CN110656365B

CN110656365B - Preparation method of strontium-doped calcium-phosphorus compound film with nano-ordered structure

Info

Publication number: CN110656365B
Application number: CN201911099172.8A
Authority: CN
Inventors: 林昌健; 樊丽丽; 胡仁; 张艳梅; 胡洁洁; 杨云; 石巍; 田中群; 董骧; 段红平
Original assignee: Xiamen University; Beijing Naton Technology Group Co Ltd
Current assignee: Beijing Naton Technology Group Co Ltd
Priority date: 2019-11-12
Filing date: 2019-11-12
Publication date: 2021-05-14
Anticipated expiration: 2039-11-12
Also published as: CN110656365A

Abstract

A method for preparing a strontium-doped calcium-phosphorus compound film with a nano-ordered structure, which relates to the field of medical metal. Pretreating a medical implant material to be treated; and performing cathodic electrochemical deposition on the substrate to obtain the strontium-doped calcium-phosphorus compound film with the nano-ordered structure on the surface of the substrate. The nano-ordered calcium-phosphorus compound/strontium composite coating similar to the natural bone structure is constructed on the surface of the medical metal through electrochemical directional deposition, so that the biocompatibility and the bioactivity of the material can be greatly improved, and the clinical application can be realized. A method for preparing the micro-nano ordered secondary structure octacalcium phosphate/strontium composite coating is established. The surface construction of the calcium-phosphorus compound/strontium composite film is realized by applying an electrochemical deposition method. The invention provides an important method for manufacturing the high-bioactivity nano-ordered composite artificial bone material.

Description

Preparation method of strontium-doped calcium-phosphorus compound film with nano-ordered structure

Technical Field

The invention relates to the field of medical metal, in particular to a preparation method of a controllable strontium-doped calcium-phosphorus compound film with a nano ordered structure on the surface of medical metal through electrochemical deposition.

Background

The bone is used as an important component of hard tissues of a human body and is constructed by calcium phosphate, collagen, some trace elements (Mn, Sr, Mg, Zn, Si …) and the like, and particularly the calcium phosphate in natural bone usually has a micro-nano ordered multi-level structure. In the treatment of bone loss due to bone defects or bone defects caused by trauma, autologous bone grafts are generally used as the gold standard. However, the source of autologous bone is limited and artificially prepared calcium phosphate materials are often used as a substitute. From the viewpoint of bionics, it is necessary to prepare bone tissue substitutes which are as close as possible to the structure and components of natural bones of human bodies. The calcium phosphate has high bioactivity, and can be converted into bone-like apatite under physiological condition, which is favorable for adhesion, proliferation and differentiation of osteocyte. With the advent of aging society, osteoporosis has become a global health problem. Osteoporosis can lead to increased bone fragility and increased risk of fracture. The underlying cause is mainly the loss of balance between bone resorption and bone formation. The effect of strontium on bone has attracted much attention from researchers over the past several decades due to the development of the anti-osteoporosis drug strontium ranelate. However, it has been reported that the effect of strontium depends mainly on the dosage, low strontium concentration increases the osteogenesis rate, and high strontium dosage causes abnormal bone mineralization and metabolism, so that the amount of strontium ion incorporated into the calcium-phosphorus salt during preparation needs to be strictly controlled.

Because strontium ions and calcium phosphate have important functions in bone metabolism, the combination of the strontium ions and the calcium phosphate has extremely excellent performance, and researchers have great interest in the combination of the strontium ions and the calcium phosphate. Researchers have used electrochemical deposition, micro-arc oxidation, electrophoretic deposition, air plasma spraying and other methods to prepare HA (DCPD) and strontium ion composite coatings^[1-5]. In the existing many related researches, the calcium phosphate biological material with the micro-nano ordered multi-level structure cannot be effectively prepared. The electrochemical deposition method is a method for preparing the bone substitute material with great potential. The preparation condition is mild, and the controllable micro-nano ordered multi-level structure calcium phosphate biological material can be realized by regulating and controlling the parameters of the electrochemical deposition methodThe preparation method can obviously improve the biocompatibility and the bioactivity of the product. Strontium ions are doped into the electrolyte, and the conditions such as a certain deposition mode, deposition temperature and the like are controlled, so that the strontium ion/calcium phosphate composite material with an ordered structure can be obtained by codeposition on the surface of the medical metal. The strontium ions can directly participate in the deposition process or influence the growth of the deposition layer, and the appearance of the generated film can be regulated. The strontium/calcium phosphate prepared by the electrochemical method has excellent bioactivity, can be expected to accelerate the growth of bones and the fixation of implanted materials in vivo, shortens the treatment period of patients, and is particularly suitable for osteoporosis patients.

Disclosure of Invention

The invention aims to provide a method for preparing a strontium-doped calcium-phosphorus compound film layer with a nano ordered structure, which has a bone-like structure and uniform chemical properties, in a controllable manner under mild conditions.

The invention comprises the following steps:

1) pretreating a medical implant material to be treated;

2) and performing cathodic electrochemical deposition on the substrate to obtain the strontium-doped calcium-phosphorus compound film with the nano-ordered structure on the surface of the substrate.

In the step 1), the substrate is made of medical implant materials and the like, and the medical implant materials can be medical implant metals and the like; the medical implant metal can be one of titanium, titanium alloy, stainless steel and the like; the substrate pretreatment may be specifically performed by: soaking the medical implant material in acetone, ethanol and deionized water in sequence, ultrasonically cleaning, and washing in HNO₃Treating the mixture with HF solution and cleaning; the HNO₃The concentration of (A) can be 8% -10%, and the concentration of HF can be 0.8% -1.2%.

In step 2), the deposition solution for performing cathodic electrochemical deposition on the substrate may contain 0.01-0.14 mol/L of [ Ca [²⁺]0.04-0.4 mol/L of phosphate radical species and a certain proportion ([ Sr)²⁺]/([Sr²⁺]+[Ca²⁺]) 0.1-20%) of [ Sr%²⁺]The solution of (1); the deposition solution may use Ca (NO)₃)₂、NaH₂PO₄Or Sr (NO)₃)₂Etc.; what is needed isThe pH value of the deposition solution can be 2-6; the current density of the electrochemical deposition can be 0.1-1.5 mA/cm²(ii) a The deposition temperature of the electrochemical deposition can be 25-90 ℃, and the deposition time can be 3-60 min.

The invention constructs the nano-ordered calcium-phosphorus compound/strontium composite coating similar to the natural bone structure on the surface of the medical metal by electrochemical directional deposition, thereby greatly improving the biocompatibility and bioactivity of the material and realizing clinical application. The method for preparing the micro-nano ordered secondary structure octacalcium phosphate/strontium composite coating is established by systematically investigating the influence of a series of electrochemical deposition parameters on the deposition behavior of the calcium-phosphorus compound and strontium composite coating. The surface construction of the calcium-phosphorus compound/strontium composite film is realized by an electrochemical deposition method. Provides an important method for manufacturing the high-bioactivity nano-ordered composite artificial bone material.

Drawings

FIG. 1 is an SEM image of electrochemically deposited coatings at different magnifications. In fig. 1, the graphs a, b and c show the surface topography of the OCP coating obtained without adding strontium ions to the electrolyte (graph a is 1000 times, graph b is 5000 times, and graph c is 20000 times); d, e and f are the surface appearance of the OCP/Sr composite coating obtained by adding 1% strontium ions into the electrolyte (1000 times in d, 5000 times in e and 20000 times in f); g, h, i are the surface appearance of the OCP/Sr composite coating obtained by adding 5% strontium ions into the electrolyte (graph d is 1000 times, graph e is 5000 times, and graph f is 20000 times); the comparison of the three shows that the film crystal grains have no obvious change along with the increase of the doping amount of the strontium ions, and the whole film crystal grains are gradually changed from a lodging state to an upright state.

FIG. 2 is an EDS-Mapping chart of an electrochemically deposited coating with a strontium ion incorporation of 1%.

FIG. 3 is an EDS-Mapping plot of an electrochemically deposited coating with 5% strontium ion incorporation.

Figure 4 is an XRD pattern of the electrochemically deposited coating. In fig. 4, a represents an XRD pattern of the calcium phosphate coating prepared without adding strontium ions to the electrolyte, d is a partial enlarged view of a (2 θ 25.5 to 26.5), b is an XRD pattern prepared with 1% strontium ions added to the electrolyte, e is a partial enlarged view of b (2 θ 25.5 to 26.5), c is an XRD pattern prepared with 5% strontium ions added to the electrolyte, and f is a partial enlarged view of c (2 θ 25.5 to 26.5) with an abscissa of 2theta (deg).

FIG. 5 shows the alkaline phosphatase (ALP) activity of MC3T3-E1 cells cultured on the surface of an electrochemically deposited film for various periods of time. In fig. 5, 5% Sr/CaP is significantly different from CaP or 1% CaP, p <0.05, and p < 0.001.

Detailed Description

The following examples will further illustrate the present invention with reference to the accompanying drawings.

Example 1

Preparing the calcium phosphate film layer by an electrochemical codeposition method. Shearing the pure titanium foil to a size of 1cm multiplied by 1cm, ultrasonically cleaning the pure titanium foil in acetone, ethanol and deionized water for 15min in sequence, and then drying the pure titanium foil in the air. Preparing a solution: HF and HNO₃And (3) immersing the pretreated titanium foil into the solution for 2min at a volume ratio of 1: 10, washing with deionized water, and drying in the air. After removal, the deposition solution contained 0.03M Ca (NO)₃)₂And 0.12M NaH₂PO₄The treated titanium foil is used as an anode, the graphite rod is used as a cathode, and a constant current mode (0.5 mA/cm) is adopted²) And electrodepositing the surface of the titanium foil to obtain the Sr/calcium phosphate composite film, wherein the deposition time is 10 min. Referring to fig. 1, fig. a to c, fig. 2 and 3, and table 3, it is apparent from fig. 2 and 3 that strontium ions are uniformly distributed on the surface of the coating layer and increase as the amount of strontium ions doped in the electrolyte increases. As can be seen from comparison of the OCP/strontium composite coating (b, c) in fig. 4a with the OCP standard card, after strontium ions are added into the electrolyte, the main component of the prepared coating is also OCP, but the diffraction peak of the crystal face (010) gradually disappears. As can be seen from comparison among fig. 4d, e, and f, when strontium ions are added to the electrolyte, the diffraction peak of the crystal plane (002) is obviously shifted to the left, and according to the bragg equation 2d sin θ ═ n λ, the surface spacing becomes larger due to the decrease of the diffraction angle of the crystal plane, which indicates that the crystal lattice in the OCP film layer becomes larger due to the doping of strontium ions. The OCP coating (curve a) and the OCP/strontium composite coating (curves b and c) on the electrode both have certain preferred orientation on the (002) crystal plane, and the preferred strength of the OCP/strontium composite coating on the (002) crystal plane is more obvious. Tables 1 and 2 show the calcium-phosphorus salt/strontium composite coatingAn EDS map element analysis table shows that the doping amount of strontium ions is 1%, namely Sr/(Sr + Ca) is 1%; table 2 shows that the amount of doped strontium ions is 5%, i.e., Sr/(Sr + Ca) ═ 5%. According to EDS map element analysis results of the electrochemical deposition coating, the composite film layer is mainly composed of calcium phosphate and phosphorus salt, the calcium-phosphorus ratio is about 1.0-1.1 and is lower than the theoretical value (1.33) of the calcium-phosphorus ratio of octacalcium phosphate. The amount of strontium ions in the film layer increases with the increase of the concentration of strontium ions in the electrolyte.

TABLE 1

TABLE 2

Example 2

Preparing the 1 percent Sr/calcium phosphate composite film layer by an electrochemical codeposition method. Sr is added to the deposition solution of example 1 in a proportion of 1% to keep the total concentration of Sr and Ca constant. The other conditions were the same as in example 1. See d-f of FIG. 1 and Table 3.

Example 3

Preparing the 5 percent Sr/calcium phosphate composite film layer by an electrochemical codeposition method. Sr is added to the deposition solution of example 1 in a proportion of 5% to keep the total concentration of Sr and Ca constant. The other conditions were the same as in example 1. See FIG. 1g, h, i and Table 3.

TABLE 3

The membrane layers of examples 1-3 were prepared by electrochemical co-deposition, and the membrane layers were tested for their ability to induce differentiation of preosteoblasts MC3T3-E1 using an ALP kit. Cell density 0.5X 10⁴cells/cm²Incubation times were 1,4,7 days and the results are shown in figure 5. From the activity of alkaline phosphatase (ALP), MC3T3-E1 was found to be fine when the strontium ion content in the film was increased from 0% to 5%The alkaline phosphatase activity of the cells increases and then decreases. The fact that a certain amount of strontium ions are doped into the calcium phosphate film layer is beneficial to improving the capacity of the calcium phosphate film layer for inducing the differentiation of MC3T3-E1 cells.

Claims

1. A preparation method of a strontium-doped octacalcium phosphate film with a nano-ordered structure is characterized by comprising the following steps:

1) pretreating a substrate to be treated; the substrate is made of medical implant materials; the specific method for pretreating the substrate comprises the following steps: soaking the medical implant material in acetone, ethanol and deionized water in sequence, ultrasonically cleaning, and washing in HNO₃Treating the mixture with HF solution and cleaning; the HNO₃The concentration of (A) is 8% -10%, and the concentration of HF is 0.8% -1.2%;

2) performing cathodic electrochemical deposition on a substrate to obtain a strontium-doped octacalcium phosphate film layer with a nano-ordered structure on the surface of the substrate; the deposition solution for performing cathodic electrochemical deposition on the substrate contains 0.01-0.14 mol/L of [ Ca [²⁺]0.04-0.4 mol/L of phosphate radical species and the proportion of [ Sr²⁺]/（[Sr²⁺]+[Ca²⁺]) (= 0.1-20%) [ Sr%²⁺]The solution of (1); the deposition solution adopts Ca (NO)₃)₂、NaH₂PO₄And Sr (NO)₃)₂(ii) a The pH value of the deposition solution is 2-6; the current density of the electrochemical deposition is 0.1-1.5 mA/cm²。

2. The method for preparing the strontium-doped octacalcium phosphate film with the nano-ordered structure as claimed in claim 1, wherein in the step 1), the medical implant material is a medical implant metal.

3. The method for preparing a strontium-doped octacalcium phosphate film with a nano-ordered structure as claimed in claim 2, wherein the medical implant metal is one selected from titanium, titanium alloy and stainless steel.

4. The method for preparing the strontium-doped octacalcium phosphate film layer with the nano-ordered structure as claimed in claim 1, wherein in the step 2), the deposition temperature of the electrochemical deposition is 25-90 ℃, and the deposition time is 3-60 min.