Light-stimulus-responsive zinc-based coordination polymer, preparation method therefor, and use thereof in cardiovascular stents

Abstract

The present invention belongs to the field of biomedical technology, and relates to a light-stimulus-responsive zinc-based coordination polymer, a preparation method therefor, and a use thereof in cardiovascular stents. The chemical formula of the light-stimulus-responsive zinc-based coordination polymer of the present invention is {[Zn(OAc)2(tpeb)]·2H2O}n, where OAc is acetate, tpeb is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n=3000-60000. The crystal of the light-stimulus-responsive zinc-based coordination polymer can undergo a photochemical [2+2] cycloaddition reaction under ultraviolet light irradiation, and the reaction process is accompanied by intense and rapid crystal mechanical motion. A cardiovascular stent prepared therefrom can rapidly expand in a specified direction under ultraviolet light irradiation, and has the ability of secondary light-induced expansion, thereby overcoming the limitation of "single use" of existing stents and imparting the cardiovascular stent with the ability to dynamically adapt to vascular pathological / physiological changes.

Description

A photostimulation-responsive zinc-based coordination polymer, its preparation method, and its application in cardiovascular stents. Technical Field

[0001] This invention belongs to the field of biomedical technology, and particularly relates to a photostimulation-responsive zinc-based coordination polymer, its preparation method, and its application in cardiovascular stents. Background Technology

[0002] Vascular stenting is a primary treatment for coronary artery stenosis, atherosclerosis, and other diseases. While traditional metallic stents (such as stainless steel and cobalt-chromium alloys) and biodegradable polymer stents (such as polyvinyl alcohol (PVA), polylactic acid (PLA), and polycaprolactone (PCL)) can restore vascular patency in the short term, they still present the following key challenges: Irreversibility after a single implantation: The stent diameter is fixed after implantation, making non-invasive adjustments impossible based on dynamic changes in the blood vessel (such as secondary stenosis after restenosis or the developmental dilation needs of vascular development in children), requiring a second surgical intervention; Poor adaptability to complex lesions: For bifurcation lesions, long-segment stenosis, or areas with significant differences in vessel wall elasticity, static stents struggle to achieve dynamic adaptation of local mechanical properties (see: Miyashita K, Ninomiya K, Tobe A, Masuda S, Kotoku N, Kageyama S, Reviah P, Tsai T, Wang B, Garg S, Serruys P, Onuma Y, Expert Review of Cardiovascular Therapy, 22:8, 391-407.).

[0003] In recent years, the development of photoresponsive smart materials in the biomedical field has provided new insights into the aforementioned problems. Photoresponsive materials, due to their non-destructive, spatiotemporally controllable, highly biosafety-free, and non-contact external triggering, possess unique appeal in energy conversion, making them a research hotspot with significant potential applications in biomedicine, soft robotics, and flexible electronic devices. For example, by using a crystalline molecular material containing olefin groups in single-crystal and single-crystal composite films to achieve photomechanical motion, various human-like movements were observed when the film strips were shaped and folded into models resembling microrobots. This motion may be applicable to soft microrobots (see: Wang Y, Zhang Q, Liu Q, Abrahams B, Lang J, Angew. Chem. Int. Ed, 2024, 63, e202409472.). Near-infrared responsive 3D printing of shape memory polyurethane / magnesium composite scaffolds promotes bone defect regeneration. These scaffolds can restore their initial shape and mechanical resilience upon near-infrared light irradiation; simultaneously, they tightly fill the defect site and release magnesium ions to promote bone repair, providing an effective strategy for the clinical treatment of bone defects (see: Zhang Y, Li C, Zhang W, Deng J, Nie Y, Du X, Qin L, Lai Y, Bioactive Materials, 2022, 16, 218-231.).

[0004] However, existing light-driven stent technologies mostly focus on single-light-triggered functions, exhibiting significant shortcomings in secondary dynamic regulation. Most photosensitive components are prone to photoresponse performance degradation after long-term retention in the body, making it difficult to support multiple light-triggered events. Existing light-responsive stents lack an "on-demand secondary adjustment" design for restenosis or developmental dilation, failing to achieve non-destructive, precise, and controllable adjustment of the stent diameter. Coordination polymers (CPs) are a class of novel crystalline materials formed by the self-assembly of inorganic metal ions / clusters and organic bridging ligands through coordination bonds. Due to the precisely controllable performance, excellent biocompatibility and safety, and potential degradation resistance of CPs, CP-based stents combine light-responsive smart materials with structural tunability, providing a safer and more adaptable solution for cardiovascular disease treatment, especially suitable for growing patients and complex cases requiring personalized treatment, potentially significantly reducing reoperation rates. However, existing CPs suffer from the difficulty in degrading metal ions, leading to long-term accumulation in the body and inducing inflammation in cardiovascular sensitive areas. Meanwhile, the mechanical properties of existing coordination polymers are not compatible with the flexibility required for cardiovascular treatment.

[0005] Therefore, it remains essential to develop a bio-friendly coordination polymer with excellent mechanical properties, which can exhibit superior compressive strength and moderate flexibility under dynamic regulation. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a photostimulation-responsive zinc-based coordination polymer, its preparation method, and its application in cardiovascular stents. The photostimulation-responsive zinc-based coordination polymer crystals undergo a photochemical [2+2] cycloaddition reaction under ultraviolet light irradiation, accompanied by intense and rapid crystal mechanical movement. Cardiovascular stents prepared from this polymer can rapidly expand in a specified direction under ultraviolet light irradiation and possess the ability to expand under secondary light irradiation, overcoming the limitation of existing stents being "single-use" and endowing cardiovascular stents with the ability to dynamically adapt to vascular pathological / physiological changes.

[0007] The first objective of this invention is to provide a photostimulation-responsive zinc-based coordination polymer, wherein the chemical formula of the photostimulation-responsive zinc-based coordination polymer is {[Zn(OAc)2(tpeb)]·2H2O}. n Where OAc is acetic acid, tpeb is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n = 3000-60000.

[0008] A second objective of this invention is to provide a method for preparing the aforementioned photostimulation-responsive zinc-based coordination polymer, comprising the following steps:

[0009] Zinc salt and 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene were reacted under heating in a mixed solvent to obtain the photostimulation-responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O}. n The mixed solvent includes acetonitrile and water;

[0010] Where OAc is acetic acid, tpeb is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n = 3000-60000.

[0011] In one embodiment of the present invention, the zinc salt is selected from one or more of zinc sulfate, zinc nitrate and zinc chloride.

[0012] In one embodiment of the present invention, the volume ratio of acetonitrile to water is 1:(1-4).

[0013] In one embodiment of the present invention, the molar ratio of the zinc salt to 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene is (4-5):1.

[0014] In one embodiment of the present invention, the pH of the heating reaction is 5-6, the temperature is 100℃-150℃, and the time is 12h-24h.

[0015] A third objective of the present invention is to provide a photoresponsive thin film comprising the aforementioned photostimulation-responsive zinc-based coordination polymer.

[0016] In one embodiment of the present invention, the thickness of the photoresponsive film is 50 μm-70 μm.

[0017] A fourth objective of this invention is to provide a method for preparing the aforementioned photoresponsive thin film, comprising the following steps:

[0018] S1. The photostimulation-responsive zinc-based coordination polymer is ground and dispersed in a solvent, and then dried to obtain a powder;

[0019] S2: Add the powder described in S1 to the substrate, mix well, pour into a mold, and dry to obtain the photoresponsive film.

[0020] In one embodiment of the present invention, in S1, the solvent is selected from one or more of ethanol, acetonitrile, and water.

[0021] In one embodiment of the present invention, in S1, the drying temperature is 40°C-60°C.

[0022] In one embodiment of the present invention, in S2, the substrate is selected from one or more of polyvinyl alcohol, polypropylene, and polyvinylidene fluoride.

[0023] In one embodiment of the present invention, in S2, the drying temperature is 40°C-60°C.

[0024] A fifth objective of this invention is to provide a cardiovascular stent comprising the aforementioned photoresponsive film. The expansion of the cardiovascular stent can be controlled by external light irradiation, avoiding the need for secondary surgery due to size mismatch or restenosis associated with traditional cardiovascular stents, and significantly reducing the risk of infection and complications.

[0025] In one embodiment of the present invention, the cardiovascular stent further includes a waterproof layer disposed on the surface of the photoresponsive film.

[0026] In one embodiment of the present invention, the material of the waterproof layer is selected from one or more of polycaprolactone, carboxylated cellulose nanofibers, and genipin.

[0027] The technical solution of the present invention has the following advantages compared with the prior art:

[0028] (1) The photostimulation-responsive zinc-based coordination polymer of this invention can rapidly undergo a photochemical [2+2] cycloaddition reaction under irradiation with 365nm wavelength light, generating photostress and thus promoting photodynamic motion. This photostress effect can be further amplified by a photoresponsive film. In addition, zinc in the photostimulation-responsive zinc-based coordination polymer of this application is an essential trace element for the human body, participating in immune regulation and endothelial repair, which can reduce the risk of infection after stent implantation. The conjugated structure of 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene has fluorescent properties, and combined with the zinc coordination effect, it can be developed into a self-illuminating stent, which facilitates postoperative monitoring of stent position and degradation status through optical imaging. By regulating the metal nodes and organic ligands, its biocompatibility is significantly improved, while it also has unique potential in terms of mechanical properties and degradability. Cardiovascular stents prepared from it can gradually degrade after completing their function, avoiding chronic inflammation caused by permanent foreign body retention; non-invasive operation reduces the risk of secondary surgery.

[0029] (2) The preparation method described in this invention is simple, the reaction conditions are mild, and the photoconversion rate is fast.

[0030] (3) The cardiovascular stent described in this invention can be directed to a specific part of the cardiovascular stent by means of photostimulation response, avoiding excessive damage to blood vessels caused by overall expansion and reducing the risk of vascular tearing; the volume control is highly accurate, and no chemical reagents are involved in the entire control process, making it safe and reliable. Attached Figure Description

[0031] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0032] Figure 1 shows the {[Zn(OAc)2(tpeb)]·2H2O} of Embodiment 1 of the present invention. n A one-dimensional stacked graph of (CP1);

[0033] Figure 2 shows the {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 1 of this invention. n X-ray diffraction pattern of (CP1);

[0034] Figure 3 shows the {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 1 of this invention. n Thermogravimetric analysis diagram of (CP1);

[0035] Figure 4 shows the {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 1 of this invention. n Infrared analysis diagram of (CP1);

[0036] Figure 5 shows the 1H NMR spectra of CP1 without cycloaddition reaction and the photoproduct generated by cycloaddition reaction in Test Example 2 of the present invention;

[0037] Figure 6 shows the 1H NMR spectrum of CP1 without cycloaddition reaction and the purified photoproduct generated by cycloaddition reaction in Test Example 2 of the present invention.

[0038] Figure 7 shows the {[Zn(OAc)2(tpeb)]·2H2O} in Test Example 2 of this invention. n (CP1) Multiple mechanical motion behaviors of single crystals under 365nm and 420nm ultraviolet light;

[0039] Figure 8 shows the PXRD spectra of the front and back sides of the photoresponsive thin film in Test Example 3 of the present invention.

[0040] Figure 9 shows the SEM images of the front d-side (a) and side (b) of the photoresponsive thin film in Test Example 3 of the present invention;

[0041] Figure 10 shows the surface roughness (a) and Young's modulus (b) of the photoresponsive thin film in Test Example 3 of the present invention;

[0042] Figure 11 shows the bending behavior of the photoresponsive thin film under 365nm ultraviolet light in Test Example 3 of the present invention;

[0043] Figure 12 shows the first and second expansion processes of the 8mm cardiovascular stent in Test Example 4 of the present invention;

[0044] Figure 13 shows the first and second expansion processes of the 4mm cardiovascular stent in Test Example 4 of the present invention;

[0045] Figure 14 shows the first and second expansion processes of the 2mm cardiovascular stent in Test Example 4 of the present invention;

[0046] Figure 15 shows the first and second expansion processes of the 1mm cardiovascular stent in Test Example 4 of the present invention;

[0047] Figure 16 shows the PXRD spectra of the composite film in Test Example 5 of the present invention after treatment in air and in a blood simulation system.

[0048] Figure 17 shows the SEM images of the composite film in Test Example 5 of the present invention before (a) and after (b) light exposure in air.

[0049] Figure 18 shows the SEM images of the composite film in Test Example 5 of the present invention before (a) and after (b) light exposure in the blood simulation system;

[0050] Figure 19 shows the surface roughness (a) and Young's modulus (b) of the composite film in Test Example 5 of the present invention before illumination in air;

[0051] Figure 20 shows the surface roughness (a) and Young's modulus (b) of the composite film in Test Example 5 of the present invention after being exposed to light in air;

[0052] Figure 21 shows the surface roughness (a) and Young's modulus (b) of the composite film in Test Example 5 of the present invention before illumination in the blood simulation system;

[0053] Figure 22 shows the surface roughness (a) and Young's modulus (b) of the composite film in Test Example 5 of the present invention after illumination in a blood simulation system;

[0054] Figure 23 shows the first and second expansion processes of the 8mm cardiovascular stent in Test Example 6 of the present invention;

[0055] Figure 24 shows the first and second expansion processes of the 4mm cardiovascular stent in Test Example 6 of the present invention;

[0056] Figure 25 shows the first and second expansion processes of the 2mm cardiovascular stent in Test Example 6 of the present invention;

[0057] Figure 26 shows the primary and secondary expansion processes of the 1mm cardiovascular stent in Test Example 6 of the present invention. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0059] Example 1

[0060] The photostimulation-responsive zinc-based coordination polymer and its preparation method of the present invention specifically include the following steps:

[0061] 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene (0.06 mmol, 23.2 mg) and ZnSO4·7H2O (0.24 mmol, 86.3 mg) were added to a 15 mL thick-walled pressure-resistant bottle, followed by the addition of a mixed solution of 5.4 mL acetonitrile and 9 mL H2O. The pH of the system was adjusted to approximately 5 using 0.1 mol / L nitric acid. The bottle was then capped tightly and sonicated for 15 min. The bottle was then sealed and placed in a temperature-controlled oven at 150 °C for 24 h. After cooling to room temperature at a rate of 5 °C / h, the product was washed with anhydrous ethanol and vacuum dried to obtain pale yellow, long needle-like crystals, which were the photostimulation-responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O}. n (CP1) (Figure 1), yield of 32.9 mg (80.6% based on 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene).

[0062] Test Example 1

[0063] The photostimulation-responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} of Example 1 n The elemental, X-ray diffraction, thermogravimetric, and infrared spectra of (CP1) were analyzed, and the specific results are as follows:

[0064] (1) Elemental analysis (%): Photostimulation-responsive zinc-based coordination polymer C 31 H 31 N3O6Zn, theoretical value (%) C, 61.39; H, 5.12; N, 6.93. Measured value (%) C, 61.56; H, 5.22; N, 6.98.

[0065] (2) X-ray diffraction analysis (Figure 2): {[Zn(OAc)2(tpeb)]·2H2O} n The experimental powder X-ray diffraction pattern of (CP1) largely coincided with the simulated X-ray diffraction pattern from single-crystal data, confirming the purity of this series of complex powders. Furthermore, based on single-crystal X-ray diffraction tests, crystal data of CP1 were collected using a Bruker D8-Quest diffractometer, employing a Mo Kα (λ=0.071073nm) enhanced X-ray source, and at a test temperature of 150K; {[Zn(OAc)2(tpeb)]·2H2O} n The diffraction data and unit cell parameters of (CP1) were obtained using a CrysAlis ProAgilent Technologies (Version 1.171.36.32, 2013) program. All diffraction data were obtained through Lp factor correction and multi-scan absorption correction. {[Zn(OAc)2(tpeb)]·2H2O} n The crystal structure of (CP1) was obtained by direct analysis using the OLEX2 program, and the data was refined using the least squares matrix method; all non-hydrogen atoms were corrected for anisotropy, and all hydrogen atoms were theoretically hydrogenated according to reasonable geometric positions; {[Zn(OAc)2(tpeb)]·2H2O} n The main crystallographic parameters and structural refinement parameters of (CP1) are shown in Table 1:

[0066] Table 1

[0067] in: a R1=Σ||F o |-|F c || / Σ|F o |; b wR2={Σw(Fo 2 -F c 2 ) 2 / Σw(F o 2 ) 2} 1 / 2 ;

[0068] c GOF={Σw((F o 2 -F c 2 ) 2 ) / (np)} 1 / 2 , where n is the number of reflections and p is the total number of refining parameters.

[0069] As can be seen from Table 1, Example 1 successfully obtained a photostimulation-responsive zinc-based coordination polymer, namely {[Zn(OAc)2(tpeb)]·2H2O}. n (CP1).

[0070] (3) Thermogravimetric analysis (Figure 3): The complex has good thermal stability under N2 atmosphere, with no weight loss below 300℃, after which thermal decomposition occurs.

[0071] (4) Infrared spectroscopy (Figure 4) (potassium bromide pellet method) analysis: 3415(w), 3031(w), 2484(w), 1685(m), 1608(s), 1506(m), 1431(m), 1378(s), 1328(s), 1205(m), 1066(m), 1026(m), 978(s), 925(w), 846(s), 804(m), 736(m), 675(s), 617(m) cm -1 .

[0072] Test Example 2

[0073] The photostimulation-responsive zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} of Example 1 n(CP1) underwent a photochemical cycloaddition reaction. After irradiating the CP1 crystal under a 365 nm high-pressure mercury lamp for a period of time, the single crystal bent and cracked. Attempts were made to determine its crystal structure after irradiation, but the diffraction points of the irradiated crystal gradually weakened and eventually disappeared with increasing irradiation time, thus the crystal structure of the irradiated complex could not be obtained. Therefore, the NMR results of CP1 without the cycloaddition reaction and the photoproduct generated by the cycloaddition reaction are shown in Figure 5. Figure 5 shows the 1H NMR spectrum (400 MHz, 298 K, d6-DMSO, ppm) of CP1 without the cycloaddition reaction: δH = 8.90 (d, 6H), δH = 8.25 (d, 6H), δH = 8.18 (s, 3H), δH = 8.07 (d, 3H), δH = 7.69 (d, 3H); the 1H NMR spectrum of the photoproduct generated by the cycloaddition reaction... (400MHz, 298K, d6-DMSO, ppm): δH = 9.08 (d, 3H), δH = 8.90 (d, 3H), δH = 8.38 (d, 3H), δH =8.25(d,3H), δH=8.18(s,3H), δH=8.03(d,2H), δH=7.69(d,2H), δH=4.2-3.4(s,2H). That 1 The presence of a cyclobutane peak (in the range of 3.4 ppm to 4.2 ppm) and the migration of the pyridine peak (8.9 ppm to 9.1 ppm and 8.2 ppm to 8.3 ppm) can be observed in the HNMR spectrum, thus it can be determined that the photostimulated zinc-based coordination polymer has undergone a cycloaddition reaction.

[0074] To further determine the true extent of the photostimulation-responsive zinc-based coordination polymer, an experiment was conducted to separate and purify CP1 after photostimulation. 0.5 g of CP1 powder was irradiated under a 365 nm high-pressure mercury lamp for 48 h. The photoproducts were then separated from the tpeb monomer that had not undergone cycloaddition, weighed, and the proportion of cycloaddition reaction in the complex was calculated. The separation and proportion calculation were as follows: Approximately 0.5 g of the complex powder irradiated under a 365 nm high-pressure mercury lamp was mixed with 20 mL of 2 mol / L HNO3 solution and stirred for 24 h to decompose the complex structure. The precipitate was then filtered and washed three times with chloroform, and then vacuum dried for 24 h to obtain a deep yellow solid product, which was the photoreactive organic product. The calculated yield was 51.2% (based on tpeb). The NMR results of the purified CP1 without cycloaddition reaction and the photoproduct generated by the cycloaddition reaction are shown in Figure 6. As can be seen from Figure 6, the NMR results after the extraction are basically consistent with those in Figure 5, indicating that the photostimulation-responsive zinc-based coordination polymer underwent a cycloaddition reaction.

[0075] Based on the above experiments, this study investigated the zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} under 365nm and 420nm ultraviolet light. n The mechanical behavior of (CP1) is shown in Figure 7. As can be seen from Figure 7, under 365nm ultraviolet light, CP1 bends 30° at 1s, 70° at 2s, forms a ring at 3s, and shatters at 4s. The remaining crystal fragments vibrate at 4.5s. Under 420nm ultraviolet light, CP1 bends 12° at 2s, 20° at 3s, 40° at 5s, 70° at 8s, and forms a hook at 11s. This indicates that CP1 exhibits faster photomechanical behavior at 365nm.

[0076] Test Example 3

[0077] CP1 was ground into a uniform powder using a ball mill (approximately 30 minutes). 100 mg of the powder was then dispersed in 5 mL of ethanol and sonicated for 5 hours, followed by drying at 40°C. 10 g of a 7.7% polyvinyl alcohol (PVA) aqueous solution was then mixed with the powder and stirred for 12 hours to obtain a uniform viscous liquid. This viscous liquid was then coated onto a mold assembled from a clean, nitrogen-dried transparent polyethylene terephthalate (PET) film and white polytetrafluoroethylene (Teflon). The mold was dried in a 40°C oven for 24 hours to remove residual solvent. After the solvent had completely evaporated, the film was peeled off from the mold to obtain a pale yellow photoresponsive film (PVA-CP1).

[0078] The X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and bending behavior of the photoresponsive thin film were analyzed, and the specific results are as follows:

[0079] (1) X-ray powder diffraction analysis (Figure 8): By comparing the XRD patterns of the photostimulation-responsive zinc-based coordination polymer powder and its photoresponsive film, it was found that the photoresponsive film still has characteristic diffraction peaks consistent with the original coordination polymer, indicating that CP1 in the photoresponsive film maintains crystal integrity.

[0080] (2) Scanning electron microscopy analysis (Figure 9): (5 μm resolution) The surface of the photoresponsive film is smooth and the microstructure has no obvious undulations; (50 μm resolution) It shows that the thickness of the photoresponsive film is 50 μm, and the photostimulation responsive zinc-based coordination polymer is uniformly distributed in the internal pores, forming a multi-level composite structure, which significantly improves the mechanical properties of the photoresponsive film.

[0081] (3) Atomic force microscopy analysis (Figure 10): (tap mode, scanning range 5×5μm2) Characterization showed that the surface roughness (Ra) of the photoresponsive film was 3.30±0.15nm, indicating that it has excellent surface smoothness; through nanoindentation test combined with DMT contact mechanics model (load rate of 50μN / s, maximum load of 1mN), the elastic modulus of the photoresponsive film was measured to be 1.334±0.08GPa, confirming that it has significant resistance to compressive deformation.

[0082] (4) Bending behavior analysis (Figure 11): The photoresponsive film exhibits a rapid photoinduced bending response (135° within 50s, rate 2.7° / s) under 365nm ultraviolet light irradiation, which meets the requirements of cardiovascular stents for dynamic light-controlled deformation.

[0083] Test Example 4

[0084] Expansion study of an 8mm diameter cardiovascular stent: A photoresponsive film was cut into rectangular samples of 2.6cm × 5cm and folded along its long axis to form a double-layer structure. After leaving a 0.3mm uncut area on each side of the folded edge (closed edge), 10 parallel incisions with a width of 0.3mm were prepared along the closed edge. After unfolding the film, an 8mm × 50mm cardiovascular stent was fabricated by bonding with end strips. The cardiovascular stent was fixed on a glass tube with an outer diameter of 8mm, and the deformation process was recorded in real time using a 365nm LED light source (working distance of about 10cm) and a camera (acquisition rate of 30fps). The results are shown in Figure 12. As shown in Figure 12, under 365nm ultraviolet light excitation, the stent strips exhibit phototropic expansion characteristics. By axially rotating the glass tube to make each strip face the light source in sequence, it was observed that each structural unit could complete the first expansion within 30s after irradiation. After the first light-driven expansion, the sample was placed in a standard environment for 240h. The second light irradiation experiment adopted a continuous dynamic rotating light irradiation mode for 50min. The results showed that the cardiovascular stent could achieve controllable expansion again, and the cumulative radial expansion rate of the two experiments reached 220% of the initial diameter.

[0085] Expansion study of a 4mm diameter cardiovascular stent: A photoresponsive film was cut into rectangular samples of 1.3cm × 5cm and folded along its long axis to form a double-layer structure. After leaving a 0.3mm uncut area on each side of the folded edge (closed edge), 10 parallel incisions with a width of 1.3mm were prepared along the closed edge. After unfolding the film, a 4mm × 50mm cardiovascular stent was prepared by end-strip bonding. The cardiovascular stent was fixed on a 4mm outer diameter glass tube, and the deformation process was recorded in real time using a 365nm LED light source (working distance of about 10cm) and a camera (acquisition rate of 30fps). The results are shown in Figure 13. As shown in Figure 13, under 365nm ultraviolet light excitation, the scaffold strips exhibit phototropic expansion characteristics. By axially rotating the glass tube to make each strip face the light source in sequence, it was observed that each structural unit could complete its first expansion within 30s after irradiation. After the first light-driven expansion, the sample was placed in a standard environment for 240h. The second light irradiation experiment adopted a continuous dynamic rotating light irradiation mode for 50min. The results showed that the scaffold could achieve controllable expansion again, and the cumulative radial expansion rate of the two experiments reached 340% of the initial diameter.

[0086] Expansion study of a 2mm diameter cardiovascular stent: A photoresponsive film was cut into rectangular samples of 0.7cm × 4cm and folded along its long axis to form a double-layer structure. After leaving a 0.3mm uncut area on each side of the folded edge (closed edge), 10 parallel incisions with a width of 0.07mm were prepared along the closed edge. After unfolding the film, a 2mm × 40mm cardiovascular stent was prepared by end-strip bonding. The cardiovascular stent was fixed on a glass tube with an outer diameter of 2mm, and the deformation process was recorded in real time using a 365nm LED light source (working distance of about 10cm) and a camera (acquisition rate of 30fps). The results are shown in Figure 14. As shown in Figure 14, under 365nm ultraviolet light excitation, the scaffold strips exhibit phototropic expansion characteristics. By axially rotating the glass tube to make each strip face the light source in sequence, it was observed that each structural unit could complete the first expansion within 30s after irradiation. After the first light-driven expansion, the sample was placed in a standard environment for 240h. The second light irradiation experiment adopted a continuous dynamic rotating light irradiation mode for 50min. The results showed that the scaffold could achieve controllable expansion again, and the cumulative radial expansion rate of the two experiments reached 480% of the initial diameter.

[0087] Expansion study of a 1mm diameter cardiovascular stent: A photoresponsive film was cut into rectangular samples of 0.35cm × 3.5cm and folded along its long axis to form a double-layer structure. After leaving a 0.3mm uncut area on each side of the folded edge (closed edge), five parallel incisions with a width of 0.07mm were prepared along the closed edge. After unfolding the film, a 1mm × 35mm cardiovascular stent was prepared by end-strip bonding. The cardiovascular stent was fixed on a glass tube with an outer diameter of 1mm, and the deformation process was recorded in real time using a 365nm LED light source (working distance of about 10cm) and a camera (acquisition rate of 30fps). The results are shown in Figure 15. As shown in Figure 15, under 365nm ultraviolet light excitation, the stent strips exhibit phototropic expansion. However, the 1mm×50mm cardiovascular stent, due to its smaller size, expands sequentially and synchronously under ultraviolet light excitation, completing the first expansion within 30 seconds after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The second light irradiation experiment used a continuous dynamic rotating light irradiation mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, with the cumulative radial expansion rate reaching 520% ​​of the initial diameter.

[0088] Test Example 5

[0089] A 1 wt% polycaprolactone solution in chloroform was brushed onto the surface of the photoresponsive film. After each brushing, the film was dried in a 40°C oven until the solvent was completely evaporated. This process was repeated multiple times to ensure that a dense waterproof layer was formed on the surface of the photoresponsive film, thus obtaining the composite film (PVA / PCL-CP1).

[0090] The composite film was analyzed by X-ray powder diffraction (PXRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and bending behavior in air and in a blood simulation system (preparing a 0.9% sodium chloride solution by weighing 0.9 g of sodium chloride and adding it to 100 ml of distilled water to form a homogeneous solution; adjusting the pH to near the pH of blood (7.4) using Tris-HCl buffer solution; adjusting the solution temperature to 37 °C). The specific results are as follows:

[0091] (1) X-ray powder diffraction analysis (Figure 16): By comparing the XRD patterns of the coordination polymer powder and the composite film, it was found that the composite film still has characteristic diffraction peaks consistent with the original coordination polymerization, indicating that CP1 in the composite film maintains crystal integrity.

[0092] (2) Scanning electron microscopy analysis:

[0093] Scanning electron microscopy analysis before (a) and after (b) light exposure in air (Fig. 17): (1 μm resolution) The surface of the composite film before the light reaction is excellent and the microstructure has no obvious undulations; (10 μm resolution) The surface of the composite film after the light reaction remains smooth.

[0094] Scanning electron microscopy analysis of the composite film before (a) and after (b) light exposure in the blood simulation system (Fig. 18): (5 μm resolution) The surface of the composite film before the light reaction was excellent and the microstructure had no obvious undulations; (20 μm resolution) The surface of the composite film after the light reaction was still smooth.

[0095] (3) Atomic force microscopy analysis:

[0096] Atomic force microscopy (AFM) analysis before (Fig. 19) and after (Fig. 20) light exposure in air: AFM characterization (Ra = 120 nm, Ra = 19.4 nm) and DMT model analysis (elastic modulus of 1.339 GPa, elastic modulus of 1.706 GPa) show that the composite film has both high surface smoothness and excellent compressive strength, meeting the biocompatibility requirements of cardiovascular stents.

[0097] Atomic force microscopy (AFM) analysis of the blood simulation system before and after light exposure (Figure 21) and after light exposure (Figure 22) showed that the composite film possesses both high surface smoothness and excellent compressive strength, meeting the biocompatibility requirements of cardiovascular stents.

[0098] Test Example 6

[0099] Expansion study of an 8mm diameter cardiovascular stent: Same as test case 4, results are shown in Figure 23. Figure 23 shows that under 365nm ultraviolet light excitation, the stent strips exhibit phototropic expansion. By axially rotating the glass tube to sequentially face the light source, it was observed that each structural unit completed its first expansion within 30 seconds after irradiation. After the initial light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The secondary irradiation experiment used a continuous dynamic rotating irradiation mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, with a cumulative radial expansion rate of 220% of the initial diameter.

[0100] Expansion study of a 4mm diameter cardiovascular stent: Same as test case 4, results are shown in Figure 24. Figure 24 shows that under 365nm ultraviolet light excitation, the stent strips exhibit phototropic expansion. By axially rotating the glass tube to sequentially face the light source, it was observed that each structural unit completed its first expansion within 30 seconds after irradiation. After the initial light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The secondary irradiation experiment used a continuous dynamic rotating irradiation mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, with a cumulative radial expansion rate of 390% of the initial diameter.

[0101] Expansion study of a 2mm diameter cardiovascular stent: Same as test case 4, results are shown in Figure 25. Figure 25 shows that under 365nm ultraviolet light excitation, the stent strips exhibit phototropic expansion. By axially rotating the glass tube to sequentially face the light source, it was observed that each structural unit completed its first expansion within 30 seconds after irradiation. After the initial light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The secondary irradiation experiment used a continuous dynamic rotating irradiation mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, with a cumulative radial expansion rate of 290% of the initial diameter.

[0102] Expansion study of a 1mm diameter cardiovascular stent: Same as test case 4, results are shown in Figure 26. Figure 26 shows that under 365nm UV excitation, the stent strips exhibit phototropic expansion. However, unlike test case 4, the 1mm × 50mm cardiovascular stent, due to its smaller size, expands sequentially and synchronously under UV excitation, completing the first expansion within 30 seconds after irradiation. After the first light-driven expansion, the sample was left to stand in a standard environment for 240 hours. The second irradiation experiment used a continuous dynamic rotating irradiation mode for 50 minutes. The results showed that the stent could achieve controllable expansion again, with a cumulative radial expansion rate of 290% of the initial diameter.

[0103] Test results of the photoresponsive film and composite film show that the surface roughness and elastic modulus of the cardiovascular stent still meet clinical requirements after the addition of the waterproof layer, and the expansion performance is not affected (expansion rate >95%). This indicates that the photostimulation-responsive zinc-based coordination polymer of the embodiment has excellent functionality and mechanical stability when applied to the cardiovascular stent.

[0104] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A photo-stimuli responsive zinc-based coordination polymer, characterized in that, The photo-stimulated response zinc-based coordination polymer has a chemical formula of {[Zn(OAc)2(tpeb)]·2H2O} n wherein OAc is acetic acid, tpeb is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n = 3000-60000.

2. A method for preparing the photo-stimulated response zinc-based coordination polymer according to claim 1, characterized by, Includes the following steps: The zinc salt and 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene are heated in a mixed solvent to obtain the photo-stimulated zinc-based coordination polymer {[Zn(OAc)2(tpeb)]·2H2O} n ; the mixed solvent comprises acetonitrile and water; Where OAc is acetic acid, tpeb is 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene, and n = 3000-60000.

3. The method for preparing the photostimulation-responsive zinc-based coordination polymer according to claim 2, characterized in that, The zinc salt is selected from one or more of zinc sulfate, zinc nitrate, and zinc chloride.

4. The method for preparing the photostimulation-responsive zinc-based coordination polymer according to claim 2, characterized in that, The volume ratio of acetonitrile to water is 1:(1-4).

5. The method for preparing the photostimulation-responsive zinc-based coordination polymer according to claim 2, characterized in that, The molar ratio of the zinc salt to 1,3,5-tris(2-(pyridin-4-yl)vinyl)benzene is (4-5):

1.

6. The method for preparing the photostimulation-responsive zinc-based coordination polymer according to claim 2, characterized in that, The heating reaction is carried out at a pH of 5-6, a temperature of 100℃-150℃, and a time of 12h-24h.

7. A light-responsive thin film, characterized by, The photoresponsive film comprises the photostimulation-responsive zinc-based coordination polymer of claim 1.

8. A method for producing the light-responsive thin film according to claim 7, characterized by, Includes the following steps: S1. The photostimulation-responsive zinc-based coordination polymer of claim 1 is ground and dispersed in a solvent, and then dried to obtain a powder; S2: Add the powder described in S1 to the substrate, mix well, pour into a mold, and dry to obtain the photoresponsive film.

9. The method for producing a light-responsive thin film according to claim 8, wherein In S2, the substrate is selected from one or more of polyvinyl alcohol, polypropylene, and polyvinylidene fluoride.

10. A cardiovascular stent, characterized by, Includes the photoresponsive thin film as described in claim 7.

Images