CN109338330B

CN109338330B - Method for preparing high-quality porous tantalum metal coating implant material at ultrahigh temperature

Info

Publication number: CN109338330B
Application number: CN201811232621.7A
Authority: CN
Inventors: 赵德伟; 马志杰; 李军雷
Original assignee: Individual
Current assignee: Weitan (Dalian) Biomaterials Co.,Ltd.
Priority date: 2018-10-22
Filing date: 2018-10-22
Publication date: 2020-10-02
Anticipated expiration: 2038-10-22
Also published as: CN109338330A

Abstract

The invention discloses a method for preparing a high-quality porous tantalum metal coating implant material at ultrahigh temperature, which is used for depositing tantalum metal on the surface of a porous support by using a chemical vapor deposition method, wherein the porous support comprises an outer layer and an inner layer, the porosity of the outer layer is 30-40%, the pore diameter is 200-400 mu m, the porosity of the inner layer is 80-90%, the pore diameter is 400-600 mu m, the chemical vapor deposition reaction temperature is 1100 ℃, the hydrogen flow is 240-300 mL/min, and the chlorine flow is 200-250 mL/min. The tantalum coating implant (such as a bone fracture plate) obtained by the method has high mechanical strength, the average bending strength of the tantalum coating implant is 150-250 MPa, the tantalum coating implant has a dodecahedron-like porous structure similar to that of human cancellous bone, the elastic modulus of the tantalum coating implant is 1.5-10 GPa, and the tantalum coating implant is arranged between the cancellous bone and cortical bone and can effectively reduce stress shielding.

Description

Method for preparing high-quality porous tantalum metal coating implant material at ultrahigh temperature

Technical Field

The invention relates to a preparation method of a porous tantalum coating biomaterial, in particular to a preparation method of a high-quality porous tantalum metal coating implant material at ultrahigh temperature, and more particularly relates to a preparation method of a biological porous tantalum metal coating bone fracture plate for treating limb long bone fracture.

Background

For the fracture of long diaphysis of limbs, incision reduction internal fixation is mostly adopted clinically, and the metal materials adopted by the prior surgical implants mainly comprise medical stainless steel, pure titanium and titanium alloy series. The titanium alloy has the characteristics of small specific gravity, high strength, low elastic modulus, easy processing and forming and the like, and is developed into a more ideal functional structure material for surgical implants. However, the complex environment in the human body can cause corrosion of metal materials to release toxic elements, so that the biocompatibility is reduced; secondly, the elastic modulus of the metal material is too different from that of human bone tissue, so that the stress shielding effect is easy to generate, the growth and the remodeling of new bones are not facilitated, and even secondary fracture is caused. Therefore, people are dedicated to searching metal materials with better biocompatibility and closer mechanical properties to human bones.

The porous tantalum metal is an ideal biomedical material due to excellent biocompatibility and excellent mechanical properties. The porous structure of the bone marrow cell can influence the proliferation of osteoblasts, macromolecules are easily adsorbed by the rough surface of the bone marrow cell, and the proliferation adhesion and the osteogenesis capacity of the cells can be influenced. At present, a porous tantalum metal implant device is mainly prepared by forming a tantalum coating on the surface of an existing porous support, and the traditional method for preparing the tantalum coating mainly comprises a plasma spraying technology and a chemical vapor deposition technology. However, the plasma spraying technology can only spray the scaffold material with simple planar structure, and has the defects of uneven spraying, difficult substrate complete coverage and the like for the scaffold material with complex porous structure. Although the chemical vapor deposition method is suitable for surface treatment of a complex three-dimensional porous structure, the coating is relatively thin in preparation, and factors influencing the performance of the coating are more, such as deposition temperature, large residual thermal stress of the coating and the like, so that cracks are easily formed on the surface. In addition, the problems of unstable deposition rate, uneven coating, thin coating, and low bonding force with a base material, easily causing the coating to fall off and the like exist, the mechanical strength required by the internal fixing device cannot be achieved, and the wide clinical application is limited.

The invention patent with the application number of CN201510338752.3 discloses an implantable medical device, a preparation method of a tantalum coating pedicle screw, the bone screw in the patent application can use tantalum to prepare a metal coating, and the thickness of the prepared coating is only 2-4 microns, and the best is 3 microns under the condition that the reaction temperature is 950 ℃. The coating is extremely weak in thickness, only can play a role in surface modification, and does not have mechanical support performance, the screw support function is the strength support of the titanium screw, and the titanium screw is not a real porous tantalum metal product in a strict sense, so that the titanium screw is difficult to popularize and apply clinically.

At present, porous tantalum metal products applied clinically are mainly concentrated in the joint field, such as hip prosthesis, knee joint prosthesis, spine interbody fusion cage and the like, but bone fracture plate products applied to limb fracture are always blank clinically. The bone fracture plate has higher requirements on mechanical properties, and the tantalum metal coating prepared by vapor deposition is too thin, so that the mechanical strength of the tantalum metal product is reduced due to the thin coating, the mechanical property requirements cannot be met, and the tantalum metal product cannot be applied to clinic.

At present, a high-quality porous tantalum metal bone fracture plate is urgently needed in clinic, and the porous tantalum metal bone fracture plate not only has excellent biocompatibility of tantalum metal, but also has excellent mechanical properties. The bone fracture implant can be permanently implanted into the body without being taken out by a secondary operation while promoting the healing of the bone fracture, thereby not only saving the economic burden of a patient, but also avoiding the physiological and psychological trauma to the patient caused by the secondary operation. The development of a high-quality porous tantalum metal bone fracture plate is an important breakthrough for solving the problem.

Disclosure of Invention

Aiming at the problems of the porous tantalum coating implant material prepared by the traditional method in clinical application, the invention provides a novel biological porous tantalum coating implant material and a preparation method thereof.

The technical scheme of the invention is as follows:

a preparation method of a biological porous tantalum coating implant material, which utilizes a chemical vapor deposition method to deposit tantalum metal on the surface of a porous bracket, comprises the following steps:

(1) soaking the porous support in absolute ethyl alcohol, ultrasonically shaking and cleaning for 30-60 min, drying by using nitrogen, placing the porous support into a reaction chamber, and placing tantalum metal at the front end of the reaction chamber;

(2) introducing inert gas into the reaction chamber, purging the reaction chamber for 10-20 min, vacuumizing to 200-250 Pa, heating the reaction chamber to 1100 ℃, introducing chlorine and hydrogen, and carrying out vapor deposition reaction for 20-30 h;

in the step (2), the flow rate of the chlorine gas is 200-250 mL/min, and the flow rate of the hydrogen gas is 240-300 mL/min.

In the invention, the porous support cleaned and dried in the step (1) and the tantalum metal used as the raw material are placed in a vapor deposition reaction chamber, chlorine and hydrogen are introduced for deposition reaction, wherein the porous support is placed in a reaction tray arranged in the reaction chamber, and the tantalum metal is placed at the front end of the reaction chamber.

In the technical scheme, the porous support comprises an outer layer and an inner layer, the porosity of the outer layer is 30-40%, the pore diameter is 200-400 microns, the porosity of the inner layer is 80-90%, and the pore diameter is 400-600 microns. The porous support is composed of an inner layer and an outer layer, the thickness ratio of the inner layer to the outer layer is 1: 0.5-1.5, and the preferable thickness ratio is 1: 1. the porous scaffold is used as an implant after being coated with tantalum, such as a bone fracture plate, and is implanted into a living body for fracture fixation. One side of the implant, namely the inner layer of the porous bracket is close to the bone, the porosity of the inner layer of the porous bracket close to the bone side is controlled to be 80-90%, the pore diameter is controlled to be 400-600 mu m, and the design is beneficial to the growth of osteocytes and tissues, is convenient for bone growth and promotes fracture healing; the other side of the implant, namely the porosity of the outer layer of the porous scaffold is 30-40%, the pore diameter is 200-400 microns, and compared with the porosity and the pore diameter of the inner layer, the mechanical strength of the outer layer of the porous scaffold is improved through the design, the supporting effect of the outer layer of the porous scaffold is improved, and the problem that the mechanical strength of the existing porous scaffold is low can be solved.

In the above technical scheme, the porous support is a porous glassy carbon support or a porous silicon carbide support.

In the above technical solution, the inert gas in the step (2) is one or a mixture of two of argon and nitrogen.

In the above technical solution, the preparation method of the biological porous tantalum coating implant material further comprises: and after the reaction is finished, closing the hydrogen and the chlorine, connecting a cooling device, and cooling to below 200 ℃ under the protection of inert gas to obtain the biological porous tantalum coating implant material, wherein the inert gas is one or the mixture of argon and nitrogen.

In the technical scheme, the purity of the tantalum metal in the step (1) is 99.99-99.999%.

The invention also provides the biological porous tantalum coating implant material prepared by the method, wherein the thickness of the tantalum coating is 120-200 mu m, the average bending strength of the biological porous tantalum coating implant material is 150-250 MPa, and the elastic modulus is 1.5-10 GPa.

The invention has the beneficial effects that:

(1) in the chemical vapor deposition reaction, on the basis of the traditional CVD technology, the gasification reaction of chlorine and pure tantalum metal is added to generate gasified tantalum pentachloride, and then the chemical reaction is generated in hydrogen to generate gasified tantalum metal for deposition. Compared with the traditional vapor deposition method adopting high-valence tantalum pentachloride powder, the method can directly adopt tantalum metal, thereby greatly reducing the cost.

(2) The porous support for the tantalum coating comprises an outer layer and an inner layer, wherein the outer layer mainly plays a supporting role, the porosity is 30-40%, and the pore diameter range is 200-400 microns. The inner layer is close to the bone, the porosity is 80-90%, the bone ingrowth is facilitated, and the fracture healing is promoted.

(3) The invention combines the improvement of the preparation steps and further optimizes the chemical deposition reaction parameters to determine the parameters of specific deposition reaction temperature (1100 ℃), hydrogen flow (240-300 mL/min), chlorine flow (200-250 mL/min) and the like. The higher deposition temperature improves the molecular motion and diffusion speed of the reaction gas, improves the deposition speed and is beneficial to obtaining a thicker tantalum coating; the reaction gas can penetrate into the inner surface of the porous support due to higher gas flow rate, and the coating and the support material are integrated with each other, so that the stress borne by the bone fracture plate is more uniform. The thickness of the tantalum coating obtained by the method can reach 120-200 mu m, and the requirement of higher mechanical property is met, while the thickness of the tantalum coating obtained by the existing method is generally several microns. Meanwhile, the tantalum coating has good appearance, uniform and compact coating, the bonding force between the coating and the porous support is more than 60MPa, the anti-stripping requirement in the clinical application process can be met, and the problems that the coating prepared by the existing method is thin and uneven, the bonding force between the coating and a substrate is not enough, the coating is easy to drop and the like are effectively solved.

(4) The tantalum coating implant (such as a bone fracture plate) obtained by the method has high mechanical strength, the average bending strength of the tantalum coating implant is 150-250 MPa, the tantalum coating implant has a dodecahedron-like porous structure similar to that of human cancellous bone, the elastic modulus of the tantalum coating implant is 1.5-10 GPa, and the tantalum coating implant is arranged between the cancellous bone and cortical bone and can effectively reduce stress shielding. The tantalum coating implant has the advantages that the porosity of the inner layer of the tantalum coating implant is up to 80-85%, the porous structure is a polyhedral mutually-interwoven mesh structure and has a dodecahedron mesh structure with three-dimensional communicated and distributed pores, the implant is favorable for the growth of new bone tissues, the connection capacity with the bone tissues is enhanced, the regeneration and reconstruction of the bone tissues are promoted, the long-term biological stability of the implant is improved, and the tantalum coating implant is particularly suitable for the field of orthopedics and is suitable for the internal fixation treatment of clinical limb long bone fracture.

Drawings

FIG. 1 shows the surface topography of a porous silicon carbide stent before tantalum metal coating.

FIG. 2 shows the surface topography of the porous silicon carbide stent after tantalum metal coating.

FIG. 3 shows a cross-sectional electron micrograph of the porous silicon carbide stent after tantalum coating in example 1.

FIG. 4 is an SEM photograph showing the bonding portion of the porous silicon carbide support and the tantalum coating layer in example 1.

FIG. 5a shows the microstructure of the coating morphology of example 1 and FIG. 5b shows the results of the coating adhesion test.

FIG. 6 shows the morphology of tantalum metal coatings prepared under different temperature conditions.

FIG. 7 shows the morphology of tantalum metal coatings prepared under different hydrogen flow conditions.

Fig. 8 shows the effect of porous tantalum metal coated bone plates prepared at different temperatures on the healing of animal fractures.

Fig. 9 shows the effect of porous tantalum metal coated bone plates prepared at different temperatures on bone in-growth.

Fig. 10 shows a clinical biotype porous tantalum metal-coated bone plate for fracture fixation in example 5.

FIG. 11 shows the measurement results of the mechanical properties of bone fracture plates with porous tantalum metal coatings prepared at ultra-high temperature.

FIG. 12 shows the results of clinical application of the porous tantalum metal coated bone plate of the present invention and a conventional titanium metal bone plate to treat bone fractures.

FIG. 13 is a graph comparing the healing time for the two bone plates of FIG. 12C for treating fractures.

Detailed Description

The present invention will be described in further detail with reference to the drawings and the following detailed description, but the present invention is not limited to these embodiments. In the following examples, unless otherwise specified, the experimental methods used were all conventional methods, and materials, reagents and the like used were all available from biological or chemical companies.

Example 1 two porous tantalum metal bone plates were prepared according to different temperatures

The biological porous tantalum metal bone fracture plate for fixing the fracture of the long bone and the backbone of the limbs is prepared by permeating tantalum metal into the inner surface and the outer surface of a porous silicon carbide bracket by adopting a chemical vapor permeation method, and the preparation method comprises the following steps:

(1) pretreatment:

soaking the porous silicon carbide support in absolute ethyl alcohol, cleaning the porous silicon carbide support for 30min by using an ultrasonic vibration instrument, and drying the porous silicon carbide support by using nitrogen for later use;

(2) placing the pretreated porous silicon carbide support into a vapor deposition reaction cavity, and placing the massive tantalum metal at the front end of the reaction cavity, namely, at the inlet of chlorine; the purity of the bulk tantalum metal is 99.999%;

(3) connecting an air inlet/exhaust pipeline device, checking the sealing condition in the reaction cavity, introducing argon into the reaction cavity after the completion of the checking, purging the reaction cavity for 10min, then vacuumizing to 200Pa, heating the reaction cavity to 1100 ℃, introducing chlorine and hydrogen, and carrying out chemical vapor deposition reaction, wherein the vapor deposition reaction time is 25h, the vapor deposition reaction temperature is 1100 ℃, and the flow rate of the chlorine is 230 mL/min; the flow rate of the hydrogen is 260 mL/min;

the chemical vapor deposition reaction process comprises the following steps: chlorine and hydrogen are introduced, firstly, the chlorine and the gaseous tantalum metal are subjected to chemical reaction to generate tantalum pentachloride, then the gaseous tantalum pentachloride and the hydrogen are subjected to reduction reaction to generate gaseous tantalum metal, and the gaseous tantalum metal permeates and deposits the inner surface and the outer surface of the porous support to form the porous tantalum coating.

The porous silicon carbide support is prepared by taking porous silicon carbide as a raw material by a conventional method, and specifically comprises the following steps: based on the shape replication principle, soaking foamed plastic in slurry, curing to obtain a prefabricated body with the same porous foam structure as the foamed plastic, performing pyrolysis processing, and performing reaction sintering at 1600 ℃ to obtain the required porous silicon carbide bone fracture plate support with the net structure, wherein the porous silicon carbide support comprises an outer layer and an inner layer, the porosity of the outer layer is 30-40%, the pore diameter is 200-400 microns, the porosity of the inner layer is 80-90%, and the pore diameter is 400-600 microns. When in use, the inner layer is close to the sclerotin side, the outer layer is at the outer side of the sclerotin, and the width ratio of the inner layer to the outer layer is 1: 1.

(4) After the reaction is finished, closing the hydrogen and the chlorine, connecting the cooling device, cooling the reaction chamber under the protection of argon to be below 100 ℃, opening the reaction chamber and taking out the porous silicon carbide support with the tantalum coating.

The surface morphology changes of the porous silicon carbide support before and after the coating are observed by using a super-depth-of-field three-dimensional digital microscope system, the results are shown in figures 1 and 2, the surface morphologies of the pores before and after the coating are obviously changed, the morphology after the coating is relatively rough, the fine structure and the morphological characteristics of the pores of the porous support can be clearly observed, and good three-dimensional connectivity is shown. The color of the porous silicon carbide support before coating is brighter, and the porous silicon carbide support shows stronger light reflection in a digital microscopic image. The measurement result shows that the pore space of the inner layer of the stent before coating (figure 1) is 400-600 mu m, and the porosity is about 80-90%; after coating (FIG. 2), the pore space is 400-500 μm, and the porosity is as high as 80-85%. Porosity is determined according to the method described in the national standard GB/T21650.1-2008.

Fig. 3 is a cross-sectional electron microscope scanning photograph of the biotype bone fracture plate support with the tantalum coating, which can clearly show that metal tantalum is uniformly permeated on the inner surface and the outer surface of the pores of the more-pore silicon carbide support, the thickness of the permeated metal tantalum coating is uniform, and the coating is compact. Tables 1 and 2 show the EDX spectroscopy analysis results of the porous silicon carbide supports (materials) before and after the tantalum coating, respectively.

TABLE 1 EDX Spectroscopy analysis results of porous silicon carbide scaffolds before tantalum coating

Serial number	Element(s)	The weight percentage is%	K-ratio	GZ	GA	GF
							1	C	34.23	0.07521	0.96837	6.89600	1.00000
2	Si	65.77	0.92479	1.03211	1.01102	1.00000

TABLE 2 EDX Spectroscopy analysis results of porous silicon carbide stent surface after tantalum coating

Serial number	Element(s)	The weight percentage is%	K-ratio	GZ	GA	GF
							1	Si	2.54	0.01777	0.80427	1.82329	0.99998
2	Ta	97.46	0.98223	1.01774	0.99970	1.00000

As can be seen from table 1, the porous silicon carbide before coating mainly contains carbon and silicon, the mass fractions of which are 34.23% and 65.77%, respectively, and no other components, which fully indicates that the substrate material is a silicon carbide material with higher purity. Table 2 shows that the coating back surface becomes predominantly tantalum metal with a mass fraction of up to 97.46%, while the component containing a portion of silicon is primarily due to the silicon in the stent material slipping off onto the tantalum metal surface during the cutting process, and is not a stent surface coating component.

FIG. 4 is an SEM photograph showing the bonding portion of the porous silicon carbide support and the tantalum coating layer in example 1. As can be seen in fig. 4, the tantalum coating is tightly bonded to the stent without voids and has a thickness of about 120 μm.

FIG. 5a shows the micro-morphology of the tantalum coating on the surface of the porous stent, as shown in the figure, the tantalum metal coating is dense and uniform in thickness, the thickness difference of the tantalum metal coating on the stent is +/-10 μm, and the tantalum coating is not cracked. Figure 5b is a test of the bonding strength of tantalum coatings on silicon carbide materials, 63.2Mpa higher than tantalum metal coatings deposited on titanium metal.

Example 2

Porous tantalum metal bone plates were prepared according to the method described in example 1 at deposition temperatures of 950 ℃, 1100 ℃ and 1200 ℃ respectively.

A-C in FIG. 6 are the electron microscope scanning coating conditions of the porous tantalum metal bone fracture plate prepared at deposition temperatures of 950 deg.C, 1100 deg.C and 1200 deg.C, respectively, the tantalum coating deposited at 950 deg.C has uneven coating morphology, and the coating deposited at 1200 deg.C has peeling off and poor binding force. The coating has uneven appearance, and influences the bone ingrowth and mechanical properties of the bone fracture plate. When the temperature is 1100 ℃, the coating is uniform and compact, and the best effect is achieved.

Example 3

According to the method of the embodiment 1, the porous tantalum metal bone fracture plate is prepared under the conditions of different hydrogen flow rates of 200mL/min, 260mL/min and 320mL/min, and the deposition temperature is 1100 ℃.

A-C in FIG. 7 show the electron microscope scanning coating conditions of the porous tantalum metal bone fracture plate prepared under the conditions of different hydrogen flow rates of 200mL/min, 260mL/min and 320mL/min, respectively. When the hydrogen flow is 200mL/min, the gas flow is too low to fully react, and the tantalum coating deposited on the surface of the bracket is not uniform and falls off. When the hydrogen flow is 320mL/min, the gas flow is overlarge, and partial gas directly flows through the surface of the substrate without reacting, so that the rate of the reaction process is reduced, the coating and the substrate material cannot be firmly combined, and the appearance of the coating is stripped. When the hydrogen flow is 260mL/min, the deposition rate is stable, the coating is uniform in appearance and does not fall off.

Example 4

A male goat with the weight of about 20kg is selected as an experimental animal, and fracture modeling is carried out on the tibia of the goat. Preparing two porous tantalum metal bone fracture plates prepared at different deposition temperatures of 950 ℃ and 1100 ℃, wherein the specific data are as follows: the width of the bone fracture plate is 1.2cm, and the length of the bone fracture plate is 10 cm; the diameter of the screw is 2.7mm, and the length of the screw is 14-20 mm.

Anaesthetizing the goat, disinfecting the goat by a conventional method, laying a sheet, and sequentially cutting the skin, the subcutaneous tissue and the fascia; exposing the goat tibia, performing fracture modeling on the tibia, then performing traction reduction, after anatomical reduction is achieved, firmly fixing reduction forceps, selecting a proper bone fracture plate, separating periosteum, polishing cortical bone at the position of the bone fracture plate by using a grinding drill to form a groove with the same size as the bone fracture plate, then placing the bone fracture plate, after the bone fracture plate is firmly fixed by using screws, flushing with physiological saline, and sequentially suturing periosteum, fascia, subcutaneous tissues and skin.

For two groups of animals, the X-ray positive lateral tibial injection is carried out at 4 weeks, 8 weeks and 12 weeks after operation respectively, and the fracture healing conditions of the two groups of animals are compared (figure 8), so that when the bone fracture plate with the deposition temperature of 1100 ℃ is used, the fracture healing conditions are good, the fracture part is almost completely healed after 3 months, while the bone fracture plate with the deposition temperature of 950 ℃ still sees the fracture fragments after 3 months, and the fracture part is not fractured.

Fig. 9 is a graph of hard tissue sections of two groups of animals after 3 months, bone ingrowth is observed by VG staining, when the deposition temperature is 950 ℃, the tantalum metal coating is not uniform, the bone ingrowth is less and the ingrowth of the bone tissues is immature, while the tantalum metal coating with the deposition temperature of 1100 ℃ is uniform and compact, the ingrowth of the bone tissues in a plurality of pores is good, the purple mature bone is the bone tissue, and the bone fracture plate with the tantalum metal coating deposited at 1100 ℃ is used.

Example 5 preclinical testing

Porous tantalum metal bone plates were prepared for preclinical testing according to the method of example 1 at a deposition temperature of 1100 ℃. The width of the bone fracture plate is 12mm, and the length of the bone fracture plate is 12 cm-20 mm. The bone plate profile, and topography of the localized tantalum coating are shown in fig. 10.

The elastic modulus of the finished porous tantalum metal bone fracture plate is 3.1GPa, and the bending strength of the finished porous tantalum metal bone fracture plate is 363.2MPa when the finished porous tantalum metal bone fracture plate is measured by a three-point bending test. The elastic modulus is detected according to the method described in the national standard GB/T22315-. Measurement of mechanical properties: the bending strength and the elastic modulus of the porous tantalum metal bracket are tested by adopting an MTS-810 type mechanical property testing system of MTS company, and the loading displacement rate is 0.5 mm/min. The bending strength of the porous tantalum metal bone fracture plate is tested at room temperature, and 3 groups of test pieces are used. The prepared porous tantalum metal has good bending strength, and the elastic modulus of the porous tantalum metal is closer to that of human cortical bone (1.5-30 GPa), so that adverse effects caused by stress shielding can be effectively reduced, and the porous tantalum metal is expected to become a new-generation plant orthopedic material.

10 patients with forearm fracture were recruited for internal fixation treatment with a porous tantalum metal plate. After the brachial plexus is anesthetized, after conventional disinfection and single laying, the skin, subcutaneous tissues and fascia are cut in sequence; exposing the fracture end, performing traction reduction, after anatomical reduction is achieved, firmly fixing reduction forceps, separating periosteum after selecting a proper bone fracture plate, polishing cortical bone at the bone fracture plate by using a grinding drill to form a groove with the same size as the bone fracture plate, then placing the bone fracture plate, after the fixation of screws is firm, flushing with physiological saline, and sequentially suturing periosteum, fascia, subcutaneous tissues and skin.

FIG. 12 shows the results of the patient's fracture healing observations at the time of surgery and at 4, 8, and 12 weeks after surgery. Fig. 12A and 12B are the results of internal fixation treatment using the porous tantalum-coated bone plate of the present invention in a left distal radius fracture patient and a right monte fracture patient, respectively. Therefore, the fracture is basically healed after one month after the operation, the fracture is completely healed after three months after the operation, the fracture plastic shape is good after the healing, and the bone ingrowth is better than that of the common coating bone fracture plate (the arrow indicates the fracture part). Fig. 12C shows the results of a fixed fracture treatment of right ulna and radius comminuted fractures using a porous tantalum-coated bone plate (denoted Ta, fixed radius) and a conventional titanium bone plate (denoted Ti, fixed ulna), respectively. As can be seen by follow-up visits, the radius fracture line is fuzzy and the fracture gradually heals up two months after the operation, while the ulna fracture line is still clear and visible. When the fracture of the radius fixed by the porous tantalum coating bone fracture plate heals three months after the operation, the fracture line disappears, and the fracture line of the ulna fixed by the titanium metal bone fracture plate is still visible. As can be seen in FIG. 13, the difference in fracture healing time between the ulna and radius of the patients was statistically significant (P < 0.05).

The porous tantalum metal bone fracture plate prepared at the ultrahigh temperature has good mechanical property, the bending strength meets the requirement of implanting medical instruments, and clinical early-stage experiments further verify that the porous tantalum metal bone fracture plate has better bone ingrowth, enhances the connection capacity with bone tissues, promotes the regeneration and reconstruction of the bone tissues and accelerates the healing process compared with a common coating bone fracture plate.

While the preferred embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that the invention is not limited thereto, and that various changes and modifications may be made without departing from the spirit of the invention, and the scope of the appended claims is to be accorded the full scope of the invention.

Claims

1. A preparation method of biological porous tantalum coating implant material for internal fixation treatment of limb long bone fracture, which utilizes a chemical vapor deposition method to deposit tantalum metal on the surface of a porous bracket to form a tantalum coating, comprises the following steps:

in the step (2), the flow rate of the chlorine is 200-250 mL/min, and the flow rate of the hydrogen is 240-300 mL/min;

the porous support comprises an outer layer and an inner layer, wherein the porosity of the outer layer is 30-40%, the pore diameter is 200-400 microns, the porosity of the inner layer is 80-90%, and the pore diameter is 400-600 microns;

the thickness of the tantalum coating is 120-200 mu m, the average bending strength of the biological porous tantalum coating implant material is 150-250 MPa, and the elastic modulus is 1.5-10 GPa.

2. The method according to claim 1, wherein the porous scaffold is a porous glassy carbon scaffold or a porous silicon carbide scaffold.

3. The method according to claim 1, wherein the inert gas in step (2) is one or a mixture of argon and nitrogen.

4. The method of claim 1, further comprising: and after the reaction is finished, closing the hydrogen and the chlorine, connecting a cooling device, and cooling to below 200 ℃ under the protection of inert gas.

5. The method according to claim 4, wherein the inert gas is one or a mixture of argon and nitrogen.