A high piezoelectricity three-dimensional piezoelectric nanoscaffold of biological origin and a preparation method thereof

Abstract

This invention discloses a bio-derived, high-voltage, three-dimensional piezoelectric nanoscaffold and its preparation method, belonging to the field of medical device technology. The preparation method of this invention's three-dimensional piezoelectric nanoscaffold includes the following steps: electrospinning a solution containing chitosan, glycine, and polyethylene oxide to form a three-dimensional nanofiber structure, thereby obtaining the three-dimensional piezoelectric nanoscaffold. The three-dimensional chitosan-glycine piezoelectric nanofiber scaffold of this invention exhibits good biocompatibility, degradability, and piezoelectricity.

Description

Technical Field

[0001] This invention relates to a biologically derived, high-voltage, three-dimensional piezoelectric nanoscaffold and its preparation method, belonging to the field of medical devices. Background Technology

[0002] During tissue regeneration, cell behavior and fate are often regulated by a variety of biophysical signals, among which electrical signals play a crucial role. Traditional treatments often struggle to precisely control these biophysical signals, while piezoelectric nanofiber scaffolds offer a novel solution. Utilizing the properties of piezoelectric materials, they generate electrical signals when subjected to external forces. These signals can directly act on cells, influencing their biological behaviors such as proliferation, differentiation, and migration, thereby guiding tissue regeneration in a predetermined manner.

[0003] The nanoscale structure of piezoelectric nanofiber scaffolds enables them to mimic the extracellular matrix, providing an ideal growth environment for cells. These scaffolds not only possess excellent biocompatibility but also interact effectively with cells, promoting cell adhesion and growth. Furthermore, by adjusting the scaffold's nanostructure and piezoelectric properties, precise guidance and stimulation of different tissue cells can be achieved, meeting the regeneration needs of various tissues.

[0004] Biocompatibility and safety are crucial indicators for evaluating medical materials. For piezoelectric nanofiber scaffolds, biocompatibility and safety directly impact their efficacy and safety in vivo. Some traditional piezoelectric materials, such as piezoelectric ceramics and polyvinylidene fluoride (PVDF) polymers, contain toxic or non-biodegradable components, making them unsuitable for internal use. Biodegradable piezoelectric nanofibers, such as PLA, may trigger immune or inflammatory responses in vivo, leading to damage or dysfunction of surrounding tissues. Furthermore, most piezoelectric polymers are hydrophobic, which is detrimental to cell adhesion and growth.

[0005] Chitosan (CS) is a product obtained by deacetylation of chitin and has been proven to be biorenewable, biodegradable, immunogenic, and biocompatible. The presence of non-centrosymmetric molecular structures in CS endows CS-based materials with their own piezoelectric properties. However, due to the relatively weak piezoelectric properties of CS itself, there is currently limited research on the utilization of the piezoelectricity of CS.

[0006] Therefore, how to provide a biodegradable three-dimensional piezoelectric nanofiber scaffold based on chitosan remains a pressing technical problem that needs to be solved. Summary of the Invention

[0007] The purpose of this invention is to provide a bio-derived, high-voltage, three-dimensional piezoelectric nanoscaffold and its preparation method. A bio-derived, biodegradable three-dimensional piezoelectric nanofiber scaffold based on chitosan and glycine is prepared by electrospinning. This three-dimensional chitosan-glycine piezoelectric nanofiber scaffold has good biocompatibility, degradability, and piezoelectricity.

[0008] The present invention provides a method for preparing a three-dimensional piezoelectric nanoscaffold, comprising the following steps: electrospinning a solution containing chitosan, glycine and polyethylene oxide to form a three-dimensional nanofiber structure, thereby obtaining a three-dimensional piezoelectric nanoscaffold.

[0009] In one embodiment of the present invention, the solution containing chitosan, glycine and polyethylene oxide has a mass ratio of chitosan to polyethylene oxide of 3:2.

[0010] In one embodiment of the present invention, in the solution containing chitosan, glycine and polyethylene oxide, the mass ratio of chitosan to glycine is 1:(0.5-1), preferably 1:0.8.

[0011] In one embodiment of the present invention, the viscosity of the chitosan is 100–200 mPa·s; and / or,

[0012] The molecular weight of the polyethylene oxide is 300 kDa.

[0013] In one embodiment of the present invention, the solution containing chitosan, glycine and polyethylene oxide has a chitosan mass concentration of 2.4% and the solvent is acetic acid with a volume fraction of 80%.

[0014] In one embodiment of the present invention, the electrospinning apparatus includes an injection pump, a syringe, a high-voltage power supply, and a fiber collector.

[0015] The syringe includes a needle;

[0016] The fiber collector includes a housing made of insulating material, the inner surface of which is recessed downward to form a hemispherical concave space, and multiple metal needles are inserted horizontally in the radial direction into the inner surface, the multiple metal needles being electrically connected to each other;

[0017] The two ends of the high-voltage power supply are respectively connected to the needle tip and the multiple metal needles.

[0018] In one embodiment of the invention, the rate of the injection pump is set to 0.5 ml / h.

[0019] In one embodiment of the present invention, the applied voltage of the high-voltage power supply is 15kV.

[0020] In one embodiment of the present invention, the distance between the needle and the fiber collector is 10 cm.

[0021] The present invention further provides a three-dimensional piezoelectric nanoscaffold prepared by any of the preparation methods described above.

[0022] The present invention has the following beneficial effects:

[0023] The three-dimensional chitosan-glycine piezoelectric nanofiber scaffold prepared by the method of the present invention has good biocompatibility, degradability and piezoelectricity. Attached Figure Description

[0024] Figure 1 is a schematic diagram of electrospinning preparation using different collectors in one embodiment of the present invention. Figure 1A The left image shows a schematic diagram of electrospinning using a traditional flat plate collector, while the right image shows a schematic diagram of electrospinning using a spherical probe collector. Figure 1B This is a schematic diagram of the spherical probe collector.

[0025] In Figure 1, the markings are as follows: 100-syringe; 101-needle; 200-plate collector; 300-spherical probe collector; 301-housing; 302-metal needle.

[0026] Figure 2 These are photographs of different supports obtained from a flat plate collector (A) and a spherical probe collector (B) in one embodiment of the present invention.

[0027] Figure 3 This is a SEM image of the support obtained by the flat plate collector and the spherical probe collector in one embodiment of the present invention.

[0028] Figure 4 The output electrical signals of the flat plate collector and the spherical probe collector in one embodiment of the present invention.

[0029] Figure 5 SEM images of piezoelectric nanoscaffolds obtained with different chitosan to glycine mass ratios in one embodiment of the present invention.

[0030] Figure 6 The XRD results are shown for piezoelectric nanoscaffolds obtained by different mass ratios of chitosan to glycine in one embodiment of the present invention. Detailed Implementation

[0031] As described in the background section, while chitosan is biodegradable and biocompatible, its piezoelectricity is relatively weak. Among all bio-derived piezoelectric materials, glycine has a very high piezoelectric coefficient, and β-glycine crystals exhibit high shear piezoelectricity and an extremely high piezoelectric voltage coefficient. However, β-glycine is the most kinetically difficult to form and the least stable under environmental conditions. The inventors discovered that chitosan can effectively regulate the self-assembly kinetics of glycine molecules in its crystal structure, generating stable β-glycine that remains unchanged for several months. The stability of β-glycine may be due to the electrostatic interaction between the polar groups (amine and hydroxyl groups) of glycine and the functional groups of chitosan, forming hydrogen bonds. Therefore, this invention attempts to prepare piezoelectric nanofiber scaffolds with high piezoelectric coefficients by adding glycine to the original chitosan solution.

[0032] In the first part, the present invention provides a method for preparing a three-dimensional piezoelectric nanoscaffold, comprising the following steps: electrospinning a solution containing chitosan, glycine and polyethylene oxide to form a three-dimensional nanofiber structure, thereby obtaining a three-dimensional piezoelectric nanoscaffold.

[0033] In at least one embodiment of the present invention, the mass ratio of chitosan to polyethylene oxide in the solution comprising chitosan, glycine and polyethylene oxide is 3:2.

[0034] In at least one embodiment of the present invention, in the solution comprising chitosan, glycine, and polyethylene oxide, the mass ratio of chitosan to glycine is 1:(0.5-1), preferably 1:0.8. The inventors have found that when the mass ratio of chitosan to glycine is 1:0.8, the prepared three-dimensional piezoelectric nanoscaffold possesses the optimal pore structure and piezoelectric properties. The difference in piezoelectric properties is reflected in the degree of crystallinity of the β-phase glycine. This is because β-glycine crystals have high piezoelectric properties, which stem from the non-centrosymmetry of the crystal structure. Only highly ordered crystals can form stable electric dipole moments and generate charge or deformation under external force or electric field. A higher degree of crystallinity means a more complete crystal structure, more ordered lattice, fewer defects, and theoretically stronger piezoelectric properties.

[0035] In at least one embodiment of the present invention, the viscosity of the chitosan is 100-200 mPa·s; and the molecular weight of the polyethylene oxide is 300 kDa.

[0036] In at least one embodiment of the present invention, the solution containing chitosan, glycine, and polyethylene oxide has a chitosan mass concentration of 2.4% and the solvent is acetic acid with a volume fraction of 80%. Specifically, the solution containing chitosan, glycine, and polyethylene oxide can be prepared by stirring at 40°C for 6 hours.

[0037] As shown in Figure 1, both traditional roller and flat plate collectors in electrospinning produce flattened films, which are not conducive to three-dimensional cell growth. This is because, in traditional roller or flat plate collectors, the grounding charge is uniformly distributed over a large area, resulting in a group of fibers being deposited side-by-side in one layer. Each subsequent layer is deposited on top of the existing layer and is strongly attracted by the grounded collector, thus compressing the layers below and forming a flat, sheet-like structure with densely packed fiber layers and a flat surface. The lack of space between adjacent layers forms a two-dimensional scaffold, limiting cell growth and penetration to the surface layer. In one embodiment of the present invention, the electrospinning device includes an injection pump, a syringe, a high-voltage power supply, and a fiber collector; the syringe 100 includes a needle 101; the fiber collector includes a housing 301 made of insulating material, the inner surface of which is concave downward to form a hemispherical concave space, and multiple metal needles 302 are inserted radially horizontally into the inner surface, the multiple metal needles 302 being electrically connected to each other; the two ends of the high-voltage power supply are respectively connected to the needle 101 and the multiple metal needles 302. By replacing the traditional collector with a non-conductive spherical collector having a series of embedded metal probes, the ground charge is uniformly dispersed and concentrated on the probes, enabling the collection of nanofibers between them in mid-air. Due to the lack of uniform charge throughout the collector, the nanofiber layer can settle near the previously deposited fibers without compressing the scaffold, thus accumulating them into a fluffy three-dimensional structure with good stability.

[0038] In one embodiment of the invention, the rate of the injection pump is set to 0.5 ml / h.

[0039] In one embodiment of the present invention, the applied voltage of the high-voltage power supply is 15kV.

[0040] In one embodiment of the present invention, the distance between the needle and the fiber collector is 10 cm.

[0041] This invention further provides a three-dimensional piezoelectric nanoscaffold prepared by any of the methods described above. The three-dimensional chitosan-glycine piezoelectric nanofiber scaffold exhibits good biocompatibility, degradability, and piezoelectricity.

[0042] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0043] Unless otherwise specified, the methods used in the following embodiments are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0044] Example 1: Preparation of bio-derived, high-voltage, three-dimensional piezoelectric nanoscaffolds

[0045] As shown in Figure 1, the electrospinning apparatus includes an injection pump (not shown), a syringe 100, a high-voltage power supply (not shown), and a fiber collector; the syringe 100 includes a needle 101; the fiber collector is a spherical probe collector 300, including a housing 301 made of insulating material (such as polytetrafluoroethylene), the inner surface of the housing 301 is recessed downward to form a hemispherical concave space, and multiple metal needles 302 (such as stainless steel needles) are inserted horizontally in the radial direction into the inner surface, and the multiple metal needles are electrically connected to each other by copper wire; the two ends of the high-voltage power supply are respectively connected to the needle 101 and the multiple metal needles 302.

[0046] In the following embodiments, as a control, the conventional flat plate collector replaces the spherical probe collector 300 with the flat plate collector 200, while all other conditions remain the same.

[0047] Three-dimensional piezoelectric nanoscaffolds were prepared according to the following steps: Chitosan (CS) at 100-200 mPa·s, glycine, and polyethylene oxide (PEO) at 300 kDa were dissolved in an 80% (v / v) acetic acid solution, wherein the concentration of chitosan was 2.4% wt, the mass ratio of chitosan to PEO was 3:2, and the mass ratio of chitosan to glycine was 1:0.8. The mixture was stirred at 40°C for 6 hours until homogeneous, and then added to a syringe. The syringe pump was set to a speed of 0.5 ml / h, a voltage of 15 kV was applied to the needle, and the distance between the needle and the collector was 10 cm.

[0048] Different scaffolds obtained through flat plate collectors and spherical probe collectors, such as Figure 2 (A) and Figure 2 As shown in (B). Nanoscale results of the three-dimensional scaffold were detected by SEM, as follows... Figure 3 As shown, the scaffold has large pores, which is beneficial for cell growth.

[0049] The output electrical signals obtained by pressing a finger on the two-dimensional and three-dimensional piezoelectric fiber scaffolds obtained by the flat plate collector and the spherical probe collector are, for example... Figure 4 As shown in the figure, the results indicate that the electrical signal of the three-dimensional scaffold was significantly improved.

[0050] Example 2

[0051] The three-dimensional piezoelectric nanoscaffold was prepared according to the steps in Example 1, except that the mass ratio of chitosan to glycine was replaced with 1:0.5.

[0052] Example 3

[0053] Three-dimensional piezoelectric nanoscaffolds were prepared according to the steps in Example 1, except that the mass ratio of chitosan to glycine was replaced with 1:1.

[0054] The piezoelectric properties and structures of the scaffolds prepared from chitosan and glycine solutions with mass ratios of 1:0.5, 1:0.8, and 1:1, respectively, were compared in Examples 1-3. Figure 5 The scaffold prepared with a mass ratio of 1:0.8 shows that it has the optimal pore structure.

[0055] Meanwhile, X-ray diffraction experiments were conducted on the 3D scaffold, and the results showed that β-phase glycine crystals were successfully generated in the chitosan and glycine piezoelectric scaffold, thus improving the piezoelectric performance of the scaffold. Figure 6 The scaffold prepared at a mass ratio of 1:0.8 showed the best degree of β-phase glycine crystallinity, which means that the scaffold has higher piezoelectricity.

[0056] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including modifications made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A method for preparing a three-dimensional piezoelectric nanoscaffold, characterized in that, Includes the following steps: A three-dimensional piezoelectric nanoscaffold was obtained by electrospinning a solution containing chitosan, glycine, and polyethylene oxide.

2. The method for preparing the three-dimensional piezoelectric nanoscaffold according to claim 1, characterized in that: In the solution containing chitosan, glycine and polyethylene oxide, the mass ratio of chitosan to polyethylene oxide is 3:

2.

3. The method for preparing a three-dimensional piezoelectric nanoscaffold according to any one of claims 1-2, characterized in that: In the solution containing chitosan, glycine and polyethylene oxide, the mass ratio of chitosan to glycine is 1:(0.5-1), preferably 1:0.

8.

4. The method for preparing a three-dimensional piezoelectric nanoscaffold according to any one of claims 1-3, characterized in that: The viscosity of the chitosan is 100–200 mPa·s; and / or, The molecular weight of the polyethylene oxide is 300 kDa.

5. The method for preparing a three-dimensional piezoelectric nanoscaffold according to any one of claims 1-4, characterized in that: The solution containing chitosan, glycine, and polyethylene oxide has a chitosan mass concentration of 2.4%.

6. The method for preparing a three-dimensional piezoelectric nanoscaffold according to any one of claims 1-5, characterized in that: The electrospinning apparatus includes an injection pump, a syringe, a high-voltage power supply, and a fiber collector. The syringe includes a needle; The fiber collector includes a housing made of insulating material, the inner surface of which is recessed downward to form a hemispherical concave space, and multiple metal needles are inserted horizontally in the radial direction into the inner surface, the multiple metal needles being electrically connected to each other; The two ends of the high-voltage power supply are respectively connected to the needle tip and the multiple metal needles.

7. The method for preparing the three-dimensional piezoelectric nanoscaffold according to claim 6, characterized in that: The speed of the syringe pump is set to 0.5 ml / h.

8. The method for preparing a three-dimensional piezoelectric nanoscaffold according to any one of claims 6-7, characterized in that: The applied voltage of the high-voltage power supply is 15kV.

9. The method for preparing a three-dimensional piezoelectric nanoscaffold according to any one of claims 6-8, characterized in that: The distance between the needle and the fiber collector is 10 cm.

10. The three-dimensional piezoelectric nanoscaffold prepared by the preparation method according to any one of claims 1-9.

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