CN120837726A

CN120837726A - Method for preparing spinal fusion cage and spinal fusion cage

Info

Publication number: CN120837726A
Application number: CN202510937030.3A
Authority: CN
Inventors: 柳克银; 刘琳
Original assignee: Jiangxi Sike Biotechnology Co ltd
Current assignee: Jiangxi Sike Biotechnology Co ltd
Priority date: 2025-07-08
Filing date: 2025-07-08
Publication date: 2025-10-28

Abstract

The application relates to a preparation method of a spinal fusion device and the spinal fusion device, which comprises the steps of providing a silk fibroin hexafluoroisopropanol solution, wherein the proportion of silk fibroin powder and hexafluoroisopropanol in the silk fibroin hexafluoroisopropanol solution is 1g (1-10) mL, then uniformly mixing the silk fibroin hexafluoroisopropanol solution and a photoinitiator aqueous solution, injecting the mixture into a mould, standing and solidifying to obtain initial hydrogel, placing the initial hydrogel under ultraviolet light to carry out photocrosslinking treatment to obtain photocrosslinked hydrogel, sequentially carrying out soaking and drying treatment on the photocrosslinked hydrogel to obtain a photocrosslinked hydrogel plate, and carrying out mechanical processing based on the photocrosslinked hydrogel plate to obtain the spinal fusion device, so that the prepared spinal fusion device has good biocompatibility, has mechanical properties closer to vertebrae and proper biodegradation rate, and the preparation process can be suitable for mass production.

Description

Preparation method of spinal fusion device and spinal fusion device

Technical Field

The application relates to the technical field of biomedical appliances, in particular to a preparation method of a spinal fusion cage and the spinal fusion cage.

Background

The spinal fusion device is an instrument used for matching with spinal fusion operation, and has the functions of mainly expanding the spinal cone gap and maintaining the height of the spinal cone gap, repairing the physiological curvature of the spinal column, reconstructing and maintaining the stability of the spinal column until the bone fusion is realized locally. Currently, spinal fusion devices are classified into two types according to materials, namely, metal spinal fusion devices and non-metal spinal fusion devices, wherein the metal spinal fusion devices are represented by titanium alloy materials, and the non-metal spinal fusion devices are classified into degradable and non-degradable materials. In practical application of the spinal fusion device, it is found that the metal spinal fusion device is far higher than the elastic modulus of human vertebral bodies (3.8-11 GPa) due to the fact that the elastic modulus of a metal material is too high (for example, the elastic modulus of titanium alloy is as high as 110 GPa), so that a stress shielding effect is caused, the new bone lacks corresponding stress stimulation, the bone formation is slow, meanwhile, the adjacent vertebral bodies are osteoporosis due to the too high elastic modulus, the fusion device is prone to sinking, and finally the height of the intervertebral space is lost.

Compared with a metal spinal fusion device, the non-metal spinal fusion device has the elastic modulus more similar to that of a human cone, mainly comprises a carbon fiber spinal fusion device and a polyether ether ketone (PEEK) spinal fusion device, and can be degraded to form a polylactic acid spinal fusion device. The PEEK spinal fusion device is characterized in that carbon fibers are easy to generate fragments in a body to cause inflammatory reaction, although the elastic modulus of the PEEK spinal fusion device is close to that of cortical bone, the PEEK spinal fusion device is not biodegradable without bioactivity and is not easy to form tight connection with bone, while the polylactic acid spinal fusion device is bioabsorbable, the degradation rate is too high, local lactic acid accumulation is easy to occur during in-vivo degradation, and high-concentration lactic acid can cause inflammatory reaction.

Thus, there is a need for a spinal fusion cage that is biocompatible, mechanically similar to the spine, naturally degradable, and has a suitable degradation rate.

Disclosure of Invention

Aiming at the problems in the prior art, the application aims to provide a preparation method of a spinal fusion cage and the spinal fusion cage, wherein the main material sources of the prepared spinal fusion cage are natural, the mechanical properties of the spinal fusion cage are closer to the spine, the biocompatibility is good, and the biodegradation rate is proper.

In one aspect, the present application provides a method of making a spinal fusion cage, the method comprising:

Providing a silk fibroin hexafluoroisopropanol solution, wherein the ratio of silk fibroin powder to hexafluoroisopropanol in the silk fibroin hexafluoroisopropanol solution is 1g (1-10) mL;

Uniformly mixing the silk fibroin hexafluoroisopropanol solution and a photoinitiator aqueous solution, injecting into a mold, standing and solidifying to obtain initial hydrogel;

placing the initial hydrogel under ultraviolet irradiation for photo-crosslinking treatment to obtain photo-crosslinked hydrogel;

Sequentially carrying out soaking and drying treatment on the photocrosslinked hydrogel to obtain a photocrosslinked hydrogel plate;

and (5) machining based on the photocrosslinked hydrogel plate to obtain the spinal fusion cage.

In an exemplary embodiment, the sequentially performing the soaking and drying treatment on the photocrosslinked hydrogel to obtain a photocrosslinked hydrogel plate comprises:

placing the photocrosslinked hydrogel in ultrapure water for soaking and washing for 5-10 days to obtain soaked and washed photocrosslinked hydrogel;

and drying the soaked and washed photocrosslinked hydrogel by adopting a drying mode of naturally airing at normal temperature to obtain the photocrosslinked hydrogel plate.

In an exemplary embodiment, during the soaking and washing process, the fresh ultrapure water is replaced every day, and the normal-temperature natural drying time is 1-30 days;

in an exemplary embodiment, the machining based on the photocrosslinked hydrogel sheet material to obtain a spinal fusion cage comprises:

the photo-crosslinked hydrogel plate is integrally formed and processed into a spinal fusion device, wherein the spinal fusion device comprises a first fusion surface and a second fusion surface which are opposite to each other, bone grafting windows penetrating through the first fusion surface and the second fusion surface are formed at positions far away from the edges of the spinal fusion device, and a plurality of fixing points matched with the tantalum metal rods are distributed on the periphery of the bone grafting windows.

In an exemplary embodiment, the first and/or the second fusion surface is a rough tooth surface.

In an exemplary embodiment, after the silk fibroin hexafluoroisopropanol solution and the photoinitiator aqueous solution are uniformly mixed, the mixture is injected into a mold, and the initial hydrogel obtained by standing and solidification comprises:

and adding the photoinitiator aqueous solution into the silk fibroin hexafluoroisopropanol solution, uniformly mixing, injecting into a mold, and standing and solidifying for 1-5 days at the temperature of 5-40 ℃ to obtain the initial hydrogel.

In an exemplary embodiment, the concentration of the photoinitiator in the aqueous solution of the photoinitiator is 0.1-0.5%, and the volume ratio of the hexafluoroisopropanol solution of the silk fibroin to the aqueous solution of the photoinitiator is 5:4-5:1.

In an exemplary embodiment, the wavelength of the ultraviolet light is 254-365 nm, and the illumination time is 10-60 min.

In another aspect, the present application provides a spinal fusion cage made by the method of making any one of the spinal fusion cage glues described above.

In an exemplary embodiment, the spinal fusion device comprises a first fusion surface and a second fusion surface which are opposite to each other, wherein a bone grafting window penetrating through the first fusion surface and the second fusion surface is formed at a position far away from the edge of the spinal fusion device, a plurality of fixing points used for being matched with a tantalum metal rod are distributed on the periphery of the bone grafting window, and the first fusion surface and/or the second fusion surface are rough tooth surfaces.

According to the application, the silk fibroin hexafluoroisopropanol solution is provided, wherein the ratio of silk fibroin powder to hexafluoroisopropanol in the silk fibroin hexafluoroisopropanol solution is 1g (1-10) mL, then the silk fibroin hexafluoroisopropanol solution and the photoinitiator aqueous solution are uniformly mixed, then the mixture is poured into a mould, the initial hydrogel is obtained after standing and solidification, the initial hydrogel is subjected to photocrosslinking treatment under ultraviolet irradiation to obtain photocrosslinked hydrogel, the photocrosslinked hydrogel is sequentially subjected to soaking and drying treatment to obtain a photocrosslinked hydrogel plate, and the photocrosslinked hydrogel plate is subjected to mechanical processing to obtain the spinal fusion cage.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the following description will make a brief introduction to the drawings used in the description of the embodiments or the prior art. It is evident that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic flow chart of a method of manufacturing a spinal fusion cage according to an embodiment of the present application;

Fig. 2 is a schematic view of a spinal fusion cage made according to a method of making an embodiment of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The embodiment of the application provides a preparation method of a spinal fusion cage, as shown in fig. 1, comprising the following steps:

firstly, a step S1 is carried out, namely a silk fibroin hexafluoroisopropanol solution is provided, wherein the ratio of silk fibroin powder to hexafluoroisopropanol in the silk fibroin hexafluoroisopropanol solution is 1g (1-10) mL.

Specifically, the step of providing the silk fibroin hexafluoroisopropanol solution can comprise the steps of providing silk fibroin powder, and dissolving the silk fibroin powder in hexafluoroisopropanol to obtain the silk fibroin hexafluoroisopropanol solution, wherein the dissolving time can be 1-100 h, and the dissolving temperature can be 5-80 ℃ so as to ensure that the natural silk fibroin lyophilized powder is fully dissolved by hexafluoroisopropanol. In practical applications, the dissolution process is performed in a closed container in order to prevent volatilization of hexafluoroisopropanol.

The silk fibroin powder is prepared by sequentially degumming natural cocoons, rinsing, airing, dissolving silk, dialyzing, centrifuging and freeze-drying.

And S2, uniformly mixing the silk fibroin hexafluoroisopropanol solution and the photoinitiator aqueous solution, injecting the mixture into a mould, and standing and solidifying to obtain the initial hydrogel.

Specifically, an aqueous solution of the photoinitiator may be prepared, wherein the concentration of the photoinitiator in the aqueous solution of the photoinitiator is 0.1-0.5%, the dissolution time is 0.1-48 h, and the dissolution temperature is 5-80 ℃. The mixing mode can be mechanical mixing or oscillating and overturning mixing so as to ensure that the mixing is more uniform and improve the effect of subsequent photocrosslinking.

When the initial hydrogel is injected into a mold, the mixed solution after being uniformly mixed can be firstly poured into an injector, and then the mixed solution is injected into the mold by the injector, so that the uniformity of the initial hydrogel is improved.

Illustratively, in the implementation of the step S2, the aqueous solution of the photoinitiator is added into the hexafluoroisopropanol solution of the silk fibroin, and after being mixed uniformly, the mixture is poured into a mold, and the initial hydrogel is obtained after standing and solidifying for 1-5 days at a temperature of 5-40 ℃. Considering that the addition of the aqueous solution of silk fibroin hexafluoroisopropanol to the aqueous solution of a photoinitiator may generate floc due to rapid gel aging, resulting in non-uniformity of the material of the finally prepared spinal fusion device, embodiments of the present application add the aqueous solution of a photoinitiator to the aqueous solution of silk fibroin hexafluoroisopropanol to improve the uniformity of the material of the finally prepared spinal fusion device.

Illustratively, the volume ratio of the silk fibroin hexafluoroisopropanol solution to the photoinitiator aqueous solution is 5:4-5:1.

And step S3, placing the initial hydrogel under ultraviolet irradiation for photo-crosslinking treatment to obtain the photo-crosslinked hydrogel.

Specifically, after demolding the solidified initial hydrogel, placing the hydrogel under ultraviolet light for photo-crosslinking treatment to obtain the photo-crosslinked hydrogel. The wavelength of ultraviolet irradiation can be 254-365 nm, and the irradiation time can be 10-60 min.

And step S4, sequentially performing soaking and washing and drying treatment on the photocrosslinked hydrogel to obtain the photocrosslinked hydrogel plate.

The photocrosslinked hydrogel is placed in ultrapure water for soaking and washing for 5-10 days to obtain soaked and washed photocrosslinked hydrogel, and then the soaked and washed photocrosslinked hydrogel is dried in a drying mode of natural airing at normal temperature to obtain the photocrosslinked hydrogel plate. The deformation generated by natural airing at normal temperature is small, so that the influence on the performance of the product is small, and the mechanical property of the prepared spinal fusion cage is improved.

Illustratively, during the soaking, fresh ultrapure water is replaced daily to ensure that the soaking is adequate. The normal-temperature natural drying time can be 1-30 days.

And step S5, machining based on the photocrosslinked hydrogel plate to obtain the spinal fusion cage.

The photo-crosslinked hydrogel plate is integrally formed and processed into a spinal fusion device, wherein the spinal fusion device comprises a first fusion surface and a second fusion surface which are opposite to each other, a bone grafting window penetrating through the first fusion surface and the second fusion surface is formed at a position far away from the edge of the spinal fusion device, and a plurality of fixing points matched with a tantalum metal rod are distributed on the periphery of the bone grafting window.

Specifically, the bone grafting window can penetrate through the first fusion surface and the second fusion surface at the central position of the spinal fusion device, and the opening size of the bone grafting window can be set based on actual needs. The fixation points used for being matched with the tantalum metal rod can be uniformly distributed on the periphery of the bone grafting window, and the number of the fixation points can be 3, and the tantalum metal rod can fix the spinal fusion cage between the vertebrae through the fixation points.

The first fusion surface and/or the second fusion surface are/is tooth surfaces, that is, the first fusion surface and/or the second fusion surface may be formed with protruding teeth to increase friction force, prevent displacement or rotation, and improve stability and fusion success rate of the spinal fusion cage.

Because the silk fibroin is taken as natural high molecular protein and is photo-crosslinked with a photoinitiator, the biocompatibility of the silk fibroin and the photoinitiator is good, the problem of self brittleness of the silk fibroin can be improved, the prepared spinal fusion device has good biocompatibility, the mechanical property is closer to that of a vertebra, the biodegradation rate is adjustable, and the preparation process can be suitable for mass production.

The embodiment of the application also provides the spinal fusion cage prepared by the preparation method, and the spinal fusion cage has the advantages of natural main material sources, better mechanical property similar to the spine, good biocompatibility and proper biodegradation rate.

As shown in fig. 2, the spinal fusion device 200 includes a first fusion surface 201 and a second fusion surface 202 opposite to each other, the first fusion surface 201 and the second fusion surface 202 are used for contacting with a lamina of a vertebra, and the first fusion surface 201 and/or the second fusion surface 202 may be tooth surfaces to increase friction force, prevent displacement or rotation, and improve stability and fusion success rate of the spinal fusion device.

The bone grafting window 203 penetrating the first fusion surface 201 and the second fusion surface 202 is formed at a position far away from the edge of the spinal fusion device 200, a plurality of fixing points 204 for being matched with tantalum metal rods are distributed on the periphery of the bone grafting window 203, the number of the fixing points 204 is 3, and the tantalum metal rods fix the spinal fusion device 200 between the vertebrae through the fixing points 204, so that the spinal recovery is guided, and a stress structure is provided.

In order to further illustrate the embodiments of the present application, a method for manufacturing the spinal fusion cage according to the embodiments of the present application will be described in detail with reference to specific embodiments.

Preparation of silk fibroin powder:

(1) And degumming, namely weighing 10g of natural cocoons after removing impurities and shearing, taking 4L of purified water, adding 8.48g of sodium carbonate to dissolve the natural cocoons to obtain 2.12g/L of sodium carbonate solution, heating the solution to 50-121 ℃ in an electric furnace or a steam pot, adding the weighed cocoons into the heated sodium carbonate solution, and continuously heating the solution for 30min to degumm to obtain degummed silk. (2) And (3) rinsing, namely rinsing the degummed silk in 5L of ultrapure water, replacing the same amount of ultrapure water, and rinsing for 4 times at intervals of 20 minutes each time of water replacement to obtain the rinsed degummed silk. (3) And (3) airing, namely taking the rinsed degummed silk, spreading out, spreading, airing for 72 hours at the temperature of 30 ℃ to obtain degummed dry silk. (4) Dissolving silk, namely weighing 70g of degummed dry silk, weighing 280mL of ultrapure water and 273.7g of lithium bromide to prepare 0.977g/mL of lithium bromide solution, dissolving the weighed degummed dry silk in the lithium bromide solution, and placing the solution in an environment of 60 ℃ for 4 hours to obtain the silk fibroin lithium bromide solution. (5) And dialyzing, namely subpackaging the dissolved silk fibroin lithium bromide solution into an 8kDa semipermeable membrane, placing the semipermeable membrane into 5L of ultrapure water, starting magnetic stirring, stirring at a rotating speed of 100r/min, changing water for 1h,2h,4h,16h,20h and 24h, and collecting the dialyzed silk fibroin solution to obtain silk fibroin dialysate. (6) And centrifuging, namely separating the silk fibroin dialyzate into separate parts, placing the separate parts into a centrifuge, setting the centrifugal speed to 12000r/min, the centrifugal temperature to 5 ℃, the centrifugal time to 20min, centrifuging, and taking supernatant to obtain the silk fibroin aqueous solution. (7) Freeze drying, namely, placing the centrifugate in a refrigerator at-80 ℃ for 4 hours, then placing the centrifugate in a vacuum freeze dryer, setting the temperature of the vacuum freeze dryer to-40 ℃, freeze drying for 72 hours, and taking out to obtain the silk fibroin powder.

Example 1

10G of silk fibroin powder was weighed, 60ml of hexafluoroisopropanol was measured and placed in a container for dissolution, and the mouth of the container was sealed with a sealing film to obtain a silk fibroin hexafluoroisopropanol solution.

An appropriate amount of photoinitiator (Irgacure 5929) aqueous solution is prepared according to the concentration of 0.3%, 30ml of photoinitiator aqueous solution is measured and added into the silk fibroin hexafluoroisopropanol solution, and the mixture solution is obtained after uniform stirring.

Pouring the mixed solution into a syringe, pouring the mixed solution into a plate mold, standing at 25 ℃ for 3 days, and demolding to obtain the initial hydrogel.

And (3) carrying out photocrosslinking treatment on the initial hydrogel under ultraviolet light, setting the wavelength to 365nm, and irradiating for 30min to obtain the photocrosslinked hydrogel.

And (3) soaking and washing the photocrosslinked hydrogel with ultrapure water for 7 days, changing fresh ultrapure water every day, taking out the photocrosslinked hydrogel after soaking and washing, and naturally airing the photocrosslinked hydrogel for 20 days at normal temperature to obtain the photocrosslinked hydrogel plate. The photocrosslinked hydrogel sheet was machined into the spinal fusion cage shown in fig. 2.

Example 2

10G of silk fibroin powder was weighed, 80ml of hexafluoroisopropanol was measured and placed in a container for dissolution, and the mouth of the container was sealed with a sealing film to obtain a silk fibroin hexafluoroisopropanol solution.

Example 3

An appropriate amount of aqueous solution of a photoinitiator (Irgacure 5929) was prepared at a concentration of 0.1%, 30ml of the aqueous solution of the photoinitiator was measured and added to the above-mentioned silk fibroin hexafluoroisopropanol solution, and the mixture was stirred uniformly to obtain a mixed solution.

Example 4

And (3) carrying out photocrosslinking treatment on the initial hydrogel under ultraviolet light, setting the wavelength to 365nm, and irradiating for 60min to obtain the photocrosslinked hydrogel.

Comparative example 1

The difference from example 1 is that 30ml of ultrapure water was added to mix with the silk fibroin hexafluoroisopropanol solution, and the resultant was directly washed with a bath and dried without irradiation with ultraviolet light to obtain a plate.

Performance testing

The sheets obtained in example 1 and comparative example 1 were subjected to bending resistance test, respectively, and the test results are shown in tables 1 and 2 below.

Table 1 example 1 bending resistance test results

Table 2 comparative example 1 bending resistance test results

As shown in tables 1 and 2, the material prepared in example 1 has a bending strength of 120-158 MPa, a bending modulus of 8-12 GPa and a deflection of 0.3-0.4 mm, and the material prepared in comparative example 1 has a bending strength of 51-70 MPa, a bending modulus of 3-4 GPa and a deflection of 0.3-0.5 mm. It can be seen that the mechanical properties of example 1 are better than those of comparative example 1 and are closer to the spinal mechanical requirements of the human body.

The foregoing description has fully disclosed specific embodiments of this invention. It should be noted that any modifications to the specific embodiments of the invention may be made by those skilled in the art without departing from the scope of the invention as defined in the appended claims. Accordingly, the scope of the claims of the present invention is not limited to the foregoing detailed description.

Claims

1. A method for preparing a spinal fusion cage, comprising:

Providing a silk fibroin hexafluoroisopropanol solution; wherein the ratio of silk fibroin powder to hexafluoroisopropanol in the silk fibroin hexafluoroisopropanol solution is 1 g: (1-10) mL;

The silk fibroin hexafluoroisopropanol solution and the photoinitiator aqueous solution are uniformly mixed, injected into a mold, and allowed to stand and solidify to obtain an initial hydrogel;

placing the initial hydrogel under ultraviolet light for photocrosslinking to obtain a photocrosslinked hydrogel;

The photo-crosslinked hydrogel is sequentially subjected to soaking, washing, and drying treatments to obtain a photo-crosslinked hydrogel sheet;

The spinal fusion cage is obtained by mechanical processing based on the photo-crosslinked hydrogel sheet.

2. The method for preparing a spinal fusion cage according to claim 1, wherein the step of sequentially washing and drying the photo-crosslinked hydrogel to obtain the photo-crosslinked hydrogel sheet comprises:

placing the photocrosslinked hydrogel in ultrapure water for 5 to 10 days to obtain a washed photocrosslinked hydrogel;

The washed photo-crosslinked hydrogel is dried by air-drying at room temperature to obtain the photo-crosslinked hydrogel sheet.

3. The method for preparing a spinal fusion cage according to claim 2, characterized in that during the soaking and washing process, fresh ultrapure water is replaced every day; and the time for natural drying at room temperature is 1 to 30 days.

4. The method for preparing a spinal fusion cage according to claim 1, wherein the step of mechanically processing the photo-crosslinked hydrogel sheet to obtain the spinal fusion cage comprises:

The photo-cross-linked hydrogel sheet is integrally formed into a spinal fusion cage, wherein the spinal fusion cage includes a first fusion surface and a second fusion surface relative to each other, and a bone graft window is formed at a position away from the edge of the spinal fusion cage, which passes through the first fusion surface and the second fusion surface, and a plurality of fixing points for cooperating with tantalum metal rods are distributed around the periphery of the bone graft window.

5 . The method for preparing a spinal fusion cage according to claim 4 , wherein the first fusion surface and/or the second fusion surface is a tooth surface.

6. The method for preparing a spinal fusion cage according to any one of claims 1 to 5, wherein the step of uniformly mixing the silk fibroin hexafluoroisopropanol solution with a photoinitiator aqueous solution, injecting the mixture into a mold, and allowing the mixture to solidify to obtain an initial hydrogel comprises:

The photoinitiator aqueous solution is added to the silk fibroin hexafluoroisopropanol solution, mixed evenly, injected into a mold, and allowed to stand and solidify at a temperature of 5 to 40° C. for 1 to 5 days to obtain the initial hydrogel.

7. The method for preparing a spinal fusion cage according to claim 6, characterized in that the concentration of the photoinitiator in the photoinitiator aqueous solution is 0.1-0.5%; and the volume ratio of the silk fibroin hexafluoroisopropanol solution to the photoinitiator aqueous solution is 5:4-5:1.

8. The method for preparing a spinal fusion cage according to claim 1, wherein the wavelength of the ultraviolet light is 254-365 nm and the illumination time is 10-60 min.

9. A spinal fusion cage, characterized in that it is prepared by the method for preparing a spinal fusion cage according to any one of claims 1 to 8.

10. The spinal fusion cage according to claim 9, characterized in that the spinal fusion cage comprises a first fusion surface and a second fusion surface relative to each other, a bone grafting window is formed at a position away from the edge of the spinal fusion cage, and passes through the first fusion surface and the second fusion surface, and a plurality of fixing points for cooperating with tantalum metal rods are distributed around the periphery of the bone grafting window; the first fusion surface and/or the second fusion surface are toothed surfaces.