Preparation method of PEEK-based tantalum coating skull restoration

Abstract

According to the preparation method of the PEEK-based tantalum coating skull restoration, the tantalum coating is prepared through data modeling, fused deposition modeling 3D printing and magnetron sputtering, the preparation process is simplified, and the production efficiency and the product consistency are improved. Medical-grade PEEK serves as a substrate, a micro-nano structure is formed on the surface through laser pretreatment, an ultrathin tantalum coating (the thickness is smaller than or equal to 1 micrometer) is deposited through magnetron sputtering, the matching degree of the appearance of the prosthesis and the anatomical appearance of a skull defect area reaches + / -1 mm, and the proximity error between the elasticity modulus of a bone contact area and a host bone is smaller than or equal to + / -10%.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials and relates to implant materials for the repair of skull defects, specifically a method for preparing a PEEK-based tantalum-coated skull prosthesis. Background Technology

[0002] Skull defect repair is a common clinical orthopedic need, often caused by factors such as trauma or tumor resection. Currently, commonly used skull prostheses include titanium alloy plates and prostheses made solely of PEEK (polyetheretherketone). Titanium alloy prostheses have limitations in biocompatibility and mechanical fit, while PEEK prostheses, although possessing good biocompatibility and mechanical properties, have poor bone ingrowth capabilities, leading to poor osseointegration and a higher risk of implant loosening and displacement, thus affecting the repair outcome.

[0003] Studies have attempted to improve the osseointegration capacity of PEEK materials through surface modification, but several shortcomings exist: First, the coating has low bonding strength with the PEEK substrate and is prone to detachment; second, the matching accuracy between the prosthesis shape and the skull defect area is insufficient, making precise repair impossible; third, the manufacturing process is fragmented, lacking an integrated technical solution from data acquisition, design, modification to molding, resulting in low production efficiency and poor product consistency. These problems limit the clinical application of PEEK-based prostheses in skull defect repair. Summary of the Invention

[0004] In view of this, the present invention provides a method for preparing a PEEK-based tantalum-coated cranial prosthesis, which achieves precise adaptation between the prosthesis and the defect area, improves the bonding stability between the coating and the substrate and the osteoinductive activity, and optimizes the preparation efficiency and product consistency.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] 1. A method for preparing a PEEK-based tantalum-coated cranial prosthesis, comprising the following steps:

[0007] (1) Data acquisition and modeling of bone defect sites

[0008] (2) Preparation of PEEK substrate

[0009] After raw material pretreatment, fused deposition modeling (FDM) 3D printing is employed, with nozzle temperature at 380-400℃, heated bed temperature at 140-160℃, and chamber temperature at 110-130℃. Printing speeds are 20-30mm / s for the bottom layer, 35-45mm / s for the middle layer, and 25-35mm / s for the top layer. Layer height is 0.10-0.15mm, infill density is 55-65%, and a honeycomb infill structure is used with a hole center-to-center distance of 0.5-0.7mm. Support structure density is 15-25%, and the angle between the support and the substrate is 40-50°. After printing, the material is ultrasonically cleaned and annealed.

[0010] (3) Surface laser pretreatment

[0011] The substrate surface obtained in step (2) is activated by using an infrared femtosecond or ultraviolet nanosecond pulsed laser to adjust the surface roughness to 0.5-10 μm;

[0012] (4) Tantalum coating deposition

[0013] The PEEK substrate pretreated in step (3) was cleaned with argon plasma and a tantalum coating was prepared by DC magnetron sputtering. The sputtering power was 200-250W, the sputtering pressure was 0.6-1.0Pa, the argon flow rate was 25-35sccm, the substrate temperature was 80-100℃, the sputtering time was 30-40min, the target-substrate distance was 75-85mm, and the substrate rotated at a constant speed of 4-6r / min during the sputtering process.

[0014] (5) Post-processing

[0015] The restoration is obtained after polishing, cleaning, and disinfection.

[0016] Furthermore, in step (1), skull defect data is obtained by CT scan, a three-dimensional high-precision defect model is reconstructed using BOHOLO software, and the prosthesis structure is optimized by combining ABAQUS finite element analysis.

[0017] Furthermore, step (2) adopts fused deposition modeling 3D printing with a nozzle temperature of 390°C, a heated bed temperature of 150°C, and a chamber temperature of 120°C; the printing speed is 25mm / s for the bottom layer, 40mm / s for the middle layer, and 30mm / s for the top layer; the layer height is 0.12mm, the filling density is 60%, a honeycomb filling structure is adopted, and the center distance between the holes is 0.6mm; the support structure density is 20%, and the angle between the support and the substrate is 45°.

[0018] Furthermore, in step (3), an infrared femtosecond pulsed laser is used for surface pretreatment. The laser wavelength is 1064nm, the pulse width is 120fs, the laser power is 12W, the scanning speed is 600mm / s, the scanning line spacing is 40μm, and the spot diameter is 20μm. The treatment environment is dry air with a humidity of ≤30%.

[0019] Further, in step (4), a tantalum coating is prepared by DC magnetron sputtering with a sputtering power of 220W, a sputtering pressure of 0.8Pa, an argon flow rate of 30sccm, a substrate temperature of 90℃, a sputtering time of 35min, a target-substrate distance of 80mm, and the substrate rotating at a uniform speed of 5r / min during the sputtering process.

[0020] Furthermore, in step (4), the plasma cleaning process involves an argon flow rate of 15-25 sccm, a power of 60-100W, and a time of 8-12 min.

[0021] Furthermore, in step (4), the plasma cleaning process involves an argon flow rate of 20 sccm, a power of 80 W, and a time of 10 min.

[0022] The present invention also provides a repair obtained by the above preparation method.

[0023] The beneficial effects of this invention are as follows:

[0024] Compared with existing technologies, this technology can solve the technical problems of insufficient osseointegration capacity, low coating bonding strength, poor shape matching accuracy, and fragmented preparation process of existing cranial prostheses. It can achieve precise adaptation between the prosthesis and the defect area, improve the bonding stability and osteoinductive activity of the coating and the substrate, and optimize preparation efficiency and product consistency.

[0025] Using medical-grade PEEK as a substrate, the surface is pretreated with laser to form a micro-nano structure, and then an ultra-thin tantalum coating (thickness ≤1μm) is deposited by magnetron sputtering. The shape of the prosthesis matches the anatomical shape of the skull defect area by ±1mm, and the elastic modulus of the bone contact area is close to the host bone by ≤±10%.

[0026] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0028] Figure 1 This is a process flow diagram for PEEK-based tantalum-coated cranial prostheses. Detailed Implementation

[0029] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should also be noted that technical means not described in detail in this invention can be implemented using conventional technical means.

[0030] I. Data Acquisition and Modeling

[0031] Skull defect data were obtained by CT scans, and a three-dimensional high-precision defect model was reconstructed using BOHOLO software. The prosthesis structure was then optimized by ABAQUS finite element analysis.

[0032] II. PEEK Substrate Preparation

[0033] Based on a 3D model, personalized PEEK restorations were prepared using fused deposition modeling 3D printing technology, and parameters such as nozzle temperature and heated bed temperature were optimized to ensure molding accuracy.

[0034] (1) Raw material pretreatment: Medical grade PEEK particles (purity ≥99.9%, melt flow rate 3.8g / 10min) are selected and dried in a vacuum drying oven at 120℃ for 4.5 hours before printing to remove moisture content to ≤0.02% to avoid defects such as bubbles and voids in the printed parts;

[0035] (2) 3D printing parameters: Fused deposition modeling technology is adopted, with nozzle temperature set at 390℃, heated bed temperature at 150℃, and chamber temperature at 120℃; printing speed is 25mm / s for the bottom layer, 40mm / s for the middle layer, and 30mm / s for the top layer; layer height is 0.12mm, and infill density is 60% (using a honeycomb infill structure with a hole center distance of 0.6mm); support structure density is 20%, and the angle between the support and the substrate is 45°;

[0036] (3) Post-processing: After printing, the substrate is allowed to cool naturally to room temperature. The support structure is removed using a CNC milling machine, followed by ultrasonic cleaning (ethanol medium, power 120W, time 20min). Finally, the substrate is annealed at 180℃ for 3 hours and then slowly cooled to room temperature to eliminate internal stress and improve the dimensional stability of the substrate.

[0037] III. Surface Laser Pretreatment

[0038] The surface of PEEK restorations is activated under specific conditions using infrared femtosecond or ultraviolet nanosecond pulsed lasers, and the surface roughness is adjustable from 0.5 to 10 μm.

[0039] For example, an infrared femtosecond pulsed laser processing system was used, with a laser wavelength of 1064nm, a pulse width of 120fs, a laser power of 12W, a scanning speed of 600mm / s, a scanning line spacing of 40μm, and a spot diameter of 20μm. The processing environment was dry air (humidity ≤30%), and the processing area covered the entire surface of the PEEK base in contact with the skull.

[0040] IV. Tantalum Coating Deposition

[0041] Tantalum coatings were prepared on pretreated PEEK surfaces using magnetron sputtering technology. Parameters such as sputtering power, gas pressure, and duration were optimized to ensure coating coverage and bonding strength.

[0042] Preparation before sputtering: Place the pretreated PEEK substrate in a vacuum coating machine and first evacuate the air to a vacuum level ≤5×10. -4 Pa was then cleaned with argon plasma (argon flow rate 20 sccm, power 80 W, time 10 min) to remove residual impurities from the surface.

[0043] Sputtering parameters: High-purity tantalum target (purity ≥99.95%) was selected, sputtering power was 220W, sputtering pressure was 0.8Pa, argon flow rate was 30sccm, substrate temperature was 90℃, and sputtering time was 35min; DC magnetron sputtering mode was adopted, target-substrate distance was 80mm, and the substrate was rotated at a uniform speed of 5r / min during sputtering to ensure uniform coating thickness.

[0044] Coating parameters: The final tantalum coating thickness is 0.9μm (thickness deviation ≤ ±0.1μm), the coating coverage is 100%, and there are no exposed substrates, cracks, or pore defects;

[0045] V. Post-processing

[0046] After removing the supporting structure, the finished restoration is obtained through routine processes such as polishing, cleaning, and disinfection.

[0047] The preparation method and the obtained restoration described in this invention, as demonstrated in experiments, possess the following characteristics:

[0048] 1. Precise matching: The prosthesis is designed based on the patient's skull defect data, with a shape matching degree of ±1mm and mechanical properties that are highly matched with the host bone, significantly improving the repair effect;

[0049] 2. Strong bonding stability: The micro-nano structure constructed by laser pretreatment, in conjunction with the magnetron sputtering process, enables the tantalum coating to bond with the PEEK substrate to a strength of 28-32 MPa (tested by scratch test method, critical load Lc≥28N), which meets the industry standard for spinal implants (requiring a bonding strength of not less than 22 MPa) and effectively prevents coating peeling.

[0050] 3. Excellent osteointegration capacity: The tantalum coating has good osteoinductive activity, which can promote the adhesion, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, and improve the efficiency of osteointegration.

[0051] 4. Highly Efficient Integrated Manufacturing: Integrating key technologies such as data modeling, 3D printing, and surface modification, the manufacturing process is simplified, significantly improving production efficiency: Traditional processes have a customization cycle of 2-3 weeks, while the process of this invention shortens it to 3-5 days (efficiency improvement of over 70%); In traditional surgery, prosthesis shaping takes more than 2 hours, but the process of this invention, due to the precise matching of the prosthesis with the bone defect area (error ≤ ±1mm), eliminates the need for additional grinding during surgery, reducing surgery time by more than 50%, while the product size consistency error is controlled within ±0.1mm, effectively improving the product qualification rate;

[0052] 5. Excellent biocompatibility: Both the PEEK substrate and the tantalum coating meet medical standards and have high biocompatibility: Cytotoxicity tests show a relative growth rate (RGR) ≥95% (meeting the Grade 0 non-toxic standard in GB / T 16886.5-2017), a hemolysis rate ≤1.2% (far below the national standard threshold of ≤5%), and skin irritation tests show no irritation (meeting the requirements of no erythema or edema reaction in GB / T 16886.10-2017); moreover, the cost is relatively low, which is conducive to clinical application.

[0053] Through the combined use of laser pretreatment and magnetron sputtering, the bonding strength between the tantalum coating and the PEEK substrate is enhanced by constructing micro-nano structures, which can meet the Class 4 standard of GB / T 40262-2021. The ultra-thin tantalum coating design ensures osteoinductive activity while improving the biocompatibility and corrosion resistance of the prosthesis, with a water contact angle ≤50°.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although 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 present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a PEEK-based tantalum-coated cranial prosthesis, characterized in that, Includes the following steps: (1) Data acquisition and modeling of bone defect sites (2) Preparation of PEEK substrate After raw material pretreatment, fused deposition modeling (FDM) 3D printing is employed, with nozzle temperature at 380-400℃, heated bed temperature at 140-160℃, and chamber temperature at 110-130℃. Printing speeds are 20-30mm / s for the bottom layer, 35-45mm / s for the middle layer, and 25-35mm / s for the top layer. Layer height is 0.10-0.15mm, infill density is 55-65%, and a honeycomb infill structure is used with a hole center-to-center distance of 0.5-0.7mm. Support structure density is 15-25%, and the angle between the support and the substrate is 40-50°. After printing, ultrasonic cleaning and annealing are performed. (3) Surface laser pretreatment The substrate surface obtained in step (2) is activated by using an infrared femtosecond or ultraviolet nanosecond pulsed laser to adjust the surface roughness to 0.5-10 μm; (4) Tantalum coating deposition The PEEK substrate pretreated in step (3) was cleaned with argon plasma and a tantalum coating was prepared by DC magnetron sputtering. The sputtering power was 200-250W, the sputtering pressure was 0.6-1.0Pa, the argon flow rate was 25-35sccm, the substrate temperature was 80-100℃, the sputtering time was 30-40min, the target-substrate distance was 75-85mm, and the substrate rotated at a constant speed of 4-6r / min during the sputtering process. (5) Post-processing The restoration is obtained after polishing, cleaning, and disinfection.

2. The preparation method according to claim 1, characterized in that, Step (1) involves obtaining skull defect data through CT scan, reconstructing a three-dimensional high-precision defect model using BOHOLO software, and optimizing the prosthesis structure using ABAQUS finite element analysis.

3. The preparation method according to claim 1, characterized in that, Step (2) uses fused deposition modeling 3D printing with a nozzle temperature of 390℃, a heated bed temperature of 150℃, and a chamber temperature of 120℃; the printing speed is 25mm / s for the bottom layer, 40mm / s for the middle layer, and 30mm / s for the top layer; the layer height is 0.12mm, the filling density is 60%, a honeycomb filling structure is adopted, and the center distance between the holes is 0.6mm; the support structure density is 20%, and the angle between the support and the substrate is 45°.

4. The preparation method according to claim 1, characterized in that, In step (3), surface pretreatment is performed using an infrared femtosecond pulsed laser with a wavelength of 1064nm, a pulse width of 120fs, a laser power of 12W, a scanning speed of 600mm / s, a scanning line spacing of 40μm, and a spot diameter of 20μm. The processing environment is dry air with a humidity of ≤30%.

5. The preparation method according to claim 1, characterized in that, In step (4), a tantalum coating is prepared by DC magnetron sputtering with a sputtering power of 220W, a sputtering pressure of 0.8Pa, an argon flow rate of 30sccm, a substrate temperature of 90℃, a sputtering time of 35min, a target-substrate distance of 80mm, and the substrate rotating at a uniform speed of 5r / min during the sputtering process.

6. The preparation method according to claim 1, characterized in that, In step (4), the plasma cleaning process involves an argon flow rate of 15-25 sccm, a power of 60-100W, and a time of 8-12 min.

7. The preparation method according to claim 6, characterized in that, In step (4), the plasma cleaning process involves an argon flow rate of 20 sccm, a power of 80 W, and a time of 10 min.

8. The restoration obtained by the preparation method according to any one of claims 1-7.

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