CN105129756A - Method for preparing sub-nanometer hydroxyapatite ultrafine-needles through low-temperature mineralization - Google Patents

Abstract

The invention provides a mineralization preparing method for sub-nanometer ultrafine-needles having characteristics of hydroxyapatite. The method comprises steps as follows: a calcium salt solution and a phosphate aqueous solution are added to a mixed solution of oleic acid, ethyl alcohol and water, mineralization is performed at the temperature of 0-30 DEG C, and the pure sub-nanometer ultrafine-needles having characteristics of hydroxyapatite are obtained. The ultrafine-needles prepared with the method have the good self-assembly characteristic, can be applied to preparation of coating materials, and can also be applied to preparation of degradable biological tissue repair materials.

Description

A method for preparing subnano-scale hydroxyapatite ultrafine needles by low-temperature mineralization

technical field

The invention relates to a mineralization preparation method of subnanometer ultrafine needles with the characteristics of hydroxyapatite.

Background technique

Hydroxyapatite (Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ , HAp) is a natural mineralization of calcium apatite, which has excellent biocompatibility and bioactivity, and can interact with organic polymers in nanoscale Assembled into hard tissues such as vertebrate bones and teeth.

At present, biomineralization is the mildest method to obtain hydroxyapatite, and the prepared product is widely used in biological tissue materials. However, the products prepared in the aqueous phase system are usually large in size and irregular in shape. For the later construction of composite materials, there will be problems such as low bonding degree of organic and inorganic materials and poor assembly strength. Nano-hydroxyapatite prepared by sol-gel, hydrothermal method and calcination method has high crystallinity, but relatively long degradation period. In addition, the ultrafine and ultrafine subnanostructure of nano-hydroxyapatite is usually obtained by introducing heterogeneous ions to limit the growth of target particles in a certain dimension. The process conditions are relatively complicated and the reproducibility is poor.

Contents of the invention

The purpose of the present invention is to provide a mineralization preparation method of ultrafine sub-nanometer needles with hydroxyapatite characteristics.

The realization process of the present invention is as follows:

A method for preparing subnano-scale hydroxyapatite ultrafine needles. In a mixed system of oleic acid and ethanol, calcium salt solution and phosphate solution are added, and the final volume ratio of oleic acid, ethanol and water is (1~ 5):(5~10):(5~20), standing still at 0°C~30°C for 1~14 days to obtain pure sub-nanometer hydroxyapatite ultrafine needles.

The above calcium salt is calcium nitrate; the phosphate is selected from sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate; the molar ratio of calcium salt to phosphate is 1:1.67.

The above-mentioned final product is repeatedly washed several times with cyclohexane and ethanol, and cyclohexane is used as a detergent, and ethanol is used as a precipitation aid.

The subnano-scale ultrafine needles prepared above have a diameter of 0.5-0.8 nm and a length of 20-120 nm.

The application of the subnano hydroxyapatite ultrafine needles prepared by the above method in the preparation of coating materials or biocomposite materials.

The present invention is based on the mechanism of natural substance mineralization, learns from the presence of hydrophobic substances in the hard tissue formation environment in living organisms, changes the previous biomass mineralization system into a water phase system, and introduces hydrophobic substances into the mineralization reaction system to form a hydrophilic-hydrophobic mixed system , to obtain ultrafine subnanometer needles with hydroxyapatite properties.

Advantages and positive effects of the present invention: the present invention is based on the biomineralization method, considering that the hydroxyapatite formation environment in the organism is not only a hydrophilic body fluid environment, but also hydrophobic lipid-like organic substances exist in the environment, Therefore, by simulating this environmental model and changing the scope of the previous biomineralization system into a hydrophilic environment, a simple mixed system of oleic acid, ethanol and water was established for low-temperature mineralization to synthesize ultrafine hydroxyapatite nanoneedles. The preparation method of the present invention has cheap and easy-to-obtain raw materials, low cost, simple and easy-to-implement synthesis process, stable product quality, easy process amplification and good reproducibility; For the preparation of membrane materials, it can also be used as a filling material for composite materials; the low crystallinity of ultra-fine needles improves the degradability, and can be used to prepare artificial bone, bone cement and other biological tissue repair materials, and improve the controllable degradation of target materials sex.

Description of drawings

Fig. 1 is the TEM picture of the ultrafine sub-nanometer needle prepared in embodiment 1;

Fig. 2 is the EDS figure of the ultrafine sub-nanometer needle prepared in embodiment 1;

Fig. 3 is the infrared spectrogram of the ultrafine sub-nanometer needle prepared in embodiment 1;

Fig. 4 is the TEM picture of the ultrafine sub-nanometer needle prepared in embodiment 2;

Fig. 5 is the TEM figure of the hydroxyapatite prepared in embodiment 5;

Figure 6 is a TEM image of the self-assembly of the ultrafine sub-nanometer needles of hydroxyapatite prepared in Example 6;

Figure 7 is a TEM image of the self-assembly of the hydroxyapatite ultrafine sub-nanometer needles prepared in Example 6;

Fig. 8 is a SEM image of the hydroxyapatite ultrafine sub-nanometer needle bio-scaffold material prepared in Example 6.

Detailed ways

Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the materials and reagents used can be obtained from commercial sources.

Example 1 Preparation of subnanoscale hydroxyapatite ultrafine needles

In a 50mL beaker, add 2mL of oleic acid, 10mL of ethanol, then add 8mL of 0.25M calcium nitrate and 8mL of 0.15M sodium phosphate solution, stir evenly, seal the mouth of the beaker with a sealing film, and place it in a thermostat at 25°C. Set 7d. After the reaction, the precipitate was collected by centrifugation and washed several times with cyclohexane and ethanol to obtain the final product.

Detection by transmission electron microscopy shows that the product of the reaction is sub-nanometer ultra-fine needles, with a diameter of about 0.5-0.8 nm and a length of about 100 nm, as shown in Figure 1; EDS analysis shows that the elemental composition of the obtained sub-nanometer ultra-fine needles is similar to that of hydroxyapatite The same, as shown in Figure 2; the infrared spectrum of the product conforms to the infrared spectrum characteristics of hydroxyapatite, as shown in Figure 3.

Example 2 Preparation of subnanoscale hydroxyapatite ultrafine needles

In a 50mL beaker, add 2mL of oleic acid, 10mL of ethanol, then add 8mL of 0.25M calcium nitrate and 8mL of 0.15M ammonium phosphate solution, stir evenly, seal the mouth of the beaker with a sealing film, and place it in a refrigerator at 4°C 7d. After the reaction, the precipitate was collected by centrifugation and washed several times with cyclohexane and ethanol to obtain the final product. The product detected by the transmission electron microscope is a sub-nanometer ultrafine needle with a diameter of about 0.5-0.8nm and a length of about 25nm, as shown in Figure 4.

Example 3 Preparation of subnanoscale hydroxyapatite ultrafine needles

In a 50mL beaker, add 4mL oleic acid, 10mL ethanol, then add 10mL of 0.25M calcium nitrate and 10mL of 0.15M sodium hydrogen phosphate solution, stir evenly, seal the mouth of the beaker with a sealing film, and place it in a refrigerator at 4°C Set 14d. After the reaction, the precipitate was collected by centrifugation and washed several times with cyclohexane and ethanol to obtain the final product. The product detected by a transmission electron microscope is a sub-nanometer ultrafine needle with a diameter of about 0.5-0.8nm and a length of about 60nm.

Example 4 Preparation of subnanoscale hydroxyapatite ultrafine needles

In a 250mL beaker, add 20mL oleic acid, 40mL ethanol, then add 30mL of 0.25M calcium nitrate and 30mL of 0.15M sodium phosphate solution, stir evenly, seal the mouth of the beaker with a sealing film, and place it in a thermostat at 10°C. Set 14d. After the reaction, the precipitate was collected by centrifugation and washed several times with cyclohexane and ethanol to obtain the final product. The product detected by a transmission electron microscope is a sub-nanometer ultrafine needle with a diameter of about 0.5-0.8nm and a length of about 80nm.

Embodiment 5 Comparative example

Similar to Example 1, the difference is that the mineralization system does not introduce hydrophobic oleic acid, but introduces other hydrophilic organic molecules.

In a 50mL beaker, add 0.5g of PEG10000, 10mL of ethanol, then add 8mL of 0.25M calcium nitrate and 8mL of 0.15M sodium phosphate solution, stir evenly, seal the mouth of the beaker with a sealing film, and place in a thermostat at 25°C Stand still for 7d. After the reaction, the precipitate was collected by centrifugation and washed several times with ethanol and water to obtain the final product. The products were detected by transmission electron microscopy as irregular flakes and rods, as shown in Figure 5.

Example 6 Regulation of Self-Assembly of Subnanometer Ultrafine Needles and Membrane Application

Disperse the sub-nanometer ultra-fine needles prepared in Example 1 in a mixed solution of cyclohexane and ethanol to make a raw material solution, and perform dip-coating of the matrix material, which can be coated with a layer of apatite self-assembled film to improve the matrix material The physical and chemical properties such as preventing water infiltration corrosion and so on. Figure 6 (ethanol dispersion) and Figure 7 (ethanol plus cyclohexane dispersion) are TEM images of the assembled microstructure of the two self-assembled films.

Example 7 Application of Subnanometer Ultrafine Needles in Biological Tissue Repair Materials

The first step is the hydrophilic-hydrophobic conversion of the surface of the ultrafine needles. Take an appropriate amount of ultrafine needles prepared in Example 1 and disperse them in 2ml of cyclohexane, and add them into 10ml of aqueous solution in which 20mg of PluronicF127 is dissolved, then add 6ml of tetrahydrofuran, shake and mix to obtain a cloudy suspension. Then remove the organic solvent in the mixed solution by rotary evaporation under reduced pressure, and then wash away the excess PluronicF127 with water to obtain hydrophilic europium-doped hydroxyapatite single crystal fluorescent nanoparticles;

In the second step, 2 g of human-like collagen was dissolved in 20 g of pyrogen-free water to obtain a 13.6% (w/v) HLC aqueous solution. Weigh 8g of wet ultrafine needles according to the ratio of protein to ultrafine needles is 1:4 (w/w), sonicate for several minutes to make it into a homogenous slurry, then add an appropriate amount of the above protein aqueous solution to it, shake vigorously and mix well . The viscous solution prepared above was quickly transferred into a mold, and placed in a -80°C ultra-low temperature refrigerator for 4 hours, then vacuum freeze-dried for 48 hours. Use 0.1% genipin solution to cross-link the freeze-dried scaffold material at 37°C for 48 hours, soak and wash with pyrogen-free water several times for 1 day, then put it in an ultra-low temperature refrigerator for 4 hours, take it out and put it in a vacuum freeze dryer After drying in medium for 48 hours, the final degradable porous artificial bone scaffold material was obtained, as shown in FIG. 8 .

Claims (5)

1. A method for preparing subnano-scale hydroxyapatite ultrafine needles is characterized in that: in the mixed system of oleic acid and ethanol, adding calcium salt aqueous solution and phosphate aqueous solution, the volume of final oleic acid, ethanol, water The ratio is (1~5):(5~10):(5~20), and the pure subnano-scale hydroxyapatite ultrafine needles can be obtained by standing at 0°C-30°C for 1-14 days. 2. according to the described method of claim 1, it is characterized in that: calcium salt is calcium nitrate; Phosphate is selected from sodium phosphate, sodium hydrogen phosphate, sodium dihydrogen phosphate, ammonium phosphate, ammonium hydrogen phosphate, ammonium dihydrogen phosphate; Calcium salt The molar ratio with phosphate is 1:1.67. 3. The method according to claim 1, characterized in that: the final product obtained by repeatedly washing several times with cyclohexane and ethanol, wherein cyclohexane is a washing agent, and ethanol is a precipitant aid. 4. The method according to claim 1, characterized in that: the diameter of the prepared sub-nanometer ultra-fine needles is 0.5-0.8 nm, and the length is 20-120 nm. 5. The application of the subnano-scale hydroxyapatite ultrafine needles prepared by the method of claim 1 in the preparation of coating materials or biocomposites.