CN113603933B

CN113603933B - Method for regulating and controlling hydroxyapatite nanoparticle aggregate and application

Info

Publication number: CN113603933B
Application number: CN202110808478.7A
Authority: CN
Inventors: 韩颖超; 孙振浩; 戴红莲
Original assignee: Foshan Xianhu Laboratory
Current assignee: Foshan Xianhu Laboratory
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2023-04-11
Anticipated expiration: 2041-07-16
Also published as: CN113603933A

Abstract

The invention belongs to the technical field of materials, and discloses a method for regulating and controlling a hydroxyapatite nanoparticle aggregate and application thereof. The regulation and control method comprises the following steps: (a) Dissolving polyacrylic acid, and adjusting the pH value to be neutral or alkaline to obtain polyacrylic acid solution; (b) Adding the nano hydroxyapatite into the polyacrylic acid solution obtained in the step (a), and mixing under the ultrasonic condition to obtain the nano hydroxyapatite. The invention regulates and controls the nano hydroxyapatite to form spindle-shaped hydroxyapatite nano particle aggregates in water in a mode of combining ultrasonic dispersion with polyacrylic acid, and the dispersion degree of the spindle-shaped hydroxyapatite nano particle aggregates is high. The regulation and control method is simple and easy to implement and high in production efficiency. The hydroxyapatite nanoparticle aggregate prepared by the regulation and control method can obviously improve the compounding uniformity of the nano hydroxyapatite and the high polymer material, and prepare the composite material with the nano hydroxyapatite proportion up to 75.4 percent.

Description

Method for regulating and controlling hydroxyapatite nanoparticle aggregate and application

Technical Field

The invention belongs to the technical field of materials, and particularly relates to a regulation and control method and application of a hydroxyapatite nanoparticle aggregate.

Background

Hydroxyapatite (Ca) ₁₀ (PO ₄ ) ₆ (OH) ₂ HAP) is the major inorganic component of human hard tissue, accounting for 65% in bone and 96% in enamel. The nano HAP has higher surface area and surface roughness, and is beneficial to cell adhesion and cell matrix interaction; the high specific surface area and abundant surface adsorption sites of the nano HAP are favorable for immobilization of drugs and biomolecules; the nano HAP is beneficial to the densification and the enhancement of mechanical property of the HAP ceramic. However, nano HAP is easily formed into nanoparticles due to its small size, large specific surface area, drastically increased surface atomic number, and excessively high surface energyIrregular agglomeration occurs by van der waals forces, affecting its properties. The nano HAP particles are orderly aggregated into a nano structure by certain means, so that the original characteristics of the nano HAP particles can be kept, and the nano HAP particles can endow the material with new properties due to the special nano structure. For example, bone tissue is an ordered composite of collagen fibers and nano-HAP particles, and the crystal structure of the HAP nanoparticles after ordered aggregation plays an important role in regulating the cellular behavior or tissue function of human bones. Tooth enamel is a highly oriented calcium phosphate tissue, and under the regulation and control of protein, initial nano HAP crystals are gradually assembled into highly oriented nano HAP crystal bundles in order, and then are arranged into an ordered structure according to the stress distribution of a human body, so that the tooth enamel shows good mechanical properties and biological functions. Therefore, the research on the aggregation behavior of the nano HAP particles is of great significance.

At present, for the research on ordered aggregation of HAP nanoparticles, the HAP crystal growth behavior is mainly regulated and controlled by means of biomolecules or surfactants, so that nano HAP aggregates with specific structures are obtained, and meanwhile, new properties are endowed to materials. For example, under the control of the biological component glycine, HAP nanoparticles can assemble into rod-like HAPs, thereby forming spindle-like aggregates; utilizing glaze mature protein to regulate and control the orientation and assembly of the rod-shaped crystals of HAP, and obtaining a structure similar to tooth enamel; the nano HAP particles are prepared into nano porous microspheres, so that the medicine carrying capacity and the adsorption and release capacity to protein of the nano porous microspheres can be improved. However, since the ordered aggregation control of the HAP nanoparticles starts from nucleation and crystallization of the HAP nanoparticles, the entire cycle of controlled aggregation is long (generally several tens of hours, and at least several tens of hours), and the production efficiency of the hydroxyapatite nanoparticle aggregate is low. The production efficiency is determined by the length of the preparation period and is not closely related to the mass concentration of the hydroxyapatite nanoparticle aggregate.

Therefore, it is desirable to provide a method for regulating and controlling a hydroxyapatite nanoparticle aggregate, which can regulate and control ordered aggregation after formation of a hydroxyapatite nanocrystal and improve production efficiency of the hydroxyapatite nanoparticle aggregate.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the invention provides a method for regulating and controlling a hydroxyapatite nanoparticle aggregate, which can regulate and control ordered aggregation after hydroxyapatite nanocrystals are formed, effectively shorten the preparation period of the hydroxyapatite nanoparticle aggregate, improve the production efficiency of the hydroxyapatite nanoparticle aggregate, only need several minutes to dozens of minutes in the whole preparation process, and has the mass concentration as high as 60.3g/L.

The invention provides a method for regulating and controlling hydroxyapatite nanoparticle aggregates in a first aspect.

Specifically, the method for regulating and controlling the hydroxyapatite nanoparticle aggregate comprises the following steps:

(a) Dissolving polyacrylic acid, and adjusting the pH value to be neutral or alkaline to obtain polyacrylic acid solution;

(b) Adding the nano hydroxyapatite into the polyacrylic acid solution in the step (a), and mixing under the ultrasonic condition to obtain the hydroxyapatite nanoparticle aggregate.

According to the regulation and control method, a special structure of polyacrylic acid and a large number of carboxyl groups contained in the polyacrylic acid are combined with calcium ions on the side surface of nano-hydroxyapatite to form coordination and are adsorbed on the side surface of the nano-hydroxyapatite, aggregation of the nano-hydroxyapatite is inhibited, the formed spindle-shaped aggregate is more regular in shape, the aggregated spindle-shaped aggregate has enough repulsive force (mainly steric hindrance repulsive force) provided by polyacrylic acid molecules, van der Waals attractive force between spindle-shaped hydroxyapatite nanoparticle aggregates can be overcome, agglomeration of the spindle-shaped hydroxyapatite nanoparticle aggregates is prevented, the spindle-shaped hydroxyapatite nanoparticle aggregates are kept in a dispersed state in water, and the mass concentration of the hydroxyapatite nanoparticle aggregates is as high as 60.3g/L.

Preferably, in step (a), the pH is 7 to 13; preferably, in step (a), the pH is 7 to 9. By regulating the pH value, carboxyl groups on polyacrylic acid are deprotonated to become carboxylate radicals, and the combination of the carboxylate radicals and calcium ions is facilitated.

Preferably, in step (a), the concentration of the polyacrylic acid solution is 0.1 to 3g/L; further preferably, in step (a), the concentration of the polyacrylic acid solution is 0.2 to 2.7g/L.

Preferably, in step (b), the nano-hydroxyapatite is a rod-like particle. Further preferably, the diameter of the nano hydroxyapatite is 10-20nm, and the length of the nano hydroxyapatite is 25-70nm; more preferably, the diameter of the nano hydroxyapatite is 10-15nm, and the length of the nano hydroxyapatite is 30-60nm.

Preferably, in the step (b), the molar ratio of the nano hydroxyapatite to the polyacrylic acid is 1: (0.020-0.145); further preferably, in the step (b), the molar ratio of the nano hydroxyapatite to the polyacrylic acid is 1: (0.023-0.139). The molar ratio of the nano hydroxyapatite to the polyacrylic acid is controlled to enable the nano hydroxyapatite and the polyacrylic acid to reach an optimal combination state, so that agglomeration of spindle-shaped hydroxyapatite nanoparticle aggregates can be prevented, and the mass concentration of the hydroxyapatite nanoparticle aggregates can be improved.

Preferably, in step (b), the ultrasonic wave is mixed for 1 to 30 minutes, and the power of the ultrasonic wave is 200 to 1000W; further preferably, the ultrasonic wave is mixed for 5 to 10 minutes, and the power of the ultrasonic wave is 600 to 800W.

Preferably, in step (b), the frequency of the ultrasonic wave is 20-50KHz; further preferably, in step (b), the frequency of the ultrasonic wave is 20-40KHz; more preferably, in step (b), the frequency of the ultrasonic wave is 20 to 30KHz.

Preferably, in the step (b), the mass concentration of the hydroxyapatite nanoparticle aggregate is 6.7 to 60.3g/L.

In a second aspect, the present invention provides an aggregate of hydroxyapatite nanoparticles.

The hydroxyapatite nanoparticle aggregate is shuttle-shaped, the central diameter of the shuttle is 45-80nm, and the length of the shuttle is 270-305nm.

Preferably, the central diameter of the shuttle shape is 48.5-77.8nm, and the length of the shuttle shape is 278.6-302.8nm.

In a third aspect, the invention provides a hydroxyapatite nanoparticle composite material.

Specifically, the hydroxyapatite composite material is prepared from the following raw materials: the hydroxyapatite nanoparticle aggregate described above.

Preferably, the raw materials for preparing the hydroxyapatite composite material further comprise a high polymer material.

Preferably, the polymer material is selected from at least one of polyvinyl alcohol, polyethylene, pyrrolidone, polyacrylamide, polyethylene glycol, starch, cellulose or alginate.

Preferably, the mass ratio of the hydroxyapatite nanoparticle aggregate to the polymer material is (41.9-75.4): 100.

Compared with the prior art, the invention has the following beneficial effects:

(1) The invention regulates and controls the nano hydroxyapatite to form shuttle-type hydroxyapatite nano particle aggregates in water in a mode of combining ultrasonic dispersion and polyacrylic acid, and the dispersion degree of the shuttle-type hydroxyapatite nano particle aggregates is high. The regulation and control method is simple and easy to implement, the production efficiency is high, the whole regulation and control process only needs several minutes to dozens of minutes, and the regulation and control period is greatly shortened; and the mass concentration of the hydroxyapatite nano-particle aggregate is as high as 60.3g/L.

(2) The hydroxyapatite nanoparticle aggregate prepared by the regulation and control method can obviously improve the compounding uniformity of the nano hydroxyapatite and the high polymer material, and can prepare a hydroxyapatite composite material with the nano hydroxyapatite proportion exceeding 40 percent and reaching 75.4 percent.

Drawings

Fig. 1 is a transmission electron microscope image of the nano hydroxyapatite particles prepared in example 1;

FIG. 2 is a transmission electron micrograph of hydroxyapatite nanoparticle aggregates in example 2;

FIG. 3 is a transmission electron micrograph of hydroxyapatite nanoparticle aggregates in example 3;

FIG. 4 is a transmission electron micrograph of an aggregate of hydroxyapatite nanoparticles of example 4;

FIG. 5 is a transmission electron micrograph of an aggregate of hydroxyapatite nanoparticles of example 5;

fig. 6 is a graph of the sedimentation of the hydroxyapatite nanoparticle aggregate in example 5 after standing for 5 days;

FIG. 7 is a transmission electron micrograph of an aggregate of hydroxyapatite nanoparticles of example 6;

fig. 8 is a graph of the sedimentation of the hydroxyapatite nanoparticle aggregate in example 6 after standing for 5 days;

FIG. 9 is a scanning electron microscope image of a PVA composite fiber membrane in application example 1;

FIG. 10 is a transmission electron microscope image of a PVA composite fiber film in application example 1;

FIG. 11 is a scanning electron microscope photograph of the PVA composite fiber film in application example 2;

FIG. 12 is a transmission electron microscope photograph of a PVA composite fiber film in application example 2;

FIG. 13 is a scanning electron micrograph of the PVA composite fiber film of comparative example 1.

Detailed Description

In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples are given for illustration. It should be noted that the following examples are not intended to limit the scope of the claimed invention.

The starting materials, reagents or apparatuses used in the following examples are, unless otherwise specified, either commercially available from conventional sources or can be obtained by known methods.

Example 1

Preparing nano hydroxyapatite: first, an aqueous solution of calcium chloride (0.0668 mol/L) and an aqueous solution of diammonium hydrogen phosphate (0.04 mol/L) were prepared, respectively. Then, 100mL of an aqueous solution of diammonium phosphate was quickly poured into 100mL of an aqueous solution of calcium chloride with vigorous stirring, and ammonia was added dropwise to adjust the pH to 10-11. And then magnetically stirring the mixture at the temperature of 80 ℃ for reaction for 60 minutes, centrifuging and washing the mixture for three times to remove impurity ions to obtain white precipitate, and freezing and drying the white precipitate for later use. The white precipitate is rod-shaped nanometer hydroxyapatite particles, and the transmission electron micrograph of the white precipitate is shown in figure 1. The figure 1 shows that the nanometer hydroxyapatite particles have the diameter of 10-15nm and the length of 30-60nm.

Example 2

A method for regulating and controlling a hydroxyapatite nanoparticle aggregate comprises the following steps:

polyacrylic acid (PAA) powder was dissolved in water, and the pH thereof was adjusted to 8 with sodium hydroxide to prepare an acrylic acid solution having a concentration of 0.2 g/L. 134.0mg of the hydroxyapatite nanoparticles (HAP) prepared in example 1 were weighed, added to 20mL of an acrylic acid solution, and subjected to ultrasonic dispersion treatment at a power of 600W for 5 minutes to obtain a suspension (i.e., hydroxyapatite nanoparticle aggregates). The PAA/HAP molar ratio in the suspension is 0.01665, and the mass concentration of the nano hydroxyapatite particles is 6.7g/L. Fig. 2 is a transmission electron microscope image of hydroxyapatite nanoparticle aggregates, as shown in fig. 2, the hydroxyapatite nanoparticles in the suspension are in the form of spindle-shaped aggregates, the central diameter of the aggregates is 77.8 ± 17.1nm, and the length is 278.6 ± 53.0nm.

Example 3

polyacrylic acid (PAA) powder was dissolved in water, and the pH thereof was adjusted to 7 with sodium hydroxide to prepare a PAA solution having a concentration of 0.6 g/L. 134.0mg of the nano hydroxyapatite particles (HAP) prepared in example 1 was weighed and added into 20mL of PAA solution, and ultrasonic dispersion treatment was performed for 5 minutes at a power of 600W to obtain a suspension (i.e., hydroxyapatite nanoparticle aggregates). The molar ratio of PAA/HAP in the suspension is 0.05, and the mass concentration of the nano-hydroxyapatite particles is 6.7g/L. Fig. 3 is a transmission electron microscope image of hydroxyapatite nanoparticle aggregates, as shown in fig. 3, the hydroxyapatite nanoparticles in the suspension are in the form of spindle-shaped aggregates, the central diameter of the aggregates is 55.2 ± 9.6nm, and the length is 284.5 ± 47.9nm.

Example 4

polyacrylic acid (PAA) powder was dissolved in water, and the pH thereof was adjusted to 7 with sodium hydroxide to prepare a PAA solution having a concentration of 1.2 g/L. 134.0mg of the hydroxyapatite nanoparticles (HAP) prepared in example 1 were weighed and added to 20mL of the PAA solution, and then the mixture was subjected to ultrasonic dispersion treatment at a power of 600W for 5 minutes to obtain a suspension (i.e., hydroxyapatite nanoparticle aggregates). The molar ratio of PAA/HAP in the suspension is 0.1, and the mass concentration of the nano-hydroxyapatite particles is 6.7g/L. Fig. 4 is a transmission electron microscope image of hydroxyapatite nanoparticle aggregates, as shown in fig. 4, the hydroxyapatite nanoparticles in the suspension are in the form of spindle-shaped aggregates, the central diameter of the aggregates is 48.5 ± 7.7nm, and the length is 302.8 ± 39.7nm.

Example 5

polyacrylic acid (PAA) powder was dissolved in water, and the pH of the solution was adjusted to 9 with sodium hydroxide to prepare a PAA solution having a concentration of 0.9 g/L. 402.0mg of the nano-hydroxyapatite particles prepared in example 1 were weighed, added into 20mL of a PAA solution, and subjected to ultrasonic dispersion treatment at 650W power for 6 minutes to obtain a suspension (i.e., a hydroxyapatite nanoparticle aggregate). The molar ratio of PAA/HAP in the suspension is 0.025, and the mass concentration of the nano-hydroxyapatite particles is 20.1g/L. Fig. 5 is a transmission electron microscope image of hydroxyapatite nanoparticle aggregates. As can be seen from FIG. 5, when the mass concentration of the nano-hydroxyapatite particles is increased to 20.1g/L, the nano-hydroxyapatite particles still present the form of spindle-shaped aggregates, and no obvious agglomeration occurs between the aggregates.

Fig. 6 is a sedimentation diagram of the hydroxyapatite nanoparticle aggregate after standing for 5 days, in fig. 6, a is the hydroxyapatite nanoparticle aggregate prepared in the present example, and b is an unregulated nano HAP suspension (specifically, the preparation process is that 402.0mg of nano hydroxyapatite particles are taken, the pH value is adjusted to 9, 20mL of water is added, and the nano hydroxyapatite particles are dispersed for 6 minutes by using 650W power ultrasonic waves). As can be seen from fig. 6, after standing for 5 days, the hydroxyapatite nanoparticle aggregate prepared in this example still maintained good stability, and no significant precipitation occurred, while the unregulated nano HAP suspension did.

Example 6

Polyacrylic acid (PAA) powder was dissolved in water, and a PAA solution having a concentration of 2.7g/L was prepared by adjusting the pH to 9 with sodium hydroxide. 1206.0mg of the nano hydroxyapatite particles prepared in example 1 was weighed, added into 20mL of a PAA solution, and subjected to ultrasonic dispersion treatment at a power of 800W for 9 minutes to obtain a suspension (i.e., a hydroxyapatite nanoparticle aggregate). The molar ratio of PAA/HAP in the suspension is 0.025, and the mass concentration of the nano-hydroxyapatite particles is 60.3g/L. Fig. 7 is a transmission electron microscope image of hydroxyapatite nanoparticle aggregates in example 6. As can be seen from fig. 7, when the mass concentration of the nano-hydroxyapatite particles is further increased to 60.3g/L, the nano-hydroxyapatite particles still maintain the form of the spindle-shaped aggregates, the aggregates are still more uniformly distributed, no obvious agglomeration occurs, only the gaps between the aggregates are further reduced, and the distribution density is increased. Fig. 8 is a settlement diagram of the hydroxyapatite nanoparticle aggregate after standing for 5 days, as shown in fig. 8, after standing for 5 days, the hydroxyapatite nanoparticle aggregate still maintains good stability, and no obvious precipitation occurs.

Examples 2 to 6 all use the nano-hydroxyapatite particles prepared in example 1, and the same effect can be obtained by using commercially available nano-hydroxyapatite particles, wherein the nano-hydroxyapatite is rod-shaped particles, and the effect is more excellent. The inventor finds in experiments that if other high molecular substances are used for replacing polyacrylic acid, the regulation effect is poor, if sodium alginate is used for replacing polyacrylic acid, hydroxyapatite nanoparticles cannot be regulated well, and hydroxyapatite nanoparticle aggregates regulated by sodium alginate are greatly influenced by a salt solution. The dispersing principle of sodium alginate and polyacrylic acid is different, sodium alginate inhibits the aggregation of nano particles through electrostatic repulsion, the effect is poor, and the inhibiting effect of sodium alginate can be lost when the sodium alginate meets salt; polyacrylic acid inhibits the aggregation of nano particles through dual functions of space steric resistance and electrostatic repulsion, and is not influenced by salt in the environment.

Application example 1

A PVA composite fiber membrane (hydroxyapatite nanoparticle composite) whose raw materials include the hydroxyapatite nanoparticle aggregate prepared in example 6 and polyvinyl alcohol.

The preparation method comprises the following steps:

5.56mL of the hydroxyapatite nanoparticle aggregate suspension prepared in example 6 was diluted with deionized water to 10mL, and then 0.8g of polyvinyl alcohol was added, heated to 60 ℃, and stirred to be dissolved to obtain a spinning solution. And (3) preparing the PVA composite fiber membrane by the spinning solution through an electrostatic spinning machine, wherein the voltage is 14kV, the receiving distance is 11cm, and the advancing speed is 11 mu L/min. The mass ratio of nano HAP to PVA in the PVA composite fiber membrane (hydroxyapatite nanoparticle composite material) was 41.9%. Fig. 9 is a scanning electron microscope image of the PVA composite fiber film, fig. 10 is a transmission electron microscope image of the composite fiber film, and as can be seen from fig. 9 and fig. 10, hydroxyapatite nanoparticles are uniformly compounded in the PVA fibers.

Application example 2

The preparation method comprises the following steps:

0.8g of polyvinyl alcohol was added to 10mL of the hydroxyapatite nanoparticle aggregate prepared in example 6, heated to 60 ℃, and stirred to be dissolved to obtain a spinning solution. And (3) preparing the PVA (polyvinyl alcohol) composite fiber membrane by the spinning solution through an electrostatic spinning machine, wherein the spinning voltage is 14kV, the receiving distance is 11cm, and the advancing speed is 11 mu L/min. The mass ratio of nano HAP to PVA in the composite fiber membrane (hydroxyapatite nanoparticle composite) was 75.4%. FIG. 11 is a scanning electron microscope image of the PVA composite fiber film, and FIG. 12 is a transmission electron microscope image of the composite fiber film. As can be seen from fig. 11 and 12, the hydroxyapatite nanoparticles are uniformly compounded in the PVA fibers.

Comparative example 1

1206.0mg of the nano-hydroxyapatite particles prepared in example 1 was weighed and added to 20mL of water, and dispersed for 9 minutes by ultrasonic waves of 800W power to obtain a suspension. 0.8g of polyvinyl alcohol was added to 10mL of the obtained suspension, and heated and stirred to dissolve it, thereby obtaining a spinning solution. And (3) preparing the PVA composite fiber membrane by the spinning solution through an electrostatic spinning machine, wherein the spinning voltage is 14kV, the receiving distance is 11cm, and the advancing speed is 11 mu L/min. The mass ratio of nano HAP to PVA in the composite fiber membrane was 75.4%. Fig. 13 is a scanning electron microscope image of the PVA composite fiber membrane, as shown in fig. 13, the hydroxyapatite nanoparticles are not uniformly compounded in the PVA fibers, and many agglomerated large particles are present.

Claims

1. A method for regulating and controlling a hydroxyapatite nanoparticle aggregate is characterized by comprising the following steps:

(a) Dissolving polyacrylic acid, and adjusting the pH value to 7-9 to obtain polyacrylic acid solution;

(b) Adding nano hydroxyapatite into the polyacrylic acid solution in the step (a), and mixing under the ultrasonic condition to obtain a hydroxyapatite nanoparticle aggregate;

in the step (b), the nano hydroxyapatite is rod-shaped particles; the diameter of the nano hydroxyapatite is 10-20nm, and the length of the nano hydroxyapatite is 25-70nm;

the hydroxyapatite nanoparticle aggregate is shuttle-shaped, the central diameter of the shuttle shape is 45-80nm, and the length of the shuttle shape is 270-305nm.

2. The method for regulating and controlling the molecular weight of the polyacrylic acid according to claim 1, wherein in the step (b), the molar ratio of the nano-hydroxyapatite to the polyacrylic acid is 1: (0.020-0.145).

3. The method for controlling according to claim 1, wherein in the step (b), the ultrasonic wave is mixed for 1 to 30 minutes, and the power of the ultrasonic wave is 200 to 1000W.

4. The method for controlling according to any one of claims 1 to 3, wherein the mass concentration of the hydroxyapatite nanoparticle aggregate in the step (b) is 6.7 to 60.3g/L.

5. An aggregate of hydroxyapatite nanoparticles, prepared by the modulation method according to any one of claims 1 to 4; the hydroxyapatite nanoparticle aggregate is shuttle-shaped, the central diameter of the shuttle shape is 45-80nm, and the length of the shuttle shape is 270-305nm.

6. The hydroxyapatite composite material is characterized in that the raw materials for preparing the hydroxyapatite composite material comprise: the hydroxyapatite nanoparticle aggregate according to claim 5.

7. The hydroxyapatite composite material according to claim 6, wherein a raw material for preparing the hydroxyapatite composite material further includes a polymer material; the high polymer material is selected from at least one of polyvinyl alcohol, polyvinyl, pyrrolidone, polyacrylamide, polyethylene glycol, starch, cellulose or alginate.

8. The hydroxyapatite composite material according to claim 7, wherein the mass ratio of the hydroxyapatite nanoparticle aggregate to the polymer material is (41.9-75.4): 100.