A biodegradable zinc alloy scaffold in vitro fatigue testing system and method

Abstract

This invention provides a biodegradable zinc alloy stent in vitro fatigue testing system, comprising a biomimetic human pulsating blood flow and pressure control system and a biomimetic coronary intervention vessel model. The outlet of the biomimetic human pulsating blood flow and pressure control system is connected to the left ventricular interface in the biomimetic coronary intervention vessel model to simulate the heart's pumping function. The inlet of the biomimetic human pulsating blood flow and pressure control system is connected to the drainage interface in the biomimetic coronary intervention vessel model to simulate blood return to the atria. Driven by the biomimetic human blood flow and pressure control system and combined with real human anatomical structures, this biodegradable zinc alloy stent in vitro fatigue testing system can realistically simulate clinical surgical procedures, achieving a high degree of human body environment simulation, dynamically adjusting blood flow and pressure, and being compatible with multiple simulated solutions.

Description

Technical Field

[0001] This invention relates to the field of medical device testing and inspection technology, and more specifically to an in vitro fatigue testing system and method for a biodegradable zinc alloy stent. Background Technology

[0002] Coronary stents are implanted through catheters into narrowed blood vessels to form a supporting structure and restore blood flow. They are suitable for the treatment of coronary heart disease, such as acute myocardial infarction. Conventional coronary stents are mainly made of stainless steel, nickel-titanium alloy, or cobalt-chromium alloy, and have evolved through three generations of technology: metallic stents, drug-eluting stents, and bioresorbable stents.

[0003] First-generation metallic stents were prone to causing inflammatory reactions. To address this, second-generation drug-eluting stents coated the surface of the metallic stent with a drug-eluting film. After implantation, these stents slowly release medication to inhibit scar tissue growth around the stent and maintain coronary artery patency. However, once the medication is depleted, this inhibitory effect ceases. Third-generation bioresorbable stents dilate blood vessels in cases of arterial stenosis and dissolve and are absorbed by the body after the acute phase has passed, the stent's function has been completed, and the blood vessel has remodeled, effectively avoiding the adverse consequences of local inflammatory reactions.

[0004] Limited by materials science, early bioresorbable stents (BRS) were primarily manufactured using polymer materials (such as poly-L-lactic acid PLLA). Their initial design aimed to be absorbed in the body after supporting blood vessels and releasing anti-proliferative drugs, avoiding metal residue. However, early polymer stents suffered from insufficient radial support, excessively rapid or slow degradation rates, and poor radiopaqueness, leading to increased thrombosis risks in clinical applications. To overcome the mechanical limitations of polymer stents, research has shifted to biodegradable metallic materials, mainly magnesium alloys, iron alloys, and zinc alloy stents. Magnesium alloy stents possess good biocompatibility (magnesium ions are an essential element for the human body), are non-magnetic (doing not affect CT / MRI examinations), and have excellent mechanical properties, making them a popular choice in clinical trials. However, their rapid degradation rate is difficult to control stably, posing a significant risk after implantation. Iron alloy stents offer higher strength and a longer degradation period, but their slow degradation rate remains a major challenge. Zinc alloy stents combine the degradation advantages of magnesium alloys with the strength of iron stents and are currently the subject of large-scale research and promotion.

[0005] For high-risk Class III vascular stent implants like coronary stents, rigorous performance testing, animal experiments, and in vivo clinical implantation studies are required before the product can be marketed. Among these, the fatigue performance of the stent is particularly important, as it determines the two key indicators of safety and effectiveness when used in vivo, and has always been a focus of research and regulatory attention.

[0006] Currently, the evaluation of in vitro fatigue performance of implants mainly considers their equivalent fatigue life of 380 million cycles over 10 years under expected clinical use conditions. This is generally achieved by referring to YY / T 0808-2010, "Standard Test Method for In Vitro Pulsation Durability of Vascular Stents," to complete accelerated fatigue tests under uniform radial loads. However, for biodegradable stents, due to factors such as degradation and corrosion, it is not possible to simply use accelerated fatigue testing methods to simulate the designed 10-year in vivo lifespan within a few months. Furthermore, there are currently no suitable testing fixtures and equipment for biodegradable products to verify their degradation performance and long-term fatigue performance.

[0007] In summary, there is a need in the field for an in vitro fatigue testing system designed for biodegradable zinc alloy scaffolds to address the problem of insufficient realism in simulating the in vivo environment in existing technologies. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a biodegradable zinc alloy stent in vitro fatigue testing system. By combining a biomimetic human pulsating blood flow and pressure control system with a biomimetic coronary interventional vascular model, a biodegradable stent in vitro fatigue testing system with high human environment simulation, dynamically adjustable blood flow and pressure, and compatibility with multiple simulated solutions is formed, so as to solve the problem of insufficient realism in simulating the in vivo environment in the prior art.

[0009] Another objective of this invention is to provide a testing method based on the aforementioned biodegradable zinc alloy scaffold in vitro fatigue testing system.

[0010] To achieve the above objectives, the present invention provides a biodegradable zinc alloy stent in vitro fatigue testing system, comprising a biomimetic human pulsating blood flow and pressure control system and a biomimetic coronary interventional vessel model; the outlet of the biomimetic human pulsating blood flow and pressure control system is connected to the left ventricular interface in the biomimetic coronary interventional vessel model to simulate the heart's pumping function; the inlet of the biomimetic human pulsating blood flow and pressure control system is connected to the drainage interface in the biomimetic coronary interventional vessel model to simulate blood returning to the atrium.

[0011] Preferably, the biomimetic coronary interventional vascular model includes a mounting plate and, by means of mounting fixtures, an aortic arch, a left coronary artery group, a right coronary artery group, a radial artery, an ulnar artery, a carotid artery, a vertebral artery, a subclavian artery, an abdominal aorta, a renal artery, a common iliac artery, an external iliac artery, an internal iliac artery, and a femoral artery.

[0012] Preferably, the biomimetic coronary interventional vascular model refers to clinical CT data, extracts the vascular structure of the vascular stent implantation path, and then performs reverse engineering to generate a complete vascular structure that simulates clinical use.

[0013] Preferably, the biodegradable zinc alloy stent in vitro fatigue testing system as described in claim 2 is characterized in that the biomimetic coronary interventional vascular model is made by 3D printing process. During manufacturing, room temperature curing platinum vulcanized silicone is brushed onto the surface of the printed part. After the silicone is cured, the internal support structure is removed in sections to obtain the biomimetic silicone vascular model.

[0014] Preferably, the biodegradable zinc alloy stent in vitro fatigue testing system as described in claim 2 is characterized in that the biomimetic coronary interventional vascular model adopts a segmented design.

[0015] Preferably, the biodegradable zinc alloy stent in vitro fatigue testing system as described in claim 2 is characterized in that the left coronary artery group and the right coronary artery group are each composed of a plurality of replaceable coronary vessels.

[0016] Preferably, the biodegradable zinc alloy stent in vitro fatigue testing system as described in claim 1 is characterized in that the biomimetic human pulsating blood flow and pressure control system includes a control device and a ventricular circuit connected to the control device, wherein the ventricular circuit is connected to the biomimetic coronary interventional vessel model through a pipeline.

[0017] Preferably, the biodegradable zinc alloy stent in vitro fatigue testing system as described in claim 7 is characterized in that the ventricular circuit includes an open ventricle and a plurality of human compliance simulation cavities connected to the open ventricle via conduits, and a vascular damping simulator is installed on the conduits connecting the human compliance simulation cavities to the open ventricle.

[0018] This invention provides an in vitro fatigue testing method for a biodegradable zinc alloy scaffold, employing the aforementioned in vitro fatigue testing system for the biodegradable zinc alloy scaffold, comprising the following steps:

[0019] (A) System initialization; connect the bionic human pulsating blood flow and pressure control system and the bionic coronary interventional vascular model, add the test solution and make the temperature, pressure and flow conditions reach the physiological level of the human body;

[0020] (B) Stent implantation; The stent is delivered to the lesion site of the replaceable coronary artery via a simulated approach, and the stent is expanded using a balloon to ensure proper fit;

[0021] (C) Initial operation monitoring; record stent morphology and fatigue count;

[0022] (D) Endothelialization simulation: After running for a preset time, the machine is stopped, the replaceable coronary artery segment is removed, and a compliance tube is stacked on the inner surface of the stent to simulate the endothelialization process of the stent in the human body.

[0023] (E) Long-term fatigue test: The stent after simulating endothelialization was reassembled and continued to operate, and the degradation process and fracture of the stent were observed.

[0024] Preferably, the preset time in step (D) is one month.

[0025] Compared with existing technologies, the advantages of the biodegradable zinc alloy stent in vitro fatigue testing system and method disclosed in this invention are as follows: The biodegradable zinc alloy stent in vitro fatigue testing system is driven by a biomimetic human blood flow and pressure control system, combined with the real human anatomical structure, which can realistically simulate clinical surgical operations to form a high degree of human environment simulation, dynamically adjust blood flow and pressure, and be compatible with multiple simulated solutions; the left and right coronary arteries of the biodegradable zinc alloy stent in vitro fatigue testing system are both designed to be replaceable and detachable, which can match different stent systems of different models and specifications; the biodegradable zinc alloy stent in vitro fatigue testing system can realize the overlapping of the stent and the inner and outer layers of simulated blood vessels to simulate the endothelialization of the blood vessels after stent implantation; the biodegradable zinc alloy stent in vitro fatigue testing system adopts a segmented structure, which is more convenient to clean and can realize the cross-testing and verification requirements of different simulated body fluids, thereby enabling a more comprehensive evaluation of the degradation process and degradation performance of the biodegradable stent. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the biomimetic human pulsating blood flow and pressure control system of the biodegradable zinc alloy scaffold in vitro fatigue testing system of this application.

[0028] Figure 2 This is a schematic diagram of a biomimetic coronary interventional vessel model of an in vitro fatigue testing system for a biodegradable zinc alloy stent, as described in this application.

[0029] Figure 3 This is a schematic diagram of the left and right coronary arteries of the biomimetic coronary interventional vascular model.

[0030] Figure 4 This is a cross-sectional view of the coronary artery after stent endothelialization. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 and Figure 2 As shown, this application discloses a biodegradable zinc alloy stent in vitro fatigue testing system comprising a biomimetic human pulsating blood flow and pressure control system 1 and a biomimetic coronary intervention vessel model 2. The outlet of the biomimetic human pulsating blood flow and pressure control system 1 is connected to the left ventricular interface in the biomimetic coronary intervention vessel model 2 to simulate the heart's pumping function. The inlet of the biomimetic human pulsating blood flow and pressure control system 1 is connected to the drainage interface in the biomimetic coronary intervention vessel model 2 to simulate blood return to the atria. Driven by the biomimetic human blood flow and pressure control system and combined with real human anatomical structures, this biodegradable zinc alloy stent in vitro fatigue testing system can realistically simulate clinical surgical procedures, forming a highly simulated human environment, dynamically adjustable blood flow and pressure, and compatible with multiple simulated solutions.

[0033] The biomimetic human pulsating blood flow and pressure control system 1 includes a control device 10 and a ventricular circuit connected to the control device 10. The ventricular circuit is connected to the biomimetic coronary interventional vascular model 2 via a conduit. The ventricular circuit includes an open ventricle 11 and several human compliance simulation chambers 12 connected to the open ventricle 11 via conduits. A vascular damping simulator 13 is installed on the conduit connecting the human compliance simulation chambers 12 to the open ventricle 11. Under the control of the electronic control system software, the biomimetic human pulsating blood flow and pressure control system 1 realizes the regulation and control of pressure, cardiac output, temperature, etc., of a normal human body.

[0034] The biomimetic coronary interventional vascular model 2 includes a mounting plate 20 and, fixed to the mounting plate by a mounting fixture 200, the following arteries: aortic arch 21, left coronary artery group 221, right coronary artery group 222, radial artery 23, ulnar artery 231, carotid artery 24, vertebral artery 25, subclavian artery 26, abdominal aorta 27, renal artery 271, common iliac artery 272, external iliac artery 273, internal iliac artery 274, and femoral artery 275. The radial artery 23 and femoral artery 275 are commonly used puncture approaches in clinical practice, realistically simulating clinical surgical procedures.

[0035] The second biomimetic coronary interventional vascular model references clinical CT data to extract the approximate structure of the blood vessel along the stent implantation path. Then, it performs reverse engineering to create a complete vascular structure simulating clinical use. The second biomimetic coronary interventional vascular model is manufactured using 3D printing. During manufacturing, room-temperature curing platinum-cured silicone is brushed onto the surface of the printed part. After the silicone cures, the internal support structure is removed segment by segment to obtain a biomimetic silicone vascular model similar to the real human body.

[0036] The biomimetic coronary interventional vascular model 2 adopts a segmented design, which can be disassembled into multiple segments for separate cleaning, making cleaning more convenient. It can also meet the cross-testing and verification requirements of different simulated body fluids, thereby enabling a more comprehensive evaluation of the degradation process and degradation performance of the biodegradable stent.

[0037] like Figure 3 As shown, the left coronary artery group 221 and the right coronary artery group 222 are each composed of several replaceable coronary vessels 220. By replacing replaceable coronary vessels 220 of different sizes and shapes, different models and specifications of stent systems can be matched for testing.

[0038] Furthermore, the aortic arch 21 is connected to the left ventricle interface via the conduit 211, and the left coronary artery group 221 and the right coronary artery group 222 converge to the drain pipe 223, which is connected to the drain interface.

[0039] See Figure 4 After a period of time, the biodegradable zinc alloy stent 3 is placed in the replaceable coronary artery 220. It can be removed and a compliance tube is stacked on the inner surface of the biodegradable zinc alloy stent 3 to form a simulated regenerated endothelial vessel 2201. Then, the replaceable coronary artery 220 is reinstalled on the test fixture and fatigue is started. The degradation process and fracture of the biodegradable stent are observed over a long period of time, thereby achieving in vitro evaluation of its fatigue performance after clinical implantation.

[0040] This application also discloses an in vitro fatigue testing method for a biodegradable zinc alloy scaffold, employing the aforementioned in vitro fatigue testing system for the biodegradable zinc alloy scaffold, comprising the following steps:

[0041] (A) System initialization; connect the bionic human pulsating blood flow and pressure control system and the bionic coronary interventional vascular model, add the test solution and make the temperature, pressure and flow conditions reach the physiological level of the human body;

[0042] (B) Stent implantation; The stent is delivered to the lesion site of the replaceable coronary artery via a simulated approach, and the stent is expanded using a balloon to ensure proper fit;

[0043] (C) Initial operation monitoring; record stent morphology and fatigue count;

[0044] (D) Endothelialization simulation: After running for a preset time, the machine is stopped, the replaceable coronary artery segment is removed, and a compliance tube is stacked on the inner surface of the stent to simulate the endothelialization process of the stent in the human body; the preset time is preferably one month.

[0045] (E) Long-term fatigue test: The stent after simulating endothelialization was reassembled and continued to operate, and the degradation process and fracture of the stent were observed.

[0046] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A biodegradable zinc alloy scaffold in vitro fatigue testing system, characterized in that, It includes a biomimetic human pulsating blood flow and pressure control system and a biomimetic coronary interventional vessel model; the outlet of the biomimetic human pulsating blood flow and pressure control system is connected to the left ventricular interface in the biomimetic coronary interventional vessel model to simulate the heart's pumping function; the inlet of the biomimetic human pulsating blood flow and pressure control system is connected to the drainage interface in the biomimetic coronary interventional vessel model to simulate blood returning to the atrium.

2. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 1, characterized in that, The biomimetic coronary interventional vascular model includes an mounting plate and, by means of mounting fixtures, the aortic arch, left coronary artery group, right coronary artery group, radial artery, ulnar artery, carotid artery, vertebral artery, subclavian artery, abdominal aorta, renal artery, common iliac artery, external iliac artery, internal iliac artery, and femoral artery.

3. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 2, characterized in that, The biomimetic coronary interventional vascular model references clinical CT data, extracts the vascular structure along the vascular stent implantation path, and then performs reverse engineering to generate a complete vascular structure that simulates clinical use.

4. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 2, characterized in that, The biomimetic coronary interventional vascular model is made using 3D printing technology. During manufacturing, room temperature curing platinum vulcanized silicone is brushed onto the surface of the printed part. After the silicone cures, the internal support structure is removed in sections to obtain the biomimetic silicone vascular model.

5. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 2, characterized in that, The biomimetic coronary interventional vascular model adopts a segmented design.

6. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 2, characterized in that, The left coronary artery group and the right coronary artery group are each composed of several replaceable coronary vessels.

7. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 1, characterized in that, The biomimetic human pulsating blood flow and pressure control system includes a control device and a ventricular circuit connected to the control device. The ventricular circuit is connected to the biomimetic coronary interventional vessel model through a pipeline.

8. The biodegradable zinc alloy scaffold in vitro fatigue testing system as described in claim 7, characterized in that, The ventricular circuit includes an open ventricle and several human compliance simulation cavities connected to the open ventricle via conduits, and a vascular damping simulator is installed on the conduits connecting the human compliance simulation cavities to the open ventricle.

9. A method for in vitro fatigue testing of a biodegradable zinc alloy scaffold, characterized in that, The in vitro fatigue testing system using the aforementioned biodegradable zinc alloy scaffold includes the following steps: (A) System initialization; connect the bionic human pulsating blood flow and pressure control system and the bionic coronary interventional vascular model, add the test solution and make the temperature, pressure and flow conditions reach the physiological level of the human body; (B) Stent implantation; The stent is delivered to the lesion site of the replaceable coronary artery via a simulated approach, and the stent is expanded using a balloon to ensure proper fit; (C) Initial operation monitoring; record stent morphology and fatigue count; (D) Endothelialization simulation: After running for a preset time, the machine is stopped, the replaceable coronary artery segment is removed, and a compliance tube is stacked on the inner surface of the stent to simulate the endothelialization process of the stent in the human body. (E) Long-term fatigue test: The stent after simulating endothelialization was reassembled and continued to operate, and the degradation process and fracture of the stent were observed.

10. The in vitro fatigue testing method for the biodegradable zinc alloy scaffold as described in claim 9, characterized in that, The preset time in step (D) is one month.

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