light source.

In the experiment, lipid particles with the diameter of 1-40 mu m are controlled by optical tweezers and move to the position right below a target fluorescent sample for imaging observation. The experimental result is shown in fig. 3, and it can be seen from the figure that the fluorescence imaging quality of the fluorescence sample observed by the microscope can be effectively improved with the help of the lipid particles, and the excitation light power used in the experiment can be reduced.

2. Fluorescence imaging observation of fluorescent nanodiamond by using extracted lipid particles

The fluorescent nanodiamond cluster was observed using the microlens prepared in example 1, and a fluorescent nanodiamond sample was placed in a sample chamber above a refractive index matching fluid (a mixed solution of glycerin and sterile water, refractive index 1.36, 50 μ L) with free lipid particles. The Light Emitting Diode (LED) light source (excitation light wavelength: 540-580nm) is used for fluorescence excitation of the fluorescent nano-diamond, and the optical power of the excitation light is kept unchanged at 2.8 mW.

The experimental results are shown in fig. 3, where a1 is a superimposed image of bright field and fluorescence optical microscopy of the fluorescent nanodiamond clusters on the glass slide, b1 is a three-dimensional graph of the original fluorescence intensity of the fluorescent nanodiamond, a2 is a superimposed image of bright field of the lipid particles (diameter 9 μm) and fluorescence of the fluorescent nanodiamond clusters after lipid particle imaging, and b2 is a three-dimensional graph of fluorescence intensity after fluorescent nanodiamond enhancement, and only very weak red fluorescence imaging signals are detected directly from the positions of the fluorescent nanodiamond clusters by observation with an inverted microscope (as shown in a1 and b 1). In order to enhance the detection intensity of the fluorescence signal, lipid particles having a diameter of 9.0 μm were moved to below the fluorescent nanodiamond cluster, and the collection and enhancement of the fluorescence signal were performed (as shown in a 2). The imaging plane of the microscope is adjusted to the virtual imaging plane of the lipid particle. Thus, a magnified enhanced fluorescence imaging image (as shown by b 2) was observed.

3. Imaging detection of intracellular lipid particles on signals of microenvironment outside cells

The focused beam of the incident beam formed by the lipid particles inside the cell enables a convergence outside the cell. In the experiment, a capillary glass micro-flow tube with the wall thickness of 1-5 mu m and the inner diameter of 10-45 mu m is manufactured by a fused biconical taper method to simulate the capillary vessel in an organism, and the capillary glass micro-flow tube is closely attached to the surface of mature fat cells to simulate the position relation of the capillary vessel and the fat cells in the tissue. The capillary center is aligned with the intracellular lipid particle (> 10 μm diameter) so as to be uniform with the observation center of the objective lens. The excitation light is irradiated to the lipid particles in the cell through an inverted objective lens (magnification factor 60 times, numerical aperture 1) and is converged into the capillary tube to form strong local excitation light distribution. The fluid of the target observation cell with the fluorescent label is led into the capillary tube at a certain speed, the fluid flows from left to right, and the target observation object moves along with the fluid. And observing the image change of the target object when the target object moves by using the microscope. When the target object gradually enters the imaging detection range of the lipid particles, the imaging quality of the target object is gradually improved, and when the target object reaches the axial center of the lipid particle convergent light beam, the imaging signal is strongest.

4. Fluorescent imaging observation of subcellular structures in cells

And carrying out fluorescence imaging on the subcellular structure in the cell by using the lipid particles in the cell. The subcellular structure observed by the target is fluorescently labeled, so that the subcellular structure can be specifically recognized in the experiment. Observing under low excitation light power (1-2mW), finding a target observation object under a microscope, and capturing lipid particles (diameter: 1-8 μm) by using a light potential well (wavelength: 1064nm, power: 5mW-100mW) generated by a light tweezers control system to perform moving observation or directly performing in-situ observation by using the lipid particles (diameter: 1-40 μm).

5. Observation enhancement of intracellular subcellular structures using intracellular lipid particles

The lipid particles prepared in example 1 were used in this test example to observe the microstructures (microfilaments and lysosomes) inside the cells.

Precursor liver adipocytes at 1X 10⁴cell/cm²Is inoculated on a glass-bottom culture dish (35mm)Adding complete culture medium of preadipocytes for culturing, and placing at 37 ℃ and 5% CO₂The cells are proliferated in the cell culture chamber for 36-48 hours. Differentiation was induced when the pre-somatic adipocytes were 100% in contact with each other. The complete culture medium of the precursor adipocytes is replaced by the complete culture medium of the adipocyte-induced differentiation, and the complete culture medium is replaced once in 2 to 3 days.

(1) Cell microfilament visualization

The mature adipocytes samples after 7 days of differentiation were subjected to fluorescent labeling of the microfilament structure (dye: SIR-actin, concentration: 0.5. mu.M, staining time: 30min) and multiple washes after labeling (DPBS buffer, 1mL each, 2-3 times). After the staining was completed, the cell sample was placed on an inverted microscope for fluorescence imaging observation (as shown in a1 and a2 in FIG. 4), using an excitation light at 540 and 580nm, with the power kept at 2 mW. As shown in a1 in FIG. 4, the imaging effect of the intracellular target observation microfilament at this excitation light power blurs the indistinguishable structure. A single optical potential well (wavelength: 1064nm, power: 20mW) was added to capture lipid particles with an internal cell diameter of 7.7 μm, moved to the position of the target observation microwire, and the microscope focal plane was adjusted to the virtual image plane of the lipid particles. The clear structure of the cellular microfilament is now visible with the aid of lipid particles.

(2) Cell lysosome observation

The mature adipocytes samples after 12 days of differentiation were subjected to fluorescence labeling of lysosomes (dye: Lyso-Tracker, concentration: 0.5. mu.M, staining time: 30min) and multiple washes after labeling (DPBS buffer, 1mL each, 2-3 times). After staining was complete, the cell samples were placed on an inverted microscope for fluorescent imaging observation using excitation light at a wavelength and power maintained at 1.5 mW.

The experimental result is shown in fig. 4, and it can be seen from the figure that a is the fluorescence image of the cell microfilament of the mature fat cell, and a1 is the fluorescence image of the target cell microfilament at the optimal focal plane; a2 is a fluorescence image of the target cell microfilament obtained at the virtual image plane of the intracellular lipid particle; b is an intensity distribution normalization curve of the cell microfilament observed by the target obtained in the step a, wherein the curve I is an original intensity curve of the cell microfilament of a1, and the curve II is an intensity curve of the cell microfilament obtained after enhanced imaging of lipid particles in a2 cells; c is a fluorescence and optical micrograph of enhanced imaging of intracellular lysosomes by intracellular lipid particles, c1 and c2 are fluorescence pictures focused on the cell surface and a virtual image plane of the lipid particles (diameter: 11.3 mu m), respectively, and c3 is a bright field optical picture focused on the virtual image plane of the intracellular lipid particles (diameter: 11.3 mu m); as shown in c1, when the microscope was focused directly on the cell surface, intracellular lysosomes were not directly observed under the microscope due to weak signals. By selecting lipid particles having an inner cell diameter of 11.3 μm and observing by adjusting the microscope focal plane to the virtual image plane of the lipid particles, a clear lysosomal image can be observed in both fluorescence (c2) and bright field (c3) imaging modes.

6. Observation enhancement of signals in fluids outside cells using lipid particles inside cells

In this test example, a capillary glass tube was used to simulate a blood vessel growing around a cell, a cancer cell flowing therein was used as a target observation object, and a fluorescence signal of the cancer cell in the capillary was detected by using the long excitation light convergence ability of lipid particles.

Precursor liver adipocytes at 1X 10⁴cell/cm²The density of (2) was inoculated on a glass-bottomed culture dish (35mm), and the culture was carried out by adding a precursor adipocyte complete medium and placing at 37 ℃ and 5% CO₂The cells are proliferated in the cell culture chamber for 36-48 hours. Differentiation was induced when the pre-somatic adipocytes were 100% in contact with each other. The complete culture medium of the precursor adipocytes is replaced by the complete culture medium of the adipocyte-induced differentiation, and the complete culture medium is replaced once in 2 to 3 days. Lipid particles with larger diameter (diameter) in mature adipocytes 12 days after differentiation>10 μm) can be focused extracellularly as a detection means.

Leukemia cells are 1 × 10⁴cell/cm²The cells were inoculated in a culture flask (25mL), cultured with the addition of complete medium (IMDM + fetal bovine serum 10% + penicillin streptomycin solution 1%), and placed at 37 ℃ and 5% CO₂The cells are proliferated in the cell culture chamber for 24-48 hours. 1mL of the leukemia cell suspension was removed and Mito-Tr was addedacer fluorescent dye (0.1. mu.L, 5. mu.M) was subjected to static staining for 30 minutes. After staining, the leukemia cell suspension was centrifuged (rotation: 1000 rpm, time: 5 minutes), the supernatant was removed, and the cells were resuspended in complete medium (1 mL).

A micro-flow element is prepared by a fusion-draw method to simulate the capillary vessel of a living body. First, a capillary tube (inner diameter: about 0.9mm, wall thickness: about 0.1mm, length: about 12cm) was placed in parallel above an alcohol burner in the flame out, and left to stand for about 30 seconds, and when the glass tube was softened, the softened portion was rapidly pulled in the direction of both ports at a speed of 6mm/s by both hands, to draw a glass capillary tube having a wall thickness of 4 μm and an inner diameter of 45 μm. The capillary tube length direction is used as the experimental area (the length is 50um range).

Placing the prepared slender part of the glass capillary tube in a suspension of leukemia cells, wherein the slender part of the glass capillary tube can be filled with cell solution under the action of capillary force. The capillary slender portion was placed against the surface of mature adipocytes (adherent cells) to mimic the positional relationship of blood vessels and adipocytes within the tissue (as shown in fig. 4 a), with the center of the capillary aligned with the center of the lipid particle (20.0 μm in diameter) within the adipocytes to match the center of observation of the microscope. Sucking the leucocyte suspension (0.1mL) by using a needle tube (1mL), and injecting a small amount of suspension to the thick head part of the glass capillary tube to enable fluid generated in the capillary tube to flow from left to right so as to drive the leucocyte to move.

The fluorescence imaging result of the lipid particles inside the mature adipocytes on the leukemia cells in the liquid is shown in fig. 5, and it can be seen from the graph that the observed mitochondrial fluorescence image is weak (as shown in b 1) when the leukemia cells in the liquid are observed under an inverted microscope without entering the range of the focused light beam of the lipid particles (as shown in a 1). When the leukemia cells gradually enter the imaging range of the lipid particle (as shown in a2), their fluorescence signals are collected by the lipid particle, and the image quality is observed to gradually increase on the microscope (as shown in b 2). When the leukemia cells completely enter the axial center of the focused beam of lipid particles (as shown by a 3), the fluorescence imaging quality is obviously improved (as shown by b 3). Namely, leukemia cells gradually flow from the outer side of the projected range of the lipid particle (as shown by a1 and b 1) to the edge (as shown by a2 and b 2) to the center (as shown by a3 and b 3), and the fluorescence signal intensity changes along with the process.

7. Internalization of lipid particles into other types of cells

0.1mL of the suspension of lipid particles prepared in example 1 was taken out, added to a complete medium solution (2-5mL) suitable for other types of cells (cell types capable of causing cell exocytosis), and the extraction of the supernatant and the further addition of the complete medium were repeated 3 times to obtain a complete medium solution with lipid particles. When the target cells are cultured in a culture dish (35mm) and the culture density reaches 60-90%, the original complete culture medium is replaced by a complete culture medium mixed with lipid particles. Placing the lipid particles and target cells at 37 ℃ and 5% CO₂Was co-cultured in the cell culture chamber for 36 hours. The phenomenon and proportion of lipid particle internalization was then observed using an inverted microscope. The retention time of internalized lipid particles in other cell types can reach 12-96 hours.

8. Internalizing the extracted lipid particles into phagocytic nuclear tumor cells

The lipid particles prepared in example 1 are introduced into other types of cells by means of biological endocytosis as micro-optical elements, and phagocytes and cancer cells are taken as examples.

Phagocytes (Ana-1) at 1X 10⁴cell/cm²The cells were inoculated in a culture flask (25mL), cultured in a complete medium (RPMI1640+ fetal bovine serum 10% + penicillin streptomycin solution 1%), and left at 37 ℃ and 5% CO₂The cell culture box is used for proliferation for 24-36 hours.

Cancer cells (C127) at 1X 10⁴cell/cm²The density of (A) was inoculated on a glass-bottomed petri dish (35mm), and the whole medium (DMEM + fetal bovine serum 10% + penicillin streptomycin solution 1%) was added thereto for culture and placed at 37 ℃ and 5% CO₂The cells are proliferated in the cell culture chamber for 36-48 hours.

Precursor liver adipocytes at 1X 10⁴cell/cm²The density of the seed is inoculated on a glass bottom cultureCulturing in a culture dish (35mm), adding complete culture medium of preadipocytes, and standing at 37 deg.C and 5% CO₂The cells are proliferated in the cell culture chamber for 36-48 hours. Differentiation was induced when the pre-somatic adipocytes were 100% in contact with each other. The complete medium for the precursor adipocytes was replaced with the complete medium for the induced differentiation of adipocytes, and the complete medium was replaced once in 3 days. Mature adipocytes were obtained 12 days after differentiation. The cell culture medium in the culture dish containing the mature adipocytes was removed, and 3 washes with 3mL of cell buffer were performed, after which 1mL of sterile water was added thereto, and after standing for 30 minutes, floating lipid particles appeared in the solution.

Adding two tubes of lipid particle suspension (0.1mL) into phagocyte complete culture medium and cancer cell complete culture medium (2mL), extracting supernatant and adding complete culture medium for 3 times to obtain complete culture medium solution with lipid particles, adding the complete culture medium solution into phagocyte culture bottle and cancer cell culture dish, respectively, placing at 37 deg.C and 5% CO₂Co-culturing for 24 hours in the cell culture box. After a period of co-culture, observing under an inverted microscope, and successfully realizing that the extracted lipid particles enter phagocytes and cancer cells through endocytosis.

The observation result of the lipid particle, phagocyte and cancer cell co-culture microscope is shown in FIG. 6, and it can be seen from the figure that lipid particles with different diameters (a1(5 μm); a2(7.5 μm); b1(3.3 μm); b2(5.8 μm)) can be internalized into phagocytes (as shown in a1 and a2) and cancer cells (as shown in b1 and b 2) by means of biological endocytosis, and can be used as microlenses to amplify the fluorescence imaging signal of intracellular microstructure.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.