CN103938246A - Electrochemical method for preparing strontium-doped hydroxyapatite ridge rodlike structure coating on titanium surface - Google Patents

Abstract

The invention discloses an electrochemical method for preparing a strontium-doped hydroxyapatite coating with a ridged rod-like structure on the surface of metallic pure titanium. Prepare electrolytes with high and low concentrations containing three elements of Ca, Sr and P; use constant temperature heating equipment to heat the above two electrolytes to a certain temperature and keep them warm; use platinum as the anode and pure titanium as the cathode substrate , the two electrodes are immersed in the electrolyte during deposition; they are deposited in two concentrations of electrolyte for a certain period of time, and finally a coating composed of strontium-doped hydroxyapatite with ridged rod structure is obtained; after the deposition is completed, the substrate is taken out, cleaned and dried. The invention prepares strontium-doped hydroxyapatite coating with ridged rod structure, which increases the specific surface area of the coating and makes it have better wettability; at the same time, the doping of strontium ions changes the dissolution characteristics of the coating, It opens up a new direction for the preparation and application of modified hydroxyapatite biological coatings.

Description

Electrochemical method for preparation of strontium-doped hydroxyapatite coating with ridged rod-like structure on titanium surface

technical field

The invention relates to an electrochemical method for coating strontium-doped hydroxyapatite with a ridged rod structure on the surface of metal titanium, belonging to the field of biomedical materials.

Background technique

As a representative bioactive material, hydroxyapatite (HA) is widely used in plastic surgery. It is similar in chemical composition and crystal structure to the inorganic components in human natural bone and other hard tissues, so it can realize osseointegration by spontaneously forming bone-like apatite on the interface in contact with human tissue. There are anion and cation substitution ions such as Mg ²⁺ , Sr ²⁺ and CO ₃ ^2- in the apatite composition of natural human bone, so its properties are different from those of synthetic HA. In recent years, many studies have attempted to replace Ca ²⁺ in synthetic HA with Sr ²⁺ to synthesize strontium-doped HA (SrHA). Experimental studies in vivo and in vitro also confirmed that Sr can stimulate bone formation and inhibit bone resorption. Studies have shown that the mechanical strength of bone cement containing 5wt.% SrHA is about twice that of bone cement containing HA. In addition, SrHA can promote the attachment and proliferation of osteoblasts, and has higher cytocompatibility than pure HA. Therefore, the application of strontium-doped hydroxyapatite will greatly improve the biocompatibility of apatite materials.

The microscopic morphology of the surface of biomaterials, such as surface roughness, the size and distribution of pores in the surface porous structure, the size and orientation of the constituent units, etc., affect the surface properties of the material, thereby affecting the adhesion, spreading, migration, proliferation, differentiation and functional expression of cells. CurtisASG et al. have long reported that cells respond to the surface topography of their environment. Since then, studies have reported that different types of cells have different strong responses to the micro- or nano-structures on the surface of materials. Studies have shown that the topography of the surface of the material has certain special cell effects, such as affecting the shape of cell spreading, thereby affecting the function of cells; the adhesion behavior of cells on surfaces with different roughness is also very different. In addition, the difference in hydrophilicity and hydrophobicity of the surface of biomaterials will also have an important impact on the attachment and fixation of cells and the adhesion of later cell metabolites such as proteins and DNA.

At present, the coatings deposited on the surface of titanium by electrochemical methods are all composed of rod-shaped HA, and their composition and structure are still different from those of human natural bone apatite in terms of composition and hierarchical structure. Therefore, the preparation of strontium-doped hydroxyapatite coating with ridged rod structure can make the coating closer to natural bone in composition, and the slow release of Sr ²⁺ after implantation can provide a chemical environment closer to the body for cell proliferation and differentiation. , and a special ridged rod-like structure can be obtained to increase the specific surface area of the coating, improve its wettability and roughness, and provide more favorable conditions for cell adhesion and migration.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of single composition and structure of HA coating prepared by the existing electrochemical method, and provide an electrochemical method for preparing strontium-doped hydroxyapatite with ridged rod-shaped coating on the surface of metal titanium.

The steps of the electrochemical method for preparing strontium-doped hydroxyapatite with ridged rod-like structure coating on the surface of metal titanium are as follows:

1) Prepare a solution containing 0.54~1.08mmol·L ^-1 molar concentration of CaCl ₂ , 0.06~0.12mmol·L -1 molar concentration of SrCl ₂ , 0.36~0.72 mmol·L ^-1 molar concentration of NH ₄ ^H ₂ PO ₄ and Low-concentration electrolyte with a NaCl molar concentration of 0.1 mol·L ^-1 , the molar concentration ratio of PO ₄ ^3- to (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, the electrolyte is heated to 85°C and then kept at a constant temperature; Platinum is used as the anode, metal titanium is used as the electrode of the cathode, connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a low-concentration electrolyte for 60 minutes of electrochemical deposition;

2) Take out step 1) to complete the deposited metal titanium as the cathode, wash and remove the electrolyte residue on the surface, and place it in the air to dry naturally before use;

3) Preparation containing CaCl ₂ molar concentration of 2.16~8.64mmol·L ^-1 , SrCl ₂ molar concentration of 0.24~0.96mmol·L ^-1 , NH ₄ H ₂ PO ₄ molar concentration of 1.44~5.76 mmol·L ^-1 , ^{The molar concentration ratio of PO 4 3- to (Ca 2+ +} _Sr ^{2+ ) is} 0.6:1, the molar concentration ratio of Cit ^3- to (Ca ²⁺ +Sr ²⁺ ) is 1:1, the high-concentration electrolyte is heated to 65°C and then kept at constant temperature; platinum is used as the anode, step 1) completes the deposited metal Titanium is used as the cathode electrode, connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a high-concentration electrolyte for 30 minutes of electrochemical deposition;

4) Take out the deposited metal titanium in step 3), rinse to remove the electrolyte residue on the surface, and dry it naturally in the air to obtain a strontium-doped hydroxyapatite coating with a ridged rod-like structure.

The beneficial effect that the present invention has compared with prior art is:

1) The coating is composed of a special strontium-doped hydroxyapatite with ridged rod structure, which greatly increases the specific surface area compared with the simple rod-shaped hydroxyapatite coating, and effectively increases the adhesion and migration of bone cells and the coating , area of proliferation and differentiation;

2) The prepared coating is composed of strontium-doped hydroxyapatite, which is closer to the composition of natural bone than the synthetic pure hydroxyapatite, which has a beneficial effect on the proliferation and differentiation of bone cells, and is more conducive to cell function expression;

3) The ridged rod-like microstructure of the coating provides a specific surface area. In the early stage, the ridged structure is dissolved, and a large amount of Sr ²⁺ is released to help the proliferation of bone cells. In the later stage, the ridged structure is reduced, and the release rate of Sr ²⁺ is slowed down. differentiation of bone cells;

4) The coating composed of strontium-doped hydroxyapatite with ridged rod-like structure has good hydrophilicity and improved wettability, which is conducive to the rapid adhesion and spreading of bone cells and subsequent proliferation and differentiation.

Description of drawings

Fig. 1 is the scanning electron micrograph of the strontium-doped hydroxyapatite band-ridge rod structure coating prepared in embodiment 1;

Fig. 2 is the scanning electron micrograph of the strontium-doped hydroxyapatite band-ridge rod structure coating prepared in embodiment 2;

FIG. 3 is a scanning electron micrograph of the strontium-doped hydroxyapatite coating with ridged rod structure prepared in Example 3. FIG.

Detailed ways

Example 1

1) Preparation containing CaCl ₂ molar concentration of 0.54mmol·L ^-1 , SrCl ₂ molar concentration of 0.06mmol·L ^-1 , NH ₄ H ₂ PO ₄ molar concentration of 0.36 mmol·L ^-1 and NaCl molar concentration of 0.1 mol ·L ^-1 low-concentration electrolyte, the molar concentration ratio of PO ₄ ^3- and (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, the electrolyte is heated to 85°C and then kept at constant temperature; platinum is used as the anode, metal titanium The electrode as the cathode is connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a low-concentration electrolyte for 60 minutes of electrochemical deposition;

2) Take out step 1) to complete the deposited metal titanium as the cathode, wash and remove the electrolyte residue on the surface, and place it in the air to dry naturally before use;

3) The molar concentration of CaCl ₂ is 2.16mmol·L ^-1 , the molar concentration of SrCl ₂ is 0.24mmol·L ^-1 , the molar concentration of NH ₄ H ₂ PO ₄ is 1.44mmol·L ^-1 , and the molar concentration of sodium citrate is 2.4 mmol·L ^-1 and NaCl molar concentration of 0.1 mol·L ^-1 high-concentration electrolyte, the molar concentration ratio of PO ₄ ^3- and (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, Cit ^3- and The molar concentration ratio of (Ca ²⁺ +Sr ²⁺ ) is 1:1, the high-concentration electrolyte is heated to 65°C and then kept at a constant temperature; platinum is used as the anode, step 1) the deposited metal titanium is used as the cathode electrode, and connected to DC power supply, the control voltage is -3.0V, and the electrode is immersed in a high-concentration electrolyte for 30 minutes of electrochemical deposition;

4) Take out the deposited metal titanium in step 3), rinse to remove the electrolyte residue on the surface, and dry it naturally in the air to obtain a strontium-doped hydroxyapatite coating with a ridged rod-like structure.

Example 2

1) Preparation containing 0.81mmol·L ^-1 molar concentration of CaCl ₂ , 0.09mmol·L -1 ^molar concentration of SrCl ₂ , 0.54mmol·L ^-1 molar concentration of NH ₄ H ₂ PO ₄ and 0.1 mol molar concentration of NaCl ·L ^-1 low-concentration electrolyte, the molar concentration ratio of PO ₄ ^3- and (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, the electrolyte is heated to 85°C and then kept at constant temperature; platinum is used as the anode, metal titanium The electrode as the cathode is connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a low-concentration electrolyte for 60 minutes of electrochemical deposition;

2) Take out step 1) to complete the deposited metal titanium as the cathode, wash and remove the electrolyte residue on the surface, and place it in the air to dry naturally before use;

3) The molar concentration of CaCl ₂ is 4.32mmol·L ^-1 , the molar concentration of SrCl ₂ is 0.48mmol·L ^-1 , the molar concentration of NH ₄ H ₂ PO ₄ is 2.88 mmol·L ^-1 , and the molar concentration of sodium citrate is High-concentration electrolyte with 4.8 mmol·L ^-1 and NaCl molar concentration of 0.1 mol·L ^-1 , the molar concentration ratio of PO ₄ ^3- to (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, Cit ^3- and The molar concentration ratio of (Ca ²⁺ +Sr ²⁺ ) is 1:1, the high-concentration electrolyte is heated to 65°C and then kept at a constant temperature; platinum is used as the anode, step 1) the deposited metal titanium is used as the cathode electrode, and connected to DC power supply, the control voltage is -3.0V, and the electrode is immersed in a high-concentration electrolyte for 30 minutes of electrochemical deposition;

4) Take out the deposited metal titanium in step 3), rinse to remove the electrolyte residue on the surface, and dry it naturally in the air to obtain a strontium-doped hydroxyapatite coating with a ridged rod-like structure.

Example 3

1) Preparation containing CaCl ₂ molar concentration of 1.08mmol·L ^-1 , SrCl ₂ molar concentration of 0.12mmol·L ^-1 , NH ₄ H ₂ PO ₄ molar concentration of 0.72 mmol·L ^-1 and NaCl molar concentration of 0.1 mol ·L ^-1 low-concentration electrolyte, the molar concentration ratio of PO ₄ ^3- and (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, the electrolyte is heated to 85°C and then kept at constant temperature; platinum is used as the anode, metal titanium The electrode as the cathode is connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a low-concentration electrolyte for 60 minutes of electrochemical deposition;

2) Take out step 1) to complete the deposited metal titanium as the cathode, wash and remove the electrolyte residue on the surface, and place it in the air to dry naturally before use;

3) The molar concentration of CaCl ₂ is 8.64mmol·L ^-1 , the molar concentration of SrCl ₂ is 0.96mmol·L ^-1 , the molar concentration of NH ₄ H ₂ PO ₄ is 5.76 mmol·L ^-1 , and the molar concentration of sodium citrate is High-concentration electrolyte with 9.6 mmol·L ^-1 and NaCl molar concentration of 0.1 mol·L ^-1 , the molar concentration ratio of PO ₄ ^3- to (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, Cit ^3- and The molar concentration ratio of (Ca ²⁺ +Sr ²⁺ ) is 1:1, the high-concentration electrolyte is heated to 65°C and then kept at a constant temperature; platinum is used as the anode, step 1) the deposited metal titanium is used as the cathode electrode, and connected to DC power supply, the control voltage is -3.0V, and the electrode is immersed in a high-concentration electrolyte for 30 minutes of electrochemical deposition;

4) Take out the deposited metal titanium in step 3), rinse to remove the electrolyte residue on the surface, and dry it naturally in the air to obtain a strontium-doped hydroxyapatite coating with a ridged rod-like structure.

Claims (1)

1. an electrochemical method for preparing strontium-doped hydroxyapatite with ridged rod-like structure coating on the titanium metal surface, is characterized in that its steps are as follows: 1) Prepare a solution containing 0.54~1.08mmol·L ^-1 molar concentration of CaCl ₂ , 0.06~0.12mmol·L -1 molar concentration of SrCl ₂ , 0.36~0.72 mmol·L ^-1 molar concentration of NH ₄ ^H ₂ PO ₄ and Low-concentration electrolyte with a NaCl molar concentration of 0.1 mol·L ^-1 , the molar concentration ratio of PO ₄ ^3- to (Ca ²⁺ +Sr ²⁺ ) is 0.6:1, the electrolyte is heated to 85°C and then kept at a constant temperature; Platinum is used as the anode, metal titanium is used as the electrode of the cathode, connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a low-concentration electrolyte for 60 minutes of electrochemical deposition; 2) Take out step 1) to complete the deposited metal titanium as the cathode, wash and remove the electrolyte residue on the surface, and place it in the air to dry naturally before use; 3) Preparation containing CaCl ₂ molar concentration of 2.16~8.64mmol·L ^-1 , SrCl ₂ molar concentration of 0.24~0.96mmol·L ^-1 , NH ₄ H ₂ PO ₄ molar concentration of 1.44~5.76 mmol·L ^-1 , ^{The molar concentration ratio of PO 4 3- to (Ca 2+ +} _Sr ^{2+ ) is} 0.6:1, the molar concentration ratio of Cit ^3- to (Ca ²⁺ +Sr ²⁺ ) is 1:1, the high-concentration electrolyte is heated to 65°C and then kept at constant temperature; platinum is used as the anode, step 1) completes the deposited metal Titanium is used as the cathode electrode, connected to a DC power supply, the control voltage is -3.0V, and the electrode is immersed in a high-concentration electrolyte for 30 minutes of electrochemical deposition; 4) Take out the deposited metal titanium in step 3), rinse to remove the electrolyte residue on the surface, and dry it naturally in the air to obtain a strontium-doped hydroxyapatite coating with a ridged rod-like structure.