Left ventricle auxiliary device of electrocardio-light-operated switch

Abstract

The invention belongs to the technical field of medical apparatus and instruments, and relates to a left ventricle auxiliary device of an electrocardio-light-operated switch, which comprises an electrocardio device, an infrared laser, a negative Poisson's ratio light actuator and a PLC (programmable logic controller). The negative Poisson's ratio optical actuator comprises a negative Poisson's ratio frame, a liquid crystal elastomer sleeve and an optical fiber. The electrocardiogram device and the infrared laser are connected with the PLC at the same time, the PLC obtains a current electrocardiogram of a monitored object in real time through the electrocardiogram device, every time a new group of P points, Q points, R points, S points and T points is obtained, the infrared laser is controlled to delay t1 starting after the moment corresponding to the S points of the group, and t2 time continues to be started. The specific light actuator is prepared and applied to the left ventricle auxiliary device, and the problems that traditional heart related devices are not matched in mechanical property, the driving mode is limited, blood contact complications are likely to be caused, other functions of the heart are affected, and individuation is lacked are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices and relates to a left ventricular assist device with an electrocardiogram-photoelectric control switch. Background Art

[0002] Left ventricular assist devices (LVADs) are of great significance in the treatment of advanced heart failure, and they can significantly improve the quality of life and survival rate of patients. However, most of the existing commercial left ventricular assist devices adopt a blood pump design. These devices directly replace the pumping function of the left ventricle rather than assisting its contraction. For example, the Abbott Heartmate 3 and the Impella percutaneous heart pump, etc. They need to install an outflow tract at the aortic artery of the heart, and patients need to wear these instruments outside the body for a long time. This design not only increases the burden on patients but also may cause a series of complications such as thrombosis and infection due to direct contact between the blood and the device.

[0003] The literature (Soft robotic sleeve supports heart function[J].Science Translational Medicine, 2017.) and (Cardioprotective effect of silicon-built restraint device (ASD) for left ventricular remodeling in rat heart failure model[J].Journal of Materials Science: Materials in Medicine, 2022, 33(5):42.) both provide sleeve-type left ventricular assist devices. Such devices pump blood by squeezing the heart using air pressure or water pressure through sleeving a layer outside the heart. Although such devices can assist the left ventricle in contraction to a certain extent, their disadvantages are that the sleeve design may affect the function of the healthy right ventricle, resulting in an imbalance in the overall heart function. At the same time, the sleeve-type assist device is large in size, lacks personalized services, and is difficult to meet the specific needs of different patients.

[0004] In summary, the existing left ventricular assist devices still have many problems in terms of blood contact complications, affecting other heart functions, and lacking personalized treatment. These problems not only limit the wide application of left ventricular assist devices but also affect the treatment effect and quality of life of patients. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art and provide a left ventricular assist device with an electrocardiogram-photoelectric control switch.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A left ventricular assist device with an electrocardiogram-optical control switch, comprising an electrocardiogram device, an infrared laser, a photoactuator with a negative Poisson's ratio, and a PLC;

[0008] The photoactuator with a negative Poisson's ratio includes a negative Poisson's ratio frame, a liquid crystal elastomer sleeve, and an optical fiber;

[0009] The wall thickness of the liquid crystal elastomer sleeve is less than 100 μm;

[0010] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame;

[0011] The central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber;

[0012] When the liquid crystal elastomer sleeve is irradiated by the infrared laser emitted from the optical fiber, it shrinks and rebounds after the infrared laser irradiation is removed;

[0013] The infrared laser is used to emit laser light to the rear end of the optical fiber in the photoactuator with a negative Poisson's ratio;

[0014] The electrocardiogram device and the infrared laser are both connected to the PLC. The PLC obtains the current electrocardiogram of the monitoring object in real time through the electrocardiogram device. For each new set of P point, Q point, R point, S point, and T point obtained, it controls the infrared laser to start with a delay of t1 after the moment corresponding to the S point in this set, and continuously starts for a time of t2;

[0015] The P point is the starting point of the atrial contraction phase of the monitoring object, the Q point is the midpoint of the atrial contraction phase of the monitoring object, the R point is the end point of the atrial contraction phase and the starting point of the ventricular contraction phase of the monitoring object, the S point is the midpoint of the ventricular contraction phase of the monitoring object, and the T point is the end point of the ventricular contraction phase of the monitoring object;

[0016] The acquisition process of t1 is as follows: Obtain the historical electrocardiogram of the monitoring object. After obtaining the time intervals between all adjacent S points and Q points in the historical electrocardiogram, calculate the average value, which is t1;

[0017] The acquisition process of t2 is as follows: Obtain the historical electrocardiogram of the monitoring object. After obtaining the time intervals between all adjacent T points and R points in the historical electrocardiogram, calculate the average value, which is t2;

[0018] The number of heartbeats in the historical electrocardiogram is more than 200, and the test duration is 100 - 200 s.

[0019] The present invention can solve the problems of blood contact complications, affecting other heart functions, and lack of personalization. The specific analysis is as follows:

[0020] Avoidance of complications of blood contact: In vitro design: Only the negative Poisson's ratio photoactuator in the device needs to contact the heart, and the rest of the components are located outside the body, which greatly reduces the risk of infection and thrombosis; Non-invasive contact: The photoactuator is only bonded to the outer surface of the heart, without entering the heart chamber or contacting the blood, avoiding complications that may be caused by direct contact with blood, such as thrombosis, hemolysis, and immune rejection. Biocompatible materials: The photoactuator uses highly biocompatible materials, which further reduces the risk of tissue inflammation or rejection.

[0021] Does not affect other heart functions: Precise positioning: The negative Poisson's ratio photoactuator is small in size and can be precisely bonded to the diseased site of the heart, providing mechanical support only to the diseased area without interfering with the functions of other healthy parts of the heart; Local assistance: The design of the device focuses on assisting the functional recovery of the diseased site and will not negatively affect the electrical activity, contraction rhythm or hemodynamics of healthy myocardium; Reversible support: The bonding of the photoactuator is reversible and can be safely removed after the diseased site recovers without causing long-term effects on the heart.

[0022] Personalization: The left ventricular assist device has a highly personalized design and can be customized according to the patient's specific situation. Design the size of the photoactuator according to the size of the heart lesion: The device accurately measures the size of the patient's left ventricular lesion and designs a matching negative Poisson's ratio photoactuator. The negative Poisson's ratio structure has unique mechanical properties and can expand laterally when stressed, thereby better adapting to the morphological changes of the heart. This design ensures that the photoactuator can fit closely to the area of ​​heart lesions, providing precise mechanical support while reducing damage to surrounding healthy tissues. Design the contraction frequency of the photoactuator according to the individual electrocardiogram: The device analyzes the patient's electrocardiogram signal and adjusts the contraction frequency of the photoactuator in real time to synchronize it with the natural rhythm of the patient's heart. This synchronized design not only improves the heart's pumping efficiency, but also avoids hemodynamic disorders caused by frequency mismatch, truly realizing personalized treatment.

[0023] As the preferred technical solution:

[0024] In the left ventricular assist device with an ECG-light-controlled switch as described above, the ECG device is a Bluetooth ECG device.

[0025] In the left ventricular assist device with an ECG-light-controlled switch as described above, the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is located in the middle of the negative Poisson's ratio frame.

[0026] In the left ventricular assist device with an ECG-light-controlled switch as described above, the front and rear ends of the liquid crystal elastomer sleeve coincide with the edge of the negative Poisson's ratio frame, or extend out from the negative Poisson's ratio frame.

[0027] A left ventricular assist device with an electrocardiogram - light - controlled switch as described above, the preparation steps of the liquid crystal elastomer sleeve are as follows:

[0028] (a) Prepare a liquid crystal elastomer solution;

[0029] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve. Among them, the diameter of the cylindrical core mold is 1.3 - 1.5 times the diameter of the optical fiber;

[0030] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0031] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve. Among them, the stretching ratio is 1.5 - 2 times.

[0032] A left ventricular assist device with an electrocardiogram - light - controlled switch as described above, the diameter of the optical fiber is 0.25 - 2 mm.

[0033] A left ventricular assist device with an electrocardiogram - light - controlled switch as described above, the length of the liquid crystal elastomer sleeve is 8 - 22 cm.

[0034] A left ventricular assist device with an electrocardiogram - light - controlled switch as described above, the structural unit of the negative Poisson's ratio framework is a double - arrow shape, which is composed of a high V - shape and a low V - shape. The two sides of the high V - shape are of equal length, the two sides of the low V - shape are of equal length, the low V - shape is located inside the high V - shape, and the two ends of the low V - shape are respectively connected to the two ends of the high V - shape.

[0035] A left ventricular assist device with an electrocardiogram - light - controlled switch as described above, record the perpendicular distance from the tip of the low V - shape to the line connecting the two ends of the low V - shape as the height 1 of the structural unit, record the perpendicular distance from the tip of the high V - shape to the line connecting the two ends of the high V - shape as the height 2 of the structural unit, and record the length of the line connecting the two ends of the high V - shape as the width of the structural unit;

[0036] The photo - actuator with negative Poisson's ratio is applicable to the heart of New Zealand white rabbits. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 4 - 7, the total number of structural units in the longitudinal direction is 3 - 6, the width of the structural unit is 2 - 3.5 mm, the height 1 of the structural unit is 0.6 - 1.2 mm, the height 2 of the structural unit is 2.5 - 5 mm, and the wall thickness of the structural unit is 0.1 - 0.2 mm;

[0037] Alternatively, the optical actuator with a negative Poisson's ratio is applicable to the heart of a rat. The total number of structural units in the transverse direction of the negative Poisson's ratio frame is 4 - 6, the total number of structural units in the longitudinal direction is 3 - 5, the width of the structural unit is 1.5 - 2.5 mm, the height 1 of the structural unit is 0.5 - 0.8 mm, the height 2 of the structural unit is 2 - 3.5 mm, and the wall thickness of the structural unit is 0.1 - 0.15 mm;

[0038] Alternatively, the optical actuator with a negative Poisson's ratio is applicable to the heart of a beagle dog. The total number of structural units in the transverse direction of the negative Poisson's ratio frame is 5 - 8, the total number of structural units in the longitudinal direction is 4 - 7, the width of the structural unit is 2.5 - 4 mm, the height 1 of the structural unit is 0.8 - 1.5 mm, the height 2 of the structural unit is 3 - 6 mm, and the wall thickness of the structural unit is 0.15 - 0.25 mm.

[0039] Beneficial effects:

[0040] (1) For the left ventricular assist device of the present invention, only the optical actuator with a negative Poisson's ratio contacts the heart, and the remaining components are located outside the body. Moreover, the optical actuator is only adhered to the outer surface of the heart without contacting the blood. At the same time, high biocompatible materials are used, greatly reducing the risk of blood contact complications such as infection and thrombosis.

[0041] (2) The left ventricular assist device of the present invention is highly personalized. The size of the optical actuator can be designed according to the size of the diseased part of the patient's heart, enabling it to closely fit the diseased area and reducing damage to the surrounding healthy tissues. It can also adjust the contraction frequency of the optical actuator in real time according to the individual electrocardiogram, synchronize with the natural rhythm of the patient's heart, improve the heart pumping efficiency, avoid hemodynamic disorders, and truly achieve personalized treatment. Description of the drawings

[0042] Figure 1 Schematic diagram of the contraction - rebound of the optical actuator with a negative Poisson's ratio for Example A1;

[0043] Figure 2 Schematic diagram of the structural unit of the negative Poisson's ratio frame;

[0044] Figure 3 Transverse and longitudinal contraction ratio - time curve of the negative Poisson's ratio frame in Example A3;

[0045] Figure 4 Contraction time of liquid crystal elastomer sleeves with different wall thicknesses;

[0046] Figure 5 Relationship diagram of electrocardiogram - program - optical actuator. Detailed implementation manners

[0047] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0048] The present invention can use infrared lasers of any wavelength. In view of the fact that infrared lasers with a wavelength of 808 nm are relatively common, infrared lasers with a wavelength of 808 nm are used in the following embodiments.

[0049] The following are the test methods for relevant performance indicators in each embodiment:

[0050] Longitudinal shrinkage ratio of the liquid crystal elastomer sleeve: After the liquid crystal elastomer sleeve is placed horizontally, one end of it is fixed, and infrared laser is passed into the inside of the liquid crystal elastomer sleeve to test the longitudinal shrinkage ratio of the liquid crystal elastomer sleeve. The longitudinal shrinkage ratio = (change value of the longitudinal length of the liquid crystal elastomer sleeve / original longitudinal length of the liquid crystal elastomer sleeve) × 100%.

[0051] Shrinkage time of the liquid crystal elastomer sleeve: After the liquid crystal elastomer sleeve is placed horizontally, one end of it is fixed, and infrared laser is passed into the inside of the liquid crystal elastomer sleeve to test the change of the longitudinal shrinkage ratio of the liquid crystal elastomer sleeve with time. The time when the longitudinal shrinkage ratio reaches 90% of the maximum longitudinal shrinkage ratio is used as the shrinkage time of the liquid crystal elastomer sleeve.

[0052] Longitudinal / transverse shrinkage ratio of the negative Poisson's ratio frame: Infrared laser is passed through the assembled photoactuator with negative Poisson's ratio. After passing the infrared laser, the liquid crystal elastomer sleeve shrinks, driving the entire negative Poisson's ratio frame to shrink, and a camera is used to record the shrinkage process of the negative Poisson's ratio frame. Subsequently, video processing software (such as Jianying, Format Factory, etc.) is used to measure the maximum longitudinal length and maximum transverse width of the negative Poisson's ratio frame at different times respectively, and the time-varying curves of the longitudinal shrinkage ratio and transverse shrinkage ratio of the negative Poisson's ratio frame are obtained; among them, the power of the infrared laser is 6 W, the longitudinal shrinkage ratio = (change value of the maximum longitudinal length of the negative Poisson's ratio frame / initial value of the maximum longitudinal length of the negative Poisson's ratio frame) × 100%, and the transverse shrinkage ratio = (change value of the maximum transverse length of the negative Poisson's ratio frame / initial value of the maximum transverse length of the negative Poisson's ratio frame) × 100%.

[0053] Example A1

[0054] A preparation method of a photoactuator with negative Poisson's ratio is as follows:

[0055] (1) Preparation of main materials;

[0056] Cylindrical core mold: with a diameter of 0.35 mm;

[0057] Optical fiber: with a diameter of 0.25 mm;

[0058] (2) Prepare a negative Poisson's ratio framework and a liquid crystal elastomer sleeve respectively;

[0059] The negative Poisson's ratio framework is fabricated by 3D printing. As Figure 2 shown, the structural unit of the negative Poisson's ratio framework is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape. Denote the perpendicular distance from the tip of the low V shape to the line connecting the two ends of the low V shape as the height 1 of the structural unit, denote the perpendicular distance from the tip of the high V shape to the line connecting the two ends of the high V shape as the height 2 of the structural unit, denote the length of the line connecting the two ends of the high V shape as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 4, and the total number of structural units in the longitudinal direction is 3. The width of the structural unit is 3 mm, the height 1 of the structural unit is 1 mm, the height 2 of the structural unit is 4 mm, and the wall thickness of the structural unit is 0.16 mm;

[0060] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0061] (a) Prepare a liquid crystal elastomer solution;

[0062] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0063] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0064] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 1.5 times;

[0065] The length of the prepared liquid crystal elastomer sleeve is 12 cm, and the wall thickness is 60 μm; As Figure 1 shown, when the liquid crystal elastomer sleeve is irradiated by the infrared laser emitted from the optical fiber, it will contract, and it will rebound after removing the infrared laser. When the liquid crystal elastomer sleeve is first irradiated by the infrared laser for 100 ms, the longitudinal contraction ratio is 33%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0066] (3) Prepare a photoactuator with a negative Poisson's ratio;

[0067] Assemble a negative Poisson's ratio frame, a liquid crystal elastomer sleeve, and an optical fiber to obtain a negative Poisson's ratio photoactuator;

[0068] As Figure 1 shown, the central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing optical axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0069] Comparative Examples 1 - 5

[0070] A liquid crystal elastomer sleeve is basically the same as that in Example A1, except for the wall thickness of the liquid crystal elastomer sleeve. The wall thicknesses of the liquid crystal elastomer sleeves in Comparative Examples 1 - 5 are 100 μm, 200 μm, 300 μm, 400 μm, and 500 μm respectively.

[0071] The shrinkage times of the liquid crystal elastomer sleeves in Comparative Examples 1 - 5 are as Figure 4 shown. It can be seen from this that the wall thickness of the liquid crystal elastomer sleeve must be thin enough because only when it is thin enough can it keep up with the beating frequency of the heart.

[0072] Example A2

[0073] A preparation method for a negative Poisson's ratio photoactuator is as follows:

[0074] (1) Preparation of main materials;

[0075] Cylindrical core mold: with a diameter of 0.6 mm;

[0076] Optical fiber: with a diameter of 0.4 mm;

[0077] (2) Prepare a negative Poisson's ratio frame and a liquid crystal elastomer sleeve respectively;

[0078] The negative Poisson's ratio frame is prepared by 3D printing. The structural unit of the negative Poisson's ratio frame is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape; the perpendicular distance from the tip of the low V shape to the line connecting the two ends of the low V shape is denoted as the height 1 of the structural unit, the perpendicular distance from the tip of the high V shape to the line connecting the two ends of the high V shape is denoted as the height 2 of the structural unit, the length of the line connecting the two ends of the high V shape is denoted as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio frame is 7, the total number of structural units in the longitudinal direction is 5, the width of the structural unit is 2 mm, the height 1 of the structural unit is 0.6 mm, the height 2 of the structural unit is 2.5 mm, and the wall thickness of the structural unit is 0.1 mm;

[0079] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0080] (a) Prepare a liquid crystal elastomer solution;

[0081] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0082] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0083] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix both ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching multiple is 1.6 times;

[0084] The length of the prepared liquid crystal elastomer sleeve is 12.5 cm, and the wall thickness is 60 μm; when the liquid crystal elastomer sleeve is irradiated by an infrared laser for the first time for 100 ms, the longitudinal contraction ratio is 37%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0085] (3) Prepare a negative Poisson's ratio photoactuator;

[0086] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain the negative Poisson's ratio photoactuator;

[0087] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0088] Example A3

[0089] A preparation method of a negative Poisson's ratio photoactuator, the specific steps are as follows:

[0090] (1) Preparation of main materials;

[0091] Cylindrical core mold: with a diameter of 1.1 mm;

[0092] Optical fiber: with a diameter of 0.8 mm;

[0093] (2) Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0094] The negative Poisson's ratio framework is fabricated by a 3D printing method. The structural unit of the negative Poisson's ratio framework is a double-arrow shape, which is composed of a high V-shape and a low V-shape. The two sides of the high V-shape are of equal length, and the two sides of the low V-shape are of equal length. The low V-shape is located inside the high V-shape, and the two ends of the low V-shape are respectively connected to the two ends of the high V-shape. The vertical distance from the tip of the low V-shape to the line connecting the two ends of the low V-shape is denoted as the height 1 of the structural unit, the vertical distance from the tip of the high V-shape to the line connecting the two ends of the high V-shape is denoted as the height 2 of the structural unit, and the length of the line connecting the two ends of the high V-shape is denoted as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 4, and the total number of structural units in the longitudinal direction is 3. The width of the structural unit is 3.5 mm, the height 1 of the structural unit is 1.2 mm, the height 2 of the structural unit is 5 mm, and the wall thickness of the structural unit is 0.2 mm;

[0095] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0096] (a)Prepare a liquid crystal elastomer solution;

[0097] (b)Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0098] (c)Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0099] (d)First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 1.8 times;

[0100] The length of the prepared liquid crystal elastomer sleeve is 15 cm, and the wall thickness is 75 μm; when the liquid crystal elastomer sleeve is first irradiated by an infrared laser for 100 ms, the longitudinal contraction ratio is 44%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0101] (3)Prepare a negative Poisson's ratio photoactuator;

[0102] Assemble the negative Poisson's ratio framework, the liquid crystal elastomer sleeve and the optical fiber to obtain the negative Poisson's ratio photoactuator;

[0103] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio framework, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio framework; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio framework and in the exact middle of the negative Poisson's ratio framework; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0104] During the process that the finally obtained photo - actuator with negative Poisson's ratio is irradiated by an infrared laser in the liquid - crystal elastomer sleeve, the longitudinal / transverse contraction ratio - time curve of the negative Poisson's ratio framework is as Figure 3 shown.

[0105] Example A4

[0106] A preparation method of a photo - actuator with negative Poisson's ratio is as follows:

[0107] (1)Preparation of main materials;

[0108] Cylindrical core mold: with a diameter of 1.6 mm;

[0109] Optical fiber: with a diameter of 1.2 mm;

[0110] (2)Prepare the negative Poisson's ratio framework and the liquid - crystal elastomer sleeve respectively;

[0111] The negative Poisson's ratio framework is prepared by 3D printing. The structural unit of the negative Poisson's ratio framework is a double - arrow shape, which is composed of a high V - shape and a low V - shape. The two sides of the high V - shape are of equal length, and the two sides of the low V - shape are of equal length. The low V - shape is located inside the high V - shape, and the two ends of the low V - shape are respectively connected to the two ends of the high V - shape. Denote the perpendicular distance from the tip of the low V - shape to the line connecting the two ends of the low V - shape as the height 1 of the structural unit, denote the perpendicular distance from the tip of the high V - shape to the line connecting the two ends of the high V - shape as the height 2 of the structural unit, denote the length of the line connecting the two ends of the high V - shape as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 6, the total number of structural units in the longitudinal direction is 6, the width of the structural unit is 3 mm, the height 1 of the structural unit is 0.8 mm, the height 2 of the structural unit is 3 mm, and the wall thickness of the structural unit is 0.13 mm;

[0112] The preparation process of the liquid - crystal elastomer sleeve is as follows:

[0113] (a)Prepare a liquid - crystal elastomer solution;

[0114] (b)Immerse the cylindrical core mold in the liquid - crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid - crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid - crystal elastomer sleeve;

[0115] (c)Soak the intermediate of the liquid - crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid - crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid - crystal elastomer sleeve;

[0116] (d)First stretch the intermediate of the liquid - crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid - crystal elastomer sleeve, where the stretching multiple is 2 times;

[0117] The length of the prepared liquid crystal elastomer sleeve is 18 cm, and the wall thickness is 90 μm; when the liquid crystal elastomer sleeve is irradiated by infrared laser for the first time for 100 ms, the longitudinal contraction ratio is 50%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0118] (3)Prepare a negative Poisson's ratio photoactuator;

[0119] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain a negative Poisson's ratio photoactuator;

[0120] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0121] Example A5

[0122] A preparation method of a negative Poisson's ratio photoactuator is as follows:

[0123] (1)Prepare the main materials;

[0124] Cylindrical core mold: The diameter is 0.4 mm;

[0125] Optical fiber: The diameter is 0.3 mm;

[0126] (2)Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0127] The negative Poisson's ratio frame is prepared by 3D printing. The structural unit of the negative Poisson's ratio frame is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape; the perpendicular distance from the tip of the low V shape to the connection line of the two ends of the low V shape is denoted as the height 1 of the structural unit, the perpendicular distance from the tip of the high V shape to the connection line of the two ends of the high V shape is denoted as the height 2 of the structural unit, the length of the connection line of the two ends of the high V shape is denoted as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio frame is 4, the total number of structural units in the longitudinal direction is 4, the width of the structural unit is 2 mm, the height 1 of the structural unit is 0.5 mm, the height 2 of the structural unit is 2 mm, and the wall thickness of the structural unit is 0.1 mm;

[0128] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0129] (a)Configure the liquid crystal elastomer solution;

[0130] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. After repeating this process multiple times, let it stand until the solvent in the liquid crystal elastomer solution adhering to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0131] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and simultaneously perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0132] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix both ends thereof, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, wherein the stretching multiple is 1.5 times;

[0133] The length of the obtained liquid crystal elastomer sleeve is 8 cm, and the wall thickness is 60 μm; when the liquid crystal elastomer sleeve is irradiated by an infrared laser for the first time for 100 ms, the longitudinal contraction ratio is 33%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0134] (3) Prepare a negative Poisson's ratio photoactuator;

[0135] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain the negative Poisson's ratio photoactuator;

[0136] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0137] Example A6

[0138] A preparation method of a negative Poisson's ratio photoactuator, the specific steps are as follows:

[0139] (1) Preparation of main materials;

[0140] Cylindrical core mold: The diameter is 0.9 mm;

[0141] Optical fiber: The diameter is 0.6 mm;

[0142] (2) Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0143] The negative Poisson's ratio framework is fabricated by 3D printing. The structural unit of the negative Poisson's ratio framework is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape. Denote the vertical distance from the tip of the low V shape to the line connecting the two ends of the low V shape as the height 1 of the structural unit, the vertical distance from the tip of the high V shape to the line connecting the two ends of the high V shape as the height 2 of the structural unit, and the length of the line connecting the two ends of the high V shape as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 6, and the total number of structural units in the longitudinal direction is 5. The width of the structural unit is 1.5 mm, the height 1 of the structural unit is 0.5 mm, the height 2 of the structural unit is 2 mm, and the wall thickness of the structural unit is 0.1 mm.

[0144] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0145] (a) Prepare a liquid crystal elastomer solution;

[0146] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0147] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0148] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 1.6 times;

[0149] The length of the prepared liquid crystal elastomer sleeve is 10 cm, and the wall thickness is 70 μm. When the liquid crystal elastomer sleeve is first irradiated with infrared laser for 100 ms, the longitudinal contraction ratio is 37%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0150] (3) Prepare a photoactuator with negative Poisson's ratio;

[0151] Assemble the negative Poisson's ratio framework, the liquid crystal elastomer sleeve and the optical fiber to obtain a photoactuator with negative Poisson's ratio;

[0152] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio framework, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio framework; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio framework and in the exact middle of the negative Poisson's ratio framework; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0153] Example A7

[0154] A preparation method of a photo - actuator with a negative Poisson's ratio is as follows:

[0155] (1)Preparation of main materials;

[0156] Cylindrical core mold: with a diameter of 1.3 mm;

[0157] Optical fiber: with a diameter of 1 mm;

[0158] (2)Prepare a negative Poisson's ratio framework and a liquid crystal elastomer sleeve respectively;

[0159] The negative Poisson's ratio framework is made by 3D printing. The structural unit of the negative Poisson's ratio framework is a double - arrow shape, which is composed of a high V - shape and a low V - shape. The two sides of the high V - shape are of equal length, and the two sides of the low V - shape are of equal length. The low V - shape is located inside the high V - shape, and the two ends of the low V - shape are respectively connected to the two ends of the high V - shape. Denote the vertical distance from the tip of the low V - shape to the connection line of the two ends of the low V - shape as the height 1 of the structural unit, denote the vertical distance from the tip of the high V - shape to the connection line of the two ends of the high V - shape as the height 2 of the structural unit, denote the length of the connection line of the two ends of the high V - shape as the width of the structural unit. The total number of transverse structural units of the negative Poisson's ratio framework is 4, the total number of longitudinal structural units is 3, the width of the structural unit is 2.5 mm, the height 1 of the structural unit is 0.8 mm, the height 2 of the structural unit is 3.5 mm, and the wall thickness of the structural unit is 0.15 mm;

[0160] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0161] (a)Prepare a liquid crystal elastomer solution;

[0162] (b)Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process several times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0163] (c)Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0164] (d)First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching multiple is 1.8 times;

[0165] The length of the prepared liquid crystal elastomer sleeve is 10.5 cm, and the wall thickness is 75 μm; when the liquid crystal elastomer sleeve is irradiated with infrared laser for the first time for 100 ms, the longitudinal contraction ratio is 44%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0166] (3)Prepare a negative Poisson's ratio photoactuator;

[0167] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain a negative Poisson's ratio photoactuator;

[0168] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0169] Example A8

[0170] A preparation method of a negative Poisson's ratio photoactuator is as follows:

[0171] (1)Preparation of main materials;

[0172] Cylindrical core mold: diameter is 2.2 mm;

[0173] Optical fiber: diameter is 1.6 mm;

[0174] (2)Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0175] The negative Poisson's ratio frame is prepared by 3D printing. The structural unit of the negative Poisson's ratio frame is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape; the perpendicular distance from the tip of the low V shape to the connection line of the two ends of the low V shape is denoted as the height 1 of the structural unit, the perpendicular distance from the tip of the high V shape to the connection line of the two ends of the high V shape is denoted as the height 2 of the structural unit, the length of the connection line of the two ends of the high V shape is denoted as the width of the structural unit. The total number of transverse structural units of the negative Poisson's ratio frame is 6, the total number of longitudinal structural units is 4, the width of the structural unit is 2 mm, the height 1 of the structural unit is 0.8 mm, the height 2 of the structural unit is 3 mm, and the wall thickness of the structural unit is 0.13 mm;

[0176] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0177] (a)Prepare the liquid crystal elastomer solution;

[0178] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. After repeating this process multiple times, let it stand until the solvent in the liquid crystal elastomer solution adhering to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0179] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and simultaneously perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0180] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 2 times;

[0181] The length of the prepared liquid crystal elastomer sleeve is 12 cm and the wall thickness is 80 μm; when the liquid crystal elastomer sleeve is first irradiated with infrared laser for 100 ms, the longitudinal contraction ratio is 50%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0182] (3) Prepare a negative Poisson's ratio photoactuator;

[0183] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain the negative Poisson's ratio photoactuator;

[0184] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0185] Example A9

[0186] A preparation method of a negative Poisson's ratio photoactuator, the specific steps are as follows:

[0187] (1) Preparation of main materials;

[0188] Cylindrical core mold: The diameter is 1.2 mm;

[0189] Optical fiber: The diameter is 0.8 mm;

[0190] (2) Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0191] The negative Poisson's ratio framework is fabricated by a 3D printing method. The structural unit of the negative Poisson's ratio framework is a double-arrow shape, which is composed of a high V-shape and a low V-shape. The two sides of the high V-shape are of equal length, and the two sides of the low V-shape are of equal length. The low V-shape is located inside the high V-shape, and the two ends of the low V-shape are respectively connected to the two ends of the high V-shape. Denote the perpendicular distance from the tip of the low V-shape to the line connecting the two ends of the low V-shape as the height 1 of the structural unit, denote the perpendicular distance from the tip of the high V-shape to the line connecting the two ends of the high V-shape as the height 2 of the structural unit, and denote the length of the line connecting the two ends of the high V-shape as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 5, and the total number of structural units in the longitudinal direction is 5. The width of the structural unit is 3 mm, the height 1 of the structural unit is 0.8 mm, the height 2 of the structural unit is 3 mm, and the wall thickness of the structural unit is 0.15 mm.

[0192] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0193] (a)Prepare a liquid crystal elastomer solution;

[0194] (b)Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0195] (c)Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0196] (d)First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 1.5 times;

[0197] The length of the prepared liquid crystal elastomer sleeve is 15 cm, and the wall thickness is 70 μm. When the liquid crystal elastomer sleeve is first irradiated by an infrared laser for 100 ms, the longitudinal contraction ratio is 33%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0198] (3)Prepare a negative Poisson's ratio photoactuator;

[0199] Assemble the negative Poisson's ratio framework, the liquid crystal elastomer sleeve and the optical fiber to obtain a negative Poisson's ratio photoactuator;

[0200] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio framework, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio framework; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio framework and in the exact middle of the negative Poisson's ratio framework; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0201] Example A10

[0202] A preparation method of a photo - actuator with a negative Poisson's ratio, the specific steps are as follows:

[0203] (1) Preparation of main materials;

[0204] Cylindrical core mold: with a diameter of 1.7 mm;

[0205] Optical fiber: with a diameter of 1.2 mm;

[0206] (2) Prepare a negative Poisson's ratio framework and a liquid crystal elastomer sleeve respectively;

[0207] The negative Poisson's ratio framework is prepared by 3D printing. The structural unit of the negative Poisson's ratio framework is a double - arrow shape, which is composed of a high V - shape and a low V - shape. The two sides of the high V - shape are of equal length, and the two sides of the low V - shape are of equal length. The low V - shape is located inside the high V - shape, and the two ends of the low V - shape are respectively connected to the two ends of the high V - shape. Denote the perpendicular distance from the tip of the low V - shape to the line connecting the two ends of the low V - shape as the height 1 of the structural unit, denote the perpendicular distance from the tip of the high V - shape to the line connecting the two ends of the high V - shape as the height 2 of the structural unit, denote the length of the line connecting the two ends of the high V - shape as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 6, the total number of structural units in the longitudinal direction is 5, the width of the structural unit is 3.6 mm, the height 1 of the structural unit is 1.1 mm, the height 2 of the structural unit is 4.4 mm, and the wall thickness of the structural unit is 0.2 mm;

[0208] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0209] (a) Configure a liquid crystal elastomer solution;

[0210] (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0211] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0212] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 1.6 times;

[0213] The length of the prepared liquid crystal elastomer sleeve is 22 cm, and the wall thickness is 95 μm; when the liquid crystal elastomer sleeve is irradiated by an infrared laser for the first time for 100 ms, the longitudinal contraction ratio is 37%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0214] (3) Prepare a negative Poisson's ratio photoactuator;

[0215] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain a negative Poisson's ratio photoactuator;

[0216] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0217] Example A11

[0218] A preparation method of a negative Poisson's ratio photoactuator, the specific steps are as follows:

[0219] (1) Preparation of main materials;

[0220] Cylindrical core mold: The diameter is 2.3 mm;

[0221] Optical fiber: The diameter is 1.6 mm;

[0222] (2) Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0223] The negative Poisson's ratio frame is prepared by 3D printing. The structural unit of the negative Poisson's ratio frame is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape; the perpendicular distance from the tip of the low V shape to the line connecting the two ends of the low V shape is denoted as the height 1 of the structural unit, the perpendicular distance from the tip of the high V shape to the line connecting the two ends of the high V shape is denoted as the height 2 of the structural unit, the length of the line connecting the two ends of the high V shape is denoted as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio frame is 5, the total number of structural units in the longitudinal direction is 4, the width of the structural unit is 4 mm, the height 1 of the structural unit is 1.5 mm, the height 2 of the structural unit is 5 mm, and the wall thickness of the structural unit is 0.25 mm;

[0224] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0225] (a) Configure the liquid crystal elastomer solution;

[0226] (b)Immerse the cylindrical core mold in the liquid crystal elastomer solution and then take it out. After repeating this process multiple times, let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0227] (c)Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and simultaneously perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0228] (d)First stretch the intermediate of the liquid crystal elastomer sleeve and fix both ends thereof, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, wherein the stretching ratio is 1.8 times;

[0229] The length of the prepared liquid crystal elastomer sleeve is 20 cm, and the wall thickness is 90 μm; when the liquid crystal elastomer sleeve is first irradiated with infrared laser for 100 ms, the longitudinal contraction ratio is 44%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0230] (3)Prepare a negative Poisson's ratio photoactuator;

[0231] Assemble the negative Poisson's ratio frame, the liquid crystal elastomer sleeve and the optical fiber to obtain the negative Poisson's ratio photoactuator;

[0232] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and in the exact middle of the negative Poisson's ratio frame; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing optical axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0233] Example A12

[0234] A preparation method of a negative Poisson's ratio photoactuator, the specific steps are as follows:

[0235] (1)Preparation of main materials;

[0236] Cylindrical core mold: with a diameter of 3 mm;

[0237] Optical fiber: with a diameter of 2 mm;

[0238] (2)Prepare the negative Poisson's ratio frame and the liquid crystal elastomer sleeve respectively;

[0239] The negative Poisson's ratio framework is fabricated by a 3D printing method. The structural unit of the negative Poisson's ratio framework is a double-arrow shape, which is composed of a high V-shape and a low V-shape. The two sides of the high V-shape are of equal length, and the two sides of the low V-shape are of equal length. The low V-shape is located inside the high V-shape, and the two ends of the low V-shape are respectively connected to the two ends of the high V-shape. Denote the perpendicular distance from the tip of the low V-shape to the line connecting the two ends of the low V-shape as the height 1 of the structural unit, and denote the perpendicular distance from the tip of the high V-shape to the line connecting the two ends of the high V-shape as the height 2 of the structural unit. Denote the length of the line connecting the two ends of the high V-shape as the width of the structural unit. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 7, and the total number of structural units in the longitudinal direction is 7. The width of the structural unit is 2.5 mm, the height 1 of the structural unit is 0.8 mm, the height 2 of the structural unit is 3 mm, and the wall thickness of the structural unit is 0.15 mm.

[0240] The preparation process of the liquid crystal elastomer sleeve is as follows:

[0241] (a) Prepare a liquid crystal elastomer solution;

[0242] (b) Immerse a cylindrical core mold in the liquid crystal elastomer solution and then take it out. Repeat this process multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve;

[0243] (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and at the same time perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve;

[0244] (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve, where the stretching ratio is 2 times;

[0245] The length of the obtained liquid crystal elastomer sleeve is 21 cm, and the wall thickness is 95 μm. When the liquid crystal elastomer sleeve is first irradiated with infrared laser for 100 ms, the longitudinal contraction ratio is 50%. After removing the infrared laser irradiation, the longitudinal contraction ratio of the liquid crystal elastomer sleeve drops to 0%;

[0246] (3) Prepare a negative Poisson's ratio photoactuator;

[0247] Assemble the negative Poisson's ratio framework, the liquid crystal elastomer sleeve and the optical fiber to obtain the negative Poisson's ratio photoactuator;

[0248] The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio framework, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio framework; the liquid crystal elastomer sleeve is located inside the negative Poisson's ratio framework and in the exact middle of the negative Poisson's ratio framework; the central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber.

[0249] A left ventricular assist device with an electrocardiogram (ECG)-optical control switch, comprising a Bluetooth ECG device, an infrared laser, a photoactuator with a negative Poisson's ratio, and a PLC; the photoactuator with a negative Poisson's ratio is any one of the photoactuators with a negative Poisson's ratio prepared in Examples A1 to A12; the infrared laser is used to emit laser to the rear end of the optical fiber in the photoactuator with a negative Poisson's ratio;

[0250] The Bluetooth ECG device and the infrared laser are both connected to the PLC. The PLC obtains the current electrocardiogram of the monitored object in real time through the Bluetooth ECG device. For each new set of P point, Q point, R point, S point, and T point obtained, it controls the infrared laser to start with a delay of t1 after the moment corresponding to this set of S points and continuously start for a time of t2;

[0251] As Figure 5 shown, the P point is the starting point of the atrial contraction phase of the monitored object, the Q point is the midpoint of the atrial contraction phase of the monitored object, the R point is the end point of the atrial contraction phase and the starting point of the ventricular contraction phase of the monitored object, the S point is the midpoint of the ventricular contraction phase of the monitored object, and the T point is the end point of the ventricular contraction phase of the monitored object;

[0252] The acquisition process of t1 is as follows: Obtain the historical electrocardiogram of the monitored object. After obtaining the time intervals between all adjacent S points and Q points in the historical electrocardiogram, calculate the average value, which is t1;

[0253] The acquisition process of t2 is as follows: Obtain the historical electrocardiogram of the monitored object. After obtaining the time intervals between all adjacent T points and R points in the historical electrocardiogram, calculate the average value, which is t2;

[0254] The number of heartbeats in the historical electrocardiogram is more than 200, and the test duration is 100 - 200 s.

[0255] Example B1

[0256] A left ventricular assist treatment method based on an ECG-optical control switch, using the left ventricular assist device with an ECG-optical control switch as described above. The photoactuator with a negative Poisson's ratio in the device is the photoactuator with a negative Poisson's ratio prepared in Example A1. The specific steps are as follows:

[0257] (1) Select the animals to be treated;

[0258] The animals are New Zealand white rabbits. Relevant information: The New Zealand white rabbits are selected at 2 - 3 months old, with a body weight of 2 ± 0.5 kg. The infarction model is left ventricular transmural myocardial infarction. The size of the infarction is a circle with a diameter of 8 - 10 mm. After infarction, the left ventricular end-diastolic volume (LVEDV) drops to 6 - 7 mL, the left ventricular end-systolic volume (LVESV) drops to 2 - 3 mL, the left ventricular ejection fraction (EF) drops to 40 - 45%, and the left ventricular fractional shortening (FS) drops to 20 - 25%;

[0259] (2) Obtain t1 and t2;

[0260] Obtain the electrocardiogram of the animal to be treated (the number of heartbeats is more than 200, and the test duration is 100 - 200 s). After obtaining the time intervals between all adjacent S points and Q points in the electrocardiogram, calculate the average value, which is t1. After obtaining the time intervals between all adjacent T points and R points in the electrocardiogram, calculate the average value, which is t2;

[0261] (3) Assist the left ventricle of the animal;

[0262] Bond the light actuator with negative Poisson's ratio to the left ventricle of the animal through biocompatible glue, and keep the central axis of the liquid crystal elastomer sleeve in the light actuator with negative Poisson's ratio parallel to the long axis direction of the animal's heart. At this time, start the Bluetooth electrocardiogram device to obtain the electrocardiogram of the animal;

[0263] Set the light passing frequency of the laser (4 Hz), delay time t1, and continuous startup time t2 in the PLC program. Control the laser to turn on and off by the PLC. After the laser is turned on, the liquid crystal elastomer sleeve in the light actuator with negative Poisson's ratio contracts longitudinally, driving the negative Poisson's ratio frame to contract synchronously. After the laser is turned off, the liquid crystal elastomer sleeve returns to the original state, driving the negative Poisson's ratio frame to return to the original state synchronously. Repeat this process to synchronously assist the contraction and relaxation of the left ventricle.

[0264] Take videos of the light actuator with negative Poisson's ratio beating on the heart through a high-speed camera. Calculate that the longitudinal contraction of the light actuator with negative Poisson's ratio can reach 35 - 50%, far reaching the contraction ratio of the normal left ventricle of the heart (20 - 30%). Then the light actuator with negative Poisson's ratio can effectively assist the contraction of the left ventricle; Take videos of the light actuator with negative Poisson's ratio beating on the heart through a high-speed camera. Calculate that the longitudinal contraction of the light actuator with negative Poisson's ratio can beat in the same frequency as the heart, with an error less than 5 ms; Monitoring by a small animal ultrasonic scanner shows that after treatment with the left ventricle assist device, the LVEDV of the animal decreases by 60 - 80%, the LVESV decreases by 70 - 90%, the EF increases by 40 - 50%, and the FS increases by 50 - 60%.

[0265] Example B2

[0266] A left ventricle assist treatment method based on an electrocardiogram - light control switch, using the left ventricle assist device with an electrocardiogram - light control switch as described above. The light actuator with negative Poisson's ratio in the device is the light actuator with negative Poisson's ratio prepared in Example A5. The specific steps are as follows:

[0267] (1) Select the animal to be treated;

[0268] The animals were Sprague-Dawley (SD) rats, with the following relevant information: The SD rats were 6 - 9 weeks old and weighed 200 ± 50 g. The infarction model was a transmural myocardial infarction of the left ventricle. The size of the infarction was a circle with a diameter of 5 - 6 mm. After infarction, the left ventricular end-diastolic volume (LVEDV) decreased to 1 - 1.2 mL, the left ventricular end-systolic volume (LVESV) decreased to 0.4 - 0.7 mL, the ejection fraction (EF) decreased to 35 - 40%, and the fractional shortening (FS) decreased to 13 - 20%.

[0269] (2)Obtain t1 and t2;

[0270] Obtain the electrocardiogram of the animals to be treated (the number of heartbeats is more than 200, and the test duration is 100 - 200 s). After obtaining the time intervals between all adjacent S points and Q points in the electrocardiogram and taking the average value, t1 is obtained. After obtaining the time intervals between all adjacent T points and R points in the electrocardiogram and taking the average value, t2 is obtained;

[0271] (3)Assist the left ventricle of the animal;

[0272] Bond the photoactuator with negative Poisson's ratio to the left ventricle of the animal using a bioadhesive, and keep the central axis of the liquid crystal elastomer sleeve in the photoactuator with negative Poisson's ratio parallel to the long axis direction of the animal's heart. At this time, start the Bluetooth electrocardiogram device to obtain the electrocardiogram of the animal;

[0273] Set the light passing frequency of the laser (4 Hz), the delay time t1, and the continuous startup time t2 in the PLC program. Control the laser to turn on and off by the PLC. After the laser is turned on, the liquid crystal elastomer sleeve in the photoactuator with negative Poisson's ratio contracts longitudinally, driving the negative Poisson's ratio frame to contract synchronously. After the laser is turned off, the liquid crystal elastomer sleeve returns to its original state, driving the negative Poisson's ratio frame to return to its original state synchronously. Repeat this process to synchronously assist the contraction and relaxation of the left ventricle.

[0274] Take videos of the photoactuator with negative Poisson's ratio beating on the heart using a high-speed camera. Calculate that the longitudinal contraction of the photoactuator with negative Poisson's ratio can reach 35 - 50%, far exceeding the contraction ratio of the left ventricle of a normal heart (20 - 30%). Then the photoactuator with negative Poisson's ratio can effectively assist the contraction of the left ventricle. Take videos of the photoactuator with negative Poisson's ratio beating on the heart using a high-speed camera. Calculate that the longitudinal contraction of the photoactuator with negative Poisson's ratio can beat at the same frequency as the heart, with an error of less than 5 ms. Tests show that after treatment with the left ventricular assist device, the LVEDV of the animal decreases by 60 - 80%, the LVESV decreases by 70 - 90%, the EF increases by 40 - 50%, and the FS increases by 50 - 60%.

Claims

1. A left ventricular assist device with an electrocardiogram - light control switch, characterized in that, It includes an electrocardiogram device, an infrared laser, a photoactuator with a negative Poisson's ratio, and a PLC; The photoactuator with a negative Poisson's ratio includes a negative Poisson's ratio frame, a liquid crystal elastomer sleeve, and an optical fiber; The wall thickness of the liquid crystal elastomer sleeve is less than 100 μm; The central axis of the liquid crystal elastomer sleeve is parallel to the longitudinal direction of the negative Poisson's ratio frame, and the liquid crystal elastomer sleeve is fixedly connected to the negative Poisson's ratio frame; The central axis of the liquid crystal elastomer sleeve is collinear with the outgoing light axis of the optical fiber, and the rear end of the liquid crystal elastomer sleeve is sleeved on the front end of the optical fiber; When the liquid crystal elastomer sleeve is irradiated by the infrared laser emitted from the optical fiber, it contracts, and rebounds after removing the infrared laser irradiation; The infrared laser is used to emit laser to the rear end of the optical fiber in the photoactuator with a negative Poisson's ratio; The electrocardiogram device and the infrared laser are both connected to the PLC. The PLC obtains the current electrocardiogram of the monitoring object in real time through the electrocardiogram device. Every time a new set of P point, Q point, R point, S point, and T point is obtained, it controls the infrared laser to start with a delay of t1 after the moment corresponding to the S point in this set, and continuously starts for t2 time; The P point is the starting point of the atrial contraction phase of the monitoring object, the Q point is the midpoint of the atrial contraction phase of the monitoring object, the R point is the end point of the atrial contraction phase and the starting point of the ventricular contraction phase of the monitoring object, the S point is the midpoint of the ventricular contraction phase of the monitoring object, and the T point is the end point of the ventricular contraction phase of the monitoring object; The acquisition process of t1 is: obtain the historical electrocardiogram of the monitoring object, and after obtaining the time intervals between all adjacent S points and Q points in the historical electrocardiogram, calculate the average value, which is t1; The acquisition process of t2 is: obtain the historical electrocardiogram of the monitoring object, and after obtaining the time intervals between all adjacent T points and R points in the historical electrocardiogram, calculate the average value, which is t2; The number of heartbeats in the historical electrocardiogram is more than 200, and the test duration is 100 - 200 s.

2. The left ventricular assist device of an electrocardiogram-photoelectric control switch according to claim 1, wherein The electrocardiogram device is a Bluetooth electrocardiogram device.

3. The left ventricular assist device of an electrocardio-optic control switch according to claim 1, characterized in that, The liquid crystal elastomer sleeve is located inside the negative Poisson's ratio frame and is exactly in the middle of the negative Poisson's ratio frame.

4. The left ventricular assist device of an electrocardiogram-photoelectric control switch according to claim 3, characterized in that, The front and rear ends of the liquid crystal elastomer sleeve coincide with the edge of the negative Poisson's ratio frame, or extend out from the negative Poisson's ratio frame.

5. The left ventricular assist device of an electrocardio-optic control switch according to claim 1, characterized in that, The preparation steps of the liquid crystal elastomer sleeve are as follows: (a) Configure the liquid crystal elastomer solution; (b) Immerse the cylindrical core mold in the liquid crystal elastomer solution and take it out, repeat multiple times, and then let it stand until the solvent in the liquid crystal elastomer solution attached to the surface of the cylindrical core mold volatilizes, forming an intermediate of the liquid crystal elastomer sleeve. Among them, the diameter of the cylindrical core mold is 1.3 - 1.5 times the diameter of the optical fiber; (c) Immerse the intermediate of the liquid crystal elastomer sleeve and the cylindrical core mold together in an aqueous ethanol solution or ethanol, and simultaneously perform ultrasonic oscillation. After the intermediate of the liquid crystal elastomer sleeve is separated from the cylindrical core mold, take out the intermediate of the liquid crystal elastomer sleeve; (d) First stretch the intermediate of the liquid crystal elastomer sleeve and fix its two ends, and then perform ultraviolet light irradiation to obtain the liquid crystal elastomer sleeve. Among them, the stretching multiple is 1.5 - 2 times.

6. The left ventricular assist device of an electrocardio-optic control switch according to claim 5, characterized in that, The diameter of the optical fiber is 0.25 - 2 mm.

7. The left ventricular assist device of an electrocardio-optic control switch according to claim 1, characterized in that, The length of the liquid crystal elastomer sleeve is 8 - 22 cm.

8. The left ventricular assist device of an electrocardiogram-photoelectric control switch according to claim 1, wherein The structural unit of the negative Poisson's ratio framework is a double-arrow shape, which is composed of a high V shape and a low V shape. The two sides of the high V shape are of equal length, and the two sides of the low V shape are of equal length. The low V shape is located inside the high V shape, and the two ends of the low V shape are respectively connected to the two ends of the high V shape.

9. The left ventricular assist device of an electrocardiogram-photoelectric control switch according to claim 8, characterized in that, The perpendicular distance from the tip of the low V shape to the line connecting the two ends of the low V shape is denoted as the height 1 of the structural unit, the perpendicular distance from the tip of the high V shape to the line connecting the two ends of the high V shape is denoted as the height 2 of the structural unit, and the length of the line connecting the two ends of the high V shape is denoted as the width of the structural unit; The photoactuator with negative Poisson's ratio is applicable to the heart of New Zealand white rabbits. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 4 - 7, the total number of structural units in the longitudinal direction is 3 - 6, the width of the structural unit is 2 - 3.5 mm, the height 1 of the structural unit is 0.6 - 1.2 mm, the height 2 of the structural unit is 2.5 - 5 mm, and the wall thickness of the structural unit is 0.1 - 0.2 mm; Alternatively, the photoactuator with negative Poisson's ratio is applicable to the heart of rats. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 4 - 6, the total number of structural units in the longitudinal direction is 3 - 5, the width of the structural unit is 1.5 - 2.5 mm, the height 1 of the structural unit is 0.5 - 0.8 mm, the height 2 of the structural unit is 2 - 3.5 mm, and the wall thickness of the structural unit is 0.1 - 0.15 mm; Alternatively, the photoactuator with negative Poisson's ratio is applicable to the heart of beagle dogs. The total number of structural units in the transverse direction of the negative Poisson's ratio framework is 5 - 8, the total number of structural units in the longitudinal direction is 4 - 7, the width of the structural unit is 2.5 - 4 mm, the height 1 of the structural unit is 0.8 - 1.5 mm, the height 2 of the structural unit is 3 - 6 mm, and the wall thickness of the structural unit is 0.15 - 0.25 mm.

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