A flexible piezoelectric composite scaffold mimicking cartilage and a method of preparing the same

Abstract

The application provides a flexible piezoelectric composite scaffold simulating cartilage and a preparation method thereof, and relates to the field of medical materials.The flexible piezoelectric composite scaffold simulating cartilage is prepared by filling chitosan / polyvinyl alcohol fibers outside a barium titanate-flexible resin piezoelectric scaffold.The method for preparing the flexible piezoelectric composite scaffold is simple, and the flexible piezoelectric composite scaffold simulating cartilage prepared by the method has good biocompatibility and good flexible mechanical properties under the action of ultrasound, and can effectively stimulate the proliferation of osteoblasts and promote bone regeneration based on the electric stimulation function of the piezoelectric scaffold.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical materials, in particular to a flexible piezoelectric composite scaffold simulating cartilage and a preparation method thereof. BACKGROUND

[0002] Osteoarthritis has always been one of the diseases that plague mankind, especially more and more teenagers have also begun to show knee degenerative changes, cartilage damage and other problems. Cartilage tissue basically does not have a vascular network, so it is difficult for repair cells to move to the damaged area to achieve the effect of repairing damaged cartilage tissue. Therefore, once the cartilage necrosis occurs, there is usually a serious lack of sufficient blood, nutrient and other material supply, resulting in the phenomenon that the cartilage cannot self-repair. Under normal circumstances, damaged cartilage tissue is usually replaced by fibrous hyperplastic tissue, and functional decline or complete loss is caused.

[0003] Common means for repairing cartilage damage include conservative treatment, microfracture surgery, autologous cartilage cell implantation, autologous osteochondral transplantation, and biomaterial implantation. However, conservative treatment, microfracture surgery, autologous cartilage cell implantation, and autologous osteochondral transplantation can cause immune inflammation, so biomaterial implantation is increasingly used to treat cartilage damage and cartilage deficiency. How to solve the problem of the possible rapid absorption of biological implant materials by cartilage and improve the cartilage repair capacity is the focus of researchers.

[0004] Electrical stimulation has been proven to promote the proliferation of chondrocytes and the synthesis of extracellular matrix molecules, thereby accelerating the healing of cartilage defects. Therefore, developing a non-toxic, safe, minimally invasive treatment, a scaffold with high cartilage induction and angiogenesis capacity, degradability, cell proliferation promotion, and self-powered stimulation is an effective means to improve cartilage repair. Piezoelectric composite material is an intelligent material with piezoelectricity and flexible mechanical properties, which has good biocompatibility, mechanical properties, low inflammatory response, and is conducive to cell proliferation, and has received high attention in the research of cartilage bone repair scaffolds. SUMMARY

[0005] Therefore, the present application provides a flexible piezoelectric composite scaffold simulating cartilage and a preparation method thereof. The present application is a composite scaffold simulating cartilage by filling chitosan / polyvinyl alcohol fibers outside the barium titanate-flexible resin piezoelectric scaffold, as shown in the schematic diagram of the flexible piezoelectric composite scaffold simulating cartilage. Figure 1 The scaffold has good biocompatibility, flexible mechanical properties, and degradability.

[0006] The present application is implemented by using the following technical solutions:

[0007] A preparation method of a flexible piezoelectric composite scaffold simulating cartilage, comprising the following steps:

[0008] (1) configuring a flexible resin matrix

[0009] Mixing barium titanate and flexible resin with a volume ratio of 0.5-1:9-9.5, stirring, then adding curing agent, stirring uniformly, pouring into the mold, defoaming, curing to obtain the flexible resin matrix, namely the barium titanate-flexible resin piezoelectric scaffold;

[0010] (2) preparing a chitosan / polyvinyl alcohol fiber gel pre-solution

[0011] Dissolve polyvinyl alcohol fiber in deionized water, heat and stir at 75-80℃ for 25-30min to obtain a polyvinyl alcohol fiber solution; then dissolve chitosan in deionized water and stir to obtain a chitosan solution; finally mix the polyvinyl alcohol fiber solution and the chitosan solution with a volume ratio of 5-7:3-5, stir uniformly to obtain the chitosan / polyvinyl alcohol fiber gel pre-solution;

[0012] (3) preparing a flexible piezoelectric composite scaffold simulating cartilage

[0013] First, mix the chitosan / polyvinyl alcohol fiber gel pre-solution and crosslinking agent with a mass ratio of 10:0.1-0.3, stir for 30min to obtain a gel pre-solution / crosslinking agent mixed solution; then immerse the barium titanate-flexible resin piezoelectric scaffold in the gel pre-solution / crosslinking agent mixed solution, stand for 24h, then freeze-dry to obtain the flexible piezoelectric composite scaffold simulating cartilage.

[0014] Further, the flexible resin is polydimethylsiloxane (PDMS).

[0015] Preferably, the viscosity of the flexible resin is 1500mpa·s-1800mpa·s.

[0016] Preferably, the particle diameter of the barium titanate is 200nm-800nm.

[0017] Preferably, the piezoelectric constant of the barium titanate is 100pC / N-120pC / N.

[0018] Further, the curing agent is a dimer acid polyamide curing agent, preferably hydrogenated C18 unsaturated fatty acid dimer acid.

[0019] Preferably, the mass ratio of the curing agent to the flexible resin is 0.01-0.1:1.

[0020] Preferably, the mass fraction of polyvinyl alcohol fiber in the polyvinyl alcohol fiber solution is 10%-15%.

[0021] Preferably, the mass fraction of chitosan in the chitosan solution is 1%-5%.

[0022] Furthermore, the cross-linking agent is glutaraldehyde.

[0023] Preferably, the freeze-drying process is performed by cooling the temperature from room temperature to -40°C at a cooling rate of 3°C / min and then freezing for 48 hours.

[0024] Another object of the present invention is to provide a flexible piezoelectric composite scaffold for simulating cartilage, which is prepared by the above-mentioned method for preparing the flexible piezoelectric composite scaffold for simulating cartilage.

[0025] Furthermore, the porosity of the cartilage-simulating flexible piezoelectric composite scaffold is 60%-80%, and the fracture strength is 1.94 MPa-2.11 MPa.

[0026] Furthermore, the ultrasonic intensity of the flexible piezoelectric composite scaffold simulating cartilage is 0.8W / cm 2 -1.6W / cm 2 , it generates a charge signal under the condition of a duty cycle of 60%-100%.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The preparation method of the flexible piezoelectric composite scaffold for simulating cartilage of the present invention is simple, and the prepared flexible piezoelectric composite scaffold for simulating cartilage has good biocompatibility and good flexible mechanical properties under the action of ultrasound.

[0029] 2. The flexible piezoelectric composite scaffold prepared by the present invention not only has mechanical properties close to those of human cartilage, but can also effectively stimulate the proliferation of osteoblasts based on the electrical stimulation function of the piezoelectric scaffold.

[0030] 3. In the process of preparing a flexible piezoelectric composite scaffold that simulates cartilage according to the present invention, the prepared gel prefabricated solution is formed by mixing a chitosan solution and a polyvinyl alcohol fiber solution, wherein chitosan and polyvinyl alcohol fiber are both natural osteogenic materials that can be absorbed by the human body, and the polysaccharide mixture can effectively promote bone regeneration and can be absorbed by the human body. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the flexible piezoelectric composite stent for simulating cartilage of the present invention;

[0032] Figure 2 Graphs showing the tensile mechanical properties of the flexible piezoelectric composite supports prepared in Examples 1-3, (a) a histogram showing elongation at break, and (b) a histogram showing tensile strength at break;

[0033] Figure 3 This is a schematic diagram of a cell experiment under ultrasound in the present invention;

[0034] Figure 4Graph showing the results of a cell live-death experiment after co-culturing mouse cells with the flexible piezoelectric composite scaffold prepared in Example 1-3 for 3 days;

[0035] Figure 5 Graph showing the ALP activity detection results after co-culturing the flexible piezoelectric composite scaffold prepared in Example 1-3 with mouse cells for 7 days. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the embodiments.

[0037] Example 1

[0038] A method for preparing a flexible piezoelectric composite scaffold for simulating cartilage comprises the following steps:

[0039] (1) Preparation of flexible resin matrix

[0040] 30.7 g of barium titanate powder was added to 50 g of polydimethylsiloxane (PDMS, density 1.1 g / cm 3 , volume 45.45 ml), stirred, mixed evenly, added 2.5 g of hydrogenated C18 unsaturated fatty acid dimer acid, and then quickly stirred and mixed evenly, poured into the bracket mold, and then placed the bracket mold in a defoamer for defoaming and curing for 24 hours to obtain a flexible resin matrix, i.e., barium titanate-polydimethylsiloxane piezoelectric bracket;

[0041] (2) Preparation of chitosan / polyvinyl alcohol fiber gel prefabricated solution

[0042] First, 10g of polyvinyl alcohol fiber was dissolved in 90g of deionized water, heated and stirred at 80°C for 30min to obtain a polyvinyl alcohol fiber solution; then, 2g of chitosan was dissolved in 8g of deionized water and stirred to obtain a chitosan solution; then, the polyvinyl alcohol fiber solution and the chitosan solution were mixed in a volume ratio of 5:5 and stirred to obtain a chitosan / polyvinyl alcohol fiber gel prefabricated solution;

[0043] (3) Preparation of flexible piezoelectric composite scaffolds simulating cartilage

[0044] First, weigh 30g of chitosan / polyvinyl alcohol fiber gel prefabricated solution, add 0.9g of glutaraldehyde, and stir for 30 minutes to obtain a gel prefabricated solution / cross-linker mixed solution; then soak the barium titanate-polydimethylsiloxane piezoelectric scaffold in the gel prefabricated solution / cross-linker mixed solution, put it into a freeze-drying treatment box after 24 hours, cool it from room temperature to -40℃ at a cooling rate of 3℃ / min, and then freeze it for 48 hours; then, remove the excess gel at the edge of the barium titanate-polydimethylsiloxane piezoelectric scaffold to obtain a flexible piezoelectric composite scaffold that simulates cartilage.

[0045] Example 2

[0046] A method for preparing a flexible piezoelectric composite scaffold for simulating cartilage comprises the following steps:

[0047] (1) Configure a flexible resin matrix

[0048] 30.7 g of barium titanate powder was added to 50 g of polydimethylsiloxane (PDMS, density 1.1 g / cm 3 , volume 45.45 ml), stirred, mixed evenly, added 2.5 g of hydrogenated C18 unsaturated fatty acid dimer acid, and then quickly stirred and mixed evenly, poured into the bracket mold, and then placed the bracket mold in a defoamer for defoaming and curing for 24 hours to obtain a flexible resin matrix, i.e., barium titanate-polydimethylsiloxane piezoelectric bracket;

[0049] (2) Preparation of chitosan / polyvinyl alcohol fiber gel prefabricated solution

[0050] First, 10g of polyvinyl alcohol fiber was dissolved in 90g of deionized water, heated and stirred at 80°C for 30min to obtain a polyvinyl alcohol fiber solution; then, 2g of chitosan was dissolved in 8g of deionized water and stirred to obtain a chitosan solution; then, the polyvinyl alcohol fiber solution and the chitosan solution were mixed in a volume ratio of 6:4 and stirred to obtain a chitosan / polyvinyl alcohol fiber gel prefabricated solution;

[0051] (3) Preparation of flexible piezoelectric composite scaffolds simulating cartilage

[0052] First, weigh 30g of chitosan / polyvinyl alcohol fiber gel prefabricated solution, add 0.9g of glutaraldehyde, and stir for 30 minutes to obtain a gel prefabricated solution / cross-linker mixed solution; then soak the barium titanate-polydimethylsiloxane piezoelectric scaffold in the gel prefabricated solution / cross-linker mixed solution, put it into a freeze-drying treatment box after 24 hours, cool it from room temperature to -40℃ at a cooling rate of 3℃ / min, and then freeze it for 48 hours; then, remove the excess gel at the edge of the barium titanate-polydimethylsiloxane piezoelectric scaffold to obtain a flexible piezoelectric composite scaffold that simulates cartilage.

[0053] Example 3

[0054] A method for preparing a flexible piezoelectric composite scaffold for simulating cartilage comprises the following steps:

[0055] (1) Configure a flexible resin matrix

[0056] 30.7 g of barium titanate powder was added to 50 g of polydimethylsiloxane (PDMS, density 1.1 g / cm 3 , volume 45.45 ml), stirred, mixed evenly, added 2.5 g of hydrogenated C18 unsaturated fatty acid dimer acid, and then quickly stirred and mixed evenly, poured into the bracket mold, and then placed the bracket mold in a defoamer for defoaming and curing for 24 hours to obtain a flexible resin matrix, i.e., barium titanate-polydimethylsiloxane piezoelectric bracket;

[0057] (2) Preparation of chitosan / polyvinyl alcohol fiber gel prefabricated solution

[0058] First, 10g of polyvinyl alcohol fiber was dissolved in 90g of deionized water, heated and stirred at 80°C for 30min to obtain a polyvinyl alcohol fiber solution; then, 2g of chitosan was dissolved in 8g of deionized water and stirred to obtain a chitosan solution; then, the polyvinyl alcohol fiber solution and the chitosan solution were mixed in a volume ratio of 7:3 and stirred to obtain a chitosan / polyvinyl alcohol fiber gel prefabricated solution;

[0059] (3) Preparation of flexible piezoelectric composite scaffolds simulating cartilage

[0060] First, weigh 30g of chitosan / polyvinyl alcohol fiber gel prefabricated solution, add 0.9g of glutaraldehyde, and stir for 30 minutes to obtain a gel prefabricated solution / cross-linker mixed solution; then soak the barium titanate-polydimethylsiloxane piezoelectric scaffold in the gel prefabricated solution / cross-linker mixed solution, put it into a freeze-drying treatment box after 24 hours, cool it from room temperature to -40℃ at a cooling rate of 3℃ / min, and then freeze it for 48 hours; then, remove the excess gel at the edge of the barium titanate-polydimethylsiloxane piezoelectric scaffold to obtain a flexible piezoelectric composite scaffold that simulates cartilage.

[0061] Figure 2 The tensile mechanical properties of the flexible piezoelectric composite bracket prepared in Example 1-3 are shown in FIG. Figure 2 (b) The tensile fracture strength histogram shows that the tensile fracture strengths of the flexible piezoelectric composite supports prepared in Example 1, Example 2, and Example 3 are 2.11 MPa, 2.01 MPa, and 1.94 MPa, respectively. The differences are not obvious, but according to Figure 2 (a) The elongation at break histogram shows that the elongations at break for Examples 1, 2, and 3 are 74%, 67%, and 49%, respectively. This indicates that as the volume ratio of the polyvinyl alcohol fiber solution to the chitosan solution decreases, the tensile strength of the scaffold decreases slightly, but the elongation at break varies significantly.

[0062] The schematic diagram of the cell experiment under ultrasound of the present invention is as follows Figure 3 Reference Figure 3 The flexible piezoelectric composite scaffolds prepared in Examples 1-3 were used to carry out cell live / death experiments and alkaline phosphatase (ALP) activity detection experiments to verify the biocytocompatibility and osteogenic performance of each bone scaffold (mouse MC3T3-E1 cells were used to carry out cell live / death experiments and alkaline phosphatase (ALP) activity detection).

[0063] The results of the cell live-death experiment after culturing the flexible piezoelectric composite scaffold prepared in Example 1-3 with mouse cells for 3 days are shown in FIG. Figure 4The ALP activity detection results of the flexible piezoelectric composite scaffold prepared by the examples 1-3 after being co-cultured with the mouse cells for 7 days are shown in the figure Figure 5 . The cell live / dead experiment detection method is to use mouse osteoblasts (MC3T3-E1, national identification cell culture system, China) as experimental materials, co-culture with the flexible piezoelectric composite scaffold prepared by the examples 1-3, and after 72h, the dye is prepared by the Calcein / PI cell live / dead kit, the scaffold after co-culture is treated, and then the software is used to count the cell live / dead ratio on the scaffold; the alkaline phosphatase (ALP) quantitative analysis experiment method is to use mouse osteoblasts (MC3T3-E1, national identification cell culture system, China) as experimental materials, co-culture with the blank scaffold-free group and the flexible piezoelectric composite scaffold prepared by the examples 1-3, and apply ultrasonic wave with the intensity of 0.8W / cm 2 -1.6W / cm 2 , duty cycle 60%-100%, for 1min. After 7 days, the protein expression on the scaffold is monitored by the alkaline phosphatase (ALP) detection kit, and the ALP activity detection results are shown in the figure Figure 5 .

[0064] As can be seen from Figure 4 , the cell survival rate of the flexible piezoelectric composite scaffold prepared by the examples 1, 2 and 3 is greater than 89%, which proves that the flexible piezoelectric composite scaffold has good cell compatibility. At the same time, combined with Figure 5 , compared with the blank control group, the ALP activity of the flexible piezoelectric composite scaffold prepared by the examples 1-3 under the action of ultrasonic wave is significantly improved, which proves that the scaffold has good osteogenic effect.

[0065] The above only describes the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.

Claims

1. A method for preparing a flexible piezoelectric composite scaffold simulating cartilage, characterized in that: The following steps are involved: (1) Preparation of flexible resin matrix Barium titanate and flexible resin are mixed in a volume ratio of 0.5-1:9-9.5, stirred, and then a curing agent is added. After stirring evenly, the mixture is molded, defoamed, and cured to obtain the flexible resin matrix, i.e., the barium titanate-flexible resin piezoelectric support; (2) Preparation of chitosan / polyvinyl alcohol fiber gel prefabricated solution Dissolving polyvinyl alcohol fiber in deionized water, heating and stirring at 75° C. to 80° C. for 25 to 30 minutes to obtain a polyvinyl alcohol fiber solution; then dissolving chitosan in deionized water and stirring to obtain a chitosan solution; then mixing the polyvinyl alcohol fiber solution and the chitosan solution in a volume ratio of 5 to 7:3 to 5, and stirring evenly to obtain a chitosan / polyvinyl alcohol fiber gel prefabricated solution; (3) Preparation of flexible piezoelectric composite scaffolds simulating cartilage The chitosan / polyvinyl alcohol fiber gel prefabricated solution and a crosslinker were first mixed in a mass ratio of 10:0.1-0.3 and stirred for 30 minutes to obtain a gel prefabricated solution / crosslinker mixed solution; the barium titanate-flexible resin piezoelectric scaffold was then immersed in the gel prefabricated solution / crosslinker mixed solution, allowed to stand for 24 hours, and then freeze-dried, and cut to obtain the cartilage-mimicking flexible piezoelectric composite scaffold; The flexible resin is polydimethylsiloxane.

2. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The viscosity of the flexible resin is 1500 mPa·s to 1800 mPa·s.

3. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The particle diameter of the barium titanate is 200 nm to 800 nm, and the piezoelectric constant is 100 pC / N to 120 pC / N.

4. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The curing agent is a dimer acid polyamide curing agent.

5. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The mass ratio of the curing agent to the flexible resin is 0.01-0.1:

1.

6. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The mass fraction of the polyvinyl alcohol fiber in the polyvinyl alcohol fiber solution is 10% to 15%; the mass fraction of the chitosan in the chitosan solution is 1% to 5%.

7. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The cross-linking agent is glutaraldehyde.

8. The method for preparing the flexible piezoelectric composite scaffold for simulating cartilage according to claim 1, characterized in that: The freeze-drying process was performed by cooling the temperature from room temperature to ~40°C at a cooling rate of 3°C / min and then freezing for 48 hours.

9. A flexible piezoelectric composite stent simulating cartilage, characterized in that: The flexible piezoelectric composite scaffold for simulating cartilage is prepared by the preparation method of any one of claims 1 to 8; the flexible piezoelectric composite scaffold for simulating cartilage has a porosity of 60% to 80%, a breaking strength of 1.94 MPa to 2.11 MPa, and an ultrasonic intensity of 0.8 W / cm 2 ~1.6W / cm 2 , the charge signal is generated under the condition of duty cycle 60%~100%.

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