CN112121227A - Preparation method of medical composite coating of strontium titanate/strontium hydroxyapatite on titanium metal surface - Google Patents

Abstract

The invention relates to a preparation method for a strontium titanate/strontium hydroxyapatite medical composite coating on a titanium metal surface. , and then ultrasonically washed and dried; the pretreated titanium sheet was used as the anode, and the platinum sheet electrode was used as the cathode. After anodizing at room temperature, the titanium sheet was cleaned and dried, and annealed in a tube furnace; the obtained titanium sheet was placed in 16ml , in Sr(OH)2 solution, hydrothermally reacted at 200 ° C for 1.5-2 h, taken out, cleaned and dried; the obtained titanium sheet was placed in a mixed electrolyte of calcium salt and strontium salt for constant current deposition, and the electrolyte composition was: 0.034 M‑0.04M Ca(NO)3, 0.02M‑0.06M Sr(NO)3, 0.025M NH4H2PO3, 0.1M Na(NO)3. The preparation method of the strontium titanate/strontium hydroxyapatite medical composite coating on the titanium metal surface of the present invention prepares the strontium element-containing composite coating on the surface of the titanium substrate for the first time, which is divided into a strontium nanotube coating and a strontium hydroxy phosphorus coating Limestone coating, which greatly improves the performance of titanium matrix implants.

Description

Preparation of a strontium titanate/strontium hydroxyapatite medical composite coating on titanium surface method

technical field

The invention belongs to the cross technical field of materials and biomedicine, in particular to a preparation method of a strontium titanate/strontium hydroxyapatite composite medical coating on a titanium metal surface.

Background technique

Titanium and titanium alloys are the most excellent implant materials at present because of their high mechanical strength, low elastic modulus and chemical inertness. Since titanium and titanium-based alloys are still quite different in performance from human bone tissue, the following two problems will still arise after entering the human environment as implant materials: 1. Due to the biological inertness of titanium metal, the surface biological activity is not ideal, and its bone-promoting Poor generation ability, resulting in poor integration of the implant with the surrounding tissue, and loosening of the implant when the time is too long; 2. Since the titanium implant alone does not have bactericidal and anti-inflammatory properties, the implant enters the body, There may be an inflammatory reaction around the implant due to bacterial infection. At present, functional modification of titanium surface to improve its osseointegration with surrounding tissues is still a current research hotspot. The micro-nano structure effect on the surface of titanium implants plays a leading role in inducing the proliferation and differentiation of osteoblasts. The main purpose of people is to change the surface morphology, structure and composition characteristics of titanium implants through physical and chemical means, so as to achieve The purpose of improving the biological properties of implants.

Hydroxyapatite, or HA for short, is widely used as a substitute material for bone tissue repair due to its very similar composition to calcium phosphate, a component of human bone, with good biocompatibility and osteopromoting ability. However, hydroxyapatite also has disadvantages, such as poor tensile strength and low toughness, which also limits the application of hydroxyapatite in implant materials to a large extent.

In recent years, strontium ranelate has been widely used in the treatment of female osteoporosis, and the role of strontium in bone repair has also been verified by people. The introduction of strontium-containing drugs to patients with osteoporosis significantly reduces the risk of fractures. Strontium is a natural trace element in human bones and has the effect of stimulating the differentiation of osteoblasts.

But so far, there is no method to combine strontium, hydroxyapatite and titanium metal to improve the performance of titanium matrix implants. If they can be effectively combined, this is a new attempt and will have a wide range of application value. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of strontium titanate/strontium hydroxyapatite composite medical coating on titanium metal surface, so as to overcome the shortcomings of poor antibacterial properties and poor biocompatibility of existing medical titanium materials. In the method, a uniform titanium dioxide nanotube array is produced by surface anodic oxidation, hydrothermally modified into strontium titanate nanotubes, and a layer of strontium-doped hydroxyapatite biocomposite coating is electrochemically deposited on its surface. The strontium ions in the implant are gradually released into the surrounding environment of the implant over time, which can improve the osteogenic properties of the implant. The surface of the strontium hydroxyapatite coating has a dense structure and a rough surface. Compared with pure titanium implants, It is beneficial to the successful implantation of the implant in the human body; the combination of electrochemistry and hydrothermal method, the conditions are mild, and the biological performance of the existing implant can be effectively improved.

The purpose of this invention is to realize through the following technical solutions:

A preparation method of strontium titanate/strontium hydroxyapatite medical composite coating on titanium metal surface, comprising the following steps:

A. Titanium pretreatment

The titanium sheet with a purity of ≥ 99.7% is polished step by step with SiC sandpaper until the surface has no obvious scratches. Organic reagents are used, deionized water is ultrasonically washed, mixed acid solution is soaked for 10-15 seconds, deionized water is ultrasonically washed and dried. ;

B. Anodizing

The titanium sheet pretreated in step A was used as the anode, the platinum sheet electrode was used as the cathode, and anodization was performed at room temperature. And annealed in a tube furnace;

C. Hydrothermal reaction

The titanium sheet obtained in step B was placed in 16 ml of Sr(OH) ₂ solution, hydrothermally reacted at 200 ° C for 1.5-2 h, taken out, washed and dried;

D. Electrochemical deposition

The titanium sheet obtained in step C is placed in a mixed electrolyte of calcium salt and strontium salt for constant current deposition, and the electrolyte is composed of: 0.034M-0.04M Ca(NO) ₃ , 0.02M-0.06M Sr(NO) ) ₃ , _{0.025M NH4H2PO3} , 0.1M Na(NO _{)3 .}

Further, in step A, the organic reagents are ethanol and acetone.

Further, in step A, the mixed acid solution is HF:HNO ₃ :H ₂ O=1:5:10vt%.

Further, in step B, the anodic oxidation voltage is 30V-50V, and the anodic oxidation time is 1-2h.

Further, in step B, the specific steps of the annealing treatment are: placing the titanium sheet in a tube furnace to program the temperature, first setting the heating rate to 10°C/min, heating to 500°C, holding for 2 hours, and then cooling with the furnace to 10°C/min. room temperature.

Further, in step C, the concentration of the Sr(OH) ₂ solution is 0.018M-0.025M.

Further, in step D, the constant current deposition process adopts a three-electrode system, the titanium sheet obtained in step C is used as the working electrode, the platinum electrode is used as the counter electrode, and the saturated calomel electrode (SCE) is used as the reference electrode, wherein the constant current deposition current The density was 0.8-2 mA/cm ² and the deposition time was 40-60 min.

Further, the pH value of the electrolyte was kept at 4.5, the deposition temperature was kept at 65°C, and magnetic stirring was used.

Compared with the prior art, the beneficial effects of the present invention are: the present invention prepares a strontium element-containing composite coating on the surface of the titanium substrate for the first time, which is divided into a strontium-containing nanotube coating and a strontium-containing hydroxyapatite coating; The strontium in the coating is gradually released into the human environment, which can play the role of strontium ions in bone repair; secondly, the rough surface morphology of hydroxyapatite is also conducive to the colonization of osteoblasts; among them, the choice of tubular titanium dioxide coating can also Strengthening the mechanical fit between the composite coating and the substrate can solve the practical problem that the existing coating is easy to fall off.

Description of drawings

The electron microscope picture of titanium dioxide nanotube coating in Fig. 1 embodiment 1;

The electron microscope picture of strontium titanate coating in Fig. 2 embodiment 1;

Fig. 3 is a scanning electron microscope image of Example 1.

Detailed ways

Example 1

Cut a titanium plate with a thickness of 1mm into a 10x10mm size titanium sheet, and use 400, 800, 1200 sandpaper to polish the surface of the titanium sheet step by step until the surface of the titanium sheet is smooth and has no obvious scratches. Afterwards, the titanium sheets were immersed in 10 ml of ethanol, acetone, and deionized water, respectively, and ultrasonically cleaned for 10 minutes, and then cleaned and dried to remove impurities on the surface of the titanium sheets. Then, a mixed solution of HF, HNO ₃ and H ₂ O with a volume ratio of 1:5:10 was prepared, and the titanium sheet was immersed in the mixed acid for 10-15s to remove the surface metal oxide film, washed and dried.

The pretreated titanium sheet was used as the anode, the platinum sheet electrode was used as the cathode, and anodization was carried out in a 0.5 wt% HF solution. The voltage was 50v, and the oxidation time was 1h. After cleaning and drying, the titanium sheet was annealed at a heating rate of 10 °C/min, kept at 500 °C for 90 min, and then cooled in a furnace, at which point more stable anatase titanium dioxide was obtained.

Immerse the heat-treated titanium sheet in 16ml, 0.02M Sr(OH) ₂ solution, and select a 25ml autoclave for the reaction kettle. At 200 °C, the hydrothermal reaction was carried out for 2 h. After cooling, the excess solution on the surface was rinsed with deionized water, and dried at 60 °C for use.

One-step constant-current deposition was performed using the above-mentioned hydrothermally reacted titanium sheet as a substrate. The electrolyte composition was 0.034M Ca(NO) ₃ , 0.06MSr(NO) ₃ , 0.025M NH ₄ H ₂ PO ₃ , and 0.1M Na(NO) ₃ . The pH of the electrolyte was adjusted to 4.5, and the temperature was maintained at 65° C. with magnetic stirring during electrochemical deposition. The deposition current is 1 mA/cm ² , and the deposition time is 40 mim.

Example 2

Cut a titanium plate with a thickness of 1mm into a 10x10mm size titanium sheet, and use 400, 800, 1200 sandpaper to polish the surface of the titanium sheet step by step until the surface of the titanium sheet is smooth and has no obvious scratches. Afterwards, the titanium sheets were immersed in 10 ml of ethanol, acetone, and deionized water, respectively, and ultrasonically cleaned for 10 minutes, and then cleaned and dried to remove impurities on the surface of the titanium sheets. Then, a mixed solution of HF, HNO ₃ and H ₂ O with a volume ratio of 1:5:10 was prepared, and the titanium sheet was immersed in the mixed acid for 10-15s to remove the surface metal oxide film, washed and dried.

The pretreated titanium sheet was used as the anode, the platinum sheet electrode was used as the cathode, and anodization was carried out in a 0.5 wt% HF solution. The voltage was 60v, and the oxidation time was 2h. After cleaning and drying, the titanium sheet was annealed at a heating rate of 10 °C/min, kept at 500 °C for 90 min, and then cooled in a furnace, at which point more stable anatase titanium dioxide was obtained.

Immerse the heat-treated titanium sheet in 16ml, 0.025M Sr(OH) ₂ solution, and select a 25ml high-pressure reactor for the reaction kettle. At 200 °C, the hydrothermal reaction was carried out for 2 h. After cooling, the excess solution on the surface was rinsed with deionized water, and dried at 60 °C for use.

One-step constant-current deposition was performed using the above-mentioned hydrothermally reacted titanium sheet as a substrate. The electrolyte composition was 0.04M Ca(NO) ₃ , 0.02M Sr(NO) ₃ , 0.025M NH ₄ H ₂ PO ₃ , 0.1M Na(NO) ₃ . The pH of the electrolyte was adjusted to 4.5, and the temperature was maintained at 65° C. with magnetic stirring during electrochemical deposition. The deposition current is 2mA/cm ² and the deposition time is 60mim.

Claims (8)

1. a preparation method of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating, is characterized in that, comprises the following steps: A. Titanium pretreatment The titanium sheet with a purity of ≥99.7% is polished step by step with SiC sandpaper until the surface has no obvious scratches, organic reagents are used, deionized water is ultrasonically washed, mixed acid solution is soaked for 10-15 seconds, deionized water is ultrasonically washed and dried; B. Anodizing The titanium sheet pretreated in step A was used as the anode, the platinum sheet electrode was used as the cathode, and anodization was performed at room temperature. And annealed in a tube furnace; C. Hydrothermal reaction The titanium sheet obtained in step B was placed in 16 ml of Sr(OH) ₂ solution, hydrothermally reacted at 200 ° C for 1.5-2 h, taken out, washed and dried; D. Electrochemical deposition The titanium sheet obtained in step C is placed in a mixed electrolyte of calcium salt and strontium salt for constant current deposition, and the electrolyte is composed of: 0.034M-0.04M Ca(NO) ₃ , 0.02M-0.06M Sr(NO) ) ₃ , _{0.025M NH4H2PO3} , 0.1M Na(NO _{)3 .} 2 . The method for preparing a strontium titanate/strontium hydroxyapatite medical composite coating on a titanium metal surface according to claim 1 , wherein in step A, the organic reagents are ethanol and acetone. 3 . 3. the preparation method of a kind of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating according to claim 1, is characterized in that: step A, described mixed _acid solution is HF:HNO :H ₂ O = 1:5:10 vt%. 4. the preparation method of a kind of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating according to claim 1, is characterized in that: step B, described anodic oxidation voltage is 30V-50V, anodic oxidation The time is 1-2h. 5. the preparation method of a kind of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating according to claim 1, is characterized in that: step B, the concrete step of described annealing treatment is: The temperature was programmed in a tube furnace. First, the heating rate was set to 10 °C/min, and the temperature was raised to 500 °C, maintained for 2 h, and then cooled to room temperature with the furnace. 6. the preparation method of a kind of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating according to claim 1, is characterized in that: in step C, the concentration of described Sr(OH ₎ solution is 0.018 M-0.025M. 7. the preparation method of a kind of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating according to claim 1, is characterized in that: step D, described constant current deposition process adopts three-electrode system, with The titanium sheet obtained in step C is the working electrode, the platinum electrode is the counter electrode, and the saturated calomel electrode is the reference electrode, wherein the constant current deposition current density is 0.8-2 mA/cm ² , and the deposition time is 40-60 min. 8. the preparation method of a kind of titanium metal surface strontium titanate/strontium hydroxyapatite medical composite coating according to claim 7, is characterized in that: described electrolyte pH value is kept at 4.5, and deposition temperature is kept at 65 °C and use magnetic stirring.

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