Bone implant imitating lantern unfolding and locking and with self-energized coating and preparation method of bone implant

Abstract

The invention discloses a bone implant imitating lantern unfolding locking and a self-energized coating and a preparation method of the bone implant, and belongs to the field of medical implants.The bone implant is designed by imitating a contraction structure of a lantern, is in a slender state at the temperature lower than the martensite phase transformation temperature and is in an open lantern shape at the temperature higher than the austenite phase transformation temperature, and the self-energized coating is in a self-energized state. The superelasticity and the shape memory effect of the memory alloy are utilized, self-adaptive expansion and planar locking are achieved in a medullary cavity, and the instant three-dimensional mechanical stability superior to that of a traditional bone fracture plate and an intramedullary nail is provided. The surface of the bone implant is coated with a functional gradient coating, so that in-vivo biochemical energy and mechanical energy can be actively captured, growth factor release and cell behaviors can be intelligently and sequentially regulated and controlled according to the in-vivo biochemical energy and mechanical energy, and in-vivo continuous glucose metabolism and physiological activities are directly converted into electric energy and control signals for driving bone healing; and energy self-sufficiency and logic independence are realized.

Description

Technical Field

[0001] This invention relates to the field of medical implant technology, and more specifically, to a bone implant with a lantern-like unfolding and locking mechanism and a self-powered coating, and its preparation method. Background Technology

[0002] Clinical repair of large bone defects faces two major challenges: first, achieving long-term stable fixation of the implant; and second, promoting rapid and reliable biointegration between the host bone and the implant.

[0003] In terms of fixation methods, traditional techniques mainly rely on plate screws or long intramedullary nails for bridging fixation. These methods have drawbacks, including significant surgical trauma, the need for extensive dissection of soft tissue and periosteum, damage to bone blood supply and fixation stability, heavy reliance on the holding force of screws in the cortical bone, and poor efficacy in patients with osteoporosis or short bone stumps. Furthermore, rigid fixation devices can cause stress shielding, hindering bone healing and remodeling. Some existing deployable scaffold designs are unsuitable for bone fixation scenarios subject to complex multidimensional mechanical loads.

[0004] Current mainstream approaches to promoting osseointegration rely on bio-inert porous structures (such as porous tantalum and 3D-printed porous titanium) or simple bio-coatings (such as hydroxyapatite) on the implant surface. These are all passive designs, merely providing the physical space or conductive interface for bone ingrowth, and cannot actively guide or accelerate the healing process. Although some studies have attempted to load growth factors (such as BMP-2) onto implants, they often face problems such as burst release, uncontrollable timing, the need for external device activation, or reliance on unsustainable battery power. Existing technologies lack an energy supply and regulation mechanism that can autonomously, continuously, and intelligently respond to physiological signals within the body, resulting in a slow and uncertain osseointegration process, especially with a high failure rate in cases of poor blood supply or weak patient self-repair capabilities. Summary of the Invention

[0005] To address the technical problems of unstable mechanical properties and unsustainable energy supply in existing bone implants, this invention provides a bone implant with a lantern-like unfolding and locking mechanism and a self-powered coating, as well as its preparation method. This invention enables immediate, reliable, and biomechanical fixation of the bone implant through a minimally invasive approach. Furthermore, the bone implant itself constructs an intelligent bio-interface that requires no external power supply, can sense the environment, and automatically executes repair procedures. This simultaneously overcomes the two major challenges of mechanical stability and biointegration, significantly improving the repair effect and clinical reliability of large bone defects.

[0006] The specific plan is as follows: The first aspect of this invention provides a bone implant with a lantern-like unfolding and locking mechanism and a self-powered coating, comprising: Two symmetrically arranged bases are fixedly connected to the human skeleton. The screw has two ends connected to two bases respectively, and the screw can rotate around its own axis. The upper and lower halves of the screw have reverse threads. Two nuts are symmetrically arranged, and the two nuts are respectively fitted onto the upper half thread and the lower half thread of the screw. Multiple support arms are evenly distributed around the screw along the circumference. Each support arm is fixed to two nuts at both ends. The support arms are made of shape memory alloy strips. They have a first memory shape below the martensitic transformation temperature, which is a straight strip close to the screw. They have a second memory shape above the austenitic transformation temperature, which is an arc shape that arches away from the screw. The surface of the bone implant has a functionally gradient coating.

[0007] Furthermore, the functionally graded coating comprises, from the inside out, a piezoelectric fiber substrate layer, an enzyme kinetic response active layer, and an electro-responsive factor release surface layer.

[0008] Furthermore, the second memory shape of the support arm is an arc shape that is 10% to 20% larger than the diameter of the target host's bone marrow cavity.

[0009] Furthermore, the base is a bearing, with its outer ring fixed to human bone and its inner ring fixed to the end of the screw.

[0010] Furthermore, the bone implant also includes two wrench parts, which are symmetrically fixed at both ends of the screw and located between the nut and the base.

[0011] Furthermore, the bone implant also includes bolts that pass through the support arm and lock onto the sidewall of the nut.

[0012] A second aspect of the present invention provides a method for preparing a bone implant with lantern-like deployment locking and a self-energizing coating as described in the first aspect, comprising the following steps: S1, modeled after the shrinking structure of a lantern, is used for the design and construction of bone implants; S2, constrain the support arm of the bone implant into a first memory shape and cool it, so that the support arm transforms into a flexible martensitic phase; S3 involves constructing a functional gradient coating on the surface of the bone implant to complete the preparation of the bone implant.

[0013] Furthermore, the functional gradient coating in step S3 comprises three layers, from the inside out: a piezoelectric fiber substrate layer, an enzyme kinetic response active layer, and an electro-responsive factor release surface layer. The piezoelectric fiber substrate layer is prepared as follows: Poly-L-lactic acid particles were dissolved in a mixed solvent of chloroform and N,N-dimethylformamide to prepare a poly-L-lactic acid solution with a concentration of 8-12 wt%. The volume ratio of the mixed solvent was chloroform:N,N-dimethylformamide = 7:3. Barium titanate nanoparticles were added to the above poly-L-lactic acid solution, with the amount added being 15-25 wt% of the mass of the poly-L-lactic acid particles; The mixture formed after adding barium titanate nanoparticles was stirred and then ultrasonically treated to ensure that the barium titanate nanoparticles were uniformly dispersed and formed a stable electrospinning precursor solution. Electrospinning precursor solution is injected into an injection pump, the bone implant is fixed to the grounding receiver, and the electrospinning precursor solution is sprayed onto all surfaces of the bone implant to obtain a piezoelectric fiber substrate layer.

[0014] Furthermore, the preparation method of the enzyme kinetic response active layer is as follows: Mesoporous carbon nanospheres were dispersed in PBS solution at pH 7.4. Glucose oxidase and horseradish peroxidase were added to make the final concentrations of glucose oxidase and horseradish peroxidase 5 mg / mL and 2 mg / mL, respectively. The mixture was slowly shaken and incubated at 4 °C to allow glucose oxidase and horseradish peroxidase to be fully adsorbed into the mesopores and surface of the mesoporous carbon nanospheres. Add glutaraldehyde, crosslink, and wash with PBS solution by centrifugation to redisperse the mesoporous carbon nanospheres in PBS solution to obtain an enzyme-carbon nanosphere complex dispersion with a concentration adjusted to 20 mg / mL; Dissolve sodium alginate in PBS solution to prepare a 2.0 wt% solution, which is solution A. Dissolve gelatin in PBS solution to prepare a 4.0 wt% solution, cool to room temperature, and obtain solution B; Mix solution A and solution B at a volume ratio of 1:1 to obtain solution AB. Add the enzyme-carbon sphere complex dispersion at a ratio of 10% of the total volume to solution AB and mix gently. The bone implant is placed in the spraying chamber, and the AB mixture is evenly sprayed onto the surface of the bone implant that has been covered with a piezoelectric fiber substrate. At the same time as spraying, calcium chloride solution and glutaraldehyde vapor are atomized and introduced into the spraying chamber. After the spraying is completed, an enzyme kinetic response active layer is obtained.

[0015] Furthermore, the method for preparing the electroresponsive factor release surface layer is as follows: Chitosan was dissolved in 1% acetic acid solution to prepare a 1.5 wt% solution. Polypyrrole nanowires, with a mass of 30% of the chitosan mass, were added, ultrasonically dispersed, and the pH was adjusted to 6.0 to obtain a conductive prepolymer solution. VEGF and BMP-2 were slowly added to the conductive prepolymer solution sequentially, with the total volume of VEGF and BMP-2 accounting for 5% of the conductive prepolymer solution. The bone implant, with its surface covered by a piezoelectric fiber base layer and an enzyme kinetic response active layer, was vertically immersed in the above mixture and left for 60 seconds. Then, it was pulled out of the liquid at the same speed to form a uniform liquid film on the surface. The bone implant was then immediately placed in saturated sodium tripolyphosphate vapor to allow chitosan to undergo ionic cross-linking and gelation. After air drying, a solid composite gel film was formed, and an electroresponsive factor release surface layer was obtained.

[0016] The beneficial effects of this invention are as follows: The lantern-shaped bone implant of the present invention utilizes the superelasticity and shape memory effect of shape memory alloy to achieve adaptive expansion and planar locking in the medullary cavity, providing instant three-dimensional mechanical stability that surpasses traditional bone plates and intramedullary nails. Its matching self-powered functional gradient coating can actively capture biochemical energy and mechanical energy in the body, and thereby intelligently and temporally regulate the release of growth factors and cell behavior. The functionally graded coating of this invention directly converts the continuous glucose metabolism and physiological activities in the body into electrical energy and control signals that drive bone healing through an enzyme-piezoelectric coupling mechanism, thus achieving energy self-sufficiency and logical autonomy. The excellent initial stability of this invention allows patients to undergo safe rehabilitation training in the early stages, which in turn feeds back and enhances the osteogenic therapeutic signal of the functional gradient coating through the piezoelectric effect, forming a positive cycle of more activity and more healing. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the bone implant of the present invention.

[0018] Figure 2 This is a schematic diagram of the shape memory recovery of the bone implant of the present invention.

[0019] Figure 3 This is a schematic diagram showing the morphology of the bone implant of the present invention after implantation.

[0020] The reference numerals in the appendix of this invention are as follows: 1. Bone implant; 11. Base; 12. Wrench; 13. Screw; 14. Nut; 15. Bolt; 16. Support arm. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Please see Figure 1This embodiment discloses a bone implant 1 with a lantern-like unfolding locking and self-powered coating, including a base 11, a screw 13, a nut 14, a support arm 16, a bolt 15, and a wrench 12.

[0023] There are two bases 11, which are symmetrically arranged. Preferably, the base 11 is a bearing. When the bone implant 1 is implanted into the human body, the outer ring of the bearing is fixed to the human bone, and the inner ring of the bearing can rotate freely.

[0024] There is one screw 13, whose core function is to provide axial guidance for deployment. The two ends of the screw 13 are fixed to the inner rings of two bearings, so the screw 13 can rotate synchronously with the rotation of the inner rings of the bearings. The screw 13 is made of medical-grade titanium alloy, hollow inside, and has precision threads on the surface. The threads are divided into two sections, with the upper and lower sections being reverse threads.

[0025] There are two nuts 14, which are respectively fitted onto the upper and lower threads of the screw 13. When the screw 13 rotates, the nuts 14 will move along the screw 13. The nuts 14 are hexagonal nuts 14.

[0026] There are six support arms 16 in total, evenly distributed around the screw 13 along the circumference. Each of the six support arms 16 corresponds to one of the six sides of the nut 14, and each end of the support arm 16 is fixedly connected to two nuts 14. In this embodiment, the support arms 16 are fixedly connected to the nuts 14 by bolts 15. A threaded hole is provided at the center of each side of the nut 14. This threaded hole does not penetrate the side wall of the nut 14. After the bolt 15 passes through the support arm 16, it locks into the threaded hole on the side wall of the nut 14, thereby fixing the support arm 16 to the nut 14.

[0027] The support arm 16 is made of shape memory alloy strip. Below the martensitic transformation temperature, it exhibits a first memory shape, which is a straight strip tightly attached to the screw 13, giving the entire bone implant 1 a slender shape, facilitating implantation. Above the austenitic transformation temperature, it exhibits a second memory shape, which is an arc shape arched away from the screw 13. Preferably, the support arm 16 is made of medical-grade nickel-titanium alloy (Nitinol) with excellent superelasticity and shape memory properties, preferably nickel-rich, such as NiTi-01. Its austenitic transformation completion temperature (Af) is set between 28°C and 32°C, slightly lower than the core body temperature (≈37°C). This ensures that the material remains in a robust austenitic state within the body, exhibiting superelasticity.

[0028] The second memory shape of the support arm 16 (i.e. when the support arm 16 is fully extended) is an arc with a curvature that is 10% to 20% larger than the diameter of the target host's bone marrow cavity. This arc is an involute, so when the support arm 16 is fully extended, it will apply radial compressive stress to the inner wall of the bone cortex.

[0029] There are two wrench parts 12. The external shape of the wrench parts 12 is the same as that of the hexagonal nut. The wrench parts 12 are used to facilitate wrench operation. The screw 13 is driven to rotate by the action of the wrench on the wrench parts 12. The two wrench parts 12 are symmetrically fixed at both ends of the screw 13, and the wrench parts 12 are located between the nut 14 and the base 11.

[0030] Please see Figure 2 and Figure 3 The locking process of the bone implant 1 of the present invention is as follows: Preoperatively, the entire bone implant 1 was cooled in sterile saline solution at 0–10°C to allow the support arm 16 to completely transform into a flexible martensitic phase. In this state, the support arm 16 was constrained into a straight strip shape (i.e., the first memory shape) using an installation tool. Figure 2 As shown in the left image, the bone implant 1 is at its smallest diameter at this point, allowing it to pass through a tiny incision and medullary cavity. The bone implant 1 is then inserted into a delivery sheath and pushed to the bone defect area. Upon reaching the predetermined position, the delivery sheath is retracted. Due to the strong superelasticity of the nickel-titanium alloy, the martensitic support arm 16 immediately attempts to restore its pre-constraint intermediate shape (i.e., an incompletely unfolded arc). This restoring force drives the support arm 16 to automatically and gently unfold initially until it contacts the endosteal membrane, achieving initial alignment and stability. It is worth noting that this process requires no external mechanical drive.

[0031] After implantation, blood and tissue fluid rapidly raise the temperature of the bone implant 1 to 37°C. When the temperature exceeds the austenitic phase transformation initiation temperature (As, approximately 20–25°C) and eventually exceeds Af (28–32°C), the support arm 16, especially the distal self-locking section (i.e., the end connected to the nut 14), begins to recover its inherent, larger curvature second memory shape, such as… Figure 2 As shown in the right-hand figure, because the diameter of the second shape memory is larger than the actual anatomical diameter of the medullary cavity, the recovery movement of the self-locking segment is mechanically restricted by the inner wall of the bone cortex. The enormous restoring force generated by the shape memory effect is converted into a continuous, radially outward, dynamic compressive stress acting on the inner wall of the bone cortex. The magnitude of this force is determined by the phase transformation driving force of the shape memory alloy and the constraint reaction force of the bone wall, forming an adaptive mechanical equilibrium. The involute curved surface design of the support arm 16 ensures maximum surface contact with the irregular endosteal membrane, uniformly distributing the pressure.

[0032] Since the shape memory deformation of each support arm 16 is inconsistent, it needs to be adjusted by external force to provide an additional, small axial displacement to the support arm 16. To do this, the screw 13 is slightly tightened (e.g., rotated 1-2 turns). By using a wrench to rotate the wrench part 12, the screw 13 is rotated synchronously, which in turn causes the two nuts 14 to move towards each other on the screw 13 until the geometric configuration of the support arm 16 reaches the optimal, stabilizing the shape memory restoring force, eliminating the uneven force on the support arm 16 caused by the shape memory force, stabilizing the shape memory restoring force within the preset optimal range, and completing the final locking.

[0033] The surface of the bone implant 1 has a functionally graded coating, which consists of three layers: from the inside out, the first layer is a piezoelectric fiber substrate layer, the second layer is an enzyme dynamic response active layer, and the third layer is an electroresponsive factor release surface layer.

[0034] This embodiment also provides a method for preparing a bone implant 1 with a lantern-like deployment locking and self-powered coating, which is used to prepare the above-mentioned lantern-like deployment locking and self-powered coating bone implant 1, specifically including the following steps: S1, inspired by the shrinking structure of a lantern, designed bone implant 1 and constructed according to the size of the patient's large bone defect.

[0035] S2, constrain the support arm 16 of the bone implant 1 into a straight strip shape (first memory shape), and cool it in sterile saline at 0-10°C to transform the support arm 16 into a flexible martensitic phase.

[0036] S3, construct a functional gradient coating on the surface of bone implant 1 to complete the preparation of bone implant 1.

[0037] The functional gradient coating in step S3 consists of three layers: from the inside out, the first layer is a piezoelectric fiber substrate layer, the second layer is an enzyme kinetic response active layer, and the third layer is an electro-responsive factor release surface layer.

[0038] The preparation method of the first layer of the functionally graded coating—the piezoelectric fiber substrate—is as follows: Poly-L-lactic acid particles were dissolved in a mixed solvent of chloroform and N,N-dimethylformamide to prepare a poly-L-lactic acid solution with a concentration of 8-12 wt%. The volume ratio of the mixed solvent was chloroform:N,N-dimethylformamide = 7:3. Barium titanate nanoparticles were added to the above poly-L-lactic acid solution, with the amount added being 15-25 wt% of the mass of the poly-L-lactic acid particles; The mixture formed by adding barium titanate nanoparticles was placed on a magnetic stirrer and stirred at 40°C for 12 hours, followed by 30 minutes of ultrasonic treatment to ensure uniform dispersion of barium titanate nanoparticles and form a stable electrospinning precursor solution. Electrospinning precursor solution was injected into an injection pump equipped with a 21G blunt stainless steel needle. The bone implant 1 was fixed on a rotatable grounded receiver as a collection device, and key parameters were set as follows: applied voltage: +18kV (needle) / -5kV (receiver), injection rate: 1.0mL / h, receiving distance: 18cm, ambient temperature and humidity: 25℃, relative humidity <30%. The device was started, and the electrospinning precursor solution was sprayed onto all surfaces of the bone implant 1 through the injection pump, so that L-lactic acid / barium titanate composite nanofibers were uniformly deposited on all surfaces of the bone implant 1. By controlling the slow rotation of the grounded receiver and the electrospinning time (usually 2 to 4 hours), a porous, interwoven fiber layer with a thickness of about 10 to 30μm and a fiber diameter in the range of 300 to 800nm ​​was obtained. Finally, the bone implant 1 with the deposited fibrous layer was placed in a vacuum drying oven and dried at 40°C for 24 hours to completely remove the residual solvent, thus obtaining the first layer of the functional gradient coating—the piezoelectric fiber substrate layer.

[0039] The preparation method of the second layer of the functionally graded coating—the enzyme kinetic response active layer—is as follows: Mesoporous carbon nanospheres were dispersed in PBS (phosphate buffer) solution at pH 7.4. Glucose oxidase and horseradish peroxidase were added to make the final concentrations of glucose oxidase and horseradish peroxidase 5 mg / mL and 2 mg / mL, respectively. The mixture was slowly shaken and incubated at 4 °C to allow glucose oxidase and horseradish peroxidase to be fully adsorbed into the mesopores and surface of the mesoporous carbon nanospheres. Add glutaraldehyde (final concentration 0.1%), crosslink for 1 hour, then wash three times with PBS solution by centrifugation to redisperse the mesoporous carbon nanospheres in PBS solution to obtain an enzyme-carbon nanosphere complex dispersion, and adjust the concentration to 20 mg / mL; Dissolve sodium alginate in PBS solution to prepare a 2.0 wt% solution, which is solution A. Dissolve gelatin in PBS solution to prepare a 4.0 wt% solution, cool to room temperature, and obtain solution B; Mix solution A and solution B at a volume ratio of 1:1 to obtain solution AB. Add the enzyme-carbon sphere complex dispersion at a ratio of 10% of the total volume to solution AB and mix gently to avoid generating bubbles. Bone implant 1 was placed in a spraying chamber, and the AB mixture was uniformly sprayed onto the surface of bone implant 1, which was already covered with a piezoelectric fiber substrate, using a low-pressure airflow atomizing spray gun. The parameters were: air pressure 0.2 MPa, nozzle diameter 0.3 mm, spraying distance 15 cm, and ambient temperature 20–25 °C. Simultaneously, 0.1 M calcium chloride solution and 25% glutaraldehyde vapor were atomized into the spraying chamber to gently crosslink the gelatin. This process was completed within 5 minutes, causing sodium alginate to undergo instantaneous ionic crosslinking and gelatin to undergo mild chemical crosslinking, forming a stable interpenetrating hydrogel network, which firmly embedded the enzyme-carbon sphere complex. After spraying, an enzyme-responsive active layer was obtained, with a wet thickness of approximately 50–100 μm.

[0040] The preparation method of the third layer of the functionally graded coating—the electro-responsive factor release surface layer—is as follows: Chitosan was dissolved in 1% acetic acid solution to prepare a 1.5 wt% solution. Polypyrrole nanowires (approximately 80 nm in diameter) were added, with a mass of 30% of the chitosan mass. The solution was ultrasonically dispersed and the pH was adjusted to 6.0 with NaOH solution to obtain a homogeneous, slightly viscous conductive prepolymer solution. VEGF (vascular endothelial growth factor) and BMP-2 (bone morphogenetic protein-2) were slowly added to the conductive prepolymer solution sequentially, with the total volume of VEGF and BMP-2 accounting for 5% of the conductive prepolymer solution. Bone implant 1, with a piezoelectric fiber base layer and an enzyme dynamic response active layer on its surface, was vertically immersed in the above mixture at a speed of 100 mm / min and held for 60 seconds. Then, it was pulled out of the liquid surface at the same speed to form a uniform liquid film on the surface. Immediately afterwards, bone implant 1 was placed in saturated sodium tripolyphosphate vapor to allow chitosan to undergo ionic cross-linking and gelation. Then, it was air-dried at 25°C and 50% humidity for 12 hours to form a solid composite gel film, thus obtaining the electroresponsive factor release surface layer.

[0041] Preferably, after the third coating layer is prepared, the bone implant 1 with all three coating layers is placed in an environment at 4°C for 24 hours to equilibrate, allowing each layer to achieve a stable moisture and structural balance within and between layers. Sterilization is performed using a low dose of ethylene oxide, with strict control of temperature (<40°C) and humidity during the sterilization cycle to maximize the protection of enzyme and growth factor activity. Under aseptic conditions, the bone implant 1 is sealed in a sealed bag filled with inert gas and stored at 4°C until surgical use.

[0042] The principle behind the preparation of functionally graded coatings is as follows: when the functionally graded coating comes into contact with glucose in tissue fluid, a cascade of enzymatic reactions is initiated. This reaction process involves electron transfer and proton consumption, continuously generating an ion gradient and a weak redox current (in the μA range) in the local microenvironment of the coating. The intensity of this biochemically derived electrical signal is positively correlated with the local metabolic activity (glucose concentration).

[0043] The smart release logic of the functionally graded coating is as follows: Early stage (inflammatory / vascular phase): Postoperatively, the wound site has a high metabolic rate and glucose concentration. The enzyme dynamic response active layer generates a strong microcurrent. This current preferentially triggers VEGF with shallow anchorage and low bond energy, realizing the early active release of VEGF. VEGF can stimulate the proliferation and migration of vascular endothelial cells and promote the growth of new blood vessels into the pores of the bone implant. Mid-to-late stage (repair / osteogenic phase): As inflammation subsides, glucose concentration returns to baseline, and enzymatic current production weakens. At this time, the mechanical load generated by the patient's rehabilitation training becomes dominant. Micromotion of bone implant 1 activates the piezoelectric fiber basal layer, generating intermittent high-voltage pulses. These pulses, in synergy with the baseline microcurrent, are sufficient to trigger the release of BMP-2, which is anchored deeper and has higher bond energy. BMP-2 is a potent osteogenic inducing factor. Simultaneously, the piezoelectric pulses themselves directly electrically stimulate osteogenic differentiation of cells. Under this dual effect, new bone formation around bone implant 1 is promoted, achieving biological fixation.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. The present invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the present invention.

Claims

1. A bone implant with a lantern-like deployment locking and self-powered coating, characterized in that, The bone implant (1) comprises: two bases (11) symmetrically arranged and fixed to the human bone; a screw rod (13) having two ends connected to the two bases (11) respectively, and being capable of rotating around its axis, the upper half and the lower half of the screw rod (13) being reverse threads; two nuts (14) symmetrically arranged and sleeved on the upper half thread and the lower half thread of the screw rod (13) respectively; a plurality of support arms (16) evenly distributed in the circumferential direction and centered on the screw rod (13), the two ends of each support arm (16) being fixed to the two nuts (14) respectively, the support arm (16) being made of a shape memory alloy strip, the shape memory alloy strip being in a first memory shape below the martensite phase transition temperature, the first memory shape being a straight strip closely attached to the screw rod (13), the shape memory alloy strip being in a second memory shape above the austenite phase transition temperature, the second memory shape being an arc shape arching away from the screw rod (13); wherein the surface of the bone implant (1) has a functional gradient coating.

2. The lampshade-like deployed locking and self-powered coating bone implant of claim 1, wherein, The functional gradient coating comprises, from inside to outside, a piezoelectric fiber base layer, an enzyme dynamic response active layer, and an electric response factor release surface layer.

3. The lampshade-like deployed, locking, and self-energating coated bone implant of claim 1, wherein, The second memory shape of the support arm (16) is an arc shape with a diameter 10% to 20% larger than that of the target host bone marrow cavity.

4. The lampshade-like deployed, locking, and self-energating coated bone implant of claim 1, wherein, The base (11) is a bearing, the outer ring of which is fixed to the human bone, and the inner ring of which is fixed to the end of the screw rod (13).

5. The lampshade-like deployed, lock-in-place, and self-powered coating of a bone implant of claim 1, wherein, The bone implant (1) further comprises two wrenches (12) symmetrically fixed to the two ends of the screw rod (13), and the wrench (12) is located between the nut (14) and the base (11).

6. The lampshade-like deployed, lock-in-place, and self-powered coating of a bone implant of claim 1, wherein, The bone implant (1) further comprises a bolt (15) passing through the support arm (16) and locked to the side wall of the nut (14).

7. A method of making a lantern-deployed locking and self-energating coated bone implant according to any one of claims 1-6, characterized in that, The method comprises the following steps: S1, design and construction of the bone implant (1) by imitating the structure of a lantern; S2, constraint of the support arm (16) of the bone implant (1) to the first memory shape and cooling, so that the support arm (16) is converted into a flexible martensite phase; S3, construction of the functional gradient coating on the surface of the bone implant (1) to complete the preparation of the bone implant (1).

8. The method of making a lantern-unfolding locking and self-energizing coated bone implant according to claim 7, wherein, The functional gradient coating in step S3 comprises three layers, from inside to outside, a piezoelectric fiber base layer, an enzyme dynamic response active layer, and an electric response factor release surface layer. The preparation method of the piezoelectric fiber base layer is as follows: Dissolve poly-L-lactic acid particles in a mixed solvent of chloroform and N,N-dimethylformamide to prepare a poly-L-lactic acid solution with a concentration of 8-12wt%, the volume ratio of the mixed solvent being chloroform:N,N-dimethylformamide=7:3; Add barium titanate nanoparticles to the above poly-L-lactic acid solution, the amount of addition being 15-25wt% of the mass of the poly-L-lactic acid particles; Stir the mixed solution formed after adding the barium titanate nanoparticles and then perform ultrasonic treatment to ensure uniform dispersion of the barium titanate nanoparticles, forming a stable electrospun precursor solution; Inject the electrospun precursor solution into a syringe pump, fix the bone implant (1) on a grounded receiver, and spray the electrospun precursor solution on all surfaces of the bone implant (1) to obtain the piezoelectric fiber base layer.

9. The method of making a lantern-unfolding locking and self-energating coated bone implant of claim 8, wherein, The preparation method of the enzyme dynamic response active layer is as follows: The mesoporous carbon nanospheres are dispersed in a PBS solution with a pH of 7.4, and glucose oxidase and horseradish peroxidase are added to make the final concentrations of the glucose oxidase and the horseradish peroxidase 5 mg / mL and 2 mg / mL respectively, and the glucose oxidase and the horseradish peroxidase are incubated at 4 DEG C under slow shaking to make the glucose oxidase and the horseradish peroxidase fully adsorbed into the mesopores and on the surface of the mesoporous carbon nanospheres; Glutaraldehyde is added for cross-linking, and the mesoporous carbon nanospheres are cleaned by centrifugation with a PBS solution and then re-dispersed in a PBS solution to obtain an enzyme-carbon sphere composite dispersion liquid with a concentration of 20 mg / mL; Sodium alginate is dissolved in a PBS solution to prepare a 2.0 wt% solution to obtain A liquid; Gelatin is dissolved in a PBS solution to prepare a 4.0 wt% solution, and the solution is cooled to room temperature to obtain B liquid; A liquid and B liquid are mixed at a volume ratio of 1:1 to obtain AB mixed liquid, and the enzyme-carbon sphere composite dispersion liquid is added into the AB mixed liquid at a proportion of 10% of the total volume, and the mixture is gently mixed; The bone implant (1) is placed in a spraying cabin, and the AB mixed liquid is uniformly sprayed onto the surface of the bone implant (1) covered with the piezoelectric fiber base layer, and calcium chloride solution and glutaraldehyde vapor are atomized and introduced into the spraying cabin at the same time, and the enzyme dynamic response active layer is obtained after the spraying is completed.

10. The method of making a lantern-unfolding locking and self-energizing coated bone implant according to claim 9, wherein, The preparation method of the electric response factor release surface layer is as follows: Chitosan is dissolved in a 1% acetic acid solution to prepare a 1.5 wt% solution, and polypyrrole nanowires are added with a mass of 30% of the mass of the chitosan, and the mixture is ultrasonically dispersed and adjusted to a pH of 6.0 to obtain a conductive pre-polymer liquid; VEGF and BMP-2 are slowly added into the conductive pre-polymer liquid in sequence, and the total volume of the VEGF and the BMP-2 accounts for 5% of the volume of the conductive pre-polymer liquid; The bone implant (1) with the piezoelectric fiber base layer and the enzyme dynamic response active layer on the surface is vertically immersed in the mixed liquid for 60 seconds, and then is uniformly pulled out of the liquid surface at the same speed to form a uniform liquid film on the surface, and then the bone implant (1) is immediately placed in saturated sodium tripolyphosphate vapor to make the chitosan ionically cross-linked and gelated, and then is air-dried to form a solid composite gel film, and the electric response factor release surface layer is obtained.

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