Apparatus and method for preparing a composite hydrogel scaffold

Abstract

The application relates to the field of biomedical technology, in particular to a preparation device and method of a composite hydrogel scaffold, wherein the method comprises the following steps: step one, preparation of an oxidized sodium alginate solution; step two, preparation of concentrated growth factor extraction and freeze-dried powder; step three, preparation of a methacrylic acid gelatin precursor solution; step four, preparation of a composite hydrogel solution: the methacrylic acid gelatin precursor solution and the concentrated growth factor solution are mixed in proportion, the oxidized sodium alginate solution is added, mixing is performed through a composite homogenization mechanism, a hydrogel precursor solution is prepared, light curing is performed, and a composite hydrogel scaffold is obtained; wherein the composite homogenization mechanism is used for simultaneously performing mechanical stirring and ultrasonic crushing operations on the mixed solution. Through the synergistic effect of mechanical stirring and ultrasonic, the distribution difference of central uniformity and edge aggregation is reduced, the uniform dispersion degree of functional factors in the solution is improved, and the distribution uniformity of the biological activity sites of the composite hydrogel scaffold is improved.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, specifically to a device and method for preparing a composite hydrogel scaffold. Background Technology

[0002] Composite hydrogel scaffolds are core functional materials in the interdisciplinary field of biomedicine and materials science. They are constructed using natural polymers (such as gelatin and sodium alginate) or synthetic polymers (such as acrylamide) as substrates, and are made by cross-linking and 3D printing processes, combining inorganic components or bioactive molecules such as hydroxyapatite and nanofibers. They possess both the high water content of hydrogels and a biomimetic porous structure, mimicking the microenvironment of natural human tissues to ensure cell adhesion, migration, and nutrient exchange. Simultaneously, they exhibit adjustable mechanical strength and biodegradation rates, precisely matching the regenerative needs of different tissues. Composite hydrogel scaffolds have wide applications in bone-cartilage repair, skin wound healing, and local drug delivery. They provide temporary mechanical support for damaged tissues and can achieve active repair by loading concentrated growth factors and stem cells, making them a key carrier with significant clinical translational potential in tissue engineering and regenerative medicine.

[0003] In conventional preparation processes, initial mixing of the substrate with nanoparticles, functional agents, and other additives is achieved through stirring. Ultrasonic dispersion technology (with the ultrasonic source typically placed at the center of the mixing container, radiating outwards) further breaks up component agglomerations, promoting uniform diffusion into the hydrogel precursor solution. However, in practice, the composite hydrogel precursor typically possesses a certain viscosity due to the entanglement of polymer chains, creating viscous damping for ultrasonic energy propagation. Sound waves exhibit significant distance attenuation in viscous media; as the distance from the ultrasonic source increases, the ultrasonic energy rapidly decreases. This results in sufficient ultrasonic intensity in the central region of the container to effectively tear apart component agglomerates and achieve uniform dispersion. However, near the inner wall of the container, the ultrasonic energy attenuates below the critical dispersion threshold, failing to generate sufficient mechanical vibration and cavitation effects to break up the agglomerated nanoparticles or functional agents in this area. This localized dispersion failure leads to a distribution difference in the precursor solution, with functional components exhibiting uniformity at the center and agglomeration at the edges. Consequently, the subsequently cross-linked scaffold exhibits uneven mechanical strength and an imbalance in the distribution of bioactive sites. Therefore, this application provides an apparatus and method for preparing a composite hydrogel scaffold to solve the above problems. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a device and method for preparing a composite hydrogel scaffold, which improves the uniform dispersion of functional components throughout the scaffold, thereby enhancing its mechanical and bioactivity properties and improving its tissue repair adaptability.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] On the one hand, a method for preparing a composite hydrogel scaffold is provided, comprising:

[0007] Step 1, Preparation of sodium alginate oxidized solution: Weigh a certain mass of sodium alginate oxidized powder and dissolve it in 20 mL of buffer solution; sonicate under ice bath conditions for 30-40 min to obtain sodium alginate oxidized solution;

[0008] Step 2, Concentrated Growth Factor Extraction and Freeze-Dried Powder Preparation: Obtain a blood sample, then centrifuge the blood sample to extract the concentrated growth factor from the middle part of the blood sample; pre-freeze the concentrated growth factor extract at -80℃ for 12-14 hours, then freeze-dry it for 24-28 hours to obtain the concentrated growth factor freeze-dried product; after freeze-drying, grind the concentrated growth factor freeze-dried product into powder using a grinding mortar to obtain concentrated growth factor freeze-dried powder;

[0009] Step 3, preparation of methacrylic acid gelatin precursor solution: Weigh lyophilized methacrylic acid gelatin powder and lithium phenyl-2,4,6-trimethylbenzoylphosphonate powder and add them to the buffer solution. After mixing evenly, put them into centrifuge tubes and heat the centrifuge tubes in a water bath for 40-50 minutes. The centrifuge tubes are heated by water bath heating. Then filter and sterilize, seal and store in a -20℃ refrigerator in the dark for later use.

[0010] Step 4, preparation of composite hydrogel solution: The methacrylic acid gelatin precursor solution prepared in step 3 and the concentrated growth factor solution are mixed at a mass-volume ratio of 1:1, and then the sodium alginate oxidized solution obtained in step 1 is added. The mixture is then mixed through a composite homogenization mechanism to prepare a hydrogel precursor solution. The hydrogel precursor solution is then dropped into a pre-made mold and photocured under ultraviolet light for 30-35 seconds to obtain a composite hydrogel scaffold.

[0011] The composite homogenization mechanism is used to simultaneously perform mechanical stirring and ultrasonic disruption on the mixed solution formed by the methacrylic gelatin precursor solution, the concentrated growth factor solution, and the oxidized sodium alginate solution.

[0012] Furthermore, in step one, the mass of sodium alginate powder is weighed in the range of 20–80 mg.

[0013] Furthermore, in step four, the concentration of the concentrated growth factor solution is 10% by mass.

[0014] The above scheme has the following beneficial effects: This scheme achieves the synergistic effect of mechanical stirring and ultrasonic disruption through a composite homogenization mechanism, reducing the energy attenuation problem of conventional ultrasonic dispersion in viscous precursors, effectively breaking the viscous damping limitation caused by polymer chain entanglement, reducing the distribution difference of uniformity at the center and agglomeration at the edges, and ensuring that after sodium alginate oxide, gelatin methacrylate and concentrated growth factor (10% mass percentage concentration with excellent compatibility) are mixed at a 1:1 mass-volume ratio, each functional component is uniformly dispersed throughout the entire solution system, laying the foundation for the balance of mechanical properties and biological activity of the subsequent scaffold.

[0015] On the other hand, a device for preparing a composite hydrogel scaffold is provided, including a main housing, a lifting platform, and an ultrasonic amplitude rod. The lifting platform is installed at the bottom of the main housing. A driving cavity is opened at the top of the main housing, and the ultrasonic amplitude rod is disposed in the driving cavity. The output end of the ultrasonic amplitude rod passes through the bottom wall of the driving cavity and corresponds to the center position of the lifting platform. A stirring assembly for mechanically stirring the solution is disposed in the driving cavity, and the ultrasonic amplitude rod passes through the stirring assembly.

[0016] Beneficial effects: In this solution, the stirring assembly and the ultrasonic amplitude rod work together coaxially. The stirring assembly can drive the mixed solution to circulate and break the viscous damping formed by polymer chain entanglement, reducing the edge region dispersion failure caused by the attenuation of ultrasonic energy with distance, and effectively solving the problem of "uniformity in the center and aggregation at the edge". The lifting platform can adjust the relative position of the solution and the ultrasonic amplitude rod to ensure that the ultrasonic action covers the entire solution area. The two work together to achieve uniform dispersion of functional components throughout the entire area, ensuring the uniformity of mechanical strength and the balance of bioactive sites of the subsequent scaffold, while improving the stability and efficiency of the preparation process, and adapting to the high-quality preparation requirements of tissue engineering scaffolds.

[0017] Furthermore, the stirring assembly includes a stirring motor disposed in the drive cavity. The output shaft of the stirring motor is coaxially fixedly connected to a drive gear, which meshes with a driven gear. A rotating cylinder is fixedly connected to the center of the driven gear. The bottom end of the rotating cylinder passes through the bottom wall of the drive cavity and is rotatably engaged with the main housing. A synchronization ring is provided at the bottom end of the rotating cylinder. Several stirring rods are arranged in a ring at the bottom end of the synchronization ring. The bottom ends of the stirring rods are all at the same horizontal plane as the bottom end of the ultrasonic amplitude rod. The ultrasonic amplitude rod passes through the rotating cylinder along the axial direction of the rotating cylinder.

[0018] Beneficial effects: This solution uses gear transmission to drive the rotating cylinder, ensuring stable transmission and controllable speed. This allows the synchronous ring and the ring array of stirring rods to rotate at a uniform speed, reducing localized solution stagnation caused by uneven stirring. The bottom of the stirring rod and the bottom of the ultrasonic amplitude rod are on the same horizontal plane, which can accurately cover the ultrasonic action area. The ring stirring pushes the solution from the edge to the center, breaking the viscous damping of polymer chain entanglement. Combined with ultrasonic crushing, this achieves full-area solution circulation and dispersion, solving the problem of uniformity at the center and agglomeration at the edge. At the same time, the design of the ultrasonic amplitude rod passing through the axis of the rotating cylinder avoids interference between the two movements, ensuring efficient and coordinated operation of mechanical stirring and ultrasonic crushing, further improving the uniformity of functional component dispersion.

[0019] Furthermore, all stirring rods are inclined, and the angle between the axis of the stirring rod and the axis of the synchronization ring is 15 to 25°.

[0020] Beneficial effects: The stirring rod is tilted at 15-25°, which increases the contact area with the mixed solution. When rotating, it can form an up-and-down convection circulation, continuously transporting the solution retained at the edge of the container to the central ultrasonic action zone, reducing component agglomeration in the edge area due to insufficient ultrasonic energy.

[0021] Furthermore, the surface of the stirring rod is provided with several metal plates, and the natural frequency of the metal plates is the same as the fixed frequency of the ultrasonic amplitude rod output.

[0022] Beneficial effects: Under resonant conditions, the metal sheet generates stronger local mechanical vibrations, effectively breaking down the viscous network formed by polymer chain entanglement. Through the resonance effect, the ultrasonic action range extends from the center to the edge of the container, solving the dispersion problem of uniformity at the center and agglomeration at the edge. Secondly, the high-frequency vibrations generated by resonance can enhance the cavitation effect, causing the periodic rupture of microbubbles in the mixed solution. The released impact force can further break up the agglomerates of nanoparticles and concentrated growth factors, improving the dispersion uniformity of functional components. At the same time, the coordinated movement of the metal sheet and the stirring rod can form a more complex flow field in the solution, reducing the uneven dispersion caused by dead zones in local areas, ultimately ensuring the uniformity of components throughout the hydrogel precursor solution.

[0023] Furthermore, each stirring rod consists of a main rod and a secondary rod, with the secondary rods fixedly connected to the synchronization ring; the main rods are coaxially rotatably connected to their corresponding secondary rods.

[0024] Beneficial effects: The stirring rod adopts a combination structure in which the main rod and the auxiliary rod rotate coaxially. The auxiliary rod is fixed to the synchronous ring to realize revolution, while the main rod rotates autonomously relative to the auxiliary rod, forming a dual motion mode of revolution and rotation. The revolution drives the stirring rod to circulate around the ultrasonic amplitude rod, and the rotation enables the metal plate on the surface of the main rod to quickly sweep across the entire solution area, greatly shortening the action interval of the metal plate in different areas, allowing the resonance effect to evenly cover all solution areas from the center to the edge, and reducing the aggregation caused by insufficient local ultrasonic energy.

[0025] Furthermore, each main rod is equipped with an exchange chamber, and each auxiliary rod passes through the exchange chamber. Several fan blades are welded to the inner wall of each exchange chamber. Each auxiliary rod is equipped with two exchange channels, with the two ends of the exchange channels extending into the exchange chamber and the surface of the rotating cylinder, respectively. The openings of the two exchange channels in the exchange chamber are located close to the upper and lower ends of the exchange chamber, respectively.

[0026] Beneficial effects: The heat generated by stirring and ultrasound is promptly removed by the gas flow in the exchange chamber, reducing the damage to the activity of concentrated growth factors and the stability of polymer materials caused by localized heating of the solution.

[0027] Furthermore, a transparent cover is hinged to one side of the main housing.

[0028] Beneficial effects: The transparent cover allows for real-time observation of internal stirring and sonication, facilitating control of the preparation process; the hinged design ensures easy opening and closing, prevents dust and solution splashes, protects the operating environment and equipment, and guarantees smooth preparation.

[0029] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] Figure 1 This is a schematic flowchart illustrating an embodiment of the method for preparing the composite hydrogel scaffold of the present invention;

[0031] Figure 2 This is an overall isometric view of an embodiment of the composite hydrogel scaffold preparation device of the present invention;

[0032] Figure 3 This is an isometric view of the stirring assembly in an embodiment of the composite hydrogel scaffold preparation device of the present invention;

[0033] Figure 4 for Figure 3 Enlarged view of section A in the middle;

[0034] Figure 5 A cross-sectional view of the stirring rod in an embodiment of the composite hydrogel scaffold preparation device of the present invention;

[0035] Figure 6 for Figure 5 Enlarged view of section B.

[0036] The reference numerals in the accompanying drawings of the instruction manual include: 1. Main housing; 2. Lifting platform; 3. Rotating cylinder; 4. Synchronization ring; 5. Main rod; 501. Metal plate; 502. Exchange chamber; 503. Secondary rod; 504. Exchange channel; 505. Fan blade; 6. Driven gear; 601. Driven gear; 7. Ultrasonic amplitude rod. Detailed Implementation

[0037] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The following detailed description illustrates the specific implementation method:

[0041] Example 1:

[0042] like Figure 2 and Figure 3 As shown, a composite hydrogel scaffold preparation device includes a main box 1, a lifting platform 2 and an ultrasonic amplitude rod 7. A transparent cover is hinged to one side of the main box 1, and the lifting platform 2 is installed at the bottom of the main box 1. A driving cavity is opened at the top of the main box 1, and the ultrasonic amplitude rod 7 is set in the driving cavity. The output end of the ultrasonic amplitude rod 7 passes through the bottom wall of the driving cavity and corresponds to the center position of the lifting platform 2.

[0043] A stirring motor is screwed into the drive cavity. The output shaft of the stirring motor is coaxially keyed to a drive gear 601, which meshes with a driven gear 6. A rotating cylinder 3 is integrally formed at the center of the driven gear 6. The bottom end of the rotating cylinder 3 passes through the bottom wall of the drive cavity and rotatably engages with the main housing 1. A synchronization ring 4 is integrally formed at the bottom end of the rotating cylinder 3. Several stirring rods are arranged in a ring at the bottom end of the synchronization ring 4. The bottom ends of all stirring rods are at the same horizontal plane as the bottom end of the ultrasonic amplitude rod 7; and the ultrasonic amplitude rod 7 passes through the rotating cylinder 3 along its axial direction. The stirring rods are all inclined, and the angle between the axis of the stirring rod and the axis of the synchronization ring 4 is 15–25°. Figure 4 As shown, the surface of the stirring rod is provided with several metal plates 501, and the natural frequency of the metal plates 501 is the same as the fixed frequency output by the ultrasonic amplitude rod 7. Secondly, combined with... Figure 5 As shown, each stirring rod consists of a main rod 5 and a secondary rod 503, with the secondary rods 503 fixedly connected to the synchronization ring 4. The main rods 5 and their corresponding secondary rods 503 are coaxially rotatably connected, enabling revolution and rotation during stirring. Furthermore, a silicone cap can be fitted around the surface of the rotating cylinder 3 to cover the top of the container during stirring / ultrasonication, preventing splashing of the mixed liquid.

[0044] The specific implementation process is as follows: First, open the transparent cover on one side of the main chamber 1. Place the container (e.g., a beaker) containing the mixed solution of GelMA, CGF, and OSA (preparation steps are described in Example 3) stably on the lifting platform 2. Then, adjust the height of the lifting platform 2 so that the bottom end of the ultrasonic amplitude rod 7 and the bottom end of the stirring rod are both immersed in the solution and at the same level, ensuring that the ultrasonic action and stirring range completely cover the solution system. Cover the top of the container with a silicone cap. Close the transparent cover to prevent solution splashing and environmental pollution, and to allow full monitoring of the internal reaction state through the transparent material.

[0045] Then, the stirring motor is restarted. The output shaft of the stirring motor drives the drive gear 601 to rotate, which in turn drives the driven gear 6 and the integrally formed rotating cylinder 3 to rotate synchronously. The synchronous ring 4 at the bottom of the rotating cylinder 3 then drives the ring array of stirring rods to revolve. Because the stirring rods and the axis of the synchronous ring 4 are inclined at 15-25°, a composite flow field of axial and radial directions is formed during the revolution, which promotes the viscous solution at the edge of the container to circulate towards the center, breaking the viscous damping formed by the entanglement of polymer chains. At the same time, the coaxial rotation design of the main rod 5 and the auxiliary rod 503 enables the stirring rods to rotate on their own axis based on the revolution (based on the friction between the main rod 5 and the mixed solution), further enhancing the turbulence effect of the solution and reducing the dead zone of stirring.

[0046] Simultaneously, the ultrasonic amplitude bar 7 is activated, and the fixed-frequency ultrasonic energy output by the ultrasonic amplitude bar 7 is transmitted axially to the mixed solution of GelMA, CGF, and OSA (radial transmission). The metal plate 501 on the surface of the stirring rod, due to its inherent vibration frequency being consistent with the ultrasonic frequency, quickly generates a resonance effect. In the resonant state, the metal plate 501, through an energy absorption-amplification-re-release process, converts the absorbed ultrasonic energy into its own high-frequency, high-amplitude vibration, thereby constructing multiple secondary ultrasonic sources at the edge of the container and in areas far from the center, compensating for the attenuation gap of the central ultrasonic radiation (when conventional ultrasound is radiated in viscous hydrogel precursors, energy is continuously lost due to the obstruction of polymer chain entanglement, resulting in the ultrasonic intensity in the edge region being lower than the agglomerate breakage threshold). At the same time, the resonance of the metal plate 501 also generates corresponding local strong vibrations, thereby enhancing the cavitation effect. Even in the edge region far from the ultrasonic amplitude bar 7, a sufficiently strong bubble rupture impact force can be formed to efficiently tear apart the aggregated nanoparticles or growth factor agglomerates. In addition, the revolution and rotation of the stirring rod drive the resonant metal plate 501 to circulate and sweep through the entire solution system, so that each edge region can be covered by the resonant enhanced ultrasonic effect of the metal plate 501, thereby reducing the difference in ultrasonic effect between the center and the edge, and achieving uniform and efficient dispersion of aggregates throughout the container (including the edge positions far from the center).

[0047] Throughout the process, the solution state can be clearly observed through the transparent cover. After the solution is evenly dispersed (about 15 to 20 minutes), the sonication and stirring are stopped. The prepared OSA / CGF / GelMA hydrogel precursor solution is then dropped into a preset mold and cured by irradiation with ultraviolet light for 30 to 35 seconds. After curing, the corresponding composite hydrogel scaffold is obtained.

[0048] Example 2:

[0049] The difference from Example 1 lies in the fact that, in Example 1, the synergistic effect of the stirring rod's revolution and rotation, along with the resonance of the metal sheet 501, effectively solved the dispersion problem of functional components in the solution exhibiting "uniformity at the center and aggregation at the edges." However, the relative motion between the stirring and the solution, as well as the resonance of the metal sheet 501, all generate frictional heat. In particular, the high-frequency resonance of the metal sheet 501 can cause a local temperature increase. Since many growth factors and other functional factors are heat-sensitive substances, continuous heat accumulation can easily lead to a decrease in their biological activity. Therefore, if... Figure 5 and Figure 6 As shown, this scheme also provides an exchange chamber 502 inside the main rod 5, and the auxiliary rods 503 all pass through the exchange chamber 502. Several fan blades 505 are welded to the inner wall of the exchange chamber 502. Two exchange channels 504 are provided inside the auxiliary rods 503. The two ends of the exchange channels 504 extend to the inside of the exchange chamber 502 and the surface of the rotating cylinder 3, respectively. The openings of the two exchange channels 504 in the exchange chamber 502 are close to the upper and lower ends of the exchange chamber 502, respectively.

[0050] The specific implementation process is as follows: When the main rod 5 revolves and rotates, the relative friction between the stirring and the solution will generate heat. Especially when the metal sheet 501 resonates, the resonance area is prone to local high temperature, which threatens the biological activity of heat-sensitive growth factors. At this time, the rotation of the main rod 5 drives the fan blades 505 in the exchange chamber 502 to rotate synchronously. The fan blades 505 are designed according to a preset angle. When rotating, they generate directional airflow power, which pushes the gas in the exchange chamber 502 to flow towards the exchange channel 504 near the bottom of the main rod 5 and out through the exchange channel 504 to the surface of the rotating cylinder 3, and then diffuses into the inner cavity of the main box 1. Meanwhile, another exchange channel 504 near the top of the main rod 5 introduces external gas in real time to replenish it, forming a balanced gas pressure cycle of inflow and outflow. Because the openings of the two exchange channels 504 in the exchange chamber 502 are close to the upper and lower ends respectively, the gas flow path covers the entire exchange chamber 502, realizing efficient heat exchange between the high temperature gas in the exchange chamber 502 and the ambient temperature gas. The heat generated by stirring and resonance is transferred to the exchange chamber 502 through the wall of the main rod 5 and is quickly carried away by the flowing gas, reducing the local accumulation of heat in the solution and keeping the solution temperature within a safe range where the growth factor activity is stable.

[0051] Example 3:

[0052] like Figure 1 As shown, a method for preparing a composite hydrogel scaffold includes the following steps:

[0053] Step 1, Preparation of Oxidized Sodium Alginate (OSA) Solution: Weigh 20-80 mg of OSA powder and dissolve it in 20 mL of phosphate buffered saline (PBS); sonicate in an ice bath for 30-40 min to obtain OSA solution;

[0054] Step 2, Concentrated Growth Factor (CGF) Extraction and Freeze-Dried Powder Preparation: Obtain a blood sample, then centrifuge the blood sample to extract CGF from the middle part of the blood sample; pre-freeze the CGF extract at -80℃ for 12-14 hours, then freeze-dry it for 24-28 hours to obtain freeze-dried CGF; after freeze-drying, grind the freeze-dried CGF into powder using a grinding bowl to obtain freeze-dried CGF powder;

[0055] Step 3, preparation of gelatin methacrylate (GelMA) precursor solution: Weigh 1g of lyophilized GelMA powder and 0.05g of lithium phenyl-2,4,6-trimethylbenzoylphosphonate (LAP) powder and add them to 15mL of PBS buffer. Mix well and transfer to centrifuge tubes. Heat the centrifuge tubes in a water bath for 40-50 minutes using a water-indirect heating method (e.g., wrapping them in aluminum foil for heating). Then filter and sterilize. Seal and store at -20℃ in the dark for later use.

[0056] Step 4, preparation of composite hydrogel solution: The GelMA solution and CGF solution (mass percentage concentration of 10%) prepared in Step 3 are mixed at a mass-volume ratio of 1:1, and then the OSA solution obtained in Step 1 is added to obtain an OSA / CGF / GelMA mixed solution. The container containing the OSA / CGF / GelMA mixed solution is placed in the center of the lifting platform 2, and the lifting platform 2 is raised to immerse the ultrasonic amplitude rod 7 and the stirring rod into the solution. Then, the stirring motor and the ultrasonic amplitude rod 7 are started to perform ultrasonic / stirring on the OSA / CGF / GelMA mixed solution, thereby causing the main rod 5, metal plate 501 and fan blade 505 in the stirring rod to produce corresponding movements (the specific movement process is as described in Examples 1 and 2, and will not be repeated here). After the mixing is completed, a hydrogel precursor solution is obtained. The hydrogel precursor solution is then dropped into a pre-made mold and photocured with ultraviolet light for 30-35 seconds to obtain a composite hydrogel scaffold.

[0057] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a composite hydrogel scaffold, characterized in that, include: Step 1, Preparation of sodium oxidized alginate solution: Weigh a certain mass of sodium oxidized alginate powder and dissolve it in 20 mL of buffer solution; The sodium alginate solution was obtained by ultrasonic treatment under ice bath conditions for 30–40 min. Step 2, Concentrated Growth Factor Extraction and Freeze-Dried Powder Preparation: Obtain a blood sample, then centrifuge the blood sample to extract the concentrated growth factor from the middle part of the blood sample; pre-freeze the concentrated growth factor extract at -80℃ for 12-14 hours, then freeze-dry it for 24-28 hours to obtain the concentrated growth factor freeze-dried product; after freeze-drying, grind the concentrated growth factor freeze-dried product into powder using a grinding mortar to obtain concentrated growth factor freeze-dried powder; Step 3, preparation of methacrylic acid gelatin precursor solution: Weigh lyophilized methacrylic acid gelatin powder and lithium phenyl-2,4,6-trimethylbenzoylphosphonate powder and add them to the buffer solution. After mixing evenly, put them into centrifuge tubes and heat the centrifuge tubes in a water bath for 40-50 minutes. The centrifuge tubes are heated by water bath heating. Then filter and sterilize, seal and store in a -20℃ refrigerator in the dark for later use. Step 4, preparation of composite hydrogel solution: The methacrylic acid gelatin precursor solution prepared in step 3 and the concentrated growth factor solution are mixed at a mass-volume ratio of 1:1, and then the sodium alginate oxidized solution obtained in step 1 is added. The mixture is then mixed through a composite homogenization mechanism to prepare a hydrogel precursor solution. The hydrogel precursor solution is then dropped into a pre-made mold and photocured under ultraviolet light for 30-35 seconds to obtain a composite hydrogel scaffold. The composite homogenization mechanism is used to simultaneously perform mechanical stirring and ultrasonic disruption on the mixed solution formed by the methacrylic gelatin precursor solution, the concentrated growth factor solution, and the oxidized sodium alginate solution.

2. The method for preparing the composite hydrogel scaffold according to claim 1, characterized in that, In step one, the mass of sodium alginate powder is weighed in the range of 20–80 mg.

3. The method for preparing the composite hydrogel scaffold according to claim 2, characterized in that, In step four, the concentration of the concentrated growth factor solution is 10% by mass.

4. An apparatus for preparing a composite hydrogel scaffold, comprising the composite homogenization mechanism according to claim 1, characterized in that, It includes a main housing (1), a lifting platform (2) and an ultrasonic amplitude rod (7). The lifting platform (2) is installed at the bottom of the main housing (1). The top of the main housing (1) has a drive cavity, and the ultrasonic amplitude rod (7) is set in the drive cavity. The output end of the ultrasonic amplitude rod (7) passes through the bottom wall of the drive cavity and corresponds to the center position of the lifting platform (2). The drive cavity is equipped with a stirring assembly for mechanically stirring the solution, and the ultrasonic amplitude rod (7) passes through the stirring assembly.

5. The apparatus for preparing the composite hydrogel scaffold according to claim 4, characterized in that, The stirring assembly includes a stirring motor installed in the drive chamber. The output shaft of the stirring motor is coaxially fixedly connected to a drive gear (601). The drive gear (601) meshes with a driven gear (6). A rotating cylinder (3) is fixedly connected to the center of the driven gear (6). The bottom end of the rotating cylinder (3) passes through the bottom wall of the drive chamber and rotates with the main housing (1). A synchronization ring (4) is provided at the bottom end of the rotating cylinder (3). Several stirring rods are arranged in a ring at the bottom end of the synchronization ring (4). The bottom ends of the stirring rods are all at the same horizontal plane as the bottom end of the ultrasonic amplitude rod (7). The ultrasonic amplitude rod (7) passes through the rotating cylinder (3) along the axial direction of the rotating cylinder (3).

6. The apparatus for preparing the composite hydrogel scaffold according to claim 5, characterized in that, All stirring rods are inclined, and the angle between the axis of the stirring rod and the axis of the synchronization ring (4) is 15-25°.

7. The apparatus for preparing the composite hydrogel scaffold according to claim 6, characterized in that, The surface of the stirring rod is provided with several metal plates (501), and the natural frequency of the metal plates (501) is the same as the fixed frequency output by the ultrasonic amplitude rod (7).

8. The apparatus for preparing the composite hydrogel scaffold according to claim 7, characterized in that, The stirring rods are all composed of a main rod (5) and a secondary rod (503). The secondary rods (503) are all fixedly connected to the synchronization ring (4); the main rods (5) are all coaxially rotatably connected to the corresponding secondary rods (503).

9. The apparatus for preparing the composite hydrogel scaffold according to claim 8, characterized in that, The main rod (5) is provided with an exchange chamber (502) inside, and the auxiliary rod (503) passes through the exchange chamber (502). Several fan blades (505) are welded to the inner wall of the exchange chamber (502). The auxiliary rod (503) is provided with two exchange channels (504) inside. The two ends of the exchange channels (504) extend to the exchange chamber (502) and the surface of the rotating cylinder (3) respectively. The openings of the two exchange channels (504) in the exchange chamber (502) are close to the upper and lower ends of the exchange chamber (502) respectively.

10. The apparatus for preparing the composite hydrogel scaffold according to claim 9, characterized in that, A transparent cover is hinged to one side of the main body (1).

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