A method for preparing a dopamine-coated poly(l-lactic acid) piezoelectric biomaterial

Abstract

The application discloses a preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial, S1, ultrasonic dispersion of dopamine hydrochloride in an organic solvent is carried out to obtain a dopamine hydrochloride dispersion liquid; S2, poly(L-lactic acid) powder is added into the dopamine hydrochloride dispersion liquid and stirring is carried out to obtain an electrostatic spinning liquid; S3, bubbles in the electrostatic spinning liquid are removed, a nanofiber membrane is obtained through an electrostatic spinning process, high-temperature annealing is carried out on the nanofiber membrane, and cooling is carried out, so that the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial is prepared. The preparation method adopts an interface anchoring effect, strong intermolecular interaction at an interface between dopamine and poly(L-lactic acid) is responsible for anchoring self-polarization poly(L-lactic acid) chains and promoting crystal nucleation, so that the prepared piezoelectric biomaterial exhibits significantly enhanced piezoelectric performance and excellent service life.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of piezoelectric biomaterials, in particular to a preparation method of dopamine-coated poly(L-lactic acid) piezoelectric biomaterials. BACKGROUND

[0002] Piezoelectric biomaterials are an important class of functional materials that can be used in state-of-the-art human-machine interfaces, energy conversion and sensing technologies. In modern bioelectronic systems, functional nanofibers and their associated nonwoven fabrics are particularly attractive for wearable and implantable devices that interface with soft tissues. Poly(L-lactic acid) is a piezoelectric biopolymer material widely used in medical implants, which provides a good platform for developing implantable and biodegradable piezoelectric devices if appropriate crystalline phase, direction and morphology can be achieved. However, the weak and unstable piezoelectricity of poly(L-lactic acid) is still a major challenge to realize practical applications. At present, although the crystallinity and orientation of poly(L-lactic acid) can be improved by heat annealing and mechanical stretching, the piezoelectric poly(L-lactic acid) bulk film prepared by stretching method usually has the defects of low beta phase ratio, poor stability and high rigidity.

[0003] Due to the high stretching force applied to the charged solution jet, electrospinning can effectively produce self-polarized soft piezoelectric poly(L-lactic acid) nanofibers with high crystallinity. However, the polarized poly(L-lactic acid) will partially rearrange under mechanical stretching or even temperature fluctuations of thermal motion, so it tends to depolarize or relax back to the thermodynamically more stable non-piezoelectric phase. It is still one of the biggest challenges to realize and maintain high piezoelectric performance for a long time for the development of flexible piezoelectric biomaterials based on poly(L-lactic acid). SUMMARY

[0004] The purpose of the present application is to solve the problem of weak and unstable piezoelectricity of piezoelectric biomaterials based on poly(L-lactic acid) prepared by the existing method, and to provide a preparation method of dopamine-coated poly(L-lactic acid) piezoelectric biomaterials. The method uses dopamine as a heterogeneous nucleating agent to solve the long-term stability problem of piezoelectric poly(L-lactic acid), which provides a good guarantee for the development of implantable and degradable biomedical piezoelectric devices.

[0005] To achieve the above purpose, the present application is realized by the following technical scheme:

[0006] The present application provides a preparation method of dopamine-coated poly(L-lactic acid) piezoelectric biomaterials, which comprises the following steps:

[0007] S1, preparation of a hydrochloric acid dopamine dispersion liquid: ultrasonic dispersion of hydrochloric acid dopamine in an organic solvent to obtain a hydrochloric acid dopamine dispersion liquid;

[0008] S2, preparation of electrospinning solution: poly(L-lactic acid) powder is added to the dopamine hydrochloride dispersion liquid and stirred to obtain an electrospinning solution;

[0009] S3, preparation of dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: bubbles in the electrospinning solution are removed, then a nanofiber membrane is obtained by an electrospinning process, and then the nanofiber membrane is subjected to high-temperature annealing and cooling, thereby preparing a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial.

[0010] Specifically, the preparation method of the present application adopts an interfacial anchoring effect, and the strong intermolecular interaction at the interface between dopamine and poly(L-lactic acid) is responsible for anchoring the self-polarization poly(L-lactic acid) chain and promoting crystal nucleation, so that the prepared piezoelectric biomaterial exhibits significantly enhanced piezoelectric performance and excellent service life.

[0011] Further, a preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: step S1, preparation of dopamine hydrochloride dispersion liquid: dopamine hydrochloride is dissolved in an organic solvent and subjected to ultrasonic treatment to obtain a dopamine hydrochloride dispersion liquid; wherein the concentration of the dopamine hydrochloride is 0.1-5.0 mg / ml.

[0012] Further, a preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: the organic solvent in step S1 is selected to be hexafluoroisopropanol.

[0013] Further, a preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: the ultrasonic treatment time in step S1 is 30-60 minutes.

[0014] Further, a preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: step S2, preparation of electrospinning solution: poly(L-lactic acid) powder is added to the dopamine hydrochloride dispersion liquid and stirred at 40-50°C at a speed of 300-500 rpm for 1-3 hours to obtain an electrospinning solution.

[0015] Further, a preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: the concentration of the spinning raw material poly(L-lactic acid) powder in the electrospinning solution in step S2 is 0.05-0.2 g / ml.

[0016] Further, a preparation method of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: step S3, preparation of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: the electrostatic spinning liquid is left for 1-3 hours to remove bubbles therein, and then a nanofiber membrane is obtained through an electrostatic spinning process, and then the nanofiber membrane is subjected to annealing treatment at 100-110 DEG C for 3-10 hours, and then cooled to room temperature, so that the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial is prepared.

[0017] Preferably, the annealing temperature is 105 DEG C, and the annealing time is 10 hours.

[0018] Further, a preparation method of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial: in step S3, the electrostatic spinning process parameters are as follows: the spinning temperature is 21-25 DEG C, the humidity is 35-45%, the voltage is 10-20 kV, the advancing speed is 0.5-2.0 ml / h, the receiving distance is 5-15 cm, and the needle is a 21-gauge flat needle.

[0019] Preferably, the electrostatic spinning process parameters are as follows: the spinning temperature is 23 DEG C, the humidity is 40%, the voltage is 15 kV, the advancing speed is 0.5-2.0 ml / h, the receiving distance is 5-15 cm, and the needle is a 21-gauge flat needle.

[0020] Advantages of the present application:

[0021] (1) The present application adopts an interface anchoring strategy, and solves the long-standing stability problem of piezoelectric poly(L-lactic acid) nanofiber by introducing dopamine as a heterogeneous nucleating agent, and the self-assembly of dopamine into a shell layer is crucial for the formation and arrangement of beta-phase poly(L-lactic acid), wherein the strong intermolecular interaction at the interface between dopamine and poly(L-lactic acid) is responsible for anchoring the self-polarization poly(L-lactic acid) chain and promoting crystal nucleation. The dopamine-coated poly(L-lactic acid) piezoelectric biomaterial prepared by the present application is a nanofiber material with a core / shell structure, which can exhibit significantly enhanced piezoelectric performance and excellent stability.

[0022] (2) The present application proposes a practical strategy to solve the long-standing stability problem in the manufacture of piezoelectric poly(L-lactic acid) nanostructures, and opens up a new way for the development of flexible and biodegradable electromechanical coupling devices for biomedical applications. The present application realizes the preparation of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial by using an electrostatic spinning process, which has simple process operation and good repeatability. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0024] Figure 1 The scanning electron microscope (SEM) image of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial obtained in Example 1 of the present application;

[0025] Figure 2 The transmission electron microscope (TEM) image of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial obtained in Example 1 of the present application;

[0026] Figure 3 The transmission electron microscope (TEM) image of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial obtained in Comparative Example 1 of the present application;

[0027] Figure 4 The XRD spectrum of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial obtained in Example 1 of the present application and the pure poly(L-lactic acid) fiber obtained in Comparative Example 1 of the present application;

[0028] Figure 5 The open-circuit voltage diagram of the piezoelectric materials obtained in Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0030] Example 1

[0031] A preparation method of a dopamine-coated poly(L-lactic acid) piezoelectric biomaterial is provided, which comprises the following steps:

[0032] S1, preparation of a dopamine hydrochloride dispersion liquid: 5.0 ml of hexafluoroisopropanol is measured and added into a screw glass bottle, and then 5.0 mg of dopamine hydrochloride is added into the screw glass bottle. The screw glass bottle is tightly screwed and sealed with a sealing film, and ultrasonic oscillation treatment is performed for 30 minutes to obtain a dopamine hydrochloride dispersion liquid;

[0033] S2. Preparation of electrospinning solution: 0.5 g of poly (L-lactic acid) powder was weighed and added to the above-mentioned dopamine hydrochloride dispersion and magnetically heated and stirred at 40° C. and 400 rpm for 3 hours to obtain an electrospinning solution;

[0034] S3. Preparation of dopamine-coated poly (L-lactic acid) piezoelectric biomaterial: The obtained electrospinning solution was allowed to stand for 1 hour to remove bubbles therein, and then a nanofiber membrane was obtained by electrospinning. The nanofiber membrane was then annealed at 105° C. for 10 hours and then cooled to room temperature to obtain a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial;

[0035] The electrospinning process parameters are as follows: the spinneret is a No. 21 flat needle, the voltage is 15 kV, the receiving distance is 10 cm, the electrospinning is performed at a propulsion speed of 0.8 ml / h, the spinning temperature is 23° C., and the humidity is 40%.

[0036] The scanning electron microscope (SEM) image of the dopamine-coated poly (L-lactic acid) piezoelectric biomaterial obtained in Example 1 is as follows: Figure 1 As shown by Figure 1 It can be seen that dopamine uniformly wraps the poly (L-lactic acid) fibers and is widely present.

[0037] Example 2

[0038] Provided is a method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial, the method comprising the following steps:

[0039] S1. Preparation of dopamine hydrochloride dispersion: 5.0 ml of hexafluoroisopropanol was added to a screw-capped glass bottle, and then 0.5 mg of dopamine hydrochloride was added to the screw-capped glass bottle. The screw-capped glass bottle was tightened and sealed with a sealing film, and ultrasonically shaken for 60 minutes to obtain a dopamine hydrochloride dispersion.

[0040] S2. Preparation of electrospinning solution: 0.25 g of poly (L-lactic acid) powder was weighed and added to the above-mentioned dopamine hydrochloride dispersion and magnetically heated and stirred at 45° C. and 300 rpm for 3 hours to obtain an electrospinning solution;

[0041] S3. Preparation of dopamine-coated poly (L-lactic acid) piezoelectric biomaterial: The obtained electrospinning solution was allowed to stand for 1 hour to remove bubbles therein, and then a nanofiber membrane was obtained by electrospinning. The nanofiber membrane was then annealed at 100° C. for 6 hours and then cooled to room temperature to obtain a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial;

[0042] The electrospinning process parameters are as follows: a 21-gauge flat tip needle, a voltage of 10 kV, a receiving distance of 5 cm, an electrospinning speed of 0.5 ml / h, a spinning temperature of 21 DEG C, and a humidity of 35%.

[0043] Example 3

[0044] A preparation method of dopamine-coated poly(L-lactic acid) piezoelectric biomaterials is provided, and the method comprises the following steps:

[0045] S1, preparation of a dopamine hydrochloride dispersion liquid: 5.0 ml of hexafluoroisopropanol is measured and added into a screw glass bottle, and then 25.0 mg of dopamine hydrochloride is added into the screw glass bottle. The screw glass bottle is tightly screwed and sealed with a sealing film, and ultrasonic oscillation treatment is performed for 45 minutes to obtain a dopamine hydrochloride dispersion liquid;

[0046] S2, preparation of an electrospinning liquid: 0.8 g of poly(L-lactic acid) powder is weighed and added into the dopamine hydrochloride dispersion liquid, and magnetic heating stirring is performed at 50 DEG C and a speed of 500 rpm for 2 hours to obtain an electrospinning liquid;

[0047] S3, preparation of dopamine-coated poly(L-lactic acid) piezoelectric biomaterials: the obtained electrospinning liquid is left to stand for 2 hours to remove air bubbles therein, and then a nanofiber membrane is obtained through an electrospinning process. The nanofiber membrane is then subjected to annealing treatment at 110 DEG C for 3 hours, and then cooled to room temperature, so as to obtain dopamine-coated poly(L-lactic acid) piezoelectric biomaterials;

[0048] The electrospinning process parameters are as follows: a 21-gauge flat tip needle, a voltage of 20 kV, a receiving distance of 15 cm, an electrospinning speed of 2.0 ml / h, a spinning temperature of 25 DEG C, and a humidity of 45%.

[0049] Comparative Example 1

[0050] Comparative Example 1 is different from Example 1 in that no dopamine hydrochloride is added in the preparation of piezoelectric materials, and the rest is the same as Example 1. Comparative Example 1 obtains pure poly(L-lactic acid) piezoelectric fiber materials.

[0051] Test:

[0052] (1) TEM data of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterials obtained in Example 1 and the pure poly(L-lactic acid) piezoelectric fiber materials obtained in Comparative Example 1 are tested, and the test results are shown in Figure 2 and as shown in Figure 3 , and Figure 2 and Figure 3It can be seen that the pure poly(L-lactic acid) piezoelectric fiber in Comparative Example 1 has no shell structure, i.e. no dopamine shell, compared with Example 1.

[0053] (2) The XRD data of the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial obtained in Example 1 and the pure poly(L-lactic acid) piezoelectric fiber material obtained in Comparative Example 1 were tested, and the test results are shown in Figure 4 Figure 4 It can be seen that the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial has a higher piezoelectric crystalline phase, which means stronger piezoelectric performance.

[0054] (3) The dopamine-coated poly(L-lactic acid) piezoelectric fiber material obtained in Example 1 and the pure poly(L-lactic acid) piezoelectric fiber material obtained in Comparative Example 1 were cut into a size of 1 cm x 2 cm using a cutting device, aluminum foil was used as the upper and lower electrodes, an insulating elastic material was used as a sealing protective layer to prolong the service life, a sliding table device with a fixed frequency of 4 Hz was used for reciprocating stretching and extrusion movement, and finally an electrometer was used to collect the open-circuit voltage output signal of the nanogenerator, and the output open-circuit voltage is shown in Figure 5 Figure 5 It can be seen that the dopamine-coated poly(L-lactic acid) piezoelectric biomaterial has a higher piezoelectric output.

[0055] The above is only used to explain the present application, and is not used to limit the present application. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.​​

Claims

1. A method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial, characterized in that: The method comprises the following steps: S1. Preparation of dopamine hydrochloride dispersion: ultrasonically dispersing dopamine hydrochloride in an organic solvent to obtain a dopamine hydrochloride dispersion; Wherein, the concentration of dopamine hydrochloride is 0.1-5.0 mg / ml; S2. Preparation of electrospinning solution: adding poly (L-lactic acid) powder to the dopamine hydrochloride dispersion and stirring to obtain an electrospinning solution; Wherein, the concentration of poly (L-lactic acid) powder is 0.05-0.2 g / ml; S3. Preparation of dopamine-coated poly (L-lactic acid) piezoelectric biomaterial: removing bubbles from the electrospinning solution, and then obtaining a nanofiber membrane through an electrospinning process, followed by high-temperature annealing and cooling of the nanofiber membrane to obtain a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial.

2. The method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial according to claim 1, characterized in that: The organic solvent in step S1 is hexafluoroisopropanol.

3. The method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial according to claim 1, characterized in that: The ultrasonic treatment time in step S1 is 30 to 60 minutes.

4. The method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial according to claim 1, characterized in that: Step S2, preparation of electrospinning solution: adding poly (L-lactic acid) powder to the dopamine hydrochloride dispersion and magnetically stirring at 40-50° C. at a speed of 300-500 rpm for 1-3 hours to obtain electrospinning solution.

5. The method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial according to claim 1, characterized in that: Step S3, preparation of dopamine-coated poly (L-lactic acid) piezoelectric biomaterial: the electrospinning solution is allowed to stand for 1 to 3 hours to remove bubbles therein, and then a nanofiber membrane is obtained by an electrospinning process, and then the nanofiber membrane is annealed at 100 to 110°C for 3 to 10 hours, and then cooled to room temperature to obtain a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial.

6. The method for preparing a dopamine-coated poly (L-lactic acid) piezoelectric biomaterial according to claim 1 or 5, characterized in that: The electrospinning process parameters in step S3 are as follows: spinning temperature of 21-25° C., humidity of 35-45%, voltage of 10-20 kV, propulsion speed of 0.5-2.0 ml / h, receiving distance of 5-15 cm, and a No. 21 flat-end needle.

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