Application of non-contact electrical stimulation assembly in preparation of myocardial infarction repair system

Abstract

The invention discloses an application of a non-contact electrical stimulation assembly in preparation of a myocardial infarction repair system, and the non-contact electrical stimulation assembly is a PLLA film, potassium sodium niobate nanoparticles or a PLLA film doped with the potassium sodium niobate nanoparticles. The non-contact electrical stimulation assembly generates an electric field through ultrasonic wireless driving so as to electrically stimulate infarction myocardial tissue. The PLLA film and the potassium sodium niobate nanoparticles in the non-contact electrical stimulation assembly are piezoelectric materials which do not contain lead, are good in biocompatibility and are degradable, and have higher clinical conversion value; an electric field is generated through ultrasonic wireless driving, then infarction myocardial tissue is electrically stimulated, myocardial infarction repair is promoted, ventricular remodeling is inhibited, and the problem that traditional electrical stimulation depends on invasive electrode implantation, a patient needs to carry the electrode for a long time, and then the life quality of the patient is affected is solved. Different modes of electrical stimulation can be given to cardiac muscle tissues according to requirements, and application is flexible.

Description

Technical Field

[0001] The present invention relates to the field of biomedical engineering, and in particular to the application of a non-contact electrical stimulation component in the preparation of a myocardial infarction repair system. Background Art

[0002] Cardiovascular disease is currently the leading cause of death worldwide. Due to factors such as the accelerated aging of the population, the incidence and mortality of cardiovascular disease continue to rise, and a turning point in the reduction of the disease burden has not yet been reached. Despite significant advances in cardiac surgery, cardiac intervention, and drug therapy, almost all current treatments are unable to fully restore cardiac function. Electrical stimulation has shown great potential in tissue repair. Electrical stimulation can enhance or modify neuronal function and has been widely used in clinical trials for neurological diseases. In 2023, Nature Medicine reported that an implant that delivers electrical stimulation to the spinal cord significantly improved the mobility of a patient with advanced Parkinson's disease. Electrical stimulation also has high application value in bone repair and wound healing. In 2010, Circulation reported that researchers, in a pig model of myocardial infarction, sutured pacemaker leads to the epicardium of the infarcted area and connected an external pacemaker to deliver chronic local high-frequency electrical stimulation. Electrical stimulation of the infarcted myocardial tissue inhibited fibrosis in the infarcted area by suppressing the activity of matrix metalloproteinases, thereby improving cardiac function.

[0003] However, given the unique anatomical location of the heart and the characteristics of cardiac pulsation, local electrical stimulation of the infarcted myocardium is very difficult. Traditional electrical stimulation relies on invasive electrode implantation and generates electrical stimulation by connecting external electrodes, which requires patients to carry them long-term, seriously affecting their quality of life. Long-term electrode implantation also leads to potential toxicity and infection risks. Therefore, the development of a non-contact electrical stimulation system is of great significance for electrical stimulation of infarcted myocardial tissue. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an application of a non-contact electrical stimulation component in the preparation of a myocardial infarction repair system. The mechanical energy generated by ultrasound wirelessly drives a PLLA thin film myocardial patch attached to the myocardial infarction area, a PLLA thin film myocardial patch doped with potassium sodium niobate nanoparticles, or potassium sodium niobate nanoparticles injected into the myocardial infarction area to generate an electric field, thereby electrically stimulating the infarcted myocardial tissue, achieving contactless electrical stimulation of the infarcted myocardial tissue, promoting myocardial infarction repair, inhibiting ventricular remodeling, and avoiding the problem that traditional electrical stimulation relies on invasive electrode implantation, which requires patients to carry it for a long time and thus affects the patient's quality of life.

[0005] In order to solve the above technical problems, the present invention provides an application of a non-contact electrical stimulation component in the preparation of a myocardial infarction repair system, wherein the non-contact electrical stimulation component is a PLLA film, potassium sodium niobate nanoparticles, or a PLLA film doped with potassium sodium niobate nanoparticles. The non-contact electrical stimulation component generates an electric field through ultrasonic wireless drive to electrically stimulate the infarcted myocardial tissue.

[0006] The present invention develops PLLA film, potassium sodium niobate nanoparticles or PLLA film doped with potassium sodium niobate nanoparticles, and applies them to the preparation of a myocardial infarction repair system; the PLLA film myocardial patch attached to the myocardial infarction area, the PLLA film myocardial patch doped with potassium sodium niobate nanoparticles or the potassium sodium niobate nanoparticles injected into the myocardial infarction area can be driven by ultrasonic non-contact wireless to generate an electric field, convert ultrasonic mechanical energy into an electric field, and then electrically stimulate the infarcted myocardial tissue, promote myocardial infarction repair, and inhibit ventricular remodeling, and only requires the ultrasound probe to be close to the chest surface, avoiding the problem that traditional electrical stimulation relies on invasive electrode implantation and generates electrical stimulation by connecting external electrodes, which requires patients to carry them for a long time and thus affects the patient's quality of life; at the same time, different modes of electrical stimulation can be given to the myocardial tissue according to needs, and the application is flexible.

[0007] The PLLA film and potassium sodium niobate nanoparticles of the present invention are both lead-free, biocompatible, and degradable piezoelectric materials, and have greater clinical transformation value.

[0008] Furthermore, the preparation method of the PLLA film or the PLLA film doped with potassium sodium niobate nanoparticles is:

[0009] S1. Dissolving component A in a mixture of dimethylformamide (DMF) and dichloromethane (DCM) to obtain a spinning solution, wherein the component A is PLLA powder or a mixture of PLLA powder and potassium sodium niobate nanoparticles;

[0010] S2. Electrospinning the spinning solution through an electrospinning method to obtain a PLLA film or a PLLA film doped with potassium sodium niobate nanoparticles.

[0011] Furthermore, the volume ratio of dimethylamide to dichloromethane is (1-5):1, preferably 3:2.

[0012] Furthermore, the mass concentration of PLLA in the spinning solution is 5wt%-10wt%, preferably 8wt%.

[0013] Furthermore, the mass concentration of potassium sodium niobate nanoparticles in the spinning solution is 0 wt%-2 wt%, preferably 1 wt%.

[0014] Furthermore, the electric field strength of the electrospinning is 10kV-20kV, and the rotation speed of the collecting roller is 1000r / min-2000r / min, wherein the electric field strength is preferably 10kV, and the rotation speed of the collecting roller is preferably 1500r / min.

[0015] Furthermore, the preparation method of the potassium sodium niobate nanoparticles is as follows: niobium pentoxide is added to an aqueous solution of alkali to obtain a reaction solution, a growth substrate is placed in the reaction solution, and the reaction is carried out at 150-250°C for 10-30 hours to generate potassium sodium niobate nanoparticles on the surface of the growth substrate, wherein the temperature is preferably 190°C and the reaction time is preferably 24 hours.

[0016] Furthermore, the growth substrate is a silicon wafer or a quartz substrate.

[0017] Furthermore, the concentration of the aqueous base solution is 4 mol / L-8 mol / L, and the base is a mixture of KOH and NaOH in a molar ratio of (0.5-2):1, wherein the concentration of the aqueous base solution is preferably 5 mol / L, and the molar ratio of KOH and NaOH is preferably 1:1.

[0018] Furthermore, the concentration of niobium pentoxide in the reaction solution is 0.05 g / L-0.2 g / L.

[0019] Furthermore, the thickness of the PLLA film and the PLLA film doped with potassium sodium niobate nanoparticles is 500-1000 μm.

[0020] Furthermore, the potassium sodium niobate nanoparticles are dissolved in physiological saline to form an injectable drug with a mass volume ratio of 0.5%-2%, and the dosage of the injectable drug is 10-15 μL.

[0021] Furthermore, the ultrasonic wireless driving is specifically as follows: an electrical signal with a frequency of 100-1000kHz, a cycle number of 100-1000, a period of 0.5-2s, and a voltage of 1-10V is amplified 80-120 times by a power amplifier and input into the ultrasonic probe and brought close to the electrical stimulation component.

[0022] Beneficial effects of the present invention:

[0023] The PLLA film and potassium sodium niobate nanoparticles in the non-contact electrical stimulation component of the present invention are both lead-free, biocompatible, and degradable piezoelectric materials, and have greater clinical translation value.

[0024] The non-contact electrical stimulation component of the present invention generates an electric field through ultrasonic non-contact wireless drive, converting ultrasonic mechanical energy into an electric field. This field then electrically stimulates the infarcted myocardial tissue, promoting myocardial repair and inhibiting ventricular remodeling. This avoids the invasive electrode implantation required by traditional electrical stimulation, which requires patients to carry the device long-term and thus affects their quality of life. Different modes of electrical stimulation can be delivered to myocardial tissue as needed, providing flexible applications. Furthermore, the present invention provides new ideas for clinical wireless pacemakers and other devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a SEM image of the PLLA film prepared in Example 1 of the present invention;

[0026] Figure 2 is a SEM image of potassium sodium niobate nanoparticles prepared in Example 2 of the present invention;

[0027] Figure 3 is a SEM image of a PLLA film doped with potassium sodium niobate nanoparticles prepared in Example 3 of the present invention;

[0028] Figure 4 is the input signal of the ultrasonic probe in Test Example 1 of the present invention;

[0029] Figure 5 is the electrical signal generated by the PLLA film in Test Example 1 of the present invention;

[0030] Figure 6 3 is a comparison diagram of the voltage signals generated by the PLLA film, potassium sodium niobate (KNN) nanoparticles, and the KNN-doped PLLA film in Test Example 2 of the present invention;

[0031] Figure 7 This is a model diagram of ultrasound-driven non-contact electrical stimulation of myocardial infarction mice in Test Example 3 of the present invention;

[0032] Figure 8 This is a comparison chart of the left ventricular ejection fraction of the myocardial infarction mice in each group of Test Example 3 of the present invention on days 3, 7, 14, and 28 after surgery;

[0033] Figure 9 This is a comparison chart of the left ventricular ejection fraction of the myocardial infarction mice in each group of Test Example 3 of the present invention on the 28th day;

[0034] Figure 10 This is a Masson staining image of the heart tissue of each group of myocardial infarction mice in Test Example 3 of the present invention on the 28th day;

[0035] Figure 11 This is a comparison of angiogenesis in the myocardial infarction site of each group of myocardial infarction mice in Test Example 3 of the present invention on the 28th day;

[0036] Figure 12 yes Figure 11 Histogram of neovascularization parameters in each group;

[0037] Figure 13 This is a comparison chart of the left ventricular ejection fraction of mice on the 28th day after ultrasound-driven stimulation in the 800 μm thick PLLA film used as a myocardial patch in Test Example 3, the 800 μm thick PLLA+KNN film used as a myocardial patch in Test Example 5, and the KNN injection group with a mass volume ratio of 1% in Test Example 4. DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to specific examples so that those skilled in the art can better understand the present invention and implement it, but the examples are not intended to limit the present invention.

[0039] Example 1

[0040] This embodiment relates to a method for preparing a PLLA film, comprising the following steps:

[0041] (1) PLLA powder was dissolved in a mixture of dimethylamide and dichloromethane to obtain a spinning solution; wherein the volume ratio of dimethylamide to dichloromethane was 4:1, and the concentration of PLLA in the spinning solution was 8 wt %.

[0042] (2) The spinning solution was electrospun by electrospinning to obtain a PLLA film with a thickness of 500 μm, wherein the electrospinning parameters were: electric field intensity 10 kV, collection roller speed 1500 r / min. PLLA films of different thicknesses were prepared by adjusting the concentration of the spinning solution and the spinning parameters. The PLLA film prepared in Example 1 was subjected to SEM testing, and the results were as follows: Figure 1 As shown in FIG, the PLLA film has a fiber membrane structure, and the fibers are uniform in thickness.

[0043] Example 2

[0044] This embodiment relates to a method for preparing potassium sodium niobate nanoparticles, specifically:

[0045] Niobium pentoxide was added to an aqueous solution of alkali at a concentration of 5 mol / L to obtain a reaction solution. A growth substrate silicon wafer was placed in the reaction solution and reacted at 190°C for 24 hours to form potassium sodium niobate nanoparticles on the surface of the growth substrate. The alkali was a mixture of KOH and NaOH at a molar ratio of 1:1, and the concentration of niobium pentoxide in the reaction solution was 0.1 g / L. The potassium sodium niobate nanoparticles prepared in Example 2 were subjected to SEM testing, and the results were as follows: Figure 2 As shown, the particle size distribution of potassium sodium niobate nanoparticles is uniform.

[0046] Example 3

[0047] This embodiment relates to a method for preparing a PLLA film doped with potassium sodium niobate nanoparticles, comprising the following steps:

[0048] (1) PLLA powder and potassium sodium niobate nanoparticles prepared in Example 2 were mixed and dissolved in a mixture of dimethylamide and dichloromethane to obtain a spinning solution; wherein the volume ratio of dimethylamide to dichloromethane was 4:1, the mass concentration of PLLA in the spinning solution was 8 wt %, and the mass concentration of potassium sodium niobate nanoparticles was 1 wt %;

[0049] (2) The spinning solution was electrospun by an electrospinning method to obtain a 500 μm thick PLLA film doped with potassium sodium niobate nanoparticles, wherein the electrospinning parameters were: electric field intensity 10 kV, collection roller speed 1500 r / min. PLLA films doped with different concentrations were prepared by adjusting the amount of potassium sodium niobate added to the spinning solution, and PLLA films of different thicknesses were prepared by adjusting the spinning solution concentration and spinning parameters. The PLLA film doped with potassium sodium niobate nanoparticles prepared in Example 3 was subjected to SEM testing, and the results were as follows: Figure 3 As shown, the PLLA film has a fiber membrane structure, the fibers are uniform in thickness, and potassium sodium niobate nanoparticles are evenly distributed on the fiber surface.

[0050] Test Example 1

[0051] The ultrasonic probe was placed 2-8 cm away from the PLLA film prepared in Example 1. The burst signal of the signal generator was input to the ultrasonic probe after passing through the power amplifier. The input signal of the ultrasonic probe was as follows: Figure 4 As shown in Figure 2, the PLLA film converts ultrasound into a voltage signal due to the piezoelectric effect, that is, the voltage generated by the PLLA film electrical signal circuit, as shown in Figure 2. Figure 5 As shown, Figure 4 and Figure 5 The X / Y axis coordinates are consistent, Figure 5 It can be seen that the voltage, frequency and intensity generated by the PLLA film are stable.

[0052] Test Example 2

[0053] The ultrasonic probe was placed 2-8 cm away from the PLLA film prepared in Example 1, the potassium sodium niobate (KNN) nanoparticles prepared in Example 2, and the KNN-doped PLLA film prepared in Example 3. The voltage generated by the PLLA film, potassium sodium niobate (KNN) nanoparticles, and KNN-doped PLLA film were compared under the conditions of 180 V input voltage and 1 MHz frequency. Figure 6As shown, it can be seen that the KNN-doped PLLA film prepared in Example 3 has a better effect. The voltage data generated by PLLA films of different thicknesses are shown in Table 1, and the voltage data generated by 500 μm thick PLLA films doped with different concentrations of KNN in the spinning solution are shown in Table 2.

[0054] Table 1

[0055] Group Voltage / V 500μm PLLA 2.32±0.41 800μm PLLA 2.71±0.48 1000μm PLLA 3.16±0.51

[0056] Table 2

[0057] Group Voltage / V PLLA-1wt%KNN 4.27±0.62 PLLA-2wt%KNN 4.85±0.67

[0058] Test Example 3

[0059] The mouse myocardial infarction model was established by permanently ligating the left anterior descending coronary artery, and then the chest was closed and the skin was sutured. The following groups were set up: Sham group was a sham operation group, MI was a myocardial infarction group, MI-US was a group of mice with myocardial infarction given ultrasound intervention; PLLA was a group of mice with myocardial infarction given PLLA myocardial patches but without ultrasound; PLLA-US was a group of mice with myocardial infarction given PLLA myocardial patches and ultrasound stimulation. The PLLA myocardial patch is a myocardial patch made by attaching the PLLA film of Example 1 to the myocardial infarction area of ​​the mouse. Starting from the second day of the operation, the mouse was fixed in an ultrasonic stimulation device. The mouse was fixed in a 50mL centrifuge tube. A hole was dug in the centrifuge tube in the chest area of ​​the mouse, and the ultrasound probe was directly attached to the mouse's chest. Figure 7 The ultrasound probe input voltage was 180V, the frequency was 1MHz, and stimulation was performed for 30 minutes per day for 7 consecutive days.

[0060] The left ventricular ejection fraction of myocardial infarction mice on days 3, 7, 14 and 28 after surgery was as follows Figure 8 As shown in the figure, the left ventricular ejection fraction of mice in each group on the 28th day was compared as shown in the figure. Figure 9 As shown. LVEF is the left ventricular ejection fraction, which represents the contractile function of the heart. A decrease in LVEF value indicates a decrease in contractile function. The results show that the mice with myocardial infarction themselves receive ultrasound stimulation. Figure 8 and Figure 9 As can be seen, the PLLA myocardial patch had no effect on the improvement of myocardial infarction. While it could improve myocardial infarction to a certain extent, the PLLA myocardial patch combined with ultrasound-induced radiofrequency stimulation was able to effectively increase the left ventricular ejection fraction (LVEF) in mice with MI, further improving the repair of myocardial infarction. Furthermore, the LVEF of mice in each group after ultrasound-driven stimulation using PLLA films of varying thickness as myocardial patches on day 28 is shown in Table 3. Combined with Table 1, it is clear that a higher voltage does not necessarily improve the repair effect on myocardial infarction.

[0061] Group LVEF (%) 500μm PLLA 38.05±3.59 800μm PLLA 39.71±4.04 1000μm PLLA 37.63±3.83

[0062] HE and Masson's Trichrome staining were used to detect the degree of damage and fibrosis in the myocardial infarction area of ​​each group of mice. Figure 10 As shown, blue represents the area of ​​fibrosis. The larger the area, the more severe the tissue fibrosis. The results show that the electrical stimulation generated by ultrasound-driven PLLA can effectively improve myocardial fibrosis in mice with myocardial infarction.

[0063] Figure 11 This is a comparison of angiogenesis in the myocardial infarction site of each group of mice on the 28th day. Figure 12 The figure is a bar chart of the angiogenesis parameters of each group. The red α-SMA stains the newly formed blood vessels, and the more α-SMA there is, the more angiogenesis is promoted. It can be seen that the electrical stimulation generated by ultrasound-driven PLLA can effectively promote angiogenesis in the infarcted myocardium of mice with myocardial infarction.

[0064] Test Example 4

[0065] A myocardial infarction model in mice was established by permanently ligating the left anterior descending coronary artery, and then the chest was closed and the skin was sutured. The potassium sodium niobate nanoparticles prepared in Example 2 were dissolved in normal saline to form an injectable drug with a mass volume ratio of 0.5%-2%. Two points were injected around the mouse myocardium, with 5uL of drug injected at each point. The input voltage of the ultrasound probe was 180V, the frequency was 1MHz, and the stimulation was 30 minutes per day for 7 consecutive days. Multiple groups of mice were set up and injected with drugs of different mass volume ratios. The left ventricular ejection fraction of mice in each group on the 28th day is shown in Table 4. It can be seen that when the mass volume ratio of the injected drug is 1%, it has a better myocardial infarction repair effect.

[0066] Table 4

[0067] Mass volume ratio / % LVEF (%) 0.5 36.53±3.41 1 38.04±3.72 2 34.19±3.38

[0068] Test Example 5

[0069] A mouse myocardial infarction model was established by permanently ligating the left anterior descending coronary artery, and then the chest was closed and the skin was sutured. A 800 μm thick PLLA+KNN film prepared by 1% KNN doping was attached to the myocardial infarction area of ​​the mouse as a myocardial patch. The ultrasound probe input voltage was 180 V, the frequency was 1 MHz, and the stimulation was performed for 30 minutes every day for 7 consecutive days. The left ventricular ejection fraction of the mouse on the 28th day was compared with the left ventricular ejection fraction of the 800 μm thick PLLA film as a myocardial patch group in Test Example 3 and the KNN injection group with a mass volume ratio of 1% in Test Example 4 on the 28th day after ultrasonic drive. Figure 13As shown above, it can be seen that the better the corresponding voltage is, the better the repair effect on myocardial infarction is not necessarily the case. Only the appropriate corresponding voltage can produce a better repair effect on infarcted myocardial tissue.

[0070] The above embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. Application of a non-contact electrical stimulation component in the preparation of a myocardial infarction repair system, It is characterized in that The non-contact electrical stimulation component is a PLLA film, potassium sodium niobate nanoparticles or a PLLA film doped with potassium sodium niobate nanoparticles. The non-contact electrical stimulation component generates an electric field through ultrasonic wireless drive to electrically stimulate the infarcted myocardial tissue.

2. Use of the non-contact electrical stimulation component according to claim 1 in preparing a myocardial infarction repair system, It is characterized in that The preparation method of the PLLA film or the PLLA film doped with potassium sodium niobate nanoparticles is: S1, dissolving component A in a mixture of dimethylamide and dichloromethane to obtain a spinning solution, wherein the component A is PLLA powder or a mixture of PLLA powder and potassium sodium niobate nanoparticles; S2. Electrospinning the spinning solution by an electrospinning method to obtain a PLLA film or a PLLA film doped with potassium sodium niobate nanoparticles.

3. Use of the non-contact electrical stimulation component as claimed in claim 2 in preparing a myocardial infarction repair system, It is characterized in that The volume ratio of the dimethylformamide to dichloromethane is (1-5):

1.

4. Use of the non-contact electrical stimulation component as claimed in claim 2 in preparing a myocardial infarction repair system, It is characterized in that The mass concentration of PLLA in the spinning solution is 5wt%-10wt%.

5. Use of the non-contact electrical stimulation component as claimed in claim 2 in preparing a myocardial infarction repair system, It is characterized in that The mass concentration of potassium sodium niobate in the spinning solution is 0wt%-2wt%.

6. Use of the non-contact electrical stimulation component as claimed in claim 2 in preparing a myocardial infarction repair system, It is characterized in that The electric field strength of the electrostatic spinning is 10kV-20kV, and the rotation speed of the collecting roller is 1000r / min-2000r / min.

7. Use of the non-contact electrical stimulation component according to claim 1 in preparing a myocardial infarction repair system, It is characterized in that The preparation method of the potassium sodium niobate nanoparticles is as follows: adding niobium pentoxide to an aqueous solution of alkali to obtain a reaction solution, placing a growth substrate in the reaction solution, reacting at 150-250° C. for 10-30 hours, and generating potassium sodium niobate nanoparticles on the surface of the growth substrate.

8. Use of the non-contact electrical stimulation component as claimed in claim 7 in preparing a myocardial infarction repair system, It is characterized in that The concentration of the aqueous solution of the alkali is 4 mol / L-8 mol / L, and the alkali is a mixture of KOH and NaOH in a molar ratio of (0.5-2):

1.

9. Use of the non-contact electrical stimulation component according to claim 7 in preparing a myocardial infarction repair system, It is characterized in that The concentration of niobium pentoxide in the reaction solution is 0.05 g / L-0.2 g / L.

10. Use of the non-contact electrical stimulation component according to claim 1 in preparing a myocardial infarction repair system, It is characterized in that The ultrasonic wireless driving is specifically as follows: an electrical signal with a frequency of 100-1000kHz, a cycle number of 100-1000, a period of 0.5-2s, and a voltage of 1-10V is amplified 80-120 times by a power amplifier and then input into an ultrasonic probe and brought close to the electrical stimulation component.

Images