TEMPLATE-INDUCED SILICATE-DOPED HYDROXYAPATITE AND THE PREPARATION METHOD

Abstract

A silicate-doped hydroxyapatite material has an ordered and directional growth structure. The silicon content in the silicate-doped hydroxyapatite material ranges from 0.1 wt % to 1.6 wt %, and silicon is doped in hydroxyapatite lattices in a form of silicate. A template-induced method for manufacturing the synthetic silicate-doped hydroxyapatite material above.

Claims

1. A silicate-doped hydroxyapatite material synthesized by a template-induced method using a template, wherein the silicate-doped hydroxyapatite material is grown orderly along a long axis of the template to have an ordered and directional growth structure, a content of a silicon in the silicate-doped hydroxyapatite material ranges from about 0.1 wt % to 1.6 wt %, and the silicon is doped in hydroxyapatite lattices of the silicate-doped hydroxyapatite material in a form of silicate.

2. A template-induced method for manufacturing the silicate-doped hydroxyapatite material according to claim 1, comprising: (1) providing a silicon source, a template solution, a calcium source solution, and a phosphorus source solution; (2) mixing the template solution with the calcium source solution and/or the phosphorus source solution; regulating a pH value of a calcium-containing solution to be neutral; adding the silicon source slowly, and dropwise adding a phosphorus-containing solution under a condition of stirring; regulating a pH value of a reaction system to a predetermined pH value, so that reaction goes on for a period of time; and stopping stirring, and collecting a precipitate after the reaction system stays for a period of time so as to obtain a silicate-doped hydroxyapatite material after washing, freezing, and drying, wherein when the template is a single template which is a non silk fibroin template, the calcium-containing solution is a mixture of the template solution and the calcium source solution, and the phosphorus-containing solution is the phosphorus source solution; wherein when the template is a single template which is a silk fibroin template, the calcium-containing solution is the calcium source solution, and the phosphorus-containing solution is a mixture of the template solution and the phosphorus source solution; wherein when the template contains double templates which are both non silk fibroin template, the calcium-containing solution is a mixture of either template of the double templates and the calcium source solution, and the phosphorus-containing solution is a mixture of another template of the double templates and the phosphorus source solution; and wherein when the template contains double templates and one of which is a silk fibroin template, the phosphorus-containing solution is a mixture of the silk fibroin template and the phosphorus source solution, and the calcium-containing solution is a mixture of another template of the double templates and the calcium source solution.

3. The method according to claim 2, wherein measuring by calcium element in calcium source solution, measuring by phosphorus element in phosphorus source solution, and measuring by silicon element in silicon source, a molar ratio of calcium element to a sum of phosphorus element and silicon element is about 5:3, and a molar ratio of phosphorus element to silicon element ranges from about 9:1 to about 167:1.

4. The method according to claim 2, wherein in the template solution, a mass ratio of a template to hydroxyapatite containing silicon is about 3:7.

5. The method according to claim 2, wherein the silicon source is tetraethyl orthosilicate.

6. The method according to claim 2, wherein the predetermined pH value of the reaction system in step (2) is about 7.4.

7. The method according to claim 2, wherein the reaction time in step (2) ranges from about 24 h to about 36 h.

8. The method according to claim 2, wherein the single template is a molecule template or a composite molecule template, the molecule template is one selected from a group consisting of a protein template, a polysaccharide template, and a synthetic macromolecule template, and the composite molecule template is obtained through cross linking of molecule templates; and wherein the double templates is a combination of two kinds of single template.

9. The method according to claim 8, wherein the protein template is one selected from a group consisting of a collagen template, a silk fibroin template, a fibronectin template, a laminin template, and a serum protein template; the polysaccharide template is one selected from a group consisting of a hyaluronic acid template, a chondroitin sulfate template, a chitosan template, a sodium alginate template, and a bacterial cellulose template; and the synthetic macromolecule template is one selected from a group consisting of a synthetic amphiphilic peptide template, a cetyltrimethyl ammonium bromide template, a polyacrylic acid template, a ethylenediaminetetraacetic acid template, a polystyrene sulfonate template, and a polyethylene template.

10. The method according to claim 8, wherein the composite molecule template is obtained through cross linking of molecule templates by an action of a cross-linking agent or a peptide condensing agent; and the cross linking is a mutual cross linking among a plurality kinds of molecule templates or an internal cross linking among a same kind of molecule templates.

11. A method for manufacturing a silicate-doped hydroxyapatite material, comprising: adjusting pH value of a calcium-containing solution to about pH 7.0; adding a silicon source slowly to the calcium-containing solution to form a silicon-calcium-containing solution; adding a phosphorus-containing solution dropwisely to the silicon-calcium-containing solution under stirring to form a reaction solution; adjusting pH value of the reaction solution to about pH 7.4, such that a reaction is performed in the reaction solution; and stopping stirring the reaction solution and let the reaction solution stand for a period of time so as to form a precipitate, collecting the precipitate, and washing and lyophilizing the precipitate to obtain the silicate-doped hydroxyapatite material.

12. The method of claim 11, wherein the calcium-containing solution is a mixture of a template solution having a non silk fibroin template and a calcium source solution, and the phosphorus-containing solution is a phosphorus source solution.

13. The method of claim 11, wherein the calcium-containing solution is a calcium source solution, and the phosphorus-containing solution is a mixture of a template solution having a single silk fibroin template and a phosphorus source solution.

14. The method of claim 11, wherein the the calcium-containing solution is a mixture of a first template solution having a first non silk fibroin template and a calcium source solution, and the phosphorus-containing solution is a mixture of a second template solution having a second non silk fibroin template and a phosphorus source solution.

15. The method of claim 11, wherein the calcium-containing solution is a mixture of a first template solution having a first template and a calcium source solution, the phosphorus-containing solution is a mixture of a second template solution having a second template and a phosphorus source solution, and one of the first template and the second template is a silk fibroin template.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings illustrate one or more embodiments of the invention and together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.

[0033] FIG. 1 shows an X-Ray Diffraction (XRD) diagram of synthetic silicate-doped hydroxyapatite induced by a silk fibroin template according to example 1;

[0034] FIG. 2 shows an X-Ray Fluorescence (XRF) diagram of synthetic silicate-doped hydroxyapatite induced by collagen-silk fibroin double templates according to example 3;

[0035] FIG. 3 shows an observation result with a high-resolution transmission electron microscopy of synthetic silicate-doped hydroxyapatite crystal induced by chondroitin sulfate-hyaluronic acid double templates according to example 4; and

[0036] FIG. 4 shows theoretical models of hydroxyapatite crystal structure and silicon-hydroxyapatite crystal structure, where “a” shows a crystal model of hydroxyapatite, and “b” shows a crystal model of silicon-hydroxyapatite, in which silicate is doped in hydroxyapatite lattices to replace phosphate.

[0037] FIG. 5 shows a transmission electron microscope (TEM) image of a silicate-doped hydroxyapatite material according to example 3, where the silicate-doped hydroxyapatite material is synthesized using collagen and silk fibroin double templates.

DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Various embodiments of the invention are now described in detail. Referring to the drawings, like numbers indicate like components throughout the views. As used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Moreover, titles or subtitles may be used in the specification for the convenience of a reader, which shall have no influence on the scope of the present invention.

[0039] As used herein, “around”, “about” or “approximately” shall generally mean within 20 percent, preferably within 10 percent, and more preferably within 5 percent of a given value or range. Numerical quantities given herein are approximate, meaning that the term “around”, “about” or “approximately” can be inferred if not expressly stated.

[0040] As used herein, the terms “comprising”, “including”, “carrying”, “having”, “containing”, “involving”, and the like are to be understood to be open-ended, i.e., to mean including but not limited to.

[0041] The description will be made as to the embodiments of the present invention in conjunction with the accompanying drawings in FIGS. 1-4. In accordance with the purposes of this invention, as embodied and broadly described herein, this invention, in one aspect, relates to a template-induced silicate-doped hydroxyapatite and a method of making the same.

EXAMPLE 1

[0042] A template-induced silicate-doped hydroxyapatite material can be manufactured through the following method.

[0043] (1) Silk fibroin (0.6 g) is dissolved in deionized water (100 ml), and impurities are removed through filtration so as to obtain a silk fibroin solution with a concentration of 6 mg/ml.

[0044] (2) Calcium nitrate tetrahydrate (3.29 g) is dissolved in deionized water (200 ml) so as to obtain a calcium source solution.

[0045] (3) Diammonium phosphate powder (1.052 g) is dissolved in deionized water (200 ml) so as to obtain a phosphorus source solution; and the silk fibroin solution and the phosphorus source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a silk fibroin template-phosphorus solution can be obtained.

[0046] (4) The calcium source solution is placed in water bath with a constant temperature of 37° C. and stirred, and a pH value of the solution is regulated to 7; and tetraethyl orthosilicate (TEOS) (88.6 μL) is added into the calcium source solution slowly so as to obtain a calcium-silicon solution.

[0047] (5) The silk fibroin template-phosphorus solution is dropwise added to the calcium-silicon solution which is stirred constantly at a temperature of 37° C., and a pH value thereof is regulated to be 7.4 by aqueous ammonia; stopping stirring after the reaction goes on for 24 hours, collecting a precipitation after the solution stays for 12 hours, and the precipitation is suction filtrated and washed with deionized water for at least three times; and the powder obtained therein after freezing and drying is the silicate-doped hydroxyapatite powderinduced by a silk fibroin template.

[0048] The XRD diagram of the silicate-doped hydroxyapatite powder induced by a silk fibroin template manufactured according to the present example is shown in FIG. 1. As shown by the XRD diagram in FIG. 1, hydroxyapatite characteristic diffraction peaks appear at 2θ being 28° and 32°, which coincide with characteristic peaks shown in hydroxyapatite standard card (PDF card 9-432). Therefore, the main phase of the product is hydroxyapatite. However, compared with the characteristic peaks shown in hydroxyapatite standard card, the characteristic diffraction peaks of the product (silicon-hydroxyapatite) are broadened, which shows that the crystallinity of the material decreases and particle sizes thereof are reduced due to silicon doping. It can be seen through XRF detection that, a silicon content in the silicate-doped hydroxyapatite powder induced by a silk fibroin template is 0.78 wt %.

EXAMPLE 2

[0049] A template-induced silicate-doped hydroxyapatite material can be manufactured through the following method.

[0050] (1) Collagen I (0.6 g) is dissolved in acetic acid solution (100 ml) with a concentration of 0.5% (v/v %), and impurities are removed through filtration so as to obtain a collagen I solution with a concentration of 6 mg/ml.

[0051] (2) Calcium chloride (1.546 g) is dissolved in deionized water (200 ml) so as to obtain a calcium source solution; and the collagen I solution and the calcium source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a collagen template-calcium solution can be obtained.

[0052] (3) Disodium hydrogen phosphate (1.10 g) is dissolved in deionized water (200 ml), and a phosphorus source solution can be obtained after complete dissolution.

[0053] (4) The collagen template-calcium solution is placed in water bath with a constant temperature of 37° C. and stirred, and a pH value of the solution is regulated to 7 with NaOH solution (1 M); and tetraethyl orthosilicate (TEOS) (132.9 μL) is added into the collagen template-calcium solution slowly so as to obtain a calcium-silicon solution.

[0054] (5) The phosphorus source solution is dropwise added to the calcium-silicon solution which is stirred constantly, and a pH value of the solution is regulated to 7.4 with NaOH solution (1 M); stopping stirring after the reaction goes on for 24 hours, collecting a precipitation after the solution stays for 12 hours, and the precipitation is suction filtrated and washed with deionized water for at least three times; and the powder obtained therein after freezing and drying is the silicon-doped hydroxyapatite powder induced by a collagen I template.

[0055] It can be seen through XRD analysis that, the product obtained in the present example is the silicate-doped hydroxyapatite powder induced by a collagen I template. It can be seen through XRF detection that, a silicon content in the silicate-doped hydroxyapatite powder induced by a collagen I template is 1.095 wt %.

EXAMPLE 3

[0056] A template-induced silicate-doped hydroxyapatite material can be manufactured through the following method.

[0057] (1) Collagen I (0.3 g) is dissolved in acetic acid solution (50 ml) with a concentration of 0.5% (v/v %), and impurities are removed through filtration so as to obtain a collagen I solution with a concentration of 6 mg/ml.

[0058] (2) Calcium hydroxide (1.032 g) is dissolved in deionized water (200 ml) so as to obtain a calcium source solution; and the collagen I solution and the calcium source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a collagen template-calcium solution can be obtained.

[0059] (3) Silk fibroin (0.3 g) is dissolved in deionized water (50 ml), and impurities are removed through filtration so as to obtain a silk fibroin solution with a concentration of 6 mg/ml.

[0060] (4) Ammonium dihydrogen phosphate (1.0456 g) is dissolved in deionized water (200 ml), and a phosphorus source solution can be obtained after complete dissolution; and the silk fibroin solution obtained in step (3) and the phosphorus source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a silk fibroin template-phosphorus solution can be obtained.

[0061] (5) Collagen template-calcium solution is placed in water bath with a constant temperature of 37° C. and stirred, and a pH value of the solution is regulated to 7; and tetraethyl orthosilicate (TEOS) (100.2 μL) is added into the collagen template-calcium solution slowly.

[0062] (6) The silk fibroin template-phosphorus solution obtained in step (4) is dropwise added to the collagen template-calcium solution obtained in step (5); the above mixed solution is stirred constantly and a pH value thereof is regulated to 7.4 with aqueous ammonia; stopping stirring after the reaction goes on for 24 hours, collecting a precipitation after the solution stays for 12 hours, and the precipitation is suction filtrated and washed with deionized water for at least three times; and the powder obtained therein after freezing and drying is the silicate-doped hydroxyapatite powder induced by silk fibroin-collagen double templates.

[0063] It can be seen through XRD analysis that, the product obtained in the present example is the silicate-doped hydroxyapatite powder induced by silk fibroin-collagen double templates, which shows that the silicon element is doped to hydroxyapatite material successfully. The XRF detection result of the silicate-doped hydroxyapatite powder induced by silk fibroin-collagen double templates according to the present example is shown in FIG. 2. It can be seen from FIG. 2 that, a silicon content in the silicate-doped hydroxyapatite powder induced by silk fibroin-collagen double templates is 0.85 wt %, which is close to theoretical silicon content of 0.9 wt %.

[0064] FIG. 5 shows a transmission electron microscope (TEM) image of a silicate-doped hydroxyapatite material according to this example. As shown in FIG. 5, the silicate-doped hydroxyapatite material is synthesized through template induction. Crystals of the silicate-doped hydroxyapatite material grow orderly along a long axis of the template, and the silicate-doped hydroxyapatite material has an ordered and directional growth structure.

EXAMPLE 4

[0065] A template-induced silicate-doped hydroxyapatite material can be manufactured through the following method.

[0066] (1) Medical grade chondroitin sulfate (0.3 g) is dissolved in deionized water (50 ml) so as to obtain a chondroitin sulfate template solution with a concentration of 6 mg/ml.

[0067] (2) Calcium nitrate tetrahydrate (3.29 g) is dissolved in deionized water (200 ml) so as to obtain a calcium source solution; and the chondroitin sulfate template solution obtained in step (1) and the calcium source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a chondroitin sulfate template-calcium solution can be obtained.

[0068] (3) Hyaluronic acid (0.3 g, Mw: 5 KD) is dissolved in deionized water (50 ml), and impurities are removed through filtration so as to obtain a hyaluronic acid solution with a concentration of 6 mg/ml.

[0069] (4) Diammonium phosphate (1.078 g) is dissolved in deionized water (200 ml), and a phosphorus source solution can be obtained after complete dissolution; and the hyaluronic acid solution obtained in step (3) and the phosphorus source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a hyaluronic acid template-phosphorus solution can be obtained.

[0070] (5) Chondroitin sulfate template-calcium solution is placed in water bath with a constant temperature of 37° C. and stirred, and a pH value of the solution is regulated to 7; and tetraethyl orthosilicate (TEOS) (44.3 μL) is added into the chondroitin sulfate template-calcium solution slowly so as to obtain a calcium-silicon solution.

[0071] (6) The hyaluronic acid template-phosphorus solution obtained in step (4) is dropwise added to the calcium-silicon solution obtained in step (5); the above mixed solution is stirred constantly and a pH value thereof is regulated to 7.4 with aqueous ammonia; stopping stirring after the reaction goes on for 24 hours, collecting a precipitation after the solution stays for 12 hours, and the precipitation is suction filtrated and washed with deionized water for at least three times; and the powder obtained therein after freezing and drying is the silicate-doped hydroxyapatite powder induced by hyaluronic acid-chondroitin sulfate double templates.

[0072] It can be seen through XRD analysis that, the product obtained in the present example is the silicate-doped hydroxyapatite powder induced by hyaluronic acid-chondroitin sulfate double templates. It can be seen through XRF detection that, a silicon content in the silicate-doped hydroxyapatite powder induced by hyaluronic acid-chondroitin sulfate double templates is 0.369 wt %. An observation result with a high-resolution transmission electron microscopy of the silicate-doped hydroxyapatite powder induced by hyaluronic acid-chondroitin sulfate double templates obtained in the present example is shown in FIG. 3. It can be seen from FIG. 3 that, the silicate-doped hydroxyapatite has an ordered and directional growth structure.

EXAMPLE 5

[0073] A template-induced silicate-doped hydroxyapatite material can be manufactured through the following method. (1) Fibronectin (1 g) and bovine serum albumin (0.1 g) are manufactured to be a composite molecule template taking NHS/EDC as catalyst; and the composite molecule template is dissolved in deionized water so as to obtain a composite molecule protein template solution with a concentration of 6 mg/ml.

[0074] (2) Calcium nitrate tetrahydrate (3.29 g) is dissolved in deionized water (200 ml) so as to obtain a calcium source solution; and the composite molecule protein template solution obtained in step (1) and the calcium source solution are mixed with each other and stirred to form a uniform solution, which stays for 1 hour and a composite molecule protein template-calcium solution can be obtained.

[0075] (3) Disodium hydrogen phosphate (1.00 g) is dissolved in deionized water (200 ml), and a phosphorus source solution can be obtained after complete dissolution.

[0076] (4) The composite molecule protein template-calcium solution is placed in water bath with a constant temperature of 37° C. and stirred, and a pH value of the solution is regulated to 7; and tetraethyl orthosilicate (TEOS) (177.3 μL) is added into the solution slowly so as to obtain a calcium-silicon solution.

[0077] (5) The phosphorus source solution obtained in step (3) is dropwise added to the calcium-silicon solution obtained in step (3); the above mixed solution is stirred constantly and a pH value thereof is regulated to 7.4 with aqueous ammonia; stopping stirring after the reaction goes on for 24 hours, collecting a precipitation after the solution stays for 12 hours, and the precipitation is suction filtrated and washed with deionized water for at least three times; and the powder obtained therein after freezing and drying is the silicate-doped hydroxyapatite powder induced by a composite molecule protein template.

[0078] It can be seen through XRD analysis that, the product obtained in the present example is the silicate-doped hydroxyapatite powder induced by a composite molecule protein template. It can be seen through XRF detection that, a silicon content in the silicate-doped hydroxyapatite powder induced by a composite molecule protein template is 1.532 wt %.

[0079] It is obvious that, the above embodiments are described only for better understanding, rather than restricting, the present disclosure. Any person skilled in the art can make amendments or changes based on the contents disclosed herein. It is neither necessary nor feasible to enumerate all of the embodiments. Therefore, the amendments or changes that are readily conceivable based on the technical contents disclosed herein all fall into the protection scope of the present disclosure.