Micron-size fluorescein sodium fiber phantom as well as preparation method and application thereof

Abstract

The invention discloses a micron-sized fluorescein sodium fiber phantom and a preparation method and application thereof.The preparation method comprises the steps that firstly, a fluorescein sodium solution is added into epoxy resin, the mixture is preliminarily cured to a certain viscosity, and then the fluorescein sodium fiber phantom is prepared through a wet spinning technology; preparing a mold with gradually changed depth by using a 3d printing technology, and obtaining a scattering layer containing TiO2 by using a soft etching method; and covering the surface of the fiber membrane with a scattering layer to obtain the fluorescein sodium phantom with different scattering thicknesses. The eyeball-shaped phantom is also combined with a convex lens and a hemisphere prepared through 3d printing, the conformity of fibers is utilized, the fundus blood vessel structure is simulated, and the eyeball-shaped phantom is obtained. The method is simple to operate, can produce a large number of fluorescein sodium simulators with various concentrations and multiple sizes, and is expected to provide a wide application scene in the evaluation of endoscopes, fluorescent surgical navigation equipment and fundus fluorescent radiography equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of standardization of medical diagnosis and treatment bionic phantoms and fluorescent surgical navigation equipment, and specifically relates to a micron-sized sodium fluorescein fiber phantom and a preparation method and application thereof. Background Art

[0002] Fluorescence molecular imaging (FMI) has become a valuable tool for guiding tumor surgery, and various fluorescence-guided surgery (FGS) devices are now available for open and laparoscopic surgery. Although progress has been made in this field, there is still a lack of consensus on quality control measures and system standardization. The establishment of standardized fluorescence equipment can improve manufacturing reliability, improve users' understanding of the instrument, and help regulatory agencies define and approve it. Therefore, many fluorescent biomimetic phantoms that mimic the optical properties of tissues have been created to calibrate fluorescence imaging systems. For example, polyurethane-based phantoms have been developed that combine absorption, scattering, and fluorescence of different components for evaluating multiple system parameters. Compared with typical block-shaped phantoms, phantoms designed with alternative shapes such as cylinders can be better aligned with the imaging field of view of fluorescent molecular endoscopy systems. 3D printing technology has been used to prepare biomimetic phantoms of different shapes, but their sizes are still limited to the range of hundreds of microns, which is still larger than the size of human capillaries. In addition, due to the instability of sodium fluorescein in polyurethane, phantoms based on sodium fluorescein have not yet been developed.

[0003] The method disclosed in the present invention adopts wet spinning technology to prepare micron-scale sodium fluorescein phantom fibers based on epoxy resin, and then bonds them with PDMS (polydimethylsiloxane) scattering layers of different thicknesses to prepare phantoms with different scattering depths. By regulating the content of sodium fluorescein, phantoms of a series of concentrations can be prepared to achieve the detection of the sensitivity of fluorescent imaging equipment. At the same time, the present invention discloses a method for preparing an eyeball-shaped phantom, which utilizes the flexibility and conformability of the fiber to arrange it on the surface of the hemispherical PDMS, and by bonding the lens, the evaluation of the fluorescent fundus camera can be achieved. Compared with the traditional mold method and additive manufacturing, the method of the present invention can prepare sodium fluorescein bionic phantoms of different concentrations and sizes on a large scale, has scalability, customizability and deployability, and can open up new strategies for the evaluation of fluorescent surgical navigation equipment and fluorescent fundus cameras. Summary of the invention

[0004] The purpose of the present invention is to provide a micron-sized sodium fluorescein fiber phantom and its preparation method and application. The method is simple in process and can be mass-produced. The obtained sodium fluorescein fiber has adjustable concentration, size and scattering depth, and shows application potential in fluorescent surgical navigation equipment and fluorescent fundus camera evaluation. In addition, the method adopted by the present invention is expected to be applied to fluorescent materials of various emission wavelengths, such as indocyanine green, methylene blue, IR765, quantum dots, etc.

[0005] The present invention is achieved through the following technical solutions:

[0006] A method for preparing a micron-sized sodium fluorescein fiber phantom, the method comprising the following steps:

[0007] (1) adding sodium fluorescein to an organic solvent to dissolve it; weighing epoxy resin components A and B, adding them to a beaker, and stirring them thoroughly; adding the sodium fluorescein solution to the epoxy resin and stirring them evenly;

[0008] (2) pouring the reaction product obtained in step (1) into a syringe, fixing the syringe on a syringe pump, pushing the syringe, and collecting the injected sodium fluorescein fibers on a drum;

[0009] (3) Weigh TiO2 and add it to ethanol, put it into an ultrasonic cleaning machine for ultrasonic dispersion, prepare polydimethylsiloxane (PDMS) solution, add the evenly dispersed TiO2 ethanol solution, and stir thoroughly;

[0010] (4) Using 3D printing to prepare a mold with a stepped gradient depth, pouring the solution prepared in step (3) into the mold and fully curing it to obtain PDMS scattering layers of different thicknesses, fixing the scattering layers on the surface of the sodium fluorescein fiber, and obtaining a sodium fluorescein fiber phantom for the evaluation of endoscopes and fluorescent surgical navigation equipment.

[0011] Furthermore, in the step (1), sodium fluorescein is dissolved in DMSO at a concentration of 2.5 mg / mL, and added to an epoxy resin having a mass ratio of A:B=3:1, and the volume of the added sodium fluorescein solution is 11 uL-1.1 mL.

[0012] Furthermore, in the step (2), the reaction product is poured into a syringe with a needle diameter of 0.5 mm, the syringe is placed on a syringe pump, and then the syringe is pushed at a pressure of 0.35 MPa and a speed of 1 mm / min to extrude the fiber, and the fiber is collected on a drum with a drum rotation speed of 5-100 rpm.

[0013] Furthermore, in step (3), the concentration of TiO2 in ethanol is 0.33 mg / mL, and when added to PDMS, the content of TiO2 in PDMS is controlled to be 2-8 mg / g.

[0014] Furthermore, in step (4), the gradient of the printed mold is 50 um, the step width is 5 mm, and there are 9 gradient depths in total.

[0015] Furthermore, in the step (4), the curing temperature of PDMS is 50-70°C.

[0016] A sodium fluorescein fiber mimetic prepared by the above preparation method.

[0017] An application of the above-mentioned sodium fluorescein fiber phantom in preparing an eyeball-shaped phantom is prepared by the following steps:

[0018] A semicircular concave mold was prepared by 3D printing, PDMS was poured into it to obtain a PDMS hemisphere, the sodium fluorescein fiber phantom was arranged in an emitting shape on the surface of the hemisphere, a layer of PDMS was applied on one side of the plane of the plano-convex lens, and the fiber-covered PDMS hemisphere was glued to the convex lens to obtain an eyeball phantom.

[0019] Furthermore, the diameter of the sodium fluorescein fiber phantom used is 5-100 um.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The present invention uses epoxy resin as a base material and uses wet spinning technology to prepare micron-sized sodium fluorescein phantom fibers. Earlier reports have prepared fluorescent phantoms, but they mostly use fluorescent materials such as ICG, and there are few studies on sodium fluorescein that is unstable in polyurethane. Moreover, due to the limitations of the preparation method, it is impossible to achieve the preparation of phantoms of capillary scale. The present invention uses wet spinning technology to prepare sodium fluorescein phantom fibers on a large scale, and simply gives them the characteristics of adjustable concentration and size.

[0022] 2. The present invention utilizes 3D printing technology and a mold method to prepare PDMS scattering layers of different thicknesses, which, combined with sodium fluorescein fibers, can realize the preparation of fluorescent phantoms with different scattering thicknesses.

[0023] 3. The present invention utilizes the imaging of the PDMS hemisphere and convex lens as well as the conformability and flexibility of the fiber material to realize the preparation of an eyeball-shaped fluorescent phantom, providing a solution for fundus camera evaluation.

[0024] 4. The process of the present invention is simple and controllable, with a short preparation cycle, safe, pollution-free and inexpensive. According to actual production requirements, fluorescent phantoms with different emission bands can be flexibly prepared, and have broad application prospects in endoscope and fluorescent surgical navigation equipment evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0026] Figure 1 Schematic diagram of an experimental device for preparing sodium fluorescein fiber in step 2 of the present invention;

[0027] Figure 2 is a schematic diagram of fluorescein sodium fibers of different sizes obtained in step 2 of the present invention;

[0028] Figure 3 is a schematic diagram of a PDMS scattering layer with a step-by-step gradient thickness obtained in step 4 of the present invention;

[0029] Figure 4 Schematic diagram of the eyeball-shaped phantom obtained by implementing step 5 of the present invention. DETAILED DESCRIPTION

[0030] The following is a further description of the present invention, rather than a limitation of the present invention.

[0031] Embodiment 1:

[0032] (1) Add sodium fluorescein to dimethyl sulfoxide (DMSO) to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B respectively, add them to a beaker, and stir well to mix; add 1 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0033] (2) See Figure 1 , pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a roller. The obtained sodium fluorescein fibers cannot be observed under a microscopic imaging device because the sodium fluorescein content is too low and the fluorescence signal is too weak.

[0034] Embodiment 2:

[0035] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir to mix thoroughly; add 1.5 mL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0036] (2) Pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a roller. Since the DMSO content is too high, it affects the viscosity of the epoxy resin polymer, and the mechanical properties of the collected fibers are insufficient and the fiber shape cannot be maintained.

[0037] Embodiment 3:

[0038] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir to mix thoroughly; add 100 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0039] (2) pouring the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fixing it on a syringe pump, pushing the syringe, and collecting the injected sodium fluorescein fibers on a drum;

[0040] (3) Weigh 2 g of TiO2 and add it to 50 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution, add 50 uL of the evenly dispersed TiO2 ethanol solution, and stir thoroughly. Since the added TiO2 content is too low, the scattering layer cannot play a corresponding role.

[0041] Embodiment 4:

[0042] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir thoroughly to mix; add 200 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0043] (2) Pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a drum.

[0044] (3) Weigh 2 g of TiO2 and add it to 6 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution. Add 500 uL of the evenly dispersed TiO2 ethanol solution and stir thoroughly. Since the added TiO2 content is too high, the scattering layer cannot play a corresponding role.

[0045] Embodiment 5:

[0046] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir to mix thoroughly; add 100 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0047] (2) Pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a drum.

[0048] (3) Weigh 2 g of TiO2 and add it to 6 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution. Add 50 uL of the evenly dispersed TiO2 ethanol solution and stir thoroughly.

[0049] (4) A mold with a stepped gradient depth was prepared by 3D printing, the solution prepared in step (3) was poured into the mold, and cured at 100° C. Since the curing temperature was too high, the bubbles in the PDMS could not be discharged in time, and the obtained scattering layer contained bubbles.

[0050] Embodiment 6:

[0051] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, add them to a beaker, and stir thoroughly to mix; add 500 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0052] (2) See Figure 2 , pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a drum.

[0053] (3) Weigh 2 g of TiO2 and add it to 6 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution. Add 50 uL of the evenly dispersed TiO2 ethanol solution and stir thoroughly.

[0054] (4) A mold with a stepped gradient depth is prepared by 3D printing, the solution prepared in step (3) is poured into the mold, and cured at room temperature. Since the curing temperature is too low and the required curing time is too long, the distribution of TiO2 in PDMS will be uneven.

[0055] Embodiment 7:

[0056] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir to mix thoroughly; add 100 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0057] (2) Pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a drum.

[0058] (3) Weigh 2 g of TiO2 and add it to 6 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution. Add 50 uL of the evenly dispersed TiO2 ethanol solution and stir thoroughly.

[0059] (4) See Figure 3 , using 3D printing to prepare a mold with a stepped gradient depth, pouring the solution prepared in step (3) into the mold, curing at 50-70° C. to obtain a stepped scattering layer with different depths, fixing the scattering layer on the surface of the sodium fluorescein fiber, and obtaining a sodium fluorescein fiber phantom that can be used for the evaluation of fluorescent surgical navigation equipment;

[0060] (5) A semicircular concave mold was prepared by 3D printing, and PDMS was poured into it to obtain a PDMS hemisphere. The sodium fluorescein fiber phantom was arranged in an emitting shape on the surface of the hemisphere. A layer of PDMS was applied on one side of the plane of the plano-convex lens. The fiber-covered PDMS hemisphere was glued together with a convex lens with a focal length of 30 mm. The obtained eyeball phantom could not be imaged under a fundus camera due to its large focal length.

[0061] Embodiment 8:

[0062] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir to mix thoroughly; add 100 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0063] (2) Pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a drum.

[0064] (3) Weigh 2 g of TiO2 and add it to 6 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution. Add 50 uL of the evenly dispersed TiO2 ethanol solution and stir thoroughly.

[0065] (4) using 3D printing to prepare a mold with a stepped gradient depth, pouring the solution prepared in step (3) into the mold, curing at 50-70° C. to obtain a stepped scattering layer with different depths, fixing the scattering layer on the surface of the sodium fluorescein fiber, and obtaining a sodium fluorescein fiber phantom that can be used for the evaluation of fluorescent surgical navigation equipment;

[0066] (5) A semicircular concave mold was prepared by 3D printing, and PDMS was poured into it to obtain a PDMS hemisphere. The sodium fluorescein fiber phantom was arranged in an emitting shape on the surface of the hemisphere. A layer of PDMS was applied on one side of the plane of the plano-convex lens. The fiber-covered PDMS hemisphere was glued together with a convex lens with a focal length of 8 mm. The obtained eyeball phantom could not be imaged under a fundus camera due to its small focal length.

[0067] Embodiment 9:

[0068] (1) Add sodium fluorescein to DMSO to dissolve it (concentration 2.5 mg / ml); weigh 9 g and 3 g of epoxy resin components A and B, respectively, add them to a beaker, and stir to mix thoroughly; add 100 uL of DMSO solution of sodium fluorescein to the epoxy resin and stir evenly;

[0069] (2) Pour the reaction product obtained in step (1) into a syringe with a diameter of 0.5 mm, fix it on a syringe pump, push the syringe, and collect the injected sodium fluorescein fibers on a drum.

[0070] (3) Weigh 2 g of TiO2 and add it to 6 mL of ethanol. Place it in an ultrasonic cleaner for ultrasonic dispersion. Prepare a polydimethylsiloxane (PDMS) solution. Add 50 uL of the evenly dispersed TiO2 ethanol solution and stir thoroughly.

[0071] (4) using 3D printing to prepare a mold with a stepped gradient depth, pouring the solution prepared in step (3) into the mold, curing the PDMS at 50-70° C. to obtain a stepped scattering layer with different depths, fixing the scattering layer on the surface of the sodium fluorescein fiber, and obtaining a sodium fluorescein fiber phantom that can be used for the evaluation of fluorescent surgical navigation equipment;

[0072] (5) See Figure 4 , a semicircular concave mold was prepared by 3D printing, and PDMS was poured into it to obtain a PDMS hemisphere with a diameter of 24mm; the sodium fluorescein fiber phantom was arranged on the surface of the hemisphere in an emitting shape, a layer of PDMS was applied on the plane side of the plano-convex lens, and the PDMS hemisphere covered with fibers was glued to a convex lens with a focal length of 16mm to obtain an eyeball phantom that can be imaged under a fundus camera. Among them, the diameter of the sodium fluorescein fiber phantom used was 5-100um, the diameter of the convex lens used was 25.4mm, and the focal length was 16mm.

[0073] It should be noted that in step (2), the reaction product is poured into a syringe with a needle diameter of 0.5 mm, the syringe is placed on a syringe pump, and then the syringe is pushed at a pressure of 0.35 MPa and a speed of 1 mm / min to extrude the fibers, which are then collected on a drum with a drum rotation speed of 5-100 rpm.

[0074] In step (3), the concentration of TiO2 in ethanol is 0.33 mg / mL. When added to PDMS, the content of TiO2 in PDMS is controlled to be 2-8 mg / g.

[0075] In step (4), the gradient of the printed mold is 50 um, the step width is 5 mm, and there are 9 gradient depths in total.

[0076] It is worth mentioning that the sodium fluorescein fiber phantom prepared by this study can be combined with a scattering layer prepared by 3D printing and a reasonable optical path design can be performed to evaluate equipment such as confocal microscopes, fluorescence endoscopes, and fluorescent fundus cameras.

[0077] It should be noted that in the above-mentioned embodiments of the present invention, other different schemes obtained by making specific selections within the scope of the steps, components, ratios and process parameters recorded in the present invention can all achieve the technical effects recorded in the present invention, so the present invention will no longer list them one by one.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0079] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A method for preparing a micron-sized sodium fluorescein fiber phantom, characterized in that: The method comprises the following steps: (1) adding sodium fluorescein to an organic solvent to dissolve it; weighing epoxy resin components A and B, adding them to a beaker, and stirring them thoroughly; adding the sodium fluorescein solution to the epoxy resin and stirring them evenly; (2) pouring the reaction product obtained in step (1) into a syringe, fixing the syringe on a syringe pump, pushing the syringe, and collecting the injected sodium fluorescein fibers on a drum; (3) Weigh TiO2 and add it to ethanol, put it into an ultrasonic cleaning machine for ultrasonic dispersion, prepare polydimethylsiloxane (PDMS) solution, add the evenly dispersed TiO2 ethanol solution, and stir thoroughly; (4) Using 3D printing to prepare a mold with a stepped gradient depth, pouring the solution prepared in step (3) into the mold and fully curing it to obtain PDMS scattering layers of different thicknesses, fixing the scattering layers on the surface of the sodium fluorescein fiber, and obtaining a sodium fluorescein fiber phantom for the evaluation of endoscopes and fluorescent surgical navigation equipment.

2. The method for preparing a micron-sized sodium fluorescein fiber phantom according to claim 1, characterized in that: In the step (1), fluorescein sodium is dissolved in DMSO at a concentration of 2.5 mg / mL, and added to an epoxy resin having a mass ratio of A:B=3:1, and the volume of the added fluorescein sodium solution is 11 uL-1.1 mL.

3. The method for preparing a micron-sized sodium fluorescein fiber phantom according to claim 1, characterized in that: In the step (2), the reaction product is poured into a syringe with a needle diameter of 0.5 mm, the syringe is placed on a syringe pump, and then the syringe is pushed at a pressure of 0.35 MPa and a speed of 1 mm / min to extrude the fiber, and the fiber is collected on a drum with a rotation speed of 5-100 rpm.

4. The method for preparing a micron-sized sodium fluorescein fiber phantom according to claim 1, characterized in that: In the step (3), the concentration of TiO2 in ethanol is 0.33 mg / mL. When added to PDMS, the content of TiO2 in PDMS is controlled to be 2-8 mg / g.

5. The method for preparing a micron-sized sodium fluorescein fiber phantom according to claim 1, characterized in that: In the step (4), the gradient of the printed mold is 50 um, the step width is 5 mm, and there are 9 gradient depths in total.

6. The method for preparing a micron-sized sodium fluorescein fiber phantom according to claim 1, characterized in that: In the step (4), the curing temperature of PDMS is 50-70°C.

7. A sodium fluorescein fiber phantom prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the sodium fluorescein fiber phantom according to claim 7 in preparing an eyeball-shaped phantom.

9. The use according to claim 8, characterized in that: The following steps are involved: A semicircular concave mold was prepared by 3D printing, PDMS was poured into it to obtain a PDMS hemisphere, the sodium fluorescein fiber phantom was arranged in an emitting shape on the surface of the hemisphere, a layer of PDMS was applied on one side of the plane of the plano-convex lens, and the fiber-covered PDMS hemisphere was glued to the convex lens to obtain an eyeball phantom.

10. The use according to claim 9, characterized in that: The diameter of the sodium fluorescein fiber phantom used is 5-100um.

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