Highly efficient antibacterial and osteogenesis-promoting nano-composite silicon nitride coating, and preparation method and application thereof

Abstract

The application discloses a kind of high-efficiency antibacterial bone-promoting nano composite silicon nitride coatings and preparation method and application, with implant as matrix, from bottom to top include ion intermixing layer, adhesive layer, transition layer and silicon nitride layer;Preparation method includes: (1) using high-energy particles to bombard the surface of implant and form ion intermixing layer on the surface of implant;(2) using magnetron sputtering ion plating deposition technology, adhesive layer is deposited on the surface of ion intermixing layer;(3) keep the current of silicon target unchanged, by adjusting the nitrogen flow and cavity pressure, transition layer is obtained;(4) by using glow intensity control nitrogen flow, silicon nitride layer is deposited;The obtained nano composite silicon nitride coating can be applied in the field of oral implant.The coating of the application significantly improves the osteogenesis and antibacterial properties of the implant, providing a reliable guarantee for the long-term use of the implant in vivo.

Description

Technical Field

[0001] This invention relates to the field of functional coatings, specifically to a highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating, its preparation method, and its application. Background Technology

[0002] Dental implantation is a common method for addressing tooth loss. Early osseointegration and rapid osteogenesis at the bone-implant interface are crucial for the clinical success of oral implants. The osseointegration capacity of an implant is related to its surface chemistry and morphology, and therefore, surface treatments can be used to enhance its osteogenic capacity. Commercially available sandblasting and acid etching (SLA) can alter the implant surface morphology, increasing roughness and surface area, improving mechanical fixation, promoting biofilm formation, and ultimately benefiting osseointegration. However, high roughness introduces a range of problems, including bacterial adhesion, soft tissue damage, difficulty in cleaning, and delayed bone healing.

[0003] Compared to commercial surface morphology modifications, rationally designing the surface chemical composition and structure of implants can not only effectively enhance osseointegration but also improve their antimicrobial properties. Silicon nitrides are biomedical materials with excellent mechanical strength, biocompatibility, and biochemical stability. Due to the unique chemical bonding of Si3N4, its surface readily forms hydrophilic functional groups, resulting in excellent osteogenic and antimicrobial properties. However, the inherent brittleness of Si3N4 poses a high risk of fracture and presents difficulties in manufacturing and surgery. Therefore, combining the biomedical advantages of Si3N4 with the mechanical advantages of metals by preparing Si3N4 coatings on metal surfaces presents a promising approach. Summary of the Invention

[0004] Purpose of the invention: The present invention aims to provide a highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating, and also provides a method for preparing the nanocomposite silicon nitride coating and its application.

[0005] Technical solution: The highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating provided by the present invention uses the implant as a substrate and includes, from bottom to top, an ion-mixed layer, an adhesive layer, a transition layer and a silicon nitride layer.

[0006] Furthermore, the thickness of the ion-mixed layer is 10-300 nm, the thickness of the adhesive layer is 50-500 nm, the thickness of the transition layer is 10-300 nm, and the thickness of the silicon nitride layer is 500-2000 nm.

[0007] The preparation method of the above-mentioned highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating includes the following steps:

[0008] (1) High-energy particles are used to bombard and clean the surface of the implant, and an ion-mixed layer is formed on the surface of the implant.

[0009] (2) A bonding layer is deposited on the surface of the ion-mixed layer using magnetron sputtering ion plating deposition technology;

[0010] (3) Keep the current of the silicon target material constant, and obtain the transition layer by adjusting the nitrogen flow rate and the pressure inside the cavity;

[0011] (4) By controlling the nitrogen flow rate through glow intensity, a silicon nitride layer is deposited, thus obtaining a highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating.

[0012] Further, in step (1), the high-energy particles are Ar and Si; the material of the implant is pure titanium, titanium alloy, titanium-zirconium alloy or zirconium oxide.

[0013] Furthermore, in step (2), the magnetron sputtering ion plating deposition technology uses a high-purity silicon target; the substrate bias voltage during sputtering is 60-150V, the silicon target power is 200W-3000W; the sputtering atmosphere is a mixture of argon and nitrogen, and the deposition pressure is 0.1-1.0Pa; the nitrogen composition during sputtering is controlled by a spectrometer.

[0014] Furthermore, in step (3), the set value of the pressure inside the cavity is 0.1-1.0 Pa.

[0015] Furthermore, in step (4), the glow intensity is used to control the nitrogen flow rate, and the glow intensity ranges from 35% to 75%.

[0016] The aforementioned highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating is applied in the field of dental implants.

[0017] Invention Principle: This invention first treats the implant surface by bombarding and cleaning it with high-energy particles to form an ion-mixed layer. Then, using magnetron sputtering ion plating deposition technology, a silicon layer of a certain thickness is deposited on the surface of the ion-mixed layer to form a bonding layer. Next, a transition layer is designed and prepared. Maintaining a constant current in the silicon target material, the pressure within the cavity is gradually varied by adjusting the nitrogen flow rate to obtain the transition layer. Finally, a silicon nitride layer is prepared by controlling the nitrogen flow rate through glow discharge intensity deposition. Through these steps, a nano-composite silicon nitride coating with excellent osteogenic and antibacterial properties is obtained.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0019] (1) This invention improves the osseointegration and antibacterial properties of implants through a rationally designed surface treatment process, thereby promoting implant osteoogenesis and reducing the risk of infection. Magnetron sputtering ion plating deposition technology can precisely control the chemical composition and thickness of the coating to ensure stable performance. A nano-composite silicon nitride coating suitable for the oral environment is designed and prepared to meet the specific needs of oral implants. It can be widely used in oral implants to improve the osteogenic performance of implants while possessing excellent antibacterial properties. It is expected to improve the clinical success rate and reduce the risk of infection in oral implant surgery, bringing new technological advancements to the field of oral restoration.

[0020] (2) Compared with the current mainstream surface treatment methods for oral implants, the present invention has significant professional advantages in several aspects: Although traditional sandblasting and acid etching have achieved certain results in improving surface roughness, their accompanying problems, such as bacterial adhesion, soft tissue damage, and difficulty in cleaning, limit their application in the field of oral restoration; In contrast, the present invention uses magnetron sputtering ion plating deposition technology, which can achieve precise control of surface treatment, ensure the uniformity and consistency of the surface, and improve the controllability and reliability of the coating.

[0021] (3) The silicon nitride (Si3N4) coating introduced by this invention possesses both excellent osteogenic and antibacterial properties, providing an innovative solution for the field of oral implant surface treatment. Compared to the potential infection risks associated with traditional methods, the antibacterial properties of silicon nitride effectively reduce bacterial adhesion, offering a safer and more reliable option for oral prosthetic surgery. Overall, this invention surpasses current technological levels in terms of precise control over surface treatment, osteogenic properties, and antibacterial performance, and is expected to bring significant professional advancements to the design and application of oral implants. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the nanocomposite silicon nitride coating of the present invention;

[0023] Figure 2 The surface morphology, composition, and wettability of the pure titanium and silicon nitride coatings in Example 1 are described.

[0024] Figure 3 The full spectrum (a) of the pure titanium and silicon nitride coating XPS composition in Example 1, and the detailed spectra of Ti (b), Si (c) and N (d);

[0025] Figure 4 The number of Gram-negative bacillus colonies on the surface of pure titanium and silicon nitride coating in the culture medium after 24 hours in Example 1;

[0026] Figure 5 This describes the adhesion and spreading of human bone marrow mesenchymal stem cells on the surfaces of pure titanium and silicon nitride coatings in Example 1.

[0027] Figure 6 The number of Staphylococcus aureus colonies on the SAL-treated pure titanium sample and silicon nitride coating surface in the culture medium in Example 2 after 24 hours.

[0028] Figure 7 Micro-CT and three-dimensional reconstruction of in vivo osteogenicity of SAL-treated pure titanium samples and silicon nitride coating in Example 2;

[0029] Figure 8 For in vivo osteogenic histological observation of SAL-treated pure titanium samples and silicon nitride coatings in Example 2;

[0030] Figure 9 The coating bonding strength test results for Embodiment 2 of the present invention are as follows: (a): the bonding force of the silicon nitride coating is tested using the scratch method; (b): the coating bonding strength is tested using the Rockwell indentation method. Detailed Implementation

[0031] The present invention will now be further described in conjunction with specific embodiments and accompanying drawings.

[0032] like Figure 1 As shown, the highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating provided by the present invention uses implant A as the substrate. The nanocomposite silicon nitride coating F includes, from bottom to top, an ion-mixed layer B, an adhesive layer C, a transition layer D, and a silicon nitride layer E. The thickness of the ion-mixed layer B is 10-300 nm, the thickness of the adhesive layer C is 50-500 nm, the thickness of the transition layer D is 10-300 nm, and the thickness of the silicon nitride layer E is 500-2000 nm.

[0033] Example 1: The preparation method of the nanocomposite silicon nitride coating provided in this example specifically includes the following steps:

[0034] An unbalanced DC magnetron sputtering deposition system was used, with a silicon target of 99.9% purity. A flat, mirror-polished commercial pure titanium sample (φ15mm × 1.5mm) was ultrasonically cleaned in ethanol for 20 minutes and then fixed in a triaxial fixture. When the background pressure was below 3 × 10⁻⁶... -3 At Pa, the sample was placed in Ar + The sample underwent etching and pre-cleaning for 10 minutes at a substrate bias of -400V and a frequency of 250kHz to obtain an ion-mixed layer. In the subsequent deposition stage, Ar was introduced at a flow rate of 40 sccm to sputter the target. The deposition working pressure was 0.8 Pa, and the sample was subjected to a bias of -60V for 4 minutes to obtain a binder layer. Nitrogen and silicon deposition was then performed at a bias of -70V. During silicon nitride layer deposition, the DC current of the silicon target was 3A, the nitrogen gas was controlled by glow discharge intensity and set to 65%, and the deposition time was 180 minutes, resulting in a silicon nitride composite coating with a thickness of 500 nm.

[0035] like Figure 2 As shown, the silicon nitride coating (Si3N4-Ti) did not alter the original roughness of the pure titanium (Ti) substrate surface, and EDS analysis revealed that the silicon nitride coating was silicon-rich. Figure 2 It can be seen that the hydrophilicity of the silicon nitride coating is significantly improved compared to the original pure titanium substrate, which is beneficial to subsequent cell proliferation and osteogenic formation.

[0036] like Figure 3 As shown, the surface composition of the sample was analyzed using X-ray photoelectron spectroscopy. The two peaks at 458.4-458.7 eV correspond to Ti. 4+ Characteristic Ti 2p3 / 2 and Ti 2p1 / 2 peaks were observed, while Si-O, Si-N, and Si-Si bonds were detected in the fine spectrum of Si 2p. Furthermore, the N 1s spectrum consisted of Si-ON and Si-N bonds.

[0037] Further comparisons were made on the antibacterial properties of pure titanium substrate and silicon nitride coating. Figure 4 The number of Gram-negative bacillus colonies on the surface of pure titanium and silicon nitride coating after 24 hours in the culture medium is shown. It can be seen that the number of colonies on the silicon nitride coating is significantly reduced compared to the pure titanium substrate, indicating that it has excellent antibacterial properties.

[0038] Further comparisons were made of in vitro cell adhesion between pure titanium substrates and silicon nitride coatings. Figure 5 The images show the adhesion and spread of human bone marrow mesenchymal stem cells on the surfaces of pure titanium and silicon nitride coatings. The silicon nitride coating has a larger spread area than the pure titanium substrate and exhibits more actin stress fibers.

[0039] Example 2: The preparation method of the nanocomposite silicon nitride coating provided in this example specifically includes the following steps: An unbalanced DC magnetron sputtering deposition system is used, with a silicon target of 99.9% purity. A titanium rod is bombarded with large-particle alumina abrasive for 30 seconds, followed by acid etching of the titanium sheet at 60°C for 1 hour using a mixed acid solution containing 18% hydrochloric acid and 49% sulfuric acid. The etched titanium sheet is then ultrasonically cleaned and sterilized, serving as a control group (SLA-Ti). An unetched titanium rod is fixed on a triaxial fixture within the magnetron sputtering equipment cavity to prepare the silicon nitride coating. The coating preparation process parameters are the same as in Example 1, and the prepared silicon nitride coating serves as the experimental group (Si3N4-Ti).

[0040] The bonding strength between the silicon nitride coating and the titanium substrate was tested using the scratch test. The scratch test results are as follows: Figure 6 As shown in (a), according to ASTM C1624-22, the load at which the coating peels off (marked by a white ellipse) is the maximum bonding force, which is 17.47 ± 1.49 N.

[0041] The results of the coating adhesion strength test using the Rockwell indentation method were observed using a metallographic microscope. Figure 6 In (b), it can be seen that there are no cracks or coating peeling around the indentation, which belongs to category 0 in ISO26443:2008, proving that the silicon nitride coating has good bonding performance with the titanium substrate.

[0042] Figure 7 This image shows a comparison of Staphylococcus aureus colony counts on the surfaces of SLA-Ti and Si3N4-Ti samples after 24 hours in the culture medium. Compared to the SLA-Ti sample, the Si3N4-Ti sample with a silicon nitride coating has significantly fewer colony counts, demonstrating its superior antibacterial properties.

[0043] Further osteogenic performance tests of SLA-Ti and Si3N4-Ti samples were conducted on the femoral ends of mice using micro-CT and three-dimensional reconstruction. Figure 8 As shown, at 4 weeks, only a small amount of trabeculae formed around the SLA-Ti implants, while a significant amount of trabeculae had formed around the Si3N4-Ti implants; and at 8 weeks, the Si3N4 implants were completely encapsulated by a large amount of trabeculae. This indicates that, compared to SLA-Ti, the Si3N4 coating can achieve faster and earlier osseointegration.

[0044] Further in vivo histological observation of SLA-Ti and Si3N4-Ti implants was conducted, such as... Figure 9 As shown. At 4 weeks, the new bone generated around the SLA-Ti implant has less contact with the implant and is discontinuous; in contrast, the new bone generated around the Si3N4-Ti implant has already wrapped around the implant surface and is more continuous. At 8 weeks, compared to 4 weeks, the SLA-Ti implant has generated more and thicker trabeculae on its surface, and the contact with the implant has also increased slightly. At this time, the trabeculae around the Si3N4-Ti implant have almost completely wrapped the implant surface, and there are a large number of newly generated trabeculae around the implant, which intertwine and connect to form a network.

Claims

1. A highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating, using an implant (A) as a substrate, characterized in that, The nanocomposite silicon nitride coating (F) comprises, from bottom to top, an ion-mixed layer (B), an adhesive layer (C), a transition layer (D), and a silicon nitride layer (E). The ion-mixed layer (B) is formed by bombarding the surface of the implant (A) with high-energy argon particles to clean it and form the ion-mixed layer (B) on the implant surface. The transition layer (D) is a silicon nitride layer with nitrogen atom content gradually increasing from the implant (A) to the silicon nitride layer (E). The adhesive layer (C) is a silicon layer. The thickness of the silicon nitride layer (E) is 500-2000 nm.

2. The nanocomposite silicon nitride coating according to claim 1, characterized in that, The thickness of the ion-mixed layer (B) is 10-300 nm.

3. The nanocomposite silicon nitride coating according to claim 1, characterized in that, The thickness of the adhesive layer (C) is 50-500 nm.

4. The nanocomposite silicon nitride coating according to claim 1, characterized in that, The thickness of the transition layer (D) is 10-300 nm.

5. A method for preparing a highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating as described in claim 1, characterized in that, Includes the following steps: (1) The surface of the implant (A) is bombarded and cleaned with high-energy particles, and an ion-mixed layer (B) is formed on the surface of the implant. (2) A bonding layer (C) is deposited on the surface of the ion-mixed layer (B) using magnetron sputtering ion plating deposition technology. (3) Keep the current of the silicon target constant, and obtain the transition layer (D) by adjusting the nitrogen flow rate and the pressure inside the cavity. (4) By controlling the nitrogen flow rate through glow intensity, a silicon nitride layer (E) is deposited, which is a highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating (F).

6. The preparation method according to claim 5, characterized in that, In step (2), the magnetron sputtering ion plating deposition technology uses a high-purity silicon target; the substrate bias voltage during sputtering is 60-150V, the silicon target power is 200W-3000W; the sputtering atmosphere is a mixture of argon and nitrogen, and the deposition pressure is 0.1-1.0 Pa; the nitrogen composition during sputtering is controlled by a spectrometer.

7. The preparation method according to claim 5, characterized in that, In step (3), the pressure inside the cavity is set to 0.1-1.0 Pa.

8. The preparation method according to claim 5, characterized in that, In step (4), the glow intensity ranges from 35% to 75%.

9. The application of the highly efficient antibacterial and osteogenic nanocomposite silicon nitride coating as described in claim 1 in the field of dental implants.

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