CN119280651A

CN119280651A - An artificial heart assist device based on magnetically active soft materials

Info

Publication number: CN119280651A
Application number: CN202411576158.3A
Authority: CN
Inventors: 蔡月日; 徐剑桥; 于靖军
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2024-11-06
Filing date: 2024-11-06
Publication date: 2025-01-10
Anticipated expiration: 2044-11-06
Also published as: CN119280651B

Abstract

The present invention discloses an artificial heart assist device based on magnetically active soft materials, which belongs to the application field of magnetic soft materials, and includes a simulation chamber part and an external driving part. Among them, the simulation chamber part is a cylindrical structure composed of a front and rear structural area and an extrusion functional area between the two, and the inlet and outlet ends are respectively connected to the left ventricle and the aorta, and a one-way valve is installed inside. Each part in the simulation chamber part is made of a mixed material of neodymium iron boron magnetic powder and polydimethylsiloxane, and is further connected by Ecoflex‑0050 silicone to form an integral structure, which can produce contraction movement under the drive of a unidirectional 30-50mT weak uniform magnetic field provided by the external driving part, forming an artificial ventricular assist device with pulsating blood supply.

Description

Artificial heart auxiliary device based on magnetically active soft material

Technical Field

The invention belongs to the field of application of magnetic soft materials, and relates to an artificial ventricular assist device for magnetic drive deformation, in particular to an artificial ventricular assist device based on a magnetically active soft material.

Background

Currently, ventricular assist devices have been developed in the third generation, and the ventricular assist devices of the 5 types are marketed in batches, but the ventricular assist devices of the respective types still have respective problems.

The left ventricular assist device (Left Ventricular ASSIST DEVICE, LVAD) was first applied in 1986, and the device used this time, thoratec VAD, was subsequently developed further to HEARTMATE I. The first generation LVAD is mainly a pneumatic, hydraulic and other pulsating blood pump, and the working principle is similar to that of a natural heart. Representative products include HEARTMATE I, HEARTMATE XVE, novacor, berlin Heart EXCOR, and the like. Because the single pumping volume of the pulsatile pump is relatively fixed, the pulsatile pump has weaker universality among different individuals, and auxiliary devices with different volumes are usually required to be installed for adult males, adult females and infants. And the pneumatic pulsating pump is often complicated in structure, large in volume, high in overall failure rate, obvious in noise, high in energy consumption and obvious in life influence on patients.

The second generation LVAD is mainly changed from pneumatic/hydraulic drive to a motor-driven contact axial flow pump, and blood is driven to enter and exit by a blade rotating at a high speed, so that the stability is greatly improved and the volume is reduced. Axial-flow pump LVAD products are in large numbers, with representative products including HEARTMATE II, jarvik2000, berlin Heart INCOR, HEART ASSIST, etc. Because the motor is generally used for replacing the volumetric pump, the second-generation LVAD generally has the advantages of excellent controllability, direct energy supply mode, low failure rate and the like. The blood pumping quantity can be simply adjusted by adjusting the rotating speed of the motor, and the adaptability to different individuals and different motion states is good. But has the problems of motor suction, damage to blood cells, working heat generation, no pulsatility of blood flow and the like. The motor also has certain energy supply requirements, usually needs to carry an energy supply device with him, and has limited endurance time.

The third-generation LVAD is a completely suspended non-contact centrifugal pump, and the blades are suspended in a working chamber through magnetic suspension or hydraulic suspension, so that the non-contact pumping is realized. The volume of the motor type axial flow pump is approximately the same as or slightly increased compared with that of a second generation motor type axial flow pump, but the risks of abrasion, working heat generation and blood cell damage are reduced. Improved in avoiding thrombosis and enhancing the durability of the device. Representative products include HEARTMATE III, HEARTWARE HVAD, and the like. However, the existing LVAD energy units are all located outside the body, and the wireless energy transmission manner cannot provide enough power within the safety range of the human body to enable the LVAD device to work normally, so that the LVAD energy units are powered by using wires, and the LVAD energy units are easy to cause infection. The blood pressure after the third generation LVAD implantation mainly depends on a blood pump, and the blood flow is continuous but not constant in the whole cardiac cycle, and the blood output is generated in the systolic phase and the diastolic phase of the heart, so that the blood in the diastolic phase is increased. The high-low pressure difference is only about 5mmHg, and the arterial pulse is approximately in a straight line. Long-term non-pulsatile flow may have a potential physiological impact on the patient.

Disclosure of Invention

In order to overcome the defects of the prior ventricular assist device in the aspects of in-vivo energy supply and pulsatility, the invention provides an artificial ventricular assist device based on a magnetically active soft material, which can be driven by a lower magnetic field and can supply blood in pulsatility.

The invention relates to an artificial heart auxiliary device based on magnetically active soft material, which comprises a simulation chamber part and an external driving part.

The simulation chamber part is a cylindrical structure formed by a front structure area, a rear structure area and an extrusion functional area between the front structure area and the rear structure area. The front structure area and the rear structure area are internally provided with a one-way valve which is a circular sheet structure formed by 4 sectors with the central angle of 90 degrees. A layer of silica gel film made of Ecoflex0050 is paved on the wall surface of the whole simulation chamber part of the structure.

The extrusion functional area and the one-way valve are made of magnetic active materials. The magnetic active material is a mixed material containing neodymium iron boron magnetic powder and polydimethylsiloxane. The magnetic materials in the extrusion functional area are magnetized to a remanence saturation state through a strong magnetic field in advance, the remanence directions of different areas are different by changing the magnetic field directions of all parts of the magnetic materials when magnetized through batch magnetization, different motions are generated under the action of unidirectional uniform magnetic fields, and the overall structure changes of shape retention at two ends and shrinkage in the middle are formed through combined motions.

The sector structures in the check valve are magnetized near the center of the circle, and are driven to open upwards under the action of the magnetic field, and the sector structures recover when the magnetic field is removed. The one-way valve in the front structure area is used for simulating an aortic valve to prevent the aortic backflow, and is opened when the extrusion function area contracts to allow blood to pass through, and the one-way valve in the rear structure area is used for simulating a mitral valve to prevent the pulmonary vein from flowing backwards to the left ventricle and is opened when the extrusion function area recovers.

The magnetic field is provided by an external driving part, the external driving part is a small magnetic field generator, the N pole is placed at the chest of the human body, the S pole is placed at the back of the human body, the two positions are placed in parallel, and the front face corresponds to the front face.

The invention has the advantages that:

1. in the artificial heart auxiliary device based on the magnetically active soft material, the artificial muscle (the simulated cavity part) formed by the magnetic material has good biocompatibility, strong stability, density, elastic energy which is close to the muscle of the human body and less influence on the human body;

2. The artificial heart auxiliary device based on the magnetically active soft material has extremely strong capability of penetrating the human body by the magnetic field, can apply driving in vitro, and avoids the problems of complex operation and infection caused by lead entering the human body;

3. The artificial heart auxiliary device based on the magnetically active soft material has the advantages that the driving magnetic field is low, the volume and the mass of the magnetic field generating device are equal to those of a smart phone, the artificial heart auxiliary device is highly portable, and the artificial heart auxiliary device is easy to wear;

4. the artificial heart auxiliary device based on the magnetically active soft material has the advantages that the energy consumption of the magnetic field generating device is low, and the external battery can supply energy for a long time;

5. The artificial heart auxiliary device based on the magnetically active soft material has the advantages that the heating of the magnetically driven artificial heart is low, the local heating caused in the normal working state is lower than 0.5K, and the heating is obviously lower than the heating of the existing electrically driven pump type artificial heart by about 2K;

6. the artificial heart auxiliary device based on the magnetically active soft material has the advantages that the blood flow generated by the magnetically driven artificial heart is pulsating and the same as the natural blood flow of a human body, so that negative effects on tissues and organs such as blood vessels, valves and the like can be avoided;

7. The artificial heart auxiliary device based on the magnetically active soft material has the advantages that the straight cylinder type cavity flow field is simpler, and no obvious turbulence condition is generated.

Drawings

FIG. 1 is a schematic view of the structure and position of a magnetically active soft material based artificial heart assist device of the present invention;

fig. 2 is a schematic diagram showing the deformation of the extrusion functional area driven by magnetism in the artificial heart assist device based on the magnetically active soft material of the present invention.

In the figure:

1-simulation Chamber section 2-external drive section 101-front Structure section

102-Rear structural area 103-squeeze function area 104-check valve

105-Linkage

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings.

The artificial ventricular assist device based on magnetically active soft material of the present invention comprises a simulation chamber part 1 and an external driving part 2, wherein the simulation chamber part 1 is integrally disposed inside or outside the left ventricle of the heart, and communicates with the aorta and the left ventricle of the heart, as shown in fig. 1.

The simulation chamber section 1 comprises a front structural area 101, a rear structural area 102, a compression functional area 103, a one-way valve 104 and a connecting structure 105.

The front structural area 101 is gradually reduced in cross section diameter from bottom to top, the diameter reduction ratio of the upper part is smaller than that of the lower part, the whole front structural area is funnel-shaped, and the outer wall is in smooth transition. The upper end of the front structure area 101 is used for connecting an aortic connecting pipeline of the heart, the inner diameter of the end face is the same as that of the aortic connecting pipeline, and the lower end of the front structure area 101 is used for connecting an extrusion functional area.

The rear structure area 102 has the same structure as the front structure area 101, the diameter of the cross section is gradually reduced from top to bottom, the diameter reduction ratio of the upper part is larger than that of the lower part, the rear structure area is funnel-shaped, and the outer wall is in smooth transition. The lower end of the rear structure area 102 is used for connecting a left ventricle connecting pipeline of the heart, the inner diameter of the rear structure area is the same as that of the left ventricle connecting pipeline, and the upper end of the rear structure area 102 is used for connecting an extrusion functional area.

The extrusion functional area 103 is a core area of the present invention, and has a cylindrical structure, and the upper and lower ends are respectively equal to and connected with the inner diameters of the lower end of the front structural area 101 and the upper end of the rear structural area 102.

The one-way valve 104 is used for simulating a heart valve area, mainly for preventing backflow of blood into the simulation chamber part 1. The check valve 104 has two circular sheet structures consisting of 4 circular sectors with a central angle of 90 degrees. The two check valves 104 are divided into an upper check valve and a lower check valve, wherein the upper check valve is used for simulating an aortic valve to prevent aortic backflow, the lower check valve is used for simulating a mitral valve to prevent pulmonary vein backflow and a left ventricle, the area structures near the two check valves are as simple as possible, no auxiliary structure and large curvature bend are needed to prevent local turbulence, and therefore the upper check valve and the lower check valve are respectively arranged in the upper part of the front structural area 101 and the lower part of the rear structural area 102.

The extrusion functional area 103 and the check valve 104 are made of magnetically active materials, and the same magnetically active materials as those of the extrusion functional area 103 and the check valve 104 are still added into the materials for manufacturing the front structural area 101 and the rear structural area 102 because consistency of the density, the hardness and the overall structure of the overall simulation chamber part needs to be ensured as much as possible. The magnetic active material is a mixed material containing neodymium iron boron magnetic powder and Polydimethylsiloxane (PDMS), and is prepared through the steps of putting polylactic acid material into a 3D printer, performing die printing by the 3D printer according to a die which is formed by modeling on a computer in advance, mixing the magnetic powder and the PDMS according to a certain mass ratio, specifically, the mass ratio of the front structure area 101 to the rear structure area 102 to the PDMS is 1:1, the mass ratio of the front structure area to the PDMS is 2:1 in the manufacture of a one-way valve, and stirring until the materials are fully mixed. And finally, pouring the stirred and unset material into a mould, placing the mould into a vacuum drying oven, performing bubble removal and solidification for 8 hours at room temperature, and demoulding to obtain the material.

The connecting structure 105 made of Ecoflex0050 silica gel is arranged between the connecting positions of the front structure area 101, the rear structure area 102 and the extrusion functional area 103, and the connection between the front structure area 101, the rear structure area 102 and the extrusion functional area is realized through the connecting structure 105, so that the simulation chamber part 1 is integrally spliced into a cylindrical structure, the connecting structure 105 is required to be ensured to be flush with the inner wall of the simulation chamber part 1, and the influence on blood flow is avoided. Likewise, a connecting structure 105 made of Ecoflex0050 silicone is provided between the connection positions of the front structural section 101, the rear structural section 102, and the check valve 104, so as to connect the check valves 105. Meanwhile, a layer of silica gel film made of Ecoflex0050 is further paved on the wall surface of the integral simulation chamber part 1 (comprising the inner wall surface and the outer wall surface of the front structure area 101, the rear structure area 102 and the extrusion function area 103 and the fan-shaped wall surfaces of the two one-way valves) connected by the connecting structure 105, so that the biocompatibility is enhanced, the simulation chamber part 1 containing magnetic powder is isolated from the environment in the human body, and the function of further connecting the parts is carried out.

In the artificial ventricle auxiliary device based on the magnetically active soft material, the front structure area 101 and the rear structure area 102 mainly play roles of connecting into and out of a blood vessel and providing a channel. Wherein the anterior structural section 101 is connected to the left ventricle by a left ventricular connection conduit, allowing blood to flow out of the left ventricle and into the simulation chamber portion 1, which are also connected by a connection structure 105 made of Ecoflex0050 silicone. The posterior structural section 102 is connected to the aorta by an aortic connection tube, which carries the blood pumped out by the simulated chamber section 1 to the aorta for systemic circulation, and is likewise connected between the two by a connection structure 105 made of Ecoflex0050 silicone. The magnetic material inside the front structure region 101 and the rear structure region 102 is not magnetized, and maintains an original funnel-shaped structure under the driving of a magnetic field.

The magnetic material in the extrusion functional area 103 is magnetized to a remanence saturation state through a strong magnetic field in advance, the remanence directions of different areas are different by changing the magnetic field directions of all parts of the magnetic material when magnetized through batch magnetization, so that different movements are generated under the action of unidirectional uniform strong magnetic fields, and the overall structure change with two ends kept in a shape and the contractile middle part is formed through combined movements, and the overall change is shown in fig. 2, so that the extrusion functional area 103 can contract as required and pump out blood.

The sector structures of the two check valves 104 are magnetized near the center of the circle, and are driven to be opened upwards under the action of the magnetic field, and the sector structures are restored to the original state when the magnetic field is removed, so that the sector structures are synchronously switched between opening and closing. Wherein, the upper one-way valve is opened when the squeezing functional area 103 is contracted, allowing blood to pass through, and recovering the initial state after removing the magnetic field, preventing blood from flowing back to the squeezing functional area 103 from the upper side. The lower check valve opens when the squeeze function region 103 is restored, and functions to control the flow direction. Meanwhile, in order to avoid influencing the pressure of pumped blood and stroke volume, the check valve needs to be opened before the extrusion functional area 103 works, so that the mass ratio of magnetic powder in the manufacturing material of the check valve 104 is higher (2:1), and the check valve 104 is more sensitive to the magnetic field.

The magnetic field required for the operation of the above-described simulation chamber section is provided by the external driving section 2. The external driving part 2 is a small magnetic field generator (the size and the weight of the external driving part are equivalent to those of a mobile phone), the N pole is placed at the chest of a human body, the S pole is placed at the back of the human body, the two positions are placed in parallel, and the front faces of the two positions correspond to each other. The magnetic field generator is powered by button cells and comprises a main power supply battery and two standby batteries, and can continuously work for more than 24 hours. Under the working state, a magnetic field with invariable direction and sinusoidal variation of magnetic induction intensity of 0-50 mT is generated between the two poles.

The artificial heart auxiliary device based on the magnetically active soft material can be worn by a patient in front of and behind the chest when the artificial heart auxiliary device is applied, the magnetic field generated by the magnetic field generating device can penetrate the human body almost without blocking, the artificial heart is driven to periodically beat, and the problems that the conventional ventricular auxiliary device usually needs percutaneous lead-in and no beating are solved.

Claims

1. An artificial heart assist device based on magnetically active soft materials, characterized in that it comprises a simulated chamber part and an external driving part;

The simulation chamber part is a cylindrical structure consisting of a front structure area, a rear structure area and an extrusion functional area therebetween; wherein a one-way valve is arranged in the front structure area and the rear structure area; the one-way valve is a circular sheet structure consisting of four sectors with a central angle of 90 degrees; a layer of silicone film made of Ecoflex0050 is laid on the wall of the entire simulation chamber part;

The extrusion functional area and the one-way valve are both made of magnetically active materials; the magnetically active material is a mixed material containing neodymium iron boron magnetic powder and polydimethylsiloxane; the magnetic material inside the extrusion functional area is pre-magnetized to a remanent magnetic saturation state by a strong magnetic field, and the magnetic field direction of each part of the magnetic material is changed by batch magnetization so that the remanent magnetic directions of different areas are different, and different movements are generated under the action of a unidirectional uniform magnetic field, and an overall structural change is formed by combined movement in which the shapes of the two ends are maintained and the middle part is contracted;

The part of each fan-shaped structure near the center of the circle in the one-way valve is magnetized, and the fan-shaped structures are driven to open upward as a whole under the action of the magnetic field; when the magnetic field is removed, the fan-shaped structures return to their original state;

The magnetic field is provided by an external driving part, which is a small magnetic field generator. The N pole is placed on the front chest of the human body, and the S pole is placed on the back of the human body. The two positions are placed in parallel and face each other.

2. An artificial heart assist device based on magnetically active soft materials as described in claim 1, characterized in that the front structure area and the rear structure area are funnel-shaped as a whole, with a smooth transition on the outer wall, and a large diameter section of the two is connected to the two ends of the cylindrical extrusion functional area.

3. An artificial heart assist device based on magnetically active soft materials as described in claim 1, characterized in that: the front structure area and the rear structure area are made of the same material as the extrusion functional area; and the magnetic materials inside the two are not magnetized.

4. An artificial heart assist device based on magnetically active soft materials as described in claim 1, characterized in that a connecting structure made of Ecoflex0050 silicone is arranged between the front structural area, the rear structural area and the extrusion functional area of the simulated chamber part, and the connection between the three is achieved through the connecting structure.

5. An artificial heart assist device based on magnetically active soft materials as claimed in claim 4, characterized in that the connection structure is flush with the inner wall of the simulated chamber part.

6. An artificial heart assist device based on magnetically active soft materials as described in claim 1, characterized in that a connecting structure made of Ecoflex0050 silicone is provided between the front structural area, the rear structural area and the connecting position of the one-way valve to realize the connection of the one-way valve.

7. An artificial heart assist device based on magnetically active soft materials as described in claim 1, characterized in that: the one-way valve in the front structural area opens when the squeezing functional area contracts; the one-way valve in the rear structural area opens when the squeezing functional area recovers.

8. An artificial heart assist device based on magnetically active soft materials as claimed in claim 1, characterized in that the mass proportion of magnetic powder in the one-way valve manufacturing material is higher than that in the extrusion functional area.

9. An artificial heart assist device based on magnetically active soft materials as described in claim 1, characterized in that: in the external driving part, when the two magnetic field generators are in working state, a magnetic field with a constant direction and a sinusoidal change of magnetic induction intensity of 0 to 50 mT is generated between the two poles.